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PUBLISHED BY ACC LIMITED

THE INDIAN CONCRETE JOURNAL

March 2016, Vol. 90, No. 3, Rs. 100. 80 pages.

Porous Concrete

�The Indian Concrete Journal March 2016

TECHNICAL PAPERS

12Study on reduction of pavement noise using porous concreteAbhijeet S. Gandage, V. Vinayaka Ram, Manish Panwar, Meet Shah and Rishabh Singhvi

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FEATURES

04 EDITORIAL

Structural effects of haunched braces in elevated service reservoir stagingAbhay Khandeshe and R.K. Ingle

An experimental study on the strength characteristics of slurry infiltrated fibrous ferrocement with partial replacement of natural sand by manufactured sandG.S. Sudhikumar, Mohan Kumar D.D. and Meghana N. Kumar

Performance of polymer modified polypropylene fiber reinforced concrete with low fiber volume fractionsYuwaraj M. Ghugal

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PUBLISHING / EDITORIAL / ADVERTISEMENT & CIRCULATION OFFICEThe Indian Concrete Journal

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Editor: Ashish Patil

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Ulhas Fernandes

S.M. Abbas

THE INDIAN CONCRETE JOURNAL March 2016, Volume 90, Number 3

Cover image source:J.J. Harrison [ www.wikipedia.org ]

PUBLISHED BY ACC LIMITED

THE INDIAN CONCRETE JOURNAL

March 2016, Vol. 90, No. 3, Rs. 100. 80 pages.

Porous Concrete

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Cover March 2016 Final.indd 3 2/24/2016 9:27:34 PM

06 NEWS & EVENTS

53POINT OF VIEW: Strength and durability studies of multi blended concretes containing fly ash and silica fumeG.V. Ramana, Malsani Potharaju, N.V. Mahure and Murari Ratnam

66POINT OF VIEW: Effect of mineral and chemical admixtures on the properties of mortar and concrete – A reviewRahul Singh, S.M. Gupta and Babita Saini

42 DISCUSSION FORUM: Effect of weak and soft storeys on seismic performance of reinforced concrete frames with unreinforced brick infills

� The Indian Concrete Journal March 2016

EDITORIAL

From the Editor’s Desk...

haunches, a substantial saving of steel and concrete along

with a safer and durable structure is possible!

An experimental study on the strength characteristics

of slurry infiltrated fibrous ferro-cement with partial

replacement of natural sand by manufactured sand reveals

higher flexural strength, toughness indices and impact

strength. In the next paper on polymer modified fibre

reinforced concrete, the influence of polymer and fibres on

workability and wet density of fresh concrete, the effect of

dry curing on various strengths of fibre reinforced concrete

has been investigated.

The section – Point of View features two papers – Evaluation

of the performance of multi-blended mix concretes

containing fly ash and silica fume, and A review on the

effect of mineral and chemical admixtures on the properties

of mortar and concrete.

We hope that the selection of papers in this issue interests

you. Do write to us with your feedback and views.

With Best Regards,

Ashish Patil

Under the Government’s ‘Make in India’ initiative,

corporates have committed to huge investments in various

states. NHAI and other road projects have begun work.

Focus is on the forthcoming Union Budget due this week

that should set the direction towards a concrete road for a

sustainable growth that India should witness until at-least

2020!

All eyes are on India, and all eyes are also on us as

engineers to get into ‘project mode’ to complete projects

on time and within budget!

In this issue, the first paper looks at how to cut noise from

the tyre-pavement interaction. Though concrete pavements

are more durable and cost effective when compared with

the more flexible bituminous concrete pavements, the

noise generated by the cement concrete pavements, make

it an unpopular option to deal with. Porous concrete is one

such option that has a potential for noise reduction!

Elevated water tanks are designed for worst of wind and

seismic forces. The authors analyse various types of staging

of water tanks with haunched braces for dynamic behaviour

and suggest that with a little increase in shuttering cost of

The Indian Concrete Journal March 2016�

NEWS & EVENTSNEWS & EVENTS

Structural audit & NoNdeStructive teStiNg of BuildiNgS

a one-day Professional development course on ‘Structural audit & Nondestructive testing of Buildings’ will be held at cettM, MtNl, Main Street, Hiranandani gardens Powai, Mumbai 400076 on 12th March, 2016.

the course is designed to guide the participants to carry out Structural audit, interpret their findings and Ndt results and prepare an audit report. it will also offer practical insight through case studies, deliberations on various issues and active interaction.

the contents of this course include: amendments in Maharashtra act No vi & MMc act, Structural assessment, Structural audit: Methodology, guidelines, report, Scope & limitations, Ndt: Methods, interpretation, Pros & cons, case Studies, experiences & viewpoints

this course is targeted at Practicing civil/ Structural engineers, consultants, civil engineers from government and Private Sector, Maintenance engineers, contractors, college faculty, Students.

certificates will be awarded to the participants. technoesis is accredited by cdc, dSir, Ministry of Science & technology, government of india.

Contact:Dhargalkar Technoesis (I) Pvt. Ltd.p: (022) 28461500, 28461317, 28463012, 9819732195e: [email protected]: www.technoesis.co.in

aKc’S MarcH 2016 PrograMS

the March 2016 programs of ambuja Knowledge centre include the following:

AKC (Andheri)March 10-11, 2016: Workshop on M Sand

March 18, 2016: Micro fine cement injection grouts; (Speaker: er. Yatin Joshi, National Head alccofine Business, ambuja cements ltd.)

March 22, 2016: Bridge inspection in Maharashtra with case Studies of underwater inspection; (Speaker: er. Mahesh tendulkar, director, concrete research & engineering Services Pvt. ltd.)

March 30-31, 2016: Workshop on advance concrete Mix design

AKC (Belapur)March 11, 2016: Non destructive evaluation of concrete Structures; (Speaker: er. Yogini deshpande, Principle consultant, renuka consultants)

March 16-17, 2016: Workshop on Basics of rcc design & concept

AKC (Virar)March 17, 2016: Shrinkage in concrete - challenges & Solution; (Speaker: er. avijit chaubey, Head (r&d), acc concrete group)

AKC (Thane)March 4, 2016: innovative concrete Solution for the Sustainable construction; (Speaker: er. Prateek Mathur, Head, Sales & Marketing, acc concrete group)

ContactAmbuja Knowledge Centre, Mumbaip: +91-22-4066 7620 / 9920067037e: [email protected]: www.foundationsakc.com

courSeS orgaNiSed BY cidc

cidc-uNece centre of excellence for PPP Projects in roads and Highways launches next round of case Study oriented Set of Six courses for PPPs in roads & Highways (Based on uN recommended curriculum). training Programs for middle level executives of all stakeholder organisations involved in PPPs are as follows.

introduction to Public-Private Partnerships – 2nd april, 2016 (9.30 aM to 6 PM)

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The Indian Concrete Journal March 2016 �


The Indian Concrete Journal March 2016�


good governance in Public-Private Partnerships – 16th april, 2016 (9.30 aM to 6 PM)

risks in Public-Private Partnerships – 7th May, 2016 (9.30 aM to 6 PM)

running an effective PPP Procurement - What are the Key stages in PPP Procurement? – 21st May, 2016 (9.30 aM to 6 PM)

an overview of issue related to Public-Private Part-nerships and Sustainable development - How can PPPs deliver sustainability? – 4th June, 2016 (9.30 aM to 6 PM)

a guide to the preparation of an outline Business

case – 18th June, 2016 (9.30 aM to 6 PM)

the above dates are subject to change. in all modules, glimpses of other modules shall be incorporated. the courses are replete with analysed case studies, many from india.

ContactAdesh Kumarip: +91-9999935755 e: [email protected]. w: www.cidc.in

advaNced Bridge deSigN aNd coNStructioN

the indian institute of technology (iit) Madras, chennai in association with the indian concrete institute is conducting a course on advanced Bridge design and construction during July 11 to 23, 2016 at campus.

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Syllabus for the course: review of bridge engineering and indian standards for road bridges; india-specific design considerations and site issues; typical bridge foundations; Bridge types in terms of the longitudinal layout: simply supported, continuous, framed, arch, cable stayed and suspension bridges; concrete bridge types in terms of the cross-section: slab decks, girder-and slab decks, box-girder decks; Bridge construction methods: scaffolding, span-by-span, incremental launching, balanced cantilever; introduction to reliability-based management of bridges; design of concrete for strength and durability; grouting of prestressing ducts; case studies; and industrial seminars.

the course is targeted at:

Students doing research in analysis, design, durability and assessment of bridges.

instructors teaching topics related to bridge engineering.

Practising professionals involved in planning, management, design, construction and maintenance of bridges.

Scientists or consultants offering services in investigation, inspection and rehabilitation of bridges.

the course faculty are:

Professor Joan ramon casas, School of civil engineering, technical university of catalonia (uPc), Spain.

Professor ravindra gettu, iit Madras, chennai

Professor amlan K. Sengupta, iit Madras, chennai

Contact:IIT Madras, Chennaip: (044) 22574266, 22575255, 22574277e: [email protected], [email protected]: www.iitm.ac.in

ProBaBiliStic SafetY aSSeSSMeNt iN tHe cHeMical aNd Nuclear iNduStrieS

the indian Nuclear Society is organising a workshop on ‘Probabilistic Safety assessment in the chemical and Nuclear industries’ during october 03-07, 2016 at aerB auditorium, Niyamak Bhavan, anushakti Nagar, Mumbai

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The Indian Concrete Journal March 2016 �


The Indian Concrete Journal March 201610


the workshop contents include:

introduction

reliability Maths / Statistics

life testing

System reliability

risk assessment Methodology

Hazard identification and risk assessment

application of risk assessment

ContactIndian Nuclear Societyp: 91-22-5598327e: [email protected]: www.indiannuclearsociety.in

redecoN 2016

the association of consulting civil engineers (india) will be organising redecoN 2016 during 9th – 12th November, 2016 at NiMHaNS convention centre, Bengaluru, india. this is a biennial event organised to help construction professionals to stay abreast of trends and changes in building and construction technology.

the topics of the seminar would include:

analysis and design of tall structures

construction materials

construction technology

tall structures for smart cities

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vulnerability & risk assessment

tall steel structures

Software for tall structures

ContactAssociation of Consulting Civil Engineers (I) - Bangalore Centrep: 91-080-22247466e: [email protected] [email protected]: www.accehq.net

World deMaNd for ceMeNt aNd coNcrete additiveS to reacH $24 BillioN

global demand for cement and concrete additives is forecast to grow 7.2 percent per year through 2019 to $24.0 billion. these increases reflect continuing growth in construction activity across the globe that will, in turn, drive global usage of cement. increasing additive usage rates in developing countries, as well as a broader shift to higher performing specialty additives, will further support advances in additive demand. the types of additives being used will also be impacted by environmental concerns, with the choice between blended and portland cements impacting additive demand on a regional and country basis. these and other trends are presented in World cement and concrete additives, a new study from the freedonia group, inc., a cleveland-based industry research firm.

World cement & concrete additive demand (million dollars)

% Annual Growth

Item 2009 2014 2019 2009-2014

2014-2019

Cement & Concrete Additive Demand 10940 16980 24000 9.2 7.2

North America 1985 3080 4400 9.2 7.4Western Europe 2107 2167 2760 0.6 5.0Asia/Pacific 5000 8615 12330 11.5 7.4Central & South America 393 692 1018 12.0 8.0Eastern Europe 648 996 1347 9.0 6.2Africa/Mideast 807 1430 2145 12.1 8.4

© 2016 by The Freedonia Group, Inc.

despite a more challenging economic environment, demand for cement and concrete additives in china will grow through 2019, driven by increasing urbanization and the resulting investment in public infrastructure projects

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The Indian Concrete Journal March 2016 11


such as highways and bridges, as well as by rising additive treatment rates. However, china’s role as the leading driver of global cement and concrete additives demand growth will diminish, as the importance of markets in other developing countries such as india and turkey continues to grow. according to analyst christine o’Keefe, “By 2024, india is forecast to be the third largest market for cement and concrete additives, just ahead of Japan.” growth in demand in the other countries in the asia/Pacific region and the africa/Mideast region will also benefit from increasing urban populations. construction activity is expected to remain strong or accelerate in developed regions, such as North america and Western europe, driving demand for additives for concrete in buildings. in particular, growth in the united States, the second largest market for cement and concrete additives, will outpace nearly all other developed countries.

chemicals will continue to be the largest cement and concrete additive segment by value, with gains driven by increasing demand for high strength concrete in industrialized nations, and continued penetration of advanced chemical additives into the construction industries in developing countries. growth in demand for fiber additives will outpace the other major additive types, as governments invest in large infrastructure projects that utilize fibers, such as roads and bridges. Mineral additive demand will also post gains, driven by increasing utilization of supplementary cementitious materials to further improve the performance of portland cements.

––Press release from www.freedoniagroup.com

a SoftWare tool for coNcrete Mix deSigN BaSed oN iS 10262:2009

a B.tech final year student from rguKt, Nuzividu, andhra Pradesh has developed a software tool for concrete mix design.

this concrete mix design software tool could efficiently generate mix proportions for the given conditions by full filling all the codal provisions of iS 10262:2009, iS 456:2000 and iS 383:1970. user has a flexibility to change input conditions and generated water-cement ratio during run-time by using Modify option. Hence performing different trials with different kinds of conditions are possible. for the better understanding, user can visit iS code clauses, tables and figures which are embedded in software tool. a portable document file will be generated with a detailed report of concrete mix design. So that it can useful for people working in government organizations and private sector of concrete industry. this tool containing calculations related

to the preliminary tests of concrete mix design along with the mix design calculations. in aggregate details window, calculations of sieve analysis, fineness modulus, specific gravity and moisture content are available for both the coarse and fine aggregates. user can combine graded aggregates upto three size fractions. check for maximum size of aggregate and zone of sand will be performed based on iS 383. Super plasticizers and water reducing admixtures are incorporated in this tool. fly ash can also used in concrete mix, which will replace cement content. trial mix calculations also available by varying water-cement ratio by ±10% of the preselected value. Based on the test results of trial mixes, plots of compressive strength against water-cement ratio can be generated for 7 days and 28 days.

ContactVijay Prakash KondetiRGUKT, Nuzvid, APp: 91-9966087400e: [email protected]

A sample screen of the software

12 The Indian Concrete Journal March 2016

TECHNICAL PAPER TECHNICAL PAPER

Study on reduction of pavement noise using porous concrete

Abhijeet S. Gandage, V. Vinayaka Ram, Manish Panwar, Meet Shah and Rishabh Singhvi

The Indian Concrete Journal, March 2016, Vol. 90, Issue 3, pp. 12-21.

Noise is unwanted sound. In case of roads, the interaction between pavement texture and vehicle tyres produce noise both inside and outside the vehicle. Noise, especially related to road and traffic is now seen as an environmental concern. Noise generation due to tyre-pavement interaction is dependent on various factors. Noise is one of the primary factors considered for the selection of type of pavement along with other important factors like budget, life, type of traffic, environmental variations etc. One measure to control the propagation of noise on account of tyre-pavement interaction is dissipation of noise at the pavement level by use of appropriate material combinations. It’s a very well established fact that concrete pavements are more durable and cost effective over the life span of the pavement when compared with the flexible bituminous concrete pavements. However, the noise generated by the cement concrete pavements, make it an unpopular option to deal with. Porous concrete is one such option that has a potential for noise reduction. A review on the origin and effects of noise on account of tyre-pavement interaction, factors affecting the generation of such noise and the methods to measure the tyre pavement noise are presented in the initial part of the paper. The paper also discusses the concept and mix design factors of porous concrete. The later part of the paper discusses the laboratory scale experimental setup designed and tested for the measurement of noise absorption by the porous concrete as well as the normal concrete specimen. The results obtained from the experimental studies undertaken are presented and discussed in the paper.

Keywords: Noise; tyre-pavement interaction; porous concrete.

1.0 INTRODUCTIONA good transportation system facilitates speedy and economic mobility of persons and goods to different places. India has the second largest road network in the world totaling 4.2 million kilometers [1]. In India, the flexible pavement option is very popular due to its inherent advantage in providing smooth riding surface and relatively lesser noise than compared with the cement concrete counterpart. However, with the rising costs of bitumen and durability requirements cement concrete is a preferred material for road construction. Of all the factors related to Pavement Management System (design, construction and maintenance of roads), road traffic noise is being considered as one of the critical factor.

Concrete roads produce more noise than asphalt roads. Noise, is generation of sounds that are unwanted. Noise is quantified by the term Sound Pressure Level (SPL) [2]. The intensity of noise as perceived by air is directly related to the amplitude of pressure fluctuations travelling through air. For a healthy human ear, the lowest pressure fluctuation that can be audible is 2 x 10-5N/m2. The threshold level of pain is about 63N/m2. SPL is measured mathematically as,

= 10

= 10 log where,p : ambient root mean square sound pressure (N/m2)po : reference pressure (2 x 10-5 N/m2).

13The Indian Concrete Journal March 2016

TECHNICAL PAPER

Road traffic noise can be considered as an environmental pollution as it affects public health and environment. As per a study undertaken in Denmark, 1dB increase in noise results in 1% decrease in house prices along the roads [3]. The amount of traffic noise depends on traffic volume, speed and type of vehicle along with the texture of pavement. In case of roads, the major sources of noise are the power train or propulsion noise and tyre pavement noise [3, 4]. There is one more source of noise called aerodynamic noise that is considered when the vehicle speed is in excess of 120kmph [3]. The power train noise is primarily related to vehicle engine and exhaust systems. The tyre pavement noise is related to interaction between pavement texture and vehicle tyres. At lower speeds, the power train noise is dominant and as the crossover speed is exceeded, the tyre-pavement interaction noise dominates. The crossover speed depends on the type and operating conditions of the vehicle. As the noise from engines is reduced, it decreases the crossover speed and results in quieter pavements. The generation of noise is also dependent on the type of vehicle. Trucks and freight vehicles on account of their geometry and tyre type are 10dBA louder than normal passenger cars [5].

The road traffic noise is classified as line source, as noise is transmitted along the entire length of the roadway. As the distance from the source increases, the level of noise decreases. For paved roads, by doubling the distance between the source and receptor, a reduction of 3dBA in noise level can be achieved. The Federal Highway Administration [6] has proposed a traffic noise model that helps to predict the noise levels as mentioned below; = 10

= 10 log

where,α : attenuation coefficient; α = 0.0 for hard ground or pavement and α = 0.5 for soft ground,d1 : distance from the source of noise to the first point of interest,d2 : distance from the source of noise to the second point of interest.

The road traffic noise generated affects all kinds of road users alike. In addition, it also affects the health of people who live in the vicinity of the roads. The three main stages related to road traffic noise are generation, propagation and reception [7]. In the preceding paragraph, the generation of noise has been discussed. The propagation and reception of the traffic noise is dependent on condition of the vehicle components, grade, terrain, vegetation, distance from the roadway and

shielding by barriers and buildings. The mitigation of noise levels involves combination of measures to control generation, propagation and reception. One combination could be suitable design of vehicle to control the noise generation at source along with design and construction of suitable barriers to control the reception of the noise.

2.0 TYRE PAVEMENT NOISE - REVIEWOf the different sources of noise, the propulsion noise is dominant at lower speeds of the vehicle. However, as the crossover speed of the vehicle exceeds 35km/h, the tyre pavement noise becomes a dominant source in the overall noise generated by the moving vehicle. The tyre pavement noise is caused on account of complex interaction of rolling, slipping and / or dragging of tyres and the road surface. This noise increases linearly with increase in the speed of the vehicles [2]. The various causes of tyre-pavement noise and the reasons for its amplification are tabulated in Table 1 for ready reference.

Table 1. Cause and amplification of tyre-pavement noise [5]

Cause of tyre pavement noise

1. Tread impact (Hammer effect)

Impact between tyre tread and pavement groove.

2. Air pumping (Clapper effect)

Re-trapping of forced out air between tyre and pavement.

3. Stick-slip (Sneaker effect)

Slip of rubber due to deformation and distortion under tyre.

4. Stick-snap (Suction cup effect)

Adhesion and vacuum of tyre tread block with pavement surface.

Mechanisms that amplify the tyre pavement noise

1. Acoustical horn (Horn effect)

Multiple sound wave reflection in air wedge between tyre and pavement.

2. Helmholtz resonance (Pop bottle effect)

Air in the wedge of tyre and pavement vibrates in and out with respect the entrapped air.

3. Pipe resonance (Organ pipe effect)

Pipe geometry similar to organ pipe formed on the grooves on tyre footprint area.

4. Sidewall vibrations (Pie plate effect)

Vibrations on account of tyre sidewall interaction with pavement.

5. Cavity resonance (The balloon effect)

Kicking of tyre. Experienced in the vehicle.



The intensity of the various effects as tabulated in Table 1 can be understood by the tyre-pavement noise intensity contour diagram (Figure 1).

In case of tyre pavement noise interaction, two aspects are to be considered viz. tyre-vehicle characteristics and pavement characteristics.

2.1 Tyre and vehicle characteristics

Tyre characteristics that play an important role in tyre-pavement interaction noise are tyre weight, rolling resistance, wet road hold, handling and stability, vibration characteristics, tyre type, durability and recycling potential of the tyre [5, 8]. However, of all the above mentioned properties, the most important factor governing the tyre-pavement interaction noise is the structure of tyre, which comprises of tread pattern, rubber compounds and seasonal utility. The various aspects of tyre structure are pictorially depicted through Figure 2.

The advances in automobile designs are observed to be one of major contributing factors towards noise generation. Important advances like antilock braking systems, traction control, four wheel drive, ride height control, semi-active suspension, deflation warning system, electronic stability and smart tyre technology influence the powertrain noise component.

2.2 Pavement characteristics

Road type is one of the important factors that influences the generation and propagation of traffic noise, in particular, the tyre-pavement interaction noise. Based on the type of the

material being used for the construction of the pavement, these can be asphaltic concrete (AC) or Portland cement concrete (PCC) roads. Based on worldwide survey, it is reported that dense AC pavements are 2dBA to 3dBA quieter than the quietest PCC surfaces [3]. With increasing costs of bitumen production and procurement, PCC roads are getting quite popular. However the noise generated by tyre-pavement interaction in case of PCC roads is one of the emerging problem areas for PCC pavement construction and maintenance. The noise generation in PCC pavement is primarily related to the texture pattern on the pavement surface. Apart from noise related issues, pavement surface characteristics influence skid resistance, splash and spray, visibility of road and/or markings, road grip, vehicle operating and road user costs like fuel consumption economy, vehicle and/or tyre wear, comfort of road users as well as residents staying along the road vis-à-vis noise generation.

As far as PCC pavements are concerned, there is an unique relation between noise generation potential of the pavement material and the skid resistance performance of the pavement. As per the World Road Association’s Permanent International Association of Road Congress [2, 9]. (PIARC) Technical Committee on surface characteristics, the surface texture patterns are classified as; micro texture (<0.5mm), macro texture (0.5mm to 50mm), mega texture (50mm – 500mm) and roughness (0.5m to 50m). The relative


TECHNICAL PAPER

importance of these texture patterns in performance of PCC roads can be understood from Figure 3.

The skid resistance of the pavement surface is dependent on the pavement micro texture as well as macro texture. Macro texture influences the drainage of water on the surface of the pavement and hydroplaning effect. Along with mega texture, macro texture has a significant role in the tyre-pavement noise generation as well as in-vehicle noise and rolling resistance. Higher order of macro texture has a greater contribution in noise generation. If the surface friction is increased by texturing, the noise generation also increases. Lower order of macro texture is beneficial for road noise reduction. However, the reduction in noise generation cannot be compromised with safety. As per studies carried out in Canada [3], quality of aggregates also plays an important role in surface friction rather than texture. High quality of aggregates with polishing values in the acceptable ranges for the surface mix can produce lower macro texture ensuring safety and lower noise generation.

Table 2. Various methods to measure tyre pavement noise [14]S. no. Noise measurement method Details

1. Statistical passby method (SPB)

Random sampling for measurement of sound pressure level using sound level meter. Instrument located around 7.5m or 50ft. from centre line of the route lane. Standard reference ISO 11819-1. SPB is applicable for all types of traffic noise including engine exhaust and aerodynamic noise.

2. Controlled passby method (CPB) Setup same as SPB is used for CPB. However some representative vehicle is driven at a controlled speed pass the instrument location. Measurement time is less than SPB.

3. Time averaged traffic noise SPB or CPB cannot be used for acoustic measurement in case of heavy traffic density. In such cases time averaged measurements are converted to equivalent noise levels.

4. Close proximity methods (CPX)The procedure of CPX is described in ISO 11819-2. CPX setup is mounted near the tyre and adequately covered to reduce the interference of wind noise. It primarily measures the tyre-pavement noise and the process is relatively fast. It is a field measurement of sound pressure.

5. Close proximity sound intensity (CPI) This method is a sophisticated method measuring sound intensity than sound pressure. Measurements are made in regular traffic stream at normal speeds.

6. Pavement absorptionThis method measures the acoustical properties of the pavement material. It includes laboratory measurement using Bruel Kjaer impedance tube (ASTM E-1050). In-situ measurement of pavement properties can be undertaken as per guidelines mentioned in ISO 13471-1 (2002).

7. Laboratory measurementsTyre pavement test apparatus consisting of drum diameter ranging from 1m to 15m is used to measure acoustic properties of pavement material along with mechanical issues, durability and friction studies.



Macro texture wavelength in the range of 8mm to 16mm can ensure effective drainage as well as minimizes generation of undesirable noise [10].

The texture pattern developed on the surface of PCC pavements is dependent on the method adopted viz. longitudinal tining, horizontal tining or diamond grinding [11]. The width and depth of the texture affects the tyre-pavement noise generation. Longitudinally tined pavements exhibit low exterior noise. Transversely tined pavements produce more noise than other pavement texturing methods. It is recommended from noise point of view that longitudinal tining with 19mm [11] spacing reduces noise as well as provides adequate safety. As per studies undertaken in the United States [12], in case of PCC pavements with diamond grinding the noise levels were lower by 3dB and complete absence of discrete frequencies. PCC with diamond ground texture patterns were the quietest [13] amongst all PCC pavement with different texture patterns.

2.3 Measurement of tyre pavement noise

There are various methods of measurement of tyre pavement noise. The limitation of measurement methods is that no single method is practically possible for measurement of all types of noise. The various methods [14] adopted for the measurement of the tyre pavement noise are tabulated in Table 2. Figure 4 presents the various setup used for measurement of tyre pavement noise.

3.0 POROUS CONCRETEBased on the noise generation studies and from the point of safety, there are three ways to generate low noise producing pavements viz., porous surfaces, texturing of surfaces and special tining methods. This paper is an attempt to study the noise reduction measures through porous surfaces.

Porosity of the pavement material reduces air pumping effect which in turn reduces tyre noise. Due to porosity of


TECHNICAL PAPER

the pavement, the amplifying effect of the acoustic horn is reduced due to absorption of sound waves in the pores of the concrete.

Porous pavements are those made with built-in void spaces that let water and air pass through. This concept was first experimented in AC pavements from efficient drainage and storm water management points of view. However, with the focus now on noise, porous pavements are gaining significant research interest. In case of AC pavements, two layered road sections [6] with open graded AC layer on top of stone mastic asphalt (SMA) layer or dense AC layer (DAC) are found to be effective in reducing noise levels. The concept of two layer pavement has been experimented in Europe for PCC pavements also with porous concrete pavement layer at top with conventional PCC layer laid below it.

Porous concrete (with density [15] ranging from 1600kg/m3 to 2000 kg/m3) is usually made by binding open graded aggregate with Portland cement as seen in Figure 5. It is a high porosity concrete with void content in the range of 18% to 35% [16] and compressive strengths in the range of 20MPa to 30MPa [17]. The typical flexural strength value of a porous concrete section is in the range of 1MPa to 3.5MPa. The infiltration rate of porous (pervious) concrete is in the range of 80 to 720 litres per minute per square meter. The fine aggregate component in pervious concrete is negligible or totally absent. The cementitious content [15] (270 kg/m3 to 415 kg/m3) in the porous concrete mix is sufficient enough to coat the coarse aggregate particles (aggregate content range

1190 kg/m3 to 1480 kg/m3) ensuring enough connectivity between the voids in the mix. The recommended aggregate cement ratio is 4 to 4.5 by mass. When used in pavement sections, the porous concrete layer is laid as top layer (wearing course) providing low noise emission and good drainage capacity. This layer overlays the conventional concrete layer using wet-on-wet process. The noise reduction in this composite section takes place by absorption of noise by the pervious layer and the lower pavement layers ensures strength and durability requirements for the pavement section. The typical voids ratio in porous concrete should be in the range of 15% to 20% [6]. In order to achieve efficient noise reduction the porosity should be in excess of 15%.

The noise reduction efficiency of porous concrete is also influenced by the aggregate particle size. Single sized aggregate gradation or a narrow range size gradation (between 19mm to 9mm) is preferred aggregate gradation for porous concrete mix design. A wide aggregate gradation is avoided as it will influence the voids ratio and in turn the efficiency of the porous concrete section. As per studies undertaken in Belgium, porous concrete section with 19% porosity achieved 5dBA [4] reduction in noise level. Japanese studies have achieved noise reduction of 6dBA to 8dBA [4] for dry surfaces and 4dBA to 5dBA for wet surfaces with cars travelling at speed of 40kmph to 75kmph. In case of trucks, noise reduction values of 4dBA to 8dBA and 2dBA to 3dBA are achieved for dry and wet surfaces respectively. The tests are conducted on 200mm thick sections overlaid on existing pavement sections.

One important limitation of porous concrete pavement is the tendency of pores getting clogged by particulate impurities. Also because of its low flexural strength performance, it cannot be a recommended option for highway sections at present. However, if the mix design procedures are altered to achieve better mechanical properties, then porous concrete can be a good alternative to noise reduction along with its green construction application.

4.0 LABORATORY TRIAL – POROUS CONCRETE MIX DESIGN AND NOISE ABSORPTIONAs a part of a research programme to study performance of cement concrete pavements vis-à-vis thermal stresses, skid resistance and noise, a laboratory trial was undertaken with an objective to prepare a porous concrete mix. The laboratory trials related to noise absorption experiments comprised of two parts;

Mix Design of porous concrete.a.



Design and testing of a laboratory scale test setup for noise absorption and comparison of noise absorption frequencies by a cube specimen prepared using conventional concrete and porous concrete.

4.1 Mix design, procedure and test results

Ordinary Portland cement G-53 confirming to IS:12269 – 1987, was adopted. The cement content adopted was 350kg/m3 which is an intermediate value as suggested in the literature [14]. Single sized coarse aggregate passing 20mm IS sieve and retained on 10mm IS sieve has been used. The aggregate cement ratio considered for the trial was 6:1. The water cement ratio for satisfactory consistency will vary between a narrow range of 0.38 to 0.52 [18]. Based on the suggested range of water cement ratio, an intermediate value of 0.425 was adopted in the laboratory trial. Along with the mix design for porous concrete, M-35 grade normal concrete mix design was also computed, as per guidelines mentioned in IS: 10262-2009. The mix design adopted for porous concrete and M-35 grade normal concrete have been tabulated in Table 3.

b. After the mix design computation, the concrete ingredients for porous concrete were mixed in 0.12m3 pan mixer as per guidelines mentioned in IS: 516-1959. The same procedure was adopted for preparation of cubes for M-35 grade normal concrete. A total of 9 cube specimens were prepared for each type of concrete. Along with the cube specimen, 6 nos. of beam specimen (size 50cm x 10cm x 10cm), for flexural strength, were also prepared. The temperature at the time of mixing and demoulding was 28oC. All test specimens were subjected to moist curing. Figure 6 summarizes the laboratory procedure details for preparation and testing of concrete specimens.

The test results of cube compression test and beam flexure test are summarized in Table 3.

4.2 Procedure for noise absorption test

Based on the various methods discussed in Table 2, for measurement of noise, the authors adopted the pavement

Table 3. Summary of mix design and test results for porous concrete and M-35 grade normal concrete

S. no. Porous concrete M-35

Mix design details

1. Aggregate Cement ratio 6:1 --

2. Cement 350 kg/m3 398 kg/m3

3. Coarse Aggregate 2100 kg/m3 1135 kg/m3

4. Fine Aggregate -- 560 kg/m3

5. Water 150 kg/m3 186 kg/m3

Average density (kg/m3)

1. 3 – Day 2103.7 2364.4

2. 7 – Day 2133.3 2386.2

3. 28 – Day 2200.5 2403.1

Compressive strength (MPa)

1. 3 – Day 13.4 29.5

2. 7 – Day 14.5 35.6

3. 28 – Day 24.4 41.5

Flexural strength (MPa)

1. 7 – Day 0.6 4.4

2. 28 – Day 1.5 6.3

Table 4. Observation for frequency and reflected noise volume for M-35 grade normal concrete and porous concrete

S. no. Sound wave frequency (Hz)

Refl. noise volume for M-35

grade normal concrete (dB)

Refl. noise volume for

porous concrete (dB)

1 250 29.74 28.91

2 500 58.01 53.54

3 750 53.59 51.46

4 1000 61.43 54.78

5 1250 46.59 43.26

6 1500 42.04 41.34

7 1750 45.54 39.63

8 2000 35.62 28.85

9 2250 51.88 50.72

10 2500 45.01 36.86

11 2750 43.98 36.33

12 3000 38.36 27.64

13 3250 28.87 21.71

14 3500 32.69 24.18

15 3750 43.31 27.14

16 4000 46.85 41.92

17 4250 40.91 32.87

18 4500 32.51 29.29

19 4750 46.59 43.29

20 5000 42.65 40.06


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absorption procedure for assessment of noise absorption potential of porous concrete and normal concrete.

As a part of the laboratory trial, a test setup, as presented in Figure 7 was designed. The setup comprised of a wooden box of size 40 cm x 17.5 cm x 17.5cm internally lined with thermocol. The cube specimen was placed at one end of the box. A source of sound was placed at a distance of 5cm from the cube specimen. A microphone was placed at the opposite end to record the noise volume of the reflected noise. The noise level emitted by the source was controlled by the sound mixer setup and the microphone was connected to the sound mixer unit. The frequency of the incident sound waves was controlled using the sound mixer, starting at 250Hz up to 5000Hz at an interval of 250Hz (Table 4). The test setup designed is an indirect measure for noise absorption by the respective cube specimen. Figure 8 presents the plot of reflected noise level versus frequency for both grades of concrete.



DISCUSSION AND fUTURE SCOPEFrom the graph plot (Figure 8) it was observed that the porous concrete specimen had efficient noise absorption as compared to M35 grade of normal concrete. The reflected noise levels were 5% to 35% lower in case of porous concrete specimen as compared to the M-35 grade normal concrete specimen at different frequencies. As compared to the 1600-1900kg/m3 density reported in the literature [15] for porous concrete mixes, the porous concrete specimen considered in the present study had an average 28 day density of 2200 kg/m3. This can be attributed to the aggregate cement ratio (6:1) adopted in the present study as well as relatively high cement content (350kg/m3). The aggregate cement ratio that can be adopted for porous concrete mix can be in the range of 6:1 to 10:1 [18]. The aggregate cement ratio and the cement content influence the void formation in the porous concrete specimen. It also influences the strength characteristics of the test specimen. In case of use of higher aggregate cement ratio, the density would come down further, thereby improving the noise absorption level of the concrete specimen. However, this would reduce the strength of the mix. The porous concrete mix combination, considered in the present study, exhibited the 28-day cube compressive strength and beam flexural strength in the prescribed range [17].

A limitation of this study was the measurement of voids ratio in the porous concrete specimen. As a part of future scope, relation between aggregate cement ratio, voids ratio and the noise absorption capacity will be experimented

and studied. Further, the distance of source of noise from the concrete specimen was 5cm. A variation in this distance and its impact on noise absorption will also be studied in the future scope. Also, laboratory trials will be undertaken to study the variation in strengths with variation in aggregate cement ratio as well as water cement ratio. A correlation between the voids in the porous concrete cube specimen and noise absorption performance of the given mix will be established.

5.0 CONCLUSIONSTyre pavement noise is an issue of vital importance in near future. This problem is more pronounced in case of concrete pavements. As far as performance of different pavements viz. AC and PCC is concerned, the latter have good mechanical properties, longer service life and comparatively lesser whole life cycle costs. However, the noise generation is more in case of PCC pavements. Pavement texturing is one of the important processes that affects the skid resistance performance and noise generation potential of pavement surface. However, due to continuous wear on account of tyre-pavement interaction, there is a need for frequent texturing procedures. Porous concrete is one possible solution to reduce the potential impact of tyre pavement noise. The noise absorption potential of porous concrete mix is comparatively high as compared to conventional concrete mix. However, due to low hardened state properties of porous concrete, it cannot be recommended for large scale applications. There is a huge scope for exploring options in the mix design of porous concrete with a view to improve its mechanical properties while achieving the main function of noise level reduction on these pavements.

References

Kadiyali L. R., Sustainable Concrete Pavements: Practices, Challenges and Directions, The Masterbuilder, July 2011, Vol. 13, No. 7, pp. 102-110.Relationship between Pavement Surface Texture and Highway Traffic Noise, National Cooperative Highway Research Program (NCHRP), Synthesis 268 (1998). Transportation Research Board, Washington, USA.Ahammed M. A., Tighe S. L. and Klement T., Quiet and durable pavements: Findings from an Ontario Study, Canadian Journal of Civil Engineering, July 2010, NRC Research Press, Vol. 37, pp. 1035-1044.National Concrete Pavement Technology Centre, Evaluation of US and European Concrete Pavement Noise Reduction Methods, Iowa State University, Federal Highway Authority (FHWA) and American Concrete Pavement Association (ACPA), 2006, Ames, Iowa, USA: Iowa State University, USA.Rasmussen, R. O., Bernhard R. J., Sandberg Ulf and Mun E. P., The Little Book of Quieter Pavement. US Dept. of Transportation, Federal Highway Administration (FHWA), 2007, USA. Hanson D. I., James R. S. and NeSmith C., Tire/Pavement Noise Study, National Centre for Asphalt Technology, Auburn University, and Federal Highway Administration (FHWA), 2004, USA.

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2.

3.

4.

5.

6.


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Watts G., Barrier designs to reduce road traffic noise, Proceedings of the Institution of Civil Engineers, May 2002, Issue 2, pp. 79-86.Williams A. R., Vehicle, Tire, road interaction – the vision for the future, Proceedings of the Institution of Civil Engineers, November 1997, Issue 123, pp. 220-225.Narayanan N., Weiss J., and Olek J., Reducing the noise generated in concrete pavements through modification of the surface characteristics. Portland Cement Association (PCA R & D Serial No. 2878), 2005, Illinois, USA.Ahammed M. A. and Tighe S. L., Pavement surface friction and noise: integration into the pavement management system, Canadian Journal of Civil Engineering, September 2010, NRC Research Press, Vol. 37, pp. 1331–1340.Delatte N., Concrete Pavement Design, Construction and Performance, Taylor and Francis Publishers, New York, 2008, pp. 66-68.Keummel, D. A., Sontag, R. C., Crovetti, J. A., Becker, Y., Jaeckel, J. R., and Satanovsky, A., Noise and Texture on PCC Pavements: Results

7.

8.

9.

10.

11.

12.

of a Multistate Study Report No. WI/SPR-08-99, 2000, Wisconsin Dept. of Transportation.Hanson, D. I., and Waller, B., Evaluation of the Noise Characteristics of Minneosota Pavements, Project Report submitted to Minnesota Department of Transportation, 2005.Bernhard, R., and Wayson, R. L., An Introduction to Tire/Pavement Noise in Asphalt Pavement. Purdue University, USA, 2006.Tennis P. D., Leming M. L. and Akers D. J., Pervious Concrete Pavements, Portland Cement Association (PCA) and National Ready Mix Concrete Association (NRMCA), 2004, Maryland, USA. Obla K. H., Pervious Concrete – An Overview, The Indian Concrete Journal, August 2010, Vol. 84, No. 8, pp. 9-18.Wang Y. and Wang G., Improvement of Porous Pavement, July 2011, (Web ref.: www.usgbc.org).M. S. Shetty, Concrete Technology, S. Chand Publishers, New Delhi, 1999, pp. 519-523.

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14.

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Abhijeet S. Gandage is a PhD Research Scholar in the Department of Civil Engineering, Birla Institute of Technology and Science (BITS) Pilani, Hyderabad Campus. His areas of interest are construction management concrete technology and transportation engineering.

V. Vinayaka Ram is Associate Professor in the Department of Civil Engineering, Birla Institute of Technology and Science (BITS) Pilani, Hyderabad Campus. His areas of interest are transportation engineering, pavement material characterization and concrete technology.

Manish Panwar is a Graduate Student of Department of Civil Engineering, Birla Institute of Technology and Science (BITS) Pilani, Hyderabad Campus. His areas of interest are concrete technology, sustainable development, structural engineering.

Meet Shah is a Graduate Student in the Department of Civil Engineering, Birla Institute of Technology and Science (BITS) Pilani, Hyderabad Campus. His areas of interest are construction planning, concrete technology and project management.

Rishabh Singhvi is a Graduate Student in the Department of Civil Engineering, Birla Institute of Technology and Science (BITS) Pilani, Hyderabad Campus. His areas of interest are structural engineering and concrete technology.



Structural effects of haunched braces in elevated service reservoir staging

Abhay Khandeshe and R.K. Ingle


Being life line structures, elevated water tanks shall be designed for worst of wind and seismic forces with proper mathematical modelling. Haunch is many times provided at end of brace for elevated tank. It is useful for resisting localized forces. In braces, forces are concentrated at junction rather than at span and are practically zero near mid-span. Beams with haunch are traditionally difficult to model in a practical manner as standard software did not include tapered sections till very recently. Before advent of computers, the handbook of frame constants published by the Portland Cement Association was used by structural engineers for analysis of tapered beams. However, these tables have inherent inaccuracy in interpolating force values, due to uncertainty of curvature, especially in the vicinity of maximum ordinate of the curve. While for general buildings, effectiveness of haunches is well established and reported, hardly any work has been found in literature, on staging of water tanks with haunched braces. Hence, it is proposed to analyze various types of staging of water tanks with haunched braces for dynamic behavior and compare the results. Observations indicate that, little increase in shuttering cost of haunches, result in

substantial saving of steel as well as concrete along with a more safe and durable structure.

Keywords: Elevated service reservoir; haunched beam; staging, brace.

IntROduCtIOnWater is a precious resource. However, in times of an emergency, viz, cyclones or earthquakes, it is observed that elevated water tanks often fail. They become more so in emergencies such as cyclone and earthquake. The 1999 Kocaeli earthquake in Turkey reports damage to Tubras Oil refinery with consequent fire. This substantially increased the economic loss, as the water tanks in the area failed [1].

Numerous cases of epidemic and contagious diseases are reported due to inadequate supply of pure drinking water after recent Haiti earthquake [2]. Jain & Rai also reported cases of upsetting circumstances in Killari and Bhuj earthquakes respectively because of damage to staging of elevated water tanks [3,4]. Hence water tank staging and its response against seismic/wind load is a point of critical concern. As elevated tank is a special structure, it is mandatory as per codes, that

tanks should be analyzed for worst of wind and seismic forces. This includes proper mathematical modeling to account for geometry of structure as well as loads [5,6]. The elevated service reservoirs are more susceptible to horizontal forces compared to gravity loads. The horizontal load due to earthquake or wind is a function of time period of its staging consisting of columns and braces. The addition of haunch to braces may change quantum of seismic force that will act on the staging. This will depend upon the mathematical modelling of staging. It is proposed to provide haunches to braces and study the performance of various parameters.

LIteRAtuRe SuRveyThurston conducted cyclic load testing of three haunched reinforced concrete beam-column assemblies. He observed that because of haunch, problem of high section curvatures and consequent high flexural compressive strains, buckling of the compressive steel, bond slip are circumvented. In


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addition haunches provide more room for building services as they may allow a reduction in storey height [7]. Number of researchers have presented their observations on structural repairs and strengthening of building, using increased section at junctions of column and beams. They concluded that increased sections at joints, exhibited higher strength, higher stiffness and better energy dissipation capacity than the original sections [8, 9, 10]. Vu Hong Nghiep in his research observed that varied depth (or haunched) concrete structures without stirrups are very popular in practice and still only German code gives detailed instructions for the design of these structures. He also concluded that the shear bearing capacity of haunched structures is usually larger than that of straight depth sections from experimental results. He further states that haunched structures apparently consume less quantity of materials [11].

Tapered elements in general and haunched beams in particular are analytically difficult to model for practical design. Commercial software for structural analysis have recently included tapered sections in their element libraries. Before advent of computers, the only aid for the elastic analysis of haunched beams was the handbook of frame constants for non-prismatic members, published by the Portland Cement Association (PCA). These tables were based on some hypotheses taken to simplify the problem [12]. The tables provided by Concrete Association of India for application of Moment Distribution also give some tables for analysis of haunched beams [13]. However, these tables have inherent inaccuracy in interpolating force values, due to uncertainty of curvature, especially in the vicinity of maximum ordinate of the curve. This fact is demonstrated by Tena Colugna. He stated that PCA tables are obsolete for today’s state of the art knowledge on non-prismatic members because they can lead to significant errors. He provided closed form solutions for linearly tapered elements of rectangular, square, circular cross sections and showed that stiffness factor depends on span to depth ratio of the element [14]. In a limited literature survey done for haunched beams as above, while for general buildings effectiveness of haunches is well established and reported also, hardly any work has been reported on staging of water tanks with haunched braces. Hence, it is proposed to analyze staging of water tanks with haunched braces and compare the results.

AnALySIS Of eLevAted SeRvICe ReSeRvOIRThe dynamic forces developed during an earthquake, are important in the design of liquid storage tanks. The primary structural problem occurs because of the lateral forces which causes combined bending and overturning effect. With moderate height of staging not exceeding 20 m above ground

level, earthquake loads are generally the worst lateral loads on the water tanks as compared to wind loads. In case of elevated water towers, mainly the staging consisting of columns and braces resists lateral forces. Standard literature and code specify stiffness of columns for staging as 12EI/L3 assuming junction of column and brace as fixed. This means that braces are very much stiffer as compared to columns [15,16]. However Jain and Sameer has proved contrary to this assumption of fixed junction and proved that staging is quite flexible, compared to the container [17]. Haunches provided at ends of braces for elevated tanks, are useful for resisting joint bending moment and shear forces. Because for a lateral force resisting frame, forces are concentrated at junctions rather than at mid-span. Hence, professional practice of design is to provide depth of brace, as is required to resist approximately 50 % of maximum bending moment and shear force and provide suitable haunches at the edges to achieve economy.

For the seismic analysis of water tanks, IS 1893 recommends response spectrum method [18,19]. For the tanks of moderate



staging height, it is expected that first mode of vibration will excite major mass during the earthquake. Because water tower is top heavy structure, as per code, an elevated tank may be modelled by a single degree of freedom system, with its mass concentrated at their centre of gravity. Research indicates that the single degree of freedom idealization is appropriate for closed tanks. One third or one half of the weight of the columns and braces is added to the weight of container as effective mass of container and the columns are treated as weightless springs. As per code, the damping in the system is considered as 5% of critical for concrete structure. It is a standard practice to model only prismatic section for braces, neglecting the effect of haunches during analysis. Haunches are provided at the design and detailing stage only. In this paper response of staging with haunched braces is analyzed and results are compared with and without effect of haunches.

detAILS Of tAnKSFour types of staging for water tanks consisting of four, six, eight and twelve columns, placed on periphery with capacity of tanks varying from 1 lakh liters to 25 lakh liters are considered. These are shown in Figure 1a to 1d. Additionally two grid type staging supported on nine and twelve columns respectively are also analyzed, shown in Figure 1e and 1f. Columns are assumed to be of circular cross section for all the above tanks. Three sizes of haunches such

as 100x300mm, 150x450 mm and 200x600 mm are considered in the analysis with the ratio 1 vertical (V) : 3 horizontal (H) as shown in Figure 1g. Other details are provided in Table 1 and have been taken from practical designs submitted for various Government organizations and workshop [20].

Critical direction of earthquake forces cannot be ascertained. Hence response spectrum analysis is done in two mutually perpendicular directions and results are combined by Square Root of Sum of Squares (SRSS). Seismic zone is IV as per IS 1893-Part I and hard strata for foundation is considered. Importance factor for tanks is 1.5, and response reduction factor is taken as 3. The analysis is done for tank empty as well as tank full condition. Each type of tank is analysed for four different cases i.e. one without haunch for braces and

Table 1. Salient details of tanks analyzedDescription a b c d e f

Tank 1Figure 1a

Tank 2Figure 1b

Tank 3Figure 1c

Tank 4Figure 1d

Tank 5Figure 1e

Tank 6Figure 1f

Staging Radius, m 3.43 4 5 8.65 5.375 5.525

Capacity, Lit 100 000 500000 900000 2500000 300000 450000

Clear diameter, m 6.66 12/7.5* 14.9/9.5* 21.6/16.7* 10.55 10.85

Water Depth, m 3 5.55 7.1 8.5 3.5 5

Columns, Nos 4 6 8 12 9 12

Column Diameter, mm 450 Φ 600 Φ 750 Φ 900 Φ 4– 450 Φ5 -500 Φ

8-450 Φ4-500 Φ

Staging Panel Height, m 4 4 4 4 4 4

Brace Regular 250x400 250x 450 250x600 250x700 250x400 250x400

Brace Internal N.A. N.A N.A N.A. 250x400 250x400

No of Panels 4 4 4 4 4 4

Ec, Mpa 27386 27386 27386 27386 27386 27386

Mass of ContainerDead+Water, kg 206652 872190 1610841 3547402 531120 722700

* Intze shape container- Clear diameter of wall/bottom dome


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three with different sizes of haunches provided as mentioned earlier. No haunches are provided for bottom beams.

For heavy lumped mass resting at top of relatively slender staging, buckling of staging can be critical. Hence in present studies a buckling analysis in a software is carried out and the results are presented.

MAtHeMAtICAL MOdeLLIng Of StRuCtuReIt is proposed to use ratio of 1V:3H, with changing depth of haunch in the present studies. Haunches are provided for all braces at all levels in vertical plane only as shown in Figure 2.

Haunches are considered only for braces of staging. For modeling non prismatic members, Macleod suggests, elements that take account of variation of cross sectional geometry is better option rather than mesh of uniform elements with properties considered at center of element [21]. For modeling in a software, each brace is subdivided into three segments; two non-prismatic haunch sections, one at each ends and one middle prismatic section. The variation of the bending stiffness can be assumed as linear, parabolic, or cubic for the tapered portion. The axial, shear and torsional properties will vary linearly over each segment. Tena Colugna et al observed that using cubic variation of bending stiffness, reasonable approximation even up to 88% can be achieved as compared to linear variation [22]. Hence, cubic variation of bending stiffness for modelling tapered portion of the haunches is used in these studies. Even though contribution of reinforcement is not taken into consideration for analytical modeling it is presumed that detailing of reinforcement for haunches is, as shown in Figure 3 or similar for haunch section to be effective. Columns and bottom ring beams are modeled as line elements with prismatic cross-sections.

A horizontal load of 100 kN is applied at top of staging and corresponding deflection at various brace levels in staging are noted. Maximum drift is worked out and it is compared. Lateral flexural stiffness of staging is calculated as 100/Δ where Δ is deflection at top of staging.

Buckling analysis for the same staging subjected to dead plus water load is done by a software. Stiffness considered for columns and braces is as for unstressed state and eigenvalue tolerance is tending to zero. While for analysis number of buckling modes considered are six, result of only primary mode is presented.

Dynamic properties such as fundamental time period, top deflection, variation in inter story drift, lateral stiffness of staging in flexure and buckling factor are compared for the various haunch sizes. Analysis is performed for all types of staging given in Table 1. The results are presented here for four and twelve columns staging with tank full and tank empty conditions. Results are shown in Figures 4a, 5a and 6a for four column staging (Figure 1a) and Figure 4b, 5b and



6b for twelve columns grid type staging (Figure 1f). Figure 4 suggest following observations.

Fundamental time period of tank reduces with addition of haunches. For tank full case, this reduction is from 9% to 25% for staging with four columns. For tank empty case the corresponding figures are 10% to 24% respectively as depth of haunch increases from 100 mm to 300mm. It is 12% to 31 % for staging with six columns, 13% to 28 % for staging with eight columns, and 11 to 24 % for staging with twelve columns respectively. For grid type staging with nine columns reduction in fundamental period is from 13% to 28 %. For staging with twelve columns the variation is 12% to 26 % for tank full case and 11% to 25% for tank empty case respectively. The decrease in time period is mainly due to increase in stiffness of the overall frame because of addition of haunches.

From Figure 5 it is noted that deflection at top of staging considerably reduces with addition of haunches. This reduction is from 19% to 44 % for staging with four columns, 24% to 52 % for staging with six columns, 24% to 47 % for staging with eight columns, and 22% to 46 % for staging with

twelve columns. For grid type staging with twelve columns reduction in deflection is 22% to 46 %, while for staging with nine columns reduction in deflection is 24% to 45 %. Inter story drift also gets considerably reduced due to addition of haunches. This reduction is from 10 to 30 % for staging with four columns, 15 to 36 % for staging with six columns, 15% to 32 % for staging with eight columns, and 13 to 28 % for staging with twelve columns respectively. For grid type staging with nine columns reduction in drift is 16% to 31 % and 11% to 30 % for staging with twelve columns.

Stiffness of frame should have been constant as per standard literature and code referred above, keeping size of column as constant for all the four cases considered for each type of staging [15,16]. However as per analysis performed, with addition of haunches to braces, keeping column size constant, stiffness of entire frame has increased considerably in each case. This study thus clearly highlights the importance of haunches to braces in overall stiffness of frame. The increase in stiffness varies from 23% to 77 % for staging with four columns. The corresponding values for six, eight and twelve


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columns on periphery of staging are 28% to 90 %, 30 to 88 %, and 25% to 73 % respectively. For grid type staging the increase in stiffness increases as much as 30% to 80 % and 28% to 84 % for nine columns and twelve columns staging respectively.

Buckling factor can be defined as ratio of maximum load carried by the column or structure on the verge of buckling, to actual load it is designed to resist. It governs the slenderness of columns and ultimately the overall stability or vulnerability of staging of tank. Results of buckling analysis from Figure 6 indicates that, buckling factor increases from 23% to 80 % for staging with four columns and tank full. For tank empty case the corresponding values are 23% to 75%. For staging with six columns the variation is 30% to 96 %, 30% to 87 % for staging with eight columns, and 25% to 75 % for staging with twelve columns.

For grid type staging also it increases from 30 to 75 % for nine columns staging and 29% to 83% for twelve column staging for tank full case. For tank empty case the increase is 28% to 73% for twelve columns staging.

Design forces namely base shear, additional axial force in column due to horizontal load at foundation level as well as at top of staging, bending moment in column at top of foundation and at top of staging are compared and presented in Figures 7a to 11a for four columns staging and Figures 7b to 11b for twelve columns staging. As the structure is symmetrical and columns are circular biaxial moments in columns due to earthquake in X and Y directions are converted to uniaxial moments by SRSS. For twelve columns grid type staging generally internal and external columns have different cross sections owing to different gravity loads on them. External columns resist additional axial force at top of foundation and top of staging more than the internal columns. While internal columns resist more flexure compared to external columns. Hence axial force results are presented for external columns, while bending moments at foundation and top of staging are given for internal columns.

Observations from Figure 7 shows that base shear, an important parameter of dynamic analysis increases as the stiffness of frame is increased with addition of haunches. This increase in seismic base shear varies from 11% to 35 % for staging with four columns for tank full case. For tank



empty case it varies from 11% to 36%. The variation is 14% to 44 % for staging with six columns, 14% to 38 % for staging with eight columns, and 12% to 32 % for staging with twelve columns. For grid type staging with twelve columns, base shear has increased from 14 to 38 % for tank full case and 13% to 43% for tank empty condition. Variation is 15% to 35 % for nine columns staging respectively.

Figure 8 compares additional axial force in columns at top of foundation. For twelve columns staging, external columns carry more of this force than central columns. Results of external columns are only presented.

Because of horizontal force applied on staging, the leeward columns get additional compressive load while windward columns are subjected to uplift. Due to addition of haunches this axial compressive force at base has increased for all cases with variation of 13 to 42 % for four columns staging with tank empty as well as tank full case. For twelve columns grid type staging the corresponding values are 16% to 48%. For staging with peripheral columns six, eight and twelve increase in axial force is in the range of 20% to 55 %. For nine

columns grid type staging base shear has increased from 15% to 40 %.

Moment at footing top in column increases with addition of haunches. They are compared in Figure 9.

For tank full case, base moment in columns increases from 1% to 7 % for 4 columns staging with columns placed on periphery. For tank empty case increase in moments is from 1% to 8%. Practically same values are observed for six, eight and twelve columns staging. For grid type staging with nine and twelve columns and tank full, this increase in base moment is from 3% to 12%. The corresponding values for tank empty are 4% to 16%.

Additional axial force at top of staging is compared in Figure 10.

Axial compressive force at staging top due to horizontal force increases from 1% to 5% for staging with four columns on periphery (Figure 10). This is valid for both tank full and tank empty cases. However, for grid type staging (Figures 1e and 1f) 9% to 30 % increase in axial force is observed for both


TECHNICAL PAPER

full and empty conditions, as increasing size of haunches are provided to braces. Moment in column at top of staging, increases with addition of haunches. Respective values for tank empty and full are compared in Figure 11.

Moment in column at top of staging due to seismic load has practically remained same for all cases with or without haunches for columns on periphery. For grid type staging there is increase in the moment from 1% to 5 % for staging with nine columns and 3 to 10 % for staging with twelve columns. This is seen for both tank full and empty cases.

The most obvious effect of addition of haunches is in the response of braces in staging of water towers. Moments are worked out in braces at all the three levels viz. ground, first brace and top brace level at centre of column. However design codes suggest that moments at face of support of columns or at face of haunches can be considered for design, instead of centre line values [23,25]. Aranda et al have reported that haunched beams develop an arch mechanism that improves global shear behaviour in comparison with the well-known shear behaviour of prismatic elements [24]. Further unlike building, braces in water tank are not basically subjected to gravity loads except self-weight, but mainly instrumental in

resisting horizontal loads. Hence critical values of bending moments at face of haunches for braces (Figure 12a) are calculated and compared with no haunch case in Figures 13a, 14a and 15a for four columns staging and Figures 13b, 14b and 15b for twelve columns staging respectively. For no haunch case, the moment values are calculated at face of column (Figure 12b).

Figure 13 compares critical bending moment in ground level brace for four columns and twelve columns staging in tank empty and tank full condition.



It is observed that for four columns staging, critical moment in ground brace calculated at the face of haunch reduces marginally from 1% to 8% as depth of haunch increases. This is valid for both tank full as well as tank empty case. For twelve columns grid type staging, the reduction in ground brace critical moments is substantial from 2% to 30% for tank full and empty case. Figure 14 presents relevant values for design bending moment in first brace for four and twelve columns staging.

From Figure 14, for first brace the reduction in critical moments is from 1% to 14% for four column staging for tank empty as well as full case. For twelve column grid type staging, the reduction in brace moments is from 5% to 40%. Similar results are observed for staging with peripheral columns six, eight and twelve in numbers. The comparison for top level brace is done in Figure 15.

Figure 15 indicates that design moments in top brace reduce from 2% to 9% for four column staging. For twelve column grid type staging, the reduction in brace moments is substantial from 2% to 35% for both tank empty and tank

full cases. Similar results are observed for staging with peripheral columns six, eight and twelve in numbers.

From the above studies it is also observed that, torsional moment in all the cases studied is very small, to the tune of 0.25 to 0.5 % of maximum in plane bending moment. Hence, for all practical purposes it can be safely neglected for analysis as well as design purposes.

COnCLuSIOnSThe salient conclusions due to addition of haunches to water tank staging can be summarized as follows.

As stiffness of staging increases, top deflection of staging, drift and fundamental period decreases as depth of haunch increases.

Buckling factor of staging increases with increase in haunch depth.

Base shear, additional axial force in column and bending moment in column at top of footing increases with increase in depth of haunch.

i.

ii.

iii.


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Additional axial force and bending moment at top of staging, for column increases with increase in depth of haunch.

Design bending moments in all level braces are substantially reduced as depth of haunch increases.

From the above studies, it can be observed that little increase in shuttering cost of haunches will result in substantial saving of steel as well as concrete along with a more safe and durable structure. It is suggested to perform analysis considering the effect of haunches.

References

Akgiray V , Barbarose G & Erdik M The 1999 Marmazara Earthquakes in Turkey Research Report Bogazici University 2003,Istanbul Turkey.Haiti’s Cholera Deaths Increase Al Jazeera English 31 December 2010.Jain S K & Sameer U S Bridge Struct Engr 23(1) (1993)1-16Rai D C Earthquake Spectra 18 (2002) 745-760.ACI 371R – 98 (2003) – Guide for the Analysis, Design and Construction of Concrete – Pedestal Water Towers – 2003.Indian Standard Code of practice for – Criteria for Design of RCC Staging for Overhead Water Tanks – IS: 11682 – 1985.S.J. Thurston- Cyclic Load Testing Of Three Haunched Reinforced Concrete Beam-Column Assemblies Bulletin Of The New Zealand National Society For Earthquake Engineering, Vol. 15, No. 3, September 1982.1Alexander G TSONOS Lateral Load Response Of Strengthened Reinforced Concrete Beam-To-Column Joints 12 WCEE 2000. pp1225Liu Lixian et al Strengthening of Fire-damaged Columns by Cross-sectional Enlargement: Seventh LACCEI Latin American and Caribbean Conference for Engineering and Technology (LACCEI’2009) Venezuela.Murat Engindeniz, Lawrence F. Kahn, and Abdul-Hamid Zureick Repair and Strengthening of Reinforced Concrete Beam-Column

iv.

v.

1.

2.

3.4.5.

6.

7.

8.

9.

10.

Joints: State of the Art ACI Structural Journal, V. 102, No. 2, March-April 2005.Vu Hong Nghiep - Shear Design of Straight and Haunched Concrete Beams without Stirrups Thesis Submitted for PhD. At Hamburg University, Germany 2010Handbook of frame constants: Beam factors and moment coefficients for members of variable section (1958). Portland Cement Association, Skokie, Illinois.The Applications of Moment Distribution (1978) The Concrete Association of India Bombay.Tena-Colunga, A. (1996). Stiffness formulation for nonprismatic beam elements. ASCE Journal of Structural Engineering 1996.122:12, 1484-1489Explanatory Handbook On Codes, For Earthquake Engineering (IS : 1893-1975 AND IS : 4326-1976) SP22:1982.P. Dayaratnam – Design of Reinforced Concrete Structures. – Oxford and IBH Publishing Co. – 1983.Sameer, S. K. Jain – Lateral load Analysis of frame stagings for Elevated Water Tanks Jou. Of Str. Engg. ASCE May 1994. Indian Standard Code of practice for – Criteria for Earthquake Resistant Design of Structures – IS: 1893 -1984.Reaffirmed 1998.Indian Standard Code of practice for – Criteria for Earthquake Resistant Design of Structures – IS: 1893 -2002 Part 2 Draft Code.Refresher Course in Analysis Design and Optimization of Water Tanks Intze Type (1981) Visvesvaraya Regional College of Engineering Nagpur 10. Second Edition Macleod I.A. – Modern Structural Analysis Modelling process and guidance. Thomas Telford First Edition 2005.Tena-Colunga, A et al (2012) Lateral Stiffness of Reinforced concrete Moment frames with Haunched Beams 15 WCEEE Lisboa.Indian Standard Code of practice for – Plain and Reinforced Concrete – IS: 456 -2000 fourth Revision.H I A Aranda and A Tena-Colunga (2008) Cyclic Behavior of Reinforced Concrete Haunched Beams failing in Shear.14 WCEE Beijing China.BS EN 1992-1:1-2004 Euro code Design of Concrete Structures –Part 1 General Rules and rules for Building

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12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

Abhay Khandeshe holds an M.Tech. in Structural Engineering from Government College of Engineering Pune; pursuing his Doctorate Research at Visvesvaraya National Institute of Technology, Nagpur. He is a consulting engineer for more than 30 years in the field of water retaining structures including ground supported and elevated tanks, water and sewage treatment plants, irrigation structures. He is panel consultant for various State and National level Government and Semi Government organizations. His current interests include repair and rehabilitation of structures and earthquake engineering.

Dr. R.K. Ingle is Professor in the Department of Applied Mechanics, Visvesvaraya National Institute of Technology, Nagpur. His research interest is bridges, water tanks, towers and multi storeyed buildings.



An experimental study on the strength characteristics of slurry infiltrated fibrous ferrocement with partial

replacement of natural sand by manufactured sand

G.S. Sudhikumar, Mohan Kumar D.D. and Meghana N. Kumar


The concrete composites play an important role in the field of concrete. The addition of fibers to concrete enhances the strength properties and ductility characteristics. Ferrocement is light weight and versatile material having high cracking, ductility and fatigue resistance and is additionally impermeable to make it far superior than reinforced concrete. It is used for prefabricated residential units, marine and industrial structures. Slurry infiltrated fiber concrete (SIFCON) could be considered as a special type of fiber concrete with high fiber content. The matrix consists of cement slurry or flowing cement mortar. This composite material withstands blast loading and can be used for pre-stressed concrete beams and safe vaults. Slurry infiltrated fibrous ferrocement (SIFF) is a combination of SIFCON and ferrocement and can overcome the limitations of latter. SIFF can be used for the structures like runways in aerodromes, industrial floors etc. This paper deals with an experimental investigation on the strength characteristics of SIFF with partial replacement of natural sand with peak percentage of fiber on the strength characteristics of slurry infiltrated fibrous ferrocement. The results indicated that with 1.5% of steel or galvanized iron fiber and 1% of polypropylene fiber , and with 60% replacement of natural sand by manufactured sand for steel or galvanized iron fiber and 50% replacement of natural sand by manufactured sand for polypropylene fiber yields higher compressive strength, a higher energy absorptive material which can result in higher flexural strength, toughness indices and impact strength.

Keywords: Ferrocement; fibers; fiber reinforced concrete; slurry infiltrated fibrous ferrocement; steel fiber; galvanized iron fiber; polypropylene fiber; welded mesh; chicken mesh; compressive strength; flexural strength; impact strength.

1. INTrODuCTIONToday, concrete fiber composite is the most promising and cost effective material used in the construction. Many researchers have shown that the addition of small closely spaced and uniformly dispersed fiber to concrete transforms the brittle cement composite into a more isotropic and ductile material called fiber reinforced concrete (FRC)[1].

In RCC the strength makeup is in the direction of reinforcing bars. In a structure where the tensile stresses are omni-directional, the reinforcing becomes difficult and expensive.

FRC which is made up of thin fibers dispersed randomly in all the directions impart strength to its entire volume.

FRC can be used in the preparation of various precast building units such as cladding sheets, window frames, roofing units, floor tiles, manhole covers and advanced applications in highway pavements, air field, machine foundations, industrial floorings, bridge deck overlays, sewer pipes, earthquake resistant structures and explosive resistant structures (like MX missile silos etc)[2].

Even though the performance of FRC in pavement, air fields, industrial floors and machine foundations is satisfactory, it


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has some limitations. It cannot be employed where high impact, vibration, wear and tear are expected. Many problems have to be faced during the construction of FRC, especially when the quantity of fiber used is more. The fiber should be dispersed uniformly in concrete for being effective. The fibers if put in bulk along with other ingredients do not disperse, but nest together and is called balling effect. The balling effect can be reduced to some extent by mixing the fibers and other ingredients in dry form and then adding water. The fibers present in the concrete may block the discharge port. Since the flow of FRC is low, the FRC has to be placed near to the place where it is to be used finally. Its spreading with rakes and spades is difficult and laborious. With compaction fibers realign, such that they tend to concentrate more near the surface. Therefore the compaction has to be controlled [3].

Similar to FRC, the ferrocement has also many advantages and its applications are rapidly increasing in the precast construction industry. Ferrocement make use of different types of steel meshes for its construction. Ferrocement also suffer from limitations. It cannot be employed where high impacts, vibrations, wear and tear are expected. The strength of the ferrocement increases with the increase in steel content. But when the reinforcement is more, the mortar cannot be easily forced inside without forming voids. Thus strength of ferrocement reduces [7].

The fibrous ferrocement, which is a combination of fiber reinforced concrete and ferrocement, can overcome all the above said limitations to some extent and can be employed with assurance where high impacts, vibrations, wear and tear are expected. In this new material the advantage of both ferrocement and fiber reinforced concrete are combined. The fibrous cement is becoming a promising material for bridge overlays and industrial floorings where high impacts, high vibrations and high wear and tear are expected. The reinforcements used in fibrous ferrocement are of three kinds. The first type reinforcement is welded mesh where smaller diameter bars (approx. 12 G) are kept closely in both directions and are spot welded. This mesh gives stability and shape to the structure. The second type reinforcement is chicken mesh. This is mesh of similar wires (approx 20G) which are interwoven to different openings. The spacing between the wires of chicken mesh is small. This mesh mainly distributes the stresses evenly and the cracks will be minimized. The third type of reinforcement is fiber. The fibers may be of steel, carbon, glass, polypropylene, GI etc. These fibers act as crack arresters and are randomly distributed in the concrete.

Depending upon the shape required, the cage is prepared out of welded mesh and chicken mesh. The cage can be prepared by tying the chicken mesh over the welded mesh at regular intervals by using binding wires. The calculated quantities of fibers are placed in the mould. The mortar is then infiltrated into the mould to form SIFF [4].

2. MaTerIalS aND MeThODMain objective of this experimentation is to study the strength characteristics of slurry infiltrated fibrous ferrocement with peak percentage of different of fibers with varying percentage of replacement of natural sand by manufactured sand [5]. The fibers considered for the study are steel fiber (SF), galvanized iron fiber (GIF) and polypropylene fiber (PPF). Fiber content used for steel, GI is 1.5% and a polypropylene fiber was 1%. The aspect ratios of steel and GI fibers used was 25, and that of polypropylene fiber was 1600. Different strength parameters considered for study are compressive strength, flexural strength and impact strength.

Ordinary Portland cement of 43 grade and locally available sand (passing 1.18 mm and retained on 150 micron IS sieve) with specific gravity 2.64 was used in the experimentation. To impart additional workability a super plasticizer (Conplast SP 430), 1% by weight of cement was used. The welded mesh (WM) used in the experimentation was square opening of 25 mm x 25 mm of 20 gauge. The chicken mesh (CM) used was having a hexagonal opening with 0.5 mm diameter. The cement mortar with a proportion of 1:1 was used with a water cement ratio of 0.45.

The required size of welded mesh and chicken mesh were first cut according to the mould sizes for compression, flexural and impact tests. The chicken mesh was tied to the welded mesh using binding wires at regular intervals. This forms the cage (1WM + 1CM).

Cages were prepared by tying the chicken mesh layer to welded mesh at regular intervals by using binding wire. The prepared cages were placed in the moulds which were oiled. Cement –sand slurry was prepared with a mix proportion of 1:1 with a w /c ratio of 0.45, and a superplasticizer dosage of 1% (by weight of cement). For steel and GI fibers , initially a small quantity of slurry (10 mm) was poured into the mould and then the respective cages were placed in the mould and then the fibers were placed in the mould and later on the slurry was infiltrated up to the brim level and was lightly compacted using the table vibrator. Whereas for polypropylene fibers, fibers were initially dispersed in the dry cement-sand mortar and then water of required amount was added, after placing the cages, slurry was filled into the mould and then lightly compacted. Then the moulds were



Table 1. Compressive strength test results of slurry infiltrated fibrous ferrocement using natural sand with steel, GI and polypropylene fiber.

Percentage additionof fiber

SIFF with steel fiber SIFF with GI fiber SIFF with polypropylene fiber

Compressive strength(MPa)

Percentage increaseof compressivestrength w.r.t

ref mix

Compressivestrength(MPa)


ref mix

Compressivestrength(MPa)


ref mix

0(Ref.mix) 19.33 - 19.33 - 19.33 -

0.2 26.00 34.51 21.18 9.57 22.67 17.28

0.4 26.89 39.11 22.66 17.23 25.77 33.32

0.6 28.89 49.46 24.22 25.30 27.99 44.80

0.8 30.88 59.75 25.99 34.45 30.66 58.61

1.0 32.89 70.15 27.48 42.16 32.67 69.01

1.5 36.00 86.24 34.67 79.36 28.52 47.54

2.0 33.56 73.62 31.55 63.22 27.11 40.25

covered with wet gunny bags for 12 hours. After 12 hours, the specimens were demoulded and kept in water for 28 days curing. For compressive strength, specimens of dimensions 150 x 150 x 150 mm were cast. For flexural strength, specimens of dimensions 100 x 100 x 500 mm were cast. For impact strength, specimens of diameter 152 mm and thickness 63.5 mm were cast. The specimens were demoulded after 24 hours of casting and specimens were transferred to curing tank for 28 days. After 28 days of curing, they were taken out of water and were tested for their respective strengths.

3. TeST reSulTS

3.1 Effect of varying percentages of different fibers on SIFF using natural sand

3.1.1 Test results of compressive strength [8].Compressive strength test results of slurry infiltrated fibrous ferrocement using natural sand with varying percentages of steel fiber; GI fiber and polypropylene fiber are tabulated in Table 1. The variation in the compressive strength is represented graphically in Figure 1.


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3.1.2 Test results of flexural strength [9].Flexural strength and toughness indices test results slurry infiltrated fibrous ferrocement using natural sand with varying percentages of steel fiber; GI fiber and polypropylene fiber are tabulated in Table 2. The variation in the flexural strength and toughness indices are represented graphically in Figures 2 and 3.

3.1.3 Test results of impact strength [6].Impact strength test results slurry infiltrated fibrous ferrocement using natural sand with varying percentages of steel fiber; GI fiber and polypropylene fiber are tabulated in Table 3. The variation in the impact strength is represented graphically in Figure 4.

Table 2. Flexural strength and toughness indices of slurry infiltrated fibrous ferrocement using natural sand with steel, GI and polypropylene fiber.

Percentage of fiber added



Percentage increase

of flexural strength w.r.t ref

mix

Toughness indices


Percentage increase of

flexural strength

w.r.t ref mix

Toughness indices



flexural strength

w.r.t ref mix

Toughness indices

I5 I10 I5 I10 I5 I10

0(Ref. mix) 5.33 - - - 5.33 - - - 5.33 - - -

0.2 6.67 25.14 4.83 - 6.08 14.07 3.25 - 5.67 6.38 3.11 -

0.4 7.58 42.21 5.80 - 7.08 32.83 5.66 12.67 6.17 15.76 5.22 -

0.6 8.92 67.35 6.50 13.50 7.67 43.90 6.33 13.33 7.58 42.21 5.87 -

0.8 10.16 90.62 7.20 14.80 8.58 60.98 6.88 14.88 8.33 56.29 6.28 -

1.0 10.83 103.19 7.33 16.00 9.59 79.92 7.14 16.30 9.48 77.86 6.82 -

1.5 12.67 137.71 7.50 17.50 10.58 98.50 7.23 16.61 8.67 62.66 6.90 -

2.0 9.58 79.74 8.00 18.33 8.42 57.97 7.33 17.33 7.08 32.83 7.11 -



3.2 Discussion on test result

Following observation was made with reference to the effect of varying percentage of fibers on strength characteristics of slurry infiltrated fibrous ferrocement using natural sand.

It is clear from the test result that the compressive strength, flexural strength and impact strength of slurry infiltrated fibrous ferrocement using natural sand goes on increasing up to 1.5% addition of steel and GI fiber there after that strength decreases. A higher compressive strength of 36 Mpa and 34.67 Mpa (Table 1), flexural strength of 12.67 Mpa and 10.58 Mpa (Table 2), impact strength of 22024.73 N-m, 27182.47 N-m and 19435.80 N-m, 25499.00 N-m (Table 3) for the first crack and final failure respectively. In other words, the percentage increase in compressive strength were to be 86.24%, 79.36% (Table 1), flexural strength were to be 137.71%, 98.5% (Table 2) and impact strength were to be 221.16% , 296.371% and 183%,271.82% (Table 3) for the first and final failure respectively for steel and GI fiber. The toughness indices I5 and I10 for 1.5% steel and GI fiber were found to be 7.5, 17.5 (Table 2) and 7.23, 16.61 (Table 2) respectively.

Table 3. Impact strength of slurry infiltrated fibrous ferrocement using natural sand with steel, GI and polypropylene fiber.Percentage

of fiber added


Impact strength required to cause

(N-m)


impact strength w.r.t

ref mix

Impact strength

required to cause(N-m)

Percentage increase of impact

strength w.r.t ref mix

Impact strength required to

cause(N-m)


impact strength w.r.t ref mix

First crack

Final failure

First crack

Final failure

First crack

Final failure

First crack

Final failure

First crack

Final failure

First crack

Final failure

0(Ref.mix) 6857.80 7595.20 - - 6857.80 7595.20 - - 6857.80 7595.20 - -

0.2 11756.40 14402.60 71.43 110.02 10005.70 13338.70 45.90 94.50 7339.33 9871.06 7.02 43.94

0.4 15015.33 19277.53 118.95 181.10 10988.80 14746.00 60.24 115.03 8362.80 12241.20 21.95 78.50

0.6 17385.47 20038.40 153.51 192.20 14510.30 18314.60 111.59 167.06 10295.27 13897.60 50.12 102.65

0.8 19506.47 21580.33 184.44 214.68 15991.60 20233.60 133.19 195.05 12268.13 15251.00 78.89 122.39

1.0 20907.00 25458.73 204.86 271.24 17513.40 23728.20 155.38 246.00 13237.73 16234.07 93.03 136.72

1.5 22024.73 27182.47 221.16 296.37 19435.80 25499.00 183.41 271.82 11837.20 12126.73 72.61 72.61

2.0 15809.87 17015.13 130.54 148.11 16186.90 20072.00 136.04 192.69 8726.40 11002.27 27.25 27.25

It is clear from the test result that the compressive strength, flexural strength and impact strength of slurry infiltrated fibrous ferrocement using natural sand goes on increasing up to 1% addition of polypropylene fiber there after the strength decreases. A higher compressive strength of 32.67 Mpa (Table1), flexural strength of 9.48 Mpa (Table 2), impact strength of 13237.73 N-m, 16234.07 N-m (Table 3) for the first crack and final failure respectively. In other words, the percentage increase in compressive strength were to be 69.01 %( Table 1), flexural strength were to be 77.86 % ( Table 2) and impact strength were to be 93.03%, 136.72% (Table 3) for the first and final failure respectively for polypropylene. The toughness indices I5 for 1% polypropylene fiber were to be 6.82 (Table 3).

The reason for this can be attributed to the fact that the higher percentage fibers will certainly increase the crack resisting capacity of slurry infiltrated fibrous ferrocement using natural sand thus resulting in higher compressive strength, flexural strength with higher ductility and impact strength.

Among the fiber used in slurry infiltrated fibrous ferrocement with natural sand, the performance of steel fiber was found to be good as compared to GI fiber and polypropylene


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fiber. The compressive strength, flexural strength , impact strength and toughness indices of slurry infiltrated fibrous ferrocement using natural sand with steel fibers were higher as compared to slurry infiltrated fibrous ferrocement using natural sand with GI fiber or polypropylene fiber. This is true for all the percentage addition of fiber. This may be due to the higher modulus of elasticity of steel fiber which can resist the load more effectively.

The experimental result clearly indicates that, small addition of fiber into slurry infiltrated ferrocement using natural sand (0% fiber) can enhance the strength characteristics.

3.3 Conclusions

Following conclusions can be drawn based on the study conducted on the effect of varying percentages of fibers on the strength characteristics of slurry infiltrated fibrous ferrocement using natural sand.

The slurry infiltrated fibrous ferrocement using natural sand with 1.5% steel and GI fibers or 1% for polypropylene fibers can exhibit higher compressive strength, increase flexural strength and higher ductility. More than 1.5% fibers in slurry infiltrated fibrous ferrocement using natural sand for steel and GI fibers or 1% polypropylene fibers results in decreased compressive and flexural strength.

1.

Slurry infiltrated fibrous ferrocement using natural sand with 1.5% of steel and GI fibers or 1% polypropylene fibers can exhibit a remarkable improvement in impact strength. More than 1.5% fibers in slurry infiltrated fibrous ferrocement using natural sand for steel and GI fibers or 1% polypropylene fibers results in decreased impact strength.

The performance of slurry infiltrated fibrous ferrocement using natural sand with steel fiber is more pronounced than slurry infiltrated fibrous ferrocement using natural sand with GI and polypropylene fibers.

Small addition of fiber into slurry infiltrated ferrocement using natural sand (0% fiber) can enhance the strength characteristics.

4. eFFeCT OF ParTIal rePlaCeMeNT OF N-SaND BY M-SaND

4.1 Test results

4.1.1 Test results of compressive strength [8]Following Table 4 gives the overall results of compressive strength of slurry infiltrated fibrous ferrocement with partial replacement of natural sand by manufactured sand.

2.

3.

4.

Table 4. Overall results of compressive strength of slurry infiltrated fibrous ferrocement with partial replacement of naturalsand by manufactured sand.

Percentage of N - sand

replaced by M - sand



Percentage increase of compressive strength

w.r.t ref mix



w.r.t ref mix



w.r.t ref mix

0(Ref.mix) 36.00 - 34.67 - 32.67 -

10 36.67 1.86 35.11 1.27 33.33 2.02

20 37.11 3.08 36.00 3.84 34.00 4.07

30 37.78 4.94 37.11 7.04 36.00 10.19

40 38.89 8.03 37.78 8.97 37.56 14.97

50 40.67 12.97 38.44 10.87 39.78 21.76

60 42.67 18.53 41.33 19.21 38.89 19.04

70 42.44 17.89 40.44 16.64 37.78 15.64

80 41.11 14.19 37.78 8.97 36.89 12.92

90 39.78 10.50 36.67 5.77 33.78 3.40

100 38.22 6.17 35.33 1.90 33.11 1.35



The variation in the compressive strength is represented graphically in Figure 5.

4.1.2 Test results of flexural strength [9].Following Table 5 gives the overall results of flexural strength and toughness indices of slurry infiltrated fibrous ferrocement

Table 5. Flexural strength and toughness indices of slurry infiltrated fibrous ferrocement with partial replacement of natural sand by manufactured sand.

Percentage replacement of N-sand by

M-sand




flexural strength w.r.t

ref mix

Toughness indices



flexural strength

w.r.t ref mix

Toughness indices


Percentage increase

of flexural strength

w.r.t ref mix

Toughness Indices

I5 I10 I5 I10 I5 I10

0(Ref. mix) 12.67 - 7.50 - 10.58 - 7.23 - 9.41 - 6.82 -

10 13.00 2.60 7.66 - 10.83 2.36 7.60 - 10.33 9.78 7.21 -

20 13.67 7.89 8.40 - 12.08 14.18 8.16 - 11.41 21.25 7.71 -

30 14.33 13.10 8.67 - 12.75 20.51 8.33 - 12.5 32.84 7.75 -

40 15.25 20.36 8.85 - 13.83 30.72 8.71 - 13.25 40.81 8.11 -

50 16.33 28.89 9.14 - 15.16 43.29 8.83 - 14.41 53.13 8.25 -

60 17.67 39.46 9.42 - 16.42 55.20 9.14 - 13.08 39.00 8.53 -

70 16.00 26.28 9.71 - 15.5 46.50 9.28 - 12.5 32.84 8.85 -

80 14.67 15.79 10.00 - 13.91 31.47 9.67 - 12.16 29.22 9.17 -

90 13.83 9.16 10.40 - 12.00 13.42 9.85 - 11.67 24.02 9.55 -

100 13.41 5.84 10.67 - 11.5 8.70 10.18 - 11.08 17.75 9.67 -

with partial replacement of natural sand by manufactured sand. The variation in the flexural strength and toughness induces is represented graphically in Figures 6 and 7.


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4.1.3 Test results of impact strength [6].

Following Table 6 gives the overall results of impact strength of slurry infiltrated fibrous ferrocement (SIFF) with partial replacement of natural sand by manufactured sand using

Table 6. Impact strength of slurry infiltrated fibrous ferrocement with partial replacement of natural sand by manufactured sand.

Percentage replacement

of N-sand by M-sand



(N-m)



ref mix


(N-m)



ref mix


(N-m)



ref mix

First crack

Final failure

First crack

Final failure

First crack

Final failure

First crack

Final failure

First crack

Final failure

First crack

Final failure

0(Ref.mix) 22024.73 27182.47 - - 18435.87 25499.13 - - 13271.40 16227.33 - -

10 22139.20 27714.40 0.52 1.96 18584.00 25654.00 0.80 0.61 13415.80 16409.13 1.09 1.12

20 22395.07 27492.20 1.68 1.14 18873.53 26327.33 2.37 3.25 13594.60 16900.67 2.44 4.15

30 22543.20 27835.60 2.35 2.40 19102.47 27364.27 3.62 7.31 13917.80 17291.20 4.87 6.56

40 22704.80 28212.67 3.09 3.79 19499.73 27936.60 5.77 9.56 14274.67 18018.40 7.56 11.04

50 22947.20 28320.40 4.19 4.19 19937.40 28111.67 8.14 10.25 14847.00 18718.67 11.87 15.35

60 23149.20 28778.27 5.11 5.87 21391.80 28421.40 16.03 11.46 14362.2 17850.07 8.22 10.00

70 22556.67 28360.80 2.42 4.33 20455.87 28205.93 10.96 10.62 13803.33 17681.73 4.01 8.96

80 22166.13 27822.13 0.64 2.35 19600.73 27741.33 6.32 8.79 13446.47 17008.40 1.32 4.81

90 22132.47 27754.80 0.49 2.11 19169.80 27364.27 3.98 7.31 13426.27 16927.60 1.17 4.32

100 22132.50 27357.50 0.49 0.64 18469.53 26394.67 0.18 3.51 13338.73 16496.67 0.51 1.66

different fibers with different percentages. The variation in the impact strength is represented graphically in Figure 8.



5. DISCuSSION ON TeST reSulTFollowing observation were made with reference to the effect of partial replacement of natural sand with manufactured sand with 1.5% of Steel and GI fiber or 1% of polypropylene fiber on the strength characteristics of slurry infiltrated fibrous ferrocement. It is clear from the test result that the compressive strength, flexural strength and impact strength of slurry infiltrated fibrous ferrocement goes on increasing up to 60 % replacement of natural sand by manufactured sand for steel and GI fiber and there after strength decrease. A higher compressive strength of 42.62 Mpa and 41.33 Mpa (Table 5), flexural strength of 17.67 Mpa and 16.42 Mpa (Table 5), impact strength of 23149.20 N-m, 28778.27 N-m and 21391.80N-m, 28421.40 N-m (Table 6) for the first crack and final failure respectively. In other words, the percentage increase in compressive strength were to be 18.53%, 19.21% (Table 4), flexural strength were to be 39.46% , 55.20% (Table 5) and impact strength were to be 5.11% , 5.87% and 16.03%, 11.46% (Table 6) for the first and final failure respectively for steel and GI fiber. The toughness indices I5 for 60 % replacement of natural sand by manufactured sand for steel and GI fiber were found to be 9.42 and 9.14 (Table 5) respectively. It is clear from the test result that the compressive strength, flexural strength and impact strength of slurry infiltrated fibrous ferrocement goes on increasing up 50 % replacement of natural sand by manufactured sand for polypropylene fiber and there after the strength decreases. A higher compressive strength of 39.78 Mpa (Table 4), flexural strength of 14.41 Mpa (Table 5), impact strength of 14847.00 N-m, 18718.67 N-m (Table 6) for the first crack and final failure respectively. In other words, the percentage increase in compressive strength were to be 21.76 %( Table 4), flexural strength was to be 53.13 %( Table 5) and impact strength were to be 11.87%, 15.35% (Table 6) for the first and final failure respectively for steel and GI fiber. The toughness indices I5 for 50 % replacement of natural sand by manufactured sand for polypropylene fiber were found to be 8.25 (Table 5) respectively.

The reason for this can be attributed that the higher percentage fiber will result in proper interlocking thus resulting in dense slurry infiltrated fibrous ferrocement and also certainly enhance the crack resisting capacity.

6. CONCluSIONSFollowing conclusions can be drawn based on the study conducted on the effect of varying percentages of fibers on the strength characteristics of slurry infiltrated fibrous ferrocement with partial replacement of natural sand by manufactured sand.

The slurry infiltrated fibrous ferrocement 60 % replacement of natural sand by manufactured sand

1.

for steel and GI fiber and 50 % replacement of natural sand by manufactured sand for polypropylene fiber can exhibit higher compressive strength, increase flexural strength and higher ductility. More than 60 % replacement of natural sand by manufactured sand for steel and GI fiber or 50 % replacement of natural sand by manufactured sand for polypropylene fiber results in decreased compressive and flexural strength.

It is observed that there is consistence increase in the strength of slurry infiltrated fibrous ferrocement by partial replacement of natural sand by manufactured sand. The sharp edges of the particles in the manufactured sand provide better bond with cement than rounded particle of natural sand resulting in higher strength up to optimum replacement.

60 % replacement of natural sand by manufactured sand for steel and GI fiber and 50 % replacement of natural sand by manufactured sand for polypropylene fiber show optimum reaction with optimum filler capacity.

Acknowledgements

The authors would like to thank Dr. D.S. Suresh Kumar, Director, for their encouragement throughout the work. Authors are also indebted to management authorities of the college and parents of the authors for their whole hearted support, which boosted the moral of the authors. The authors are also grateful to all the staff for their encouragement.

References

Yousry B I Shaheen , Mohamed A Safan, Abdalla M A “StructuralBehavior of Composite Reinforced Ferrocement Plates”, ISSRES / Concrete Research Letters, Vol. 3(3), September. 2012, pp. 477-490.Vikrant S Vairagade, Kavita S. Kene and Tejas R Patil “Comparative Study of Steel Fiber Reinforced over Control Concrete”, International Journal of Scientific and Research Publications, Vol. 2, Issue 5, May 2012, ISSN 2250-3153.Jimmy Susetyo, Paul Gauvreau, and Frank J. Vecchio “Effectiveness of Steel Fiber as Minimum Shear Reinforcement”, ACI Journal, Vol. 108 , Issue 4, Jan 2011, pp. 488-496.Sudarsana Rao H,. Ramana N.V and. Gnaneswar K “Behaviors of Restrained SIFCON Two Way Slabs”, Asian Journal of Civil Engineering (Building and Housing), Vol. 10, No. 4 (2009), pp. 427-449.Priyanka A. Jadhav and Dilip K. Kulkarni “Effect of replacement of natural sand by manufactured sand on the properties of cement mortar” , International Journal of Civil and Structural Engineering, Vol. 3, No. 3, 2013.Ernest K. Schrader “Impact Resistance and Test Procedure for Concrete”, ACI Journal, Vol. 78, Issue 2, Jan 1981, pp. 141-146Perumalsamy N. Balaguru and Surendra P. Shah a Text book named “Fiber-reinforced cement composites”, Illustrated Edition, McGraw-Hill, 1992.______Specification for coarse and fine aggregates from natural sources for concrete, IS 383:1970, Bureau of Indian Standards, New Delhi, India. ______Methods of test for strength of concrete, IS 516:1959, Bureau of Indian Standards, New Delhi, India.

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Professor G.S. Sudhikumar PhD holds a doctorate in civil engineering from Jawaharlal Technological University, Hyderabad. He is Professor and Head, Department of Civil Engineering, Channabasaveshwara Institute of Technology, Gubbi, Karnataka, India. He has over 24 years of teaching experience in various capacities. His main research interests are fiber reinforced concrete and slurry infiltrated ferrocement. He has published number of papers in peer-reviewed journals, national and international conferences.

Mohan Kumar D.D holds a B.E from Visveswaraya Technological University, Belagavi, Karnataka. He is a QA/QC Engineer at Al Jassra Readymix, Doha, Qatar. His research interest includes strength and durability characteristics of concrete and concrete quality control.

Meghana N. Kumar holds a B.E from Visveswaraya Technological University, Belagavi, Karnataka. She is a Quantity Surveyor at Somat Infrastructure Pvt Ltd, Bengaluru. Her research interest includes high performance concrete and recycled aggregate concrete and green concrete.

S t a t e m e n t a b o u t o w n e r s h i p p a r t i c u l a r s a b o u t n e w s p a p e r ( ' T h e I n d i a n C o n c r e t e J o u r n a l ' ) FORM IV

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I, Ashish Patil, hereby declare that the particulars given above are true to the best of my knowledge and belief.Dated : March 1, 2016 Ashish Patil

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DISCUSSION FORUM DISCUSSION FORUM

Effect of weak and soft storeys on seismic performance of reinforced concrete frames with unreinforced brick infills

DiscussionbyR.Subramaian

ReplybyNeelimaPatnalaandR.PradeepKumar

READER’SQUERYDear Sir,

This has reference to your paper titled ‘Effect of weak and soft storeys on seismic performance of reinforced concrete frames with unreinforced brick infills’ authored by Patnala V.S. Neelima and R. Pradeep Kumar published in the ICJ February 2016 issue (Vol. 90, No. 2, pp. 19-26).

It is mentioned that the type - 3 frame has columns in the ground storey designed for 2.5 times the moments. I would like to know in what way the columns were made different from the other two frames? Were the sizes of the columns increased and upto what extent ?

Regards,

R. SubramanianTandon Consultants Pvt. Ltd., New Delhi.

THEAUTHOR’SREPLYThis has reference to the query raised by a reader. Our replies are given below.

IS 1893:2002, cl.no. 7.10.3 (a) suggests

“The columns and beams of the soft storey are to be designed for 2.5 times the storey shears and moments calculated under seismic loads specified in the other relevant clauses”

In the present study, ground storey columns of Type III frame are designed for amplified forces which lead to increase in cross-section as well as reinforcement in members compared to Type I & Type II.


DISCUSSION FORUM

Table 1. Cross section details of 3 types of framesSl No Type of frame Cross section details

1. Type-I

2 Type II

3 Type III

Columns: CG1, CG2, CG3, CG4, CG5

Columns: CG1, CG2, CG3, CG4, CG5

Column: CG1

Columns: CG2, CG3, CG4, CG5

–– Patnala V.S. Neelima and R. Pradeep Kumar Earthquake Engineering Research Centre (EERC), International Institute of Information Technology, Hyderabad



Performance of polymer modified polypropylene fiber reinforced concrete with low fiber volume fractions

Yuwaraj M. Ghugal


The paper presents the results of an experimental investigation of polymer modified polypropylene fiber reinforced concrete. Various strengths considered for investigation are compressive, flexural, shear, split tensile and bond strength. The type of polymer used is styrene butadiene rubber latex. The fiber volume fraction varies from 0.1 % to 0.3 % at the interval of 0.05 % by weight of cement. The amount of polymer introduced in each mix is 10 % by weight of cement. The water contained in the polymer is included in the total water content of the mix. The influence of polymer and fibers on workability and wet density of fresh concrete has been studied. The effect of dry curing on various strengths of fiber reinforced concrete has been investigated. Other physical properties of this concrete such as dry density, crack width, shear deformations, work done during bar pullout from matrix, and elastic constants have also been investigated. The workability of fiber reinforced concrete is found to decrease with the increase in the fiber content. The improvement in various strengths except in flexural strength is observed in this fiber-polymer concrete system, compared to the normal concrete.

Keywords: Polymer; polypropylene fibers; fiber volume fractions; workability; density; dry curing; strengths; crack width; elastic constants, law of mixtures; PMFRC.

InTrOducTIOnIt is well established that the properties of fiber reinforced cement based composites are dependent on the characteristics of the fiber, the matrix, and the fiber matrix interface. The interaction between the fiber and matrix is the fundamental property that affects the performance of cement–based composites. The fibers contribute to both composite strength and stiffness. The amount and nature of contribution depend on fiber type, fiber volume fraction and matrix properties.

Because of the porous nature of the cement matrix, fiber cement composites tend to crack at a very early stage under load; this reduces the fiber-matrix interfacial bond strength, and the composite invariably fails by fiber pull-out rather than by fiber fracture. The addition of polymer dispersions to the cement matrix improves the workability

of fresh matrix and provides increased strength and stiffness, increased ductility, impermeability and adhesion capacity of material, resistance to cracking strain and increased strength of interfacial bond. Thus the balanced improvements in the mechanical, physical and durability characteristics of the matrix can be achieved according to Hosek [1], Mangat and Swamy [2], Soroushian et al. [3], Ohama et al. [4], Ghugal [5].

Mangat and Swamy [2] investigated the properties of fiber polymer concrete system using different types of polymer dispersions at a constant volume fraction of steel fibers. The effects of dry, wet and dry-wet curing on the strength, stiffness and shrinkage characteristics of polymer modified plain and fiber reinforced concretes have been studied.

Bentur [6] studied the properties of polymer modified steel fiber reinforced mortars and showed that the compressive


TECHNICAL PAPER

strength, flexural strength and spitting tensile strength can be increased by a factor of 4 to 5 relative to plain mortar of similar workability.

Bijen and Jacobs [7], Jacobs and Bijen [8] and Mujumdar et al. [9] have studied polymer addition to matrix for improving the durability of glass fiber reinforced composites. A minimum of 5% polymer solids by weight of composite appears to give some long-term strength improvement.

Wei et al. [10] studied the interface strength in steel fiber reinforced cement based composites using acrylic polymer and a mortar matrix. The addition of 15% polymer by weight of cement resulted in significant increase in the tensile strength of the matrix material, the interfacial bond strength between the matrix and steel fibers, and the energy required for fiber debonding and pullout.

Zellers [11] investigated the performance of concrete composite using high volume fractions of fibrillated polypropylene fibers. The fibers provide excellent ductility.

However, the increase in flexural strength is marginal and the post crack strength is typically less than first crack strength. The addition of fibers resulted in improved toughness characteristics and reduction in plastic shrinkage cracking.

Nutter et al. [12] determined the performance of concrete reinforced with a newly developed polypropylene fiber. The hardened concrete properties determined are compressive strength, flexural strength and average residual strength. A significant increase in the flexural strength and in an average residual strength is obtained.

For volume fraction of polypropylene less than 1%, it has been found by Nanda and Hannant [13] that increases in tensile, flexural, or compressive strengths of concrete are less than 25% and often the strength of composite is less than that of the matrix alone. This is basically due to the low modulus of elasticity of fibers combined with less than the critical volume fraction. However, composite containing 6 % continuous polypropylene film network showed significant increase in the modulus of rupture combined with extensive multiple cracking according to research of Hannant et al. [14].

A comprehensive review of literature on fiber-reinforced cement composites is given by Hannant [15], Beaudoin [16], Balaguru and Shah [17]. A considerable amount of research is currently being carried out on the performance of various fiber reinforced concrete composites; however, the studies on the performance of polymer modified FRC systems are very scant. The development of polymer modified polymeric fiber reinforced concrete composite and its performance under various states of stress is still in its infancy.

In this paper, performance of polymer modified polypropylene fiber reinforced concrete with low fiber volume fractions is evaluated for various strengths of hardened concrete.

ExpErIMEnTal prOGraMMEOrdinary Portland cement having 7 days compressive strength of 43.38 MPa and confirming to IS: 12269 [18] and fine and coarse aggregates confirming to IS: 383 [19] were used. The fineness modulus of sand was 2.61 and those of 10 mm and 20 mm coarse aggregates were 6.57 and 7.40 respectively. Polypropylene fibers having filament diameter 25 μm (micron), length 10 mm, specific gravity 0.9, Young’s modulus 5 GPa, tensile strength 400 MPa and breaking elongation 8 % were used. Styrene Butadiene Rubber Latex having viscosity 300 cps, specific gravity 1.05, percent solids 42 % and pH value 7.5 was used.

nOMEnclaTurE

a, b, c : coefficients of polynomial

Ef : modulus of elasticity of fiber

Efc : modulus of elasticity of fiber reinforced composite

Em : modulus of elasticity of matrix

fcr : flexural strength of concrete

fcu : compressive strength of cube

p/c : polymer-cement ratio

R : coefficient of regression

Vf : volume fraction of fibers, %

η1, η2 : fiber orientation and length efficiency factors, respectively

γ : specific gravity of concrete

δ : slip of rebar during de-bonding

μ : Poisson’s ratio

a, b, c = coefficients of polynomial

Ef = modulus of elasticity of fiber

Efc = modulus of elasticity of fiber reinforced composite

Em = modulus of elasticity of matrix

fcr = flexural strength of concrete

fcu = compressive strength of cube

p/c = polymercement ratio

R = coefficient of regression

Vf = volume fraction of fibers, %

η1, η2 = fiber orientation and length efficiency factors, respectively

γ = specific gravity of concrete

δ = slip of rebar during debonding

= Poisson’s ratio

τ = bond shear stress

++= δδτ (1)

= (2)

Efc = (1 – η1 η2 Vf ) Em + η1 η2 Vf Ef (3)

×= γ

(4)

= + − (5)

= (6)

: bond shear stress



The M-20 grade of concrete having mix proportions 1: 1.85: 1.30: 1.95 i.e., cement: fine aggregate: coarse aggregate (10 mm: 20 mm) with w/c ratio of 0.50 was used throughout the experimental investigation. Fibers were added in dry state of concrete mix and again ingredients were mixed thoroughly. The water modified by 10 % polymer by weight of cement was added to the dry mix and the ingredients mixed thoroughly to obtain the homogeneous, cohesive and workable mix. The mixing time after addition of polymer modified water was kept strictly constant. The water contained in the polymer was included in the total water content of the mix. A water-cement ratio of 0.5 used for normal concrete was modified for polymer modified fiber reinforced concrete (PMFRC) to keep the workability similar to that of control mix.

Cubes of 150 mm size for compressive and bond strengths, cylinders of size 150 mm dia x 300 mm long for split tensile strength, beams of size 150 mm x 150 mm x 700 mm for flexural strength and Push-off specimens of size 150 mm x

150 mm x 450 mm for shear strength were cast incorporating 0 % to 0.30 % polypropylene fibers at the interval of 0.05% by weight of cement. The push off unit used in the present study is shown in Figure 1. For each test, three specimens were cast with and without fibers. Compaction of all the specimens was done using table vibrator to avoid balling of fibers. The specimens of normal concrete were water cured and all the specimens of PMFRC were dry cured for 7 and 28 days at room temperature and were tested on 1000 kN Universal Testing Machine. In all 180 specimens were cast and tested to evaluate the strengths performance. Each value of the results presented in this paper is the average of three test samples. Details of the experimental investigation of PMFRC are given elsewhere [20].

TEsTs cOnducTEd

Universal Testing Machine (UTM) was used as a test set-up for carrying out various tests on hardened concrete. The tests were carried out for the following strength properties, viz,


TECHNICAL PAPER

compressive, flexural, split tensile, bond and shear strengths. Tests were carried out on the push off type specimens to determine the shear deformations, shear strength and shear modulus. The push off specimen was designed to fail in shear at a known plane. To ensure failure of concrete in the shear plane, steel reinforcement was placed away from the shear plane to prevent undesirable failure modes such as flexure, compression, or bearing capacity. Vertical deformations were measured on vertical plane of shear between the grooves over the gauge length of 150 mm. The deformations were noted at known intervals of loading up to failure. Shear stress is calculated as a ratio of shear load to area of shear plane and the shear modulus is calculated as a ratio of shear stress to maximum shear deformation. It is to be noted that the shear strain in this test specimen is same as linear shear deformation.

TEsT rEsulTs and dIscussIOn

Properties of fresh concrete and dry density

The workability of fresh concrete is determined with the help of slump cone test and wet density is obtained by measuring the weight and volume of wet concrete with the help of standard cylinders. It is well known that polymers entrain considerable amount of air during mixing. Since the air entrainment improves the workability of a concrete mix, the water-cement ratios of the polymer modified mixes need adjustment. The water present in the polymer is included in the total water content of the mix. The water-cement ratio of 0.5 was used for the control mix; the water cement ratios of other mixes with fiber and polymer were modified to keep their workability similar to that of the control mix. The results of workability (slump), wet density and dry density of hardened concrete are shown in Table 1. The wet density of polymer modified fiber reinforced concrete (PMFRC)

decreased continuously with the increase in the fiber volume fraction. Similar trend is observed in case of dry density of PMFRC at both ages of dry curing with increase in fiber content. The reduction in density can be contributed to an increase in entrapped air due addition of polymer and fibers during mixing of concrete.

Compressive strength

The compressive strength of concrete was obtained by conducting tests on standard cubes and on “equivalent cubes” of one broken part of a prism specimen after it had been tested for flexural strength. The restraint of the overhanging parts of the equivalent cube may result in slight increase in strength according to Neville [21] whereas BS: 1881- Part 119 [22] and IS: 516 [23] assume the strength of a modified cube to be, on average, 5% greater than that obtained from a standard cube of same size. The results of compressive strength are shown in Table 2. Results indicate that the “equivalent cube” compressive strength is higher than the actual cube strength. The increase in 7 days compressive strength varies from 17% to 31.33% and that for 28 days varies between 12 % and 33% compared to strength of standard cube compressive strength. The increase in strength of “equivalent cube” may be due to the fact that fiber reinforcement improves the ductility of material and hence the adjoining parts of “equivalent cube” play a more important role in supporting a part of the applied load. Also some energy is used in pulling out the fibers from adjoining parts of the “equivalent cube” [2].

At the age of 7 days PMFRC attained 20.15% of increase in compressive strength at 0.3% of fiber volume fraction under dry curing regime compared to that of wet cured normal concrete. However, at 28 days, PMFRC attained the same strength as that of the normal concrete. The

Table 1. Density and slump of polymer modified polypropylene fiber reinforced concrete

Fiber folumefraction

(Vf)

Water / Cement

ratio

Wet density(Kg/m3)

Dry density (Kg/m3)

Slump (mm)

7 days 28 days0.00 0.50 2637 2578 2622 450.10 0.42 2594 2527 2521 550.15 0.42 2572 2502 2496 520.20 0.42 2565 2490 2496 480.25 0.42 2559 2484 2483 420.30 0.42 2543 2480 2471 38

Table 2. Compressive strength of polymer modified fiber reinforced concrete

Fiber volumefractionVf (%)


Equivalent cube

strength (MPa)

% Increase in strength

7 days

28 days

7 days

28 days

7 days

28 days

0.00 22.93 31.55 28.97 40.66 26.34 28.880.10 21.77 28.44 28.59 32.00 31.33 12.520.15 22.66 28.88 29.30 36.00 29.30 24.650.20 24.88 29.18 29.80 36.36 19.78 24.610.25 26.22 30.66 30.43 40.74 16.06 32.880.30 27.55 31.55 32.40 41.77 17.60 32.39



influence of present polymer-fiber system on compressive strength resulted in increase in strength with increased fiber volume fraction with constant content of polymer under dry curing condition as seen from Table 2. The increase in 7 days strength with 0.3% of fiber volume fraction is 26.55 % and that at 28 days is 10.94% compared to the strength of PMFRC at 0.1% of fiber volume fraction. However, this polymer-fiber system in dry curing regime underestimates the results considerably compared to those of normal concrete subjected to wet curing for similar workability. This may be attributed to less amount of polymer content than the optimum required for complete polymerization to enhance the strengthening mechanism of concrete. Also the contribution of fibers to enhance the strength may be inadequate, as low fiber volume fractions are used. Hence further research is required with regards to the polymer and fiber content, under the same curing condition to improve the performance of PMFRC significantly compared to that of normal concrete subjected to wet curing.

Flexural load-deflection, crack width and crack location

The results of cracking load, central deflection, crack width and crack location obtained from four point beam flexure test are summarized in Table 3. The crack width (wcr) was measured on the bottom tension face of the beam using microscopic vernier. The results indicate that the peak flexural load is increased with the increase in fiber content. The increase in central deflection with increase in load is observed at both the ages of dry curing. This showed the increase in ductility of polymer modified fiber reinforced concrete. The inclusion of polymer and fibers into the concrete resulted in decrease in crack width up to 60 % compared to that of wet cured normal concrete. The reduction in crack

width may be attributed to the synergistic influence of the fiber-polymer system in the concrete. All the beam specimens have been failed in flexure within the middle third portion of the beam. All the cracks have occurred in the maximum bending moment zone and their locations from left support are given in Table 3.

Flexural and split tensile strength

The effect of age and curing on flexural strength of PMFRC is studied using four point flexure test on 150 mm x 150 mm x 700 mm prism specimens. The universal testing machine of 1000 kN capacity is used as a test set-up for carrying out this test. The results of first crack flexural strength (modulus of rupture) are shown in Table 4. The tensile splitting strength was determined using cylinders of size 150 mm (dia.) x 300 mm (length) and using broken half of a prism (beam) after it had been tested for flexural strength. The tests were conducted according to standard procedures [24-26]. The results of split tensile strength are presented in Table 4.

The results of flexural strength indicate that the strength of dry cured PMFRC mixes is less than or equal to that of the wet cured normal concrete at both ages of curing. This may be due to the inhibition of hydration process [2], low fiber-matrix interfacial bond strength and low modulus of elasticity of fiber. However, PMFRC subjected to dry curing showed the increase in the flexural and split tensile strength with increase in fiber volume fraction. The maximum increase in 28 days cylinder and prism split tensile strength of PMFRC with 0.3 % of fiber volume fraction is 8.10 % and 12.65 % respectively. The results of cylinder split and prism split tensile strength are in good agreement with each other.

Table 3. Flexural load (P), deflection (∆), crack width (wcr) and crack location in beam

Fiber Volume Fraction (Vf) , %

P, kN

∆, mm

P, kN

∆, mm

wcr , mm Crack location,

mm

7days

7days

28 days

28days

7days

28 days

7days

28days

0.00 21.40 0.33 25.40 0.51 1.00 1.00 269 2330.10 16.50 0.24 22.40 0.37 0.50 0.40 264 2710.15 18.30 0.29 19.00 0.30 0.50 0.50 251 2500.20 19.60 0.30 22.00 0.31 0.53 0.60 230 2310.25 18.40 0.32 19.80 0.31 0.45 0.60 224 2350.30 21.40 0.43 22.30 0.33 0.40 0.50 260 280

Table 4. Flexural and split tensile strengths of polymer modified fiber reinforced concrete

Fiber volumefractionVf (%)


Split tensile strength (MPa)

Cylinder split

Prism split

7 days

28 days

7 days

28 days

7 days

28 days

0.00 3.80 4.51 2.53 3.47 2.59 3.320.10 2.93 3.38 2.75 3.48 2.40 3.340.15 3.25 3.52 2.82 3.50 2.60 3.520.20 3.27 3.91 2.84 3.59 2.72 3.570.25 3.48 3.96 2.86 3.59 2.77 3.570.30 3.80 3.98 2.91 3.75 2.88 3.74


TECHNICAL PAPER

Bond strength

To study the effect of polymer and fibers on interfacial bond strength between the matrix and the reinforcing bar pull-out test was performed according to IS: 2270 [27]. A 16 mm deformed steel reinforcing bar was embedded into the concrete cube at the center up to a depth of 150 mm. The total length of bar was 500 mm. The pull-out tests were performed at a specimen age of 7 days and 28 days. All the specimens were tested up to failure of bar matrix interfacial bond. During the test in progress, slips were measured between the bar and the matrix at regular intervals. The peak load at failure of bond and the maximum slip were recorded. Also the type of failure was observed. All the specimens failed with vertical crack along the embedded length of bar with cracking sound. The results of maximum pull-out load and corresponding maximum slip are given in Table 5.

The results in Table 5 showed the increase in the slip with increase in the pull-out load of dry cured FRC at 7 days up to 0.30 % of fiber volume fraction. However, at 28 days of dry curing the pull-out load increased up to 0.20 % of fiber volume fraction and then decreased up to 0.30 % of fiber volume fraction. The slip corresponding to maximum load was found to be less than that with respect to the decreased load at 28 days.

The bond strength and the pull-out energy (maximum work done during de-bonding of bar and the matrix) have been calculated from the test data and are presented in the Table 6. The bond strength was calculated by dividing the applied load, by the surface area of the embedded length the bar over the nominal diameter of bar. The pull-out work was calculated for the slip at peak load.

The bond strength is found to increase with increase in fiber content. The maximum increase in bond strength obtained at 7 days of dry curing is 5.39 % at 0.30 % of fiber content and that at 28 days is 25.56 % at 0.20 % of fiber content when compared with that of normal concrete. The increase in strength may be due to the improved interfacial bond between the rebar and the matrix due to the increased physical and chemical adhesion because of fiber-polymer system. The maximum increase in work done at 7 days of dry curing is 100.14 % at 0.3 % of fiber content and that obtained at 28 days is 51.14 % at 0.2 % of fiber volume fraction when compared with that of the normal concrete. The pull-out work done or the dissipated bond energy increased continuously with increase in fiber volume fraction at 7 days and same is increased continuously up to 0.20 % of fiber content at 28 days of dry curing.

The bond shear stress and strain (slip) relations are obtained from the stress and strain graphs by regression analysis for normal and fiber reinforced concrete. The relationship is of the following form:













= Poisson’s ratio


++= δδτ (1)

= (2)


×= γ

(4)

= + − (5)

= (6)

... (1)

The coefficients of stress-strain relations for 7 and 28 days specimens are given in the Table 7 with their regression coefficients (R2). The excellent relationship between the bond shear stress and the strain (slip) is obtained by the second degree polynomial as all the fits gave coefficient of regression as 0.99. The above relation can be easily used to find out the bond shear modulus.

Table 5. Pullout load and slip during bar de-bonding.Fiber volume

fractionVf (%)

Pullout load (kN) Slip (mm)

7 days 28 days 7 days 28 days

0.00 61.50 64.00 7.85 8.320.10 38.73 67.30 8.66 9.770.15 48.80 80.00 7.90 9.120.20 52.20 80.40 10.30 10.010.25 63.60 79.00 10.16 9.260.30 64.80 70.20 14.96 10.67

Table 6. Bond strength and work done during de-bonding of bar.

Fiber volume fractionVf (%)

Bond strength (MPa) Work done (kN.mm)

7 days 28 days 7 days 28 days0.00 8.16 8.49 482.78 532.480.10 5.14 8.93 335.40 657.520.15 6.47 10.61 385.52 729.600.20 6.92 10.66 537.66 804.800.25 8.43 10.48 646.18 731.540.30 8.60 9.31 969.41 749.03

Table 7. Coefficients of bond shear stress and strain (slip) relationship.Vf

(%)Bond stress coefficients (7 days) Bond stress coefficients (28 days)

a b c R2 a b c R2

0.00 0.0405 0.7294 0.0072 0.994 0.0822 0.3837 0.3460 0.9990.10 0.0477 0.3102 0.0338 0.997 0.0304 0.7001 - 0.2577 0.9960.15 0.0270 1.0697 0.8605 0.990 -0.0054 0.9844 - 0.6897 0.9900.20 - 0.0256 1.4462 0.7394 0.991 0.0128 1.0553 - 0.6304 0.9950.25 - 0.0374 1.4295 0.4791 0.999 0.0160 0.9997 - 0.2660 0.9940.30 0.0185 0.3000 -0.2725 0.996 0.0599 0.2353 0.1067 0.999



Shear strength

Shear strength of concrete is obtained from direct shear test using push off specimens. Shear stress (strength) is calculated as a ratio of shear load to area of shear plane. The results of shear strength are shown in Table 8. Shear strength is found to decrease with the increase in fiber content at the age of 7 days; however, at 28 days shear strength at 0.10 % of fiber content is found increased by 6.10 % compare to that of normal concrete. The polymer modified fiber reinforced concrete subjected to dry curing showed the decrease in shear strength with increase in fiber volume fraction at 7 days. The decrease in shear strength may be attributed to the incomplete polymerization and hydration process. At 28 days, PMFRC showed the improvement in the shear strength which may be due the completion of polymerization and hydration process.

Shear deformation and shear modulus

The results of shear deformation and shear modulus are presented in Table 9. The shear modulus is calculated as a ratio of shear stress to maximum shear deformation. It is to be noted that the shear strain in this test specimen is same as linear shear deformation. Shear deformations in shear test specimens have been found to increase with increase in fiber volume fraction and shear moduli have been found to decrease at the age of 7 days. The trend of decrease in moduli at this age may be attributed to the immature interfacial bond between the fiber and the matrix. However, the reverse trend is observed at the age of 28 days for shear moduli. The maximum increase in shear modulus up to 173.13 % is observed at 0.3 % of fiber content at the age of 28 days. This may be attributed to increase in bond strength between the fiber and the matrix due to addition of polymer as an effect of enhancement in the process of polymerisation.

Elastic constants

The elastic constants viz, E, μ and G are very important and are always required in the analysis of structures. The modulus of elasticity of fiber reinforced concrete is obtained by various methods available in the standard literature. The modulus of elasticity (Efc) of composites can be determined using formula given by I.S. 456 [28] depending upon the compressive strength of concrete ( fcu). It is given by the following formula:













= Poisson’s ratio


++= δδτ (1)

= (2)


×= γ

(4)

= + − (5)

= (6)

... (2)

Modulus of elasticity of fiber reinforced composites can be calculated using law of mixtures as suggested by Hannant [15] and Tan et al., [29] as given below:













= Poisson’s ratio


++= δδτ (1)

= (2)


×= γ

(4)

= + − (5)

= (6)

... (3)

The equation of modulus of elasticity expressed in terms of compressive strength of concrete and its specific gravity given by Kakizaki, et al, [30] is modified for obtaining the modulus of elasticity of polymer modified fiber reinforced concrete as follows:













= Poisson’s ratio


++= δδτ (1)

= (2)


×= γ

(4)

= + − (5)

= (6)

... (4)

In addition, following formula is proposed to predict the modulus of elasticity of fiber reinforced concrete.













= Poisson’s ratio


++= δδτ (1)

= (2)


×= γ

(4)

= + − (5)

= (6)

... (5)

Table 8. Shear strength of polymer modified fiber reinforced concrete.

Fiber VolumeFraction

(Vf)

Shear load (kN) Shear stress (MPa)

% variation in Shear stress

7 days

28 days

7 days

28 days

7 days

28 days

0.00 131.60 136.60 5.85 6.07 -- --0.10 124.26 145.00 5.52 6.44 -5.64 6.100.15 116.00 133.20 5.16 5.92 -11.79 -2.470.20 112.00 132.45 4.98 5.89 -14.87 -2.970.25 116.00 140.40 5.16 6.24 -11.79 2.800.30 100.00 143.20 4.44 6.36 -24.10 4.78

Table 9. Shear deformations and shear modulus of polymer modified fiber concrete.

Fiber Volume

Fraction (Vf)

Shear deformation (mm) Shear modulus (MPa)

7 days 28 days 7 days 28 days0.00 1.80 4.52 3.25 1.340.10 4.34 3.75 1.27 1.720.15 3.10 2.69 1.67 2.200.20 3.15 2.91 1.58 2.020.25 2.32 2.04 2.22 3.060.30 4.27 1.74 1.04 3.66


TECHNICAL PAPER

The Poisson’s ratio (μ) is determined according to Neville [31] using strength material theory based on first flexural strength (fcr) and first crack compressive strength (fcu) and is given by the relation:













= Poisson’s ratio


++= δδτ (1)

= (2)


×= γ

(4)

= + − (5)

= (6)

... (6)

The results of elastic constants obtained by Equations (2) through (6) are presented in Table 10.

The results of modulus of elasticity obtained by Equations (2), (4) and (5) are in good agreement with each other. However, law of mixtures overestimates the results of modulus of elasticity compared to those obtained by IS code, modified Kakizaki and proposed formulae. The law of mixtures gives constant value of modulus of elasticity due to low modulus of elasticity of fiber and low fiber volume fractions. The Poisson’s ratio of PMFRC is found to vary between 0.12 and 0.14, which generally varies between the limits 0.11 and 0.21.

cOnclusIOnsFollowing conclusions are drawn from the test results and discussion of this experimental investigation.

The polymer dispersion in the concrete improves the workability of concrete, but reduces the strength of concrete even after adjusting the water-cement ratio of mix taking in to account the water contained in the polymer. This is due to the air entrainment in concrete because of addition of polymer. The dry density is reduced with increase in fiber volume fraction.

The dry cured polymer modified fiber reinforced concrete with 0.30 % of fiber volume fraction attained

1.

2.

the same compressive strength at the age of 28 days as that of wet cured normal concrete. Similar trend is observed in case of equivalent cube compressive strength.

The flexural strength of polymer modified fiber reinforced concrete has been adversely affected by the dry curing. The strength gained at 0.30% of fiber content is same as that of wet cured normal concrete at both ages of curing.

The reduction in flexural crack width up to 60 % is observed in polymer modified fiber reinforced concrete compared to the crack width of normal concrete due to synergistic influence of fiber and polymer.

The results of cylinder split and prism split tensile strengths are in good agreement with each other. However, no significant improvement is observed in split tensile strength in this polymer-fiber concrete system under dry curing regime compared to the wet cured normal concrete.

The bond shear strength increased continuously with increase in fiber content. The maximum increase in bond strength achieved is 5.4 % at 0.30 % of fiber content and 25.56 % at 0.20 % of fiber content, respectively at the age of 7 and 28 days of dry curing, when compared to that of wet cured normal concrete.

Shear strength of the polymer modified fiber reinforced concrete has been found to increase up to a maximum of 6.10 % at the age of 28 days with 0.1 % of fiber content; however, no improvement in shear strength is observed at the age of 7 days compared to the normal concrete.

Shear deformations have been increased with increase in fiber content at the age of 7 days and decreased with increase in fiber content at the age of 28 days. The maximum value of shear modulus has been increased up to 173.13 % at the age of 28 days of dry curing with 0.3 % of fiber content.

The present polymer-fiber system in concrete does not improve the results of strength of hardened concrete under dry curing regime compared to those of wet cured normal concrete. This indicates that further research is required to find out the optimum

3.

4.

5.

6.

7.

8.

9.

Table 10. Elastic constants: Modulus of elasticity and Poisson’s ratio.

Fiber volume fractionVf (%)

Modulus of elasticity (GPa)Poisson’s

ratio UsingEqn. (2)

Law of mixtures,Eqn. (3)

UsingEqn.(4)

UsingEqn.(5)

0.00 28.08 28.08 28.13 28.08 0.140.10 26.66 28.07 26.71 26.86 0.140.15 26.87 28.06 26.92 27.02 0.120.20 27.00 28.05 27.35 27.12 0.130.25 27.68 28.05 27.73 27.77 0.120.30 28.08 28.04 28.13 28.13 0.13


TECHNICAL PAPER

content of polymer and the fiber volume fraction to improve the strength properties of hardened concrete significantly.

References

Hosek J., Properties of cement mortars modified by polymer emulsion, Journal of American Concrete Institute, 1966, Vol. 63, No. 12, pp. 1411-1423.Mangat P. S., Swamy R. N., Some properties of fiber-polymer concrete systems. RILEM Materials and Structures, 1977, Vol. 10, No. 60, pp. 339-349.Soroushian P, Aouadi F, Nagi M., Latex-modified carbon fiber reinforced mortars, ACI Materials Journal, 1991, Vol. 88, No. 1, pp.11-18.Ohama Y, Demura K, Hamatsu M, Kakegawa M., Properties of polymer-modified mortars using styrene-butyl acrylate latexes with various monomer ratios, ACI Materials Journal, 1991, Vol. 88, No. 1, pp. 56-61.Ghugal Y. M., Polymer modified mortar: A material for strengthening of earthquake damaged structures. Proceedings of Tenth Symposium on Earthquake Engineering, University of Roorkee, Roorkee, India1994. pp. 203-209.Bentur A., Properties of polymer latex-cement steel fiber composites, International Journal of Cement Composites and Lightweight Concretes, 1981, Vol. 3, No. 4, 283-289.Bijen J, Jacobs M., Properties of glass fiber reinforced polymer modified cement, Journal of Materials and Structures, 1982, Vol. 15 No. 89, pp. 445-452.Jacobs MJN, Bijen J., Durability of forton polymer modified GFRC, Proceedings of Durability of Glass Fiber Reinforced Concrete Symposium, PCI, Chicago, Illinois, 1986, pp. 293-304.Mujumdar A. J., Singh B., West J. M., Properties of GRC modified by styrene butadiene rubber latex, Composites, 1987, Vol. 18, No. 1, pp. 65-65.Wei S, Mandel A. J., and Said S., Study of the interface strength in steel fiber reinforced cement based composites, Journal of ACI, 1986 Vol. 83, No. 4, pp. 597-605.Zellers R. C., High volume applications of collated fibrillated polypropylene fiber, Fiber Reinforced Cements and Concretes: Recent Developments, Elsevier, New York: 1989, pp. 316-325.Nutter C., Kalahasti S., Panchalan R. K., and Ramakrishnan V., A new synthetic structural fiber for concrete, ICFRC Technical Manual, 2005; TM 9, pp. 1-8.

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

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Nanda V. K., Hannant D. J., Fiber reinforced concrete. Concrete Buildings and Concrete Products, 1969, Vol. XLIV, No. 10, pp. 179-181. Hannant D. J., Zonsveld J. J., Hughes D. C., Polypropylene fibers in cement based materials, Composites, 1978, Vol. 9, No. 2, pp. 83-88. Hannant D. J., Fiber cements and fiber concretes. New York: John Wiley and Sons, 1978.Beaudoin J. J., Handbook of Fiber-Reinforced Concrete: Principles, Properties, Developments and applications, New Jersey: Noyes Publications, 1990. Balaguru P. N., Shah S. P., Fiber reinforced cement composites, New York: McGraw-Hill. Inc., 1992.IS: 12269. Specifications for 53 grade ordinary Portland cement. Bureau of Indian Standards. New Delhi, 1987. IS: 383. Specifications for coarse and fine aggregates from natural sources for concrete. Bureau of Indian Standards. New Delhi, 1970. Lokmanwar DM. Performance of polypropylene fiber reinforced polymer modified concrete, M.E. Dissertation, Department of Applied Mechanics, Government College of Engineering, Aurangabad, India, 2005.Neville A. M., The failure of concrete compression test specimens, Civil Engineering and Public Works Review, 1957, Vol. 52 No. 613, pp. 773-774. BS: 1881- Part 119. Method for determination of compressive strength using portions of beams broken in flexure (equivalent cube method). British Standards Institution. UK, 1983.IS: 516. Methods of tests for strength of concrete. Bureau of Indian Standards. New Delhi, 1959. Sen B. R., Bharara A. L., A new indirect tensile test for concrete: Application of the split test to prisms, Indian Concrete Journal, 1961, Vol. 35, No. 3, pp. 85-89.Ramakrishna V., Ananthanarayana Y, Sabapathi P., A standard test procedure for tensile strength of concrete, Indian Concrete Journal, 1967, Vol. 41, No. 8, pp. 322-327. IS: 5816. Method of test for splitting tensile strength of concrete cylinders. Bureau of Indian Standards. New Delhi, 1970.IS: 2770. Methods of testing bond in reinforced concrete – Part I: Pull-out test. Bureau of Indian Standards. New Delhi, 1997.I.S. 456. Code of practice for plain and reinforced concrete. Bureau of Indian Standards. New Delhi, 2000.Tan K. H., Paramasivam P., Tan K. C., Instantaneous and long term deflections of steel fiber reinforced concrete beams, ACI Structural Journal, 1994, Vol. 91, No. 4, pp. 384-394. Kakizaki M., Harada M., Soshiroda T., Kubota S., Ikeda T., and Kasai Y., Strength and elastic modulus of recycled aggregate concrete, Proceedings 2nd International RILEM Symposium on Reuse of Demolition Waste, 1988, Vol. 2, pp. 565-574. Neville A.M. Properties of concrete, ELBS edition, Longman Scientific and Technical Publication, Longman Group, UK. Ltd., 1981.

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Dr. Yuwaraj M. Ghugal holds a PhD from Indian Institute of Technology Bombay, Mumbai. He is Professor and Head of the Department of Applied Mechanics, Government College of Engineering, Karad, Maharashtra. He has research experience of 25 years and has published more than 140 research papers in international and national journals and conferences. His areas of research interest are higher order theories of analysis of beams and plates, composite materials and fibre reinforced concrete.


POINT OF VIEW

Strength and durability studies of multi blended concretes containing fly ash and silica fume

G.V. Ramana, Malsani Potharaju, N. V. Mahure and Murari Ratnam

It is of significant interest to produce high performance multi blended mix concretes by using supplementary cementatious materials (SCM). In this research an attempt is made to compare the performance of multi blended mix concretes i.e. both binary and ternary mixes with ordinary Portland cement (OPC) concrete. In binary mixes cement was partially replaced by low calcium fly ash (LCFA) or silica fume (SF) and in ternary mixes both LCFA and SF were combined to partially replace OPC. The class F fly ash is used in different proportions of 20%, 30%and 40% and silica fume of 5% and 10% by weight of cement. A constant water binder ratio of 0.42 was maintained. Super plasticizer of required quantity was added to achieve the required degree of workability. The specimens were tested for compression as well as UPV at different ages 7, 28, 56 & 91 days and also the same were subjected to electrical resistance, chloride permeability (ASTM C1202 RCPT test) and under water abrasion (UWA) at both 28 and 91 days. The addition of silica fume with LCFA increased the early age compressive strength as compared to concrete made with fly ash alone; whereas the addition of LCFA up to 30% along with 5% SF exhibited higher compressive strength at later ages and also performed better performances and improved the durability particularly lowered the chloride ion permeability and improved underwater abrasion resistance at all ages than the OPC and other multi blended concrete mixes. The ultra-sonic pulse velocity (UPV) was also carried out on all the multi blended mixes to assess the homogeneity of concrete.

1.0 INtRoductIoNSupplementary Cementitious Materials (SCMs) are widely used in mortars and concretes in various proportions, particularly for reducing the amount of cement which lead to lower both initial and life-cycle costs of concrete structures.

Moreover most SCMs are by-product materials and the use of these materials leads to reduction in waste and savings in energy consumption required to produce cement and blended mix concretes. Most recently the production of multi-blended concretes (MBC) by incorporating industrial by-products/pozzolanic materials is becoming an active area of research due to their improved properties such as workability, long-term strength and durability. According to Jones et al. (1997) [1], the multiple binder combinations are now an option which can be seriously considered for conventional structural concrete. The common blending agents used are fly ash (FA), rice husk ash (RHA), Slag, silica fume (SF), calcined clay and metakaolin. The improved properties such as rheology and cohesiveness, lower heat of hydration, lower permeability, control of alkali silica reaction and higher resistance to chemical attack are reported in the literature (Khan et al., 2000 [2]; and Mehta P. K., 1989 [3]).

In general, each of these materials possesses different properties and reacts differently in the presence of water (Toutanji et al., 2004 [4]) while some have contrasting influences on properties of concrete (Khan et al., 2000). The combination of two or more kinds of mineral admixtures has emerged as a superior choice over single admixture to improve concrete properties (Bagel, 1998 [5]; Pandey et al., 2000 [6]; and Khan et al., 2002 [7]). The research on improvement of the performance of ternary (containing two types of pozzolans) blended cement and binary blended cements (containing one type of pozzolans) nowadays are in progress.

Most of MBC have been based on the use of silica fume with another supplementary cementitious material such as slag or fly ash. It is well known that the addition of silica fume results


POINT OF VIEW POINT OF VIEW

in considerable improvement of mechanical and durability properties of concretes. Fly ash normally results in lower early strength but improved workability, whereas Silica Fume causes lower workability due to high specific surface but higher reactivity than FA. The effect of combination of SF and FA showed increase in early strength due to the balancing effect in reactivity and water demand. High cost and limited availability of silica fume and construction problems such as dispersion difficulties and increased water demand are some of the drawbacks of using this material in dosages much higher than 5%. Due to relatively low water demand of fly ash, combined use of this material with silica fume can overcome the high water demand of binary mixes containing silica fume. On the other hand increased bleeding and low cohesion which are sometimes attributed to mixes containing fly ash can be overcome through simultaneous use with silica fume.

Recently there has been a growing trend towards the use of supplementary cementitious materials in India and Bhutan for water resources structures. The long-term performance of structural components of hydroelectric power projects such as spillways, stilling basins, overfalls, bridge decks, tunnel lining, energy dissipaters, and dam foundation can be greatly influenced by the durability characteristics. This indirectly affects both initial, life cycle maintenance and repair cost of the structure. The damages to the structural components are caused by various phenomenons such as under water abrasion, alkali silica reaction and chloride ion ingress. In case of hydroelectric constructions, the determination of its durability is very important because of high strategic and economic significance. From the above discussion it can be seen that any attempt to alleviate the deterioration risk therefore implies producing concrete capable of withstanding attack by aggressive agents. The incorporation of low calcium fly ash, silica fume and combinations of both fly ash with silica fume in this research aims at activating this by improving the mechanical properties, chloride ion permeability resistance and under water abrasion resistance of concrete through multi blended mix design.

In this research an attempt is made to develop high performance multi blended normal strength concretes by using SCMs such as low calcium fly ash (LCFA) and silica fume (SF). The performance of multi blended mix concretes i.e. both binary and ternary mixes was compared with ordinary Portland cement (OPC) concrete. Binary mixes were produced by partially replacing by either low calcium fly ash (LCFA) or silica fume (SF) and ternary mixes were produced with the replacement of combination of both LCFA and SF.

The compressive strength, of the above MBC concretes was compared with OPC concrete. The performance of both MBC and OPC concrete was assessed by studying chloride ion permeability and under water abrasion resistance. Further the ultrasonic pulse velocity values were also considered in this study in order to assess the quality of both MBC and OPC concrete.

2.0 INGRedIeNtsThe concrete mix was designed as per of IS: 10262-2004 [8] and it was prepared by using the following ingredients.

2.1.1 Cement43 grade Ordinary Portland cement (OPC) conforming to IS: 8112-1989 [9] was used. The physical and chemical properties of the cement are tested. The equivalent Na2O content is 0.63%.

2.1.2 Coarse aggregateCoarse aggregate from crushed Quartzite rock was used. Flakiness and Elongation Index were maintained well below 15%. Coarse aggregate with a nominal maximum size of 20 mm and a specific gravity of 2.649 was used.

2.1.3 Fine aggregateBadarpur sand (local crushed sand) was used as fine aggregate with a fineness modulus of 2.39 and specific gravity of 2.679. Fine aggregate is classified as zone III as per IS: 2386 (I, III), 1963 [10].

2.1.4 Fly ashLCFA is categorized as a normal pozzolan, a material consisting of silicate glass, modified with aluminium, iron and alkalies. The particles are in the form of solid spheres with sizes ranging from less than 1 µ to 100 µ and an average diameter of 20 µ (Mehta, 1993 [11]). LCFA requires Ca(OH)2 to form strength-developing products (pozzolanic reactivity), and therefore is used in combination with Portland cement, which produces Ca(OH)2 during its hydration. It lowers the heat of hydration and improves the durability when used in concrete as a cement replacement. It also contributes to development of strength due to filler effect inaddition to pozzolanic reactivity. The fly ash used in this research is produced from lignite coal from Badrapur Thermal power plant in New Delhi, India. This fly ash conforms to the requirement of IS: 3812 (Part I) 2003 [12] and also ASTM C-618 [13] type F fly ash (LCFA). It has the total sum of SiO2, Al2O3 and Fe2O3 is >90% but with quite a low CaO content (0.87%).


POINT OF VIEW

2.1.5 Silica fumeSilica fume is a highly reactive material that is used in relatively small amounts to enhance the properties of concrete. It is a by-product of silicon metal and ferrosilicon alloy production. The SF is a very fine powder with spherical particles about 100 times smaller in size than those of Portland cement or fly ash. The particles are extremely fine and having diameter ranging between 0.03 and 0.3μm, with more than 95% of the particles being less than 1μm. Particle size is extremely important for both physical and chemical contributions (ASTM 1240 [14]) of silica fume in concrete. The specific surface of SF is 13 to 20 times higher than other pozzolans. Because of its very high amorphous silicon dioxide content it is very reactive pozzolanic material in concrete. The silica fume reacts with calcium hydroxide to form additional binder material called calcium silica hydrate. Silica Fume (Micro silica) used in this study was obtained from Corniche India Pvt. Ltd., Mumbai, Maharashtra, India. This Silica Fume conforms to the requirement of ASTM C1240.

2.1.6 Superplasticizer (SP) A new generation Poly Carboxylic Ether (PCE) based super-plasticizer, CEMWET SP-3000 (PCE-2) was used. This super -plasticizer is available as a medium brown coloured aqueous solution with standard specifications of ASTM C 494 [15] Type G. The specific gravity and pH value of the super plasticizer is 1.1 and 7, respectively.

2.2 Mix proportions

This paper reports the results of an experimental investigation of short term (early age) compressive strength of multi blended mix concretes. Twelve concrete mix proportions of M30 grade concrete consisting of control, binary and ternary mixes were considered for this investigation as shown in Table 1. The total cementitious material content was kept as 365 kg/m3 and a constant W/B of 0.42 was adopted. In order to get homogeneous samples, the super plasticizer was added to maintain the same slump for all the multi blended concrete mixes.

In CF series, cement (C) was replaced partially with low calcium fly ash (LCFA) by 20%, 30% and 40% for getting CF20, CF30 and CF40 mixes respectively.

In CS series the cement was replaced with silica fume (SF), by (5% and 10%) for getting CS5 and CS10 mixes respectively.

In CFS series cement was partially replaced by both silica fume at (5%, 10%) and fly ash (20%, 30%, 40%) for getting CFS725, CFS635, CFS545 and CFS721, CFS631, CFS541 mixes respectively. For example CFS635 indicates 65% cement, 30%fly ash, 5% silica fume and CFS631 indicates 60% cement, 30%fly ash, 10% silica fume.

•

•

•

Table 1. Mixes proportions for multi blended concrete mixtures studiedS. no. Mix designation W/B Cement

(Kg/m3)LCFA

(Kg/m3)SF

(Kg/m3)SP

(Kg)CA

(Kg/m3)FA

(Kg/m3)Slump (mm)

1 Control mix (M30) 0.42 365 0 0 1.83 1237 704 50

2 CF20 0.42 292 73 0 2.19 1219 694 50

3 CF30 0.42 255.5 109.5 0 2.56 1210 689 60

4 CF40 0.42 219 146 0 2.74 1202 684 70

5 CS5 0.42 346.75 0 18.25 2.92 1231 701 50

6 CS10 0.42 328.5 0 36.5 3.65 1226 698 50

7 CFS725 0.42 273.75 73 18.25 2.92 1214 691 50

8 CFS635 0.42 237.25 109.5 18.25 3.29 1206 686 50

9 CFS545 0.42 200.75 146 18.25 3.65 1197 681 70

10 CFS721 0.42 255.5 73 36.5 4.8 1208 687 50

11 CFS631 0.42 219 109.5 36.5 4.01 1200 683 50

12 CFS541 0.42 182.5 146 36.5 4.38 1191 678 70



2.3 Casting and testing of specimens

Initially cement, fly ash and SF were mixed to get the total cementitious material. This cementitious material in dry state was mixed with the mixture of fine aggregate and coarse aggregate to produce homogeneous mix. The mixture of water and SP was then added to the dry mix of cementitious and aggregate. Slump cone test was performed as per IS:1199-1959[16] to measure the slump of the concrete. 150 mm x150 mm x150 mm Cube specimens were used to determine both the compressive strength as per IS: 10086-1982[17] and UPV as per IS: 13311 (Part I) 1992[18]. A set of six cubes were

cast as per procedure laid down in IS: 516-1959 [19] for each mix of concrete. After casting, the moulds specimens were air dried for 24 h. The cube specimens were cured for 7 d, 28d, 56d, and 91 days period for conducting compression and UPV tests as shown in Figures 1, 2, and 3. A set of four cylindrical specimens of 50 mm thick and 98 mm diameter were cast for each mix of concrete. These specimens were air dried for 24 hr before they were cured for 28d, and 91 days for performing RCP Test as per ASTM C 1202 [20] and RCPT tests as shown in Figure 4. Further a set of three cylindrical disk specimens of size 100 (dia) mm x 300 (height) mm, were


POINT OF VIEW

cast for each mix of concrete. These specimens were air dried for 24 hr before they were cured for 28d and 91 days for performing UWA test as per ASTM 1138-97 [21] and the average mass loss of the abrasion–erosion is measured at 24-hr, 48hr, and 72 hr and UWA tests as shown in Figures 5 and 6. The underwater abrasion test was carried out up to 72 hr. at intervals of 24hr. The average mass loss (%) observed is the measure of abrasion resistance.

3.0 Results aNd dIscussIoNsThe details of the various tests results were discussed critically to assess the performance of the binary and ternary mixes. These test results cover compressive strength, UPV values, chloride ion permeability and underwater abrasion The compressive strength of test specimens and relative UPV test results of binary mixes (C+LCFA and C+SF) and ternary mixes (C+LCFA+SF) of varies combinations of cementitious materials at 7, 28, 56 and 91 days are shown in Table 2. The

Table 2. Compressive strength and relative UPV of all multi blended mix concretes at each test ageMix ID Compressive strength at different ages (MPa) Relative UPV values (%) at different ages

7 days 28 days 56 days 91 days 7 days 28 days 56 days 91 days

M30 24.6 31.16 33.28 38.38 100 100 100 100

CF20 22.9 30.25 32.18 38.15 104.55 103.44 103.44 103.44

CF30 18.75 28.81 32.82 39.52 110.09 106.88 106.88 106.88

CF40 17.03 25.49 31.24 36.34 103.564 100 100 100

CS5 25.83 33.31 33.62 38.84 106.139 103.442 103.442 103.442

CS10 26.5 34.26 34.38 39.68 111.881 108.031 108.031 108.031

CFS725 24.75 31.64 34.19 39.62 115.248 111.472 111.472 111.472

CFS635 25.15 32.43 34.99 41.5 101.584 101.912 101.912 101.912

CFS545 17.99 26.73 31.12 36.72 109.703 106.119 106.119 106.119

CFS721 19.74 30.05 31.08 36.68 111.089 107.457 107.457 107.457

CFS631 18.99 29.01 32.23 37.12 99.4059 97.5143 97.5143 97.5143

CFS541 16.2 24.92 30.67 35.38 111.881 108.031 108.031 108.031



results of RCPT values of all fly ash binary mix, silica fume binary mixes and ternary mixes at different ages (28d and 91d) were presented in Figure 7.

3.1 OPC + fly ash binary concrete mixes

Figure 8 shows that the variation of the compressive strength with percentage replacement of cement by LCFA at all ages. It was observed that the compressive strength decreased by 6.91%, 23.78% and 30.77% at 20, 30 and 40% replacement levels of LCFA respectively compared to OPC concrete at 7 days. The reduction in compressive strength was less at the age of 28 days with the addition of fly ash up to 40%, the percentage decrease being 2.9%, 7.5% and 11.2% respectively compared to that of OPC concrete. The grater reduction in compressive strength of CF mixes at early ages is considered to be the result of slow development of strength due to delayed setting process. This behavior is an agreement with the findings of the researchers (Mehta (1994) [22], Khan M.I et al (2002) [7]).

The relative strengths of CF20, CF30 and CF40 mixes were 96.69%, 98.62%, & 93.87% at 56 days whereas these strength were 99.40%, 102.97%, & 94.68% at 91 days respectively compared with OPC concrete. It was observed that the binary mix concretes with partial replacement up to 30% LCFA exhibited almost same strength as that of OPC concrete at later ages. The addition of fly ash improved the pozzalanic reaction at later ages due to its higher surface area and glassy phase content. This behavior is an agreement with the findings of the researchers (Mehta (1994) [22], Vagelis G. Papadakis (1999) [23] & M.A. Megat Johari et al (2011) [24]).

Figure 9 shows that the UPV values of concrete increased with the increase of LCFA content up to 30% at both ages (7d, 28 d) for all the mix combinations. The UPV values increased by 4.55%, 10.10% and 2.38% at 20%, 30% and 40% replacement levels of LCFA respectively compared to OPC concrete at 7 days. The increase in velocity at 28 days with 20 & 30% replacement was 3.44% & 6.88% respectively compared with OPC concrete. The addition of fly ash beyond 30% replacement exhibited decrease in velocity.


POINT OF VIEW

In Figure 10 shows the average charge passed (RCPT) decreased by 9.90%, 39.24% and 49.08% at 20, 30 and 40% replacement levels of fly ash respectively compared to OPC concrete at 28 days. The decrease in average charge passed at 91 days with 20, 30 and 40% replacement was 35.29%, 46.90% and 53.43% respectively compared to that of OPC concrete. It was further observed that the chloride ion permeability of fly ash binary mixes reduced with the age of the concrete. However the long term performance of all the CF binary mixes shows low and very low chloride ion permeability. It indicates that with increasing Fly ash content the resistance to chloride permeability of binary mixes is improved. The increased impermeability of the fly ash binary mix may be attributed to the fact of formation of homogeneous mix due to the addition of LCFA to concrete. The addition of LCFA also leads to significant reduction of porosity due to refinement of pore structure of concrete resulting in reduced permeability. This behavior is an agreement with the findings of the researchers (Chindaprasirt et al. [25]). The reduced permeability results in improved long-term durability and resistance to various forms of deterioration.

Figure 11 shows that the mass loss (%) (UWA) increased marginally with the addition of LCFA up to 30%, whereas abnormal increase in mass loss (%) was observed with the addition of fly ash beyond 30% at 28 days. At 91 days, these mixtures with LCFA up to 30% replacement exhibited decreased in mass loss (%). The mass loss (%) increased by 7.34%, 14.58% and 32.61% at 20, 30 and 40% replacement levels of LCFA respectively compared to OPC concrete at 28 days. The mass loss was decreased by 9.96%, 20.54% at 91 days with 20 & 30% replacements respectively whereas it was increased by 12.92% with 40% replacement compared

to that of OPC concrete. The increase in the mass loss (%) of CF mixes at 28 days is considered to be the result of lower activity of the fly ash particles at early ages. The better performance against abrasion at later ages (91days) may be attributed to the fact of improved pozzalanic reaction leading to homogeneous and strong mix. This behavior is an agreement with the findings of the researchers (Tikalsky et al (1988) [26], Naik et al (1995) [27]).

3.2 OPC + silica fume binary concrete mixes

Figure 12 shows that the variation of the compressive strength with percentage replacement of cement by SF at all ages. It was observed that the compressive strength



increased by 5.0% and 7.72% at 5 and 10% replacement levels of SF respectively compared to OPC concrete at 7 days. The improvement in compressive strength was higher at the age of 28 days with the addition of silica fume up to 10%, the percentage increase being 6.9%, 9.95% and 11.2% respectively compared to that of OPC concrete. It is well recognized that addition of SF to concrete provides a significant increase in strength of concrete at early age of hydration. SF also increases the homogeneity and decreases the number of large pores in cement paste, both of which would lead to a higher strength to SF binary mix concretes. This behavior is an agreement with the findings of the researchers (Tahir Kemal Erdem (2008) [28]). The relative strength of the CS5 and CS10 was 101.03% & 103.31% at 56 days whereas the strength was 101.20% & 103.39 % at 91 days compared with OPC concrete. It observed that the binary mix concrete with partial replacement up to 10% SF exhibited higher compressive strength as that of OPC concrete at all ages. This behavior is an agreement with the findings of the researchers (M.A. Megat Johari. et al (2010) [24]).

Figure 13 shows that the variation of the UPV values with percentage replacement of cement by SF at all ages. It was observed that that the variation of the the UPV values of concrete increased with the increase of SF content at both ages (7d and 28 d) for all combinations. The UPV values of concrete increased with the increase of SF content at both ages (7d, 28 d) for all combinations. The UPV velocity increased by 3.56% & 6.14% at 5 and 10% replacement levels

of SF respectively compared to OPC concrete at 7 days. The binary mix consisting of 5%SF did not show any increase in velocity at 28 days where as it showed an increase of 3.44% with the addition of 10% SF replacement. It was further observed that no change in UPV values was noted beyond 28 days indicating that the concrete achieved the maximum homogeneity at the age of 28 days itself. Hence, it can be concluded that the binary mix consisting of SF up to 10% exhibited enhanced quality compared to OPC concrete at all ages.

Figure 14 shows the average charge passed (RCPT) in the OPC and SF blended concrete mixes at the ages of 28 and 91 days. The silica fume binary mixes exhibited the very low chloride ion permeability for both the binary mixes of CS5 and CS10. The average charge passed in the silica fume concrete blends was 80% less than that of the control (OPC) concrete at 91 days and also the charge passed of SF binary mixes are lower than control even at the age of 28 days. The increased impermeability of the SF binary mix may be attributed to the fact that not only to the reduction of permeability of the transition zone around the aggregate in presence of silica fume, but also the reduction of permeability in the bulk paste compared to the hydrated cement paste. In addition, silica fume decreases Ca(OH)2, and further C/S ratio in C–S–H is also reduced. Thus, silica fume concrete is less permeable and highly resistant to aggressive chemical solutions. This behaviour is an agreement with the studies of other researchers Ozyildirim et al (1994) [29] & Sharfuddin Ahmed et.al (2008) [30].


POINT OF VIEW

Figure 15 shows that mass loss (%) (UWA) decreased with the addition of SF up to 10% replacement at 28 days. At 91 days, these mixtures with SF up to 10% replacement exhibited further decreased in mass loss (%). The mass loss (%) decreased by 13.50% & 19.87% at 5 and 10% replacement levels of SF respectively compared to OPC concrete at 28 days. The decrease in mass loss (%) at 91 days with 5 & 10 replacements were 34.56%, 40.22% respectively compared to that of OPC concrete. It has been clearly seen that the inclusion of silica fume in binary blends with Portland cement positively contributes to reduce the mass loss (%) of concrete mix. The densification of the matrix brought about by the pozzolanic reactions of silica fume blocks the pores and results in improving in abrasion resistance of SF blended concrete mixes Toutanji H. et al. (2004)[20]. Hence, it can be concluded that the binary mixes consisting of SF up to10% exhibited better performance to improve the abrasion resistance as compared with that of OPC concrete at both ages.This is in agreement with the findings of Sing Rajbal [31] and Yu-Wen Liu [32].

3.3 Ternary mix concretes (OPC +LCFA +SF)

Figure 16 shows that the variation of the compressive strength of ternary mix concretes consisting of combination of 5%SF with LCFA up to 40% replacement of cement and 10%SF with LCFA upto 40% replacement of cement at all ages. It was observed that the ternary mix concretes consisting of combination of 5%SF and LCFA up to 30% replacement at all ages (7d, 28d, 56d, and 91d) exhibited higher compressive strength than that of ternary mixes consisting of combinations of 10% SF with LCFA up to 30% replacement.

The percentage increases in compressive strength of ternary mix concrete consisting of 5%SF and LCFA up to 30% replacement at 7 days were 0.61% and 2.24% as compared with the OPC concrete. It was observed that the compressive strength of ternary mixes decreased with the addition of SF beyond 5%. The percentage decreases were 19.76% and 23.8% for ternary mixes consisting of 10% SF and LCFA up to 30% replacement at 7days. The percentage increases in compressive strength of ternary mix concrete consisting of 5%SF and LCFA up to 30% replacement at 7 days were 0.61% and 2.24% as compared with the OPC concrete. The addition of SF beyond 5% decreased the compressive strength of ternary mixes. The percentage decreases were 19.76% and 23.8% for ternary mixes consisting of 10% SF and LCFA up to 30% replacement at 7days.

Further it was observed that the compressive strength of ternary mixes increased with the addition of 5% SF beyond the age of 7 days. The percentage increases in compressive strength of ternary mix concrete consisting of 5%SF and LCFA up to 30% replacement were (1.54%, 4.08%), (2.73%, 5.14%) and (3.23%, 8.13%) at 28d, 56d and 91 days respectively as compared with the OPC concrete. It was also observed that the compressive strength of ternary mixes decreased with the addition of SF beyond 5%. The percentage decreases in compressive strength of ternary mix concrete consisting of 10%SF and LCFA up to 30% replacement were (3.56%, 6.9%), (6.61%, 3.16%) and (4.4%, 3.3%) at 28d, 56d and 91 days respectively as compared with the OPC concrete. Hence, it can be concluded that the ternary mix concretes



with 5% SF and LCFA up to 30% replacement exhibited higher compressive strength than that of OPC concrete at all ages.

Figure 17 shows that the ternary mix concretes consisting of combination of 5%SF and LCFA up to 30% replacement at both ages (7d & 28d) exhibited higher UPV values than that of ternary mixes consisting of combinations of 10% SF with FA up to 30% replacement. The percentage increases in UPV values of ternary mixes consisting of 5%SF and LCFA up to 30% replacement at 7 days were 11.88% & 15.25% as compared with the OPC concrete. It was observed that the ternary mixes consisting of SF beyond 5% and LCFA up to 30% showed marginal increase in UPV values. The percentage increases in UPV values of ternary mixes consisting of 5%SF and LCFA up to 30% replacement at 28 days were 8.03% & 11.47% as compared with the OPC concrete. It was observed that the ternary mixes consisting of SF beyond 5% and LCFA up to 30% showed marginal increase in UPV values.

Figure 18 shows that the variation of the charge passed (RCPT) through the ternary mix concretes consisting of combination of 5% and 10%SF with LCFA up to 40% replacement of cement at both 28 and 91 days. It was observed that all the ternary mix combinations exhibited average charge values well below the acceptable limit (Very low). The variation of average charge passed in the specimens with 5% SF are similar to the average charge passed in the specimens with 10% SF except in the ternary blend of 30% LCFA and 5% silica fume (CFS635) which

exhibited lesser decrease in charge passed compared to other ternary mixes. By the use of multi blundered mixes, it is therefore possible to overcome the relatively low 28 day durability performance of LCFA based binary mixes and compared to the control mix, and also substantial increase in chloride ion permeability resistance in later ages has been achieved. Although the binder containing 20% to 40% FA resulted in a decrease in RCPT values, the addition of SF by 5% resulted in a further decrease in RCPT values. However,


POINT OF VIEW

multi blended mix of 30% FA and 5% SF was found to be better than binary blended mixes for resisting chloride ion permeability. The decrease in charge passed with time may be attributed to the change in the pore structure distribution of the hydrated cementitious system due to the use of both fly ash and silica fume in varying proportions. The addition of these SCMS also leads to significant reduction of porosity due to refinement of pore structure of concrete resulting in reduced permeability (Oh et al (2002)[33].

Figures 19 and 20 shows that the variation of the mass loss (%) (UWA) of ternary mix concrete increased with the increase of time period (24hr, 48hr & 72hr) for all the ternary blended mix concretes. The ternary mix concretes consisting of combination of 5%SF and LCFA up to 30% replacement at 28 and 91days exhibited lower mass loss (%) than that of ternary mixes consisting of combinations of 10% SF with LCFA up to 30% replacement. The percentage decreases in mass loss (%) of ternary mixes consisting of 5%SF and LCFA up to 30% replacement at 28 days were 25.38% & 32.07 % whereas the percentage decreases in mass lossas at 91 days were 41.94% & 48.83 % as compared with the OPC concrete. It was also observed that the values of mass loss (%) of ternary mixes increased with the addition of SF beyond 5% at 28days, the percentage increases being 0.22% & 6.37% for ternary mixes consisting of 10% SF and LCFA up to 30% replacement. However the addition of SF beyond 5% with LCFA up to 30%replacemnt exhibited lower mass loss as compared to OPC concrete the percentage decrease being 15.74% & 5.78% at the age of 91 days. Though CFS631 and CFS721 exhibited lesser mass loss, the losses were not

significant compared to CFS635 and CFS725 at the age of 91 days. Hence it can be concluded that the ternary mix concretes consisting of combination of 5%SF and LCFA up to 30% replacement exhibited better abrasion resistance.

4. coNclusIoNsThe following conclusions can be drawn from the above discussions:

The strength of concrete decreased with the increase of LCFA content in all fly ash binary mixes at early ages.

The quality of fly ash binary mix concretes with LCFA content up to 30% replacement at all ages is superior to that of OPC concrete and other fly ash binary mixes.

Among both fly ash and silica fume binary mixes, the silica fume binary mixes produced with the addition of SF up to 10% found to be more resistant against chloride ion permeability and improved underwater abrasion resistance compared with fly ash binary mixes.

The binary mix concrete produced with the partial replacement of cement by LCFA up to 30% exhibited higher compressive strength at later ages. This mix demonstrated higher impermeability, and enhanced homogeneity of concrete.

The binary mix concrete produced with the partial replacement of cement by SF up to 10% exhibited higher compressive strength at all ages. This mix demonstrated higher impermeability, better control of mass loss and enhanced homogeneity of concrete.

The inclusion of SF up to 10% in binary mix concretes contributed to the improved resistance to underwater abrasion by exhibiting low percentage of mass loss. The binary mix concretes produced with addition of LCFA did not show any improvement in the underwater abrasion resistance.

The compressive strength of ternary mixes produced with the addition of LCFA up to 30% along with 5% SF exhibited higher compressive strength at later ages. These mixes demonstrated higher impermeability, improved underwater abrasion resistance and enhanced homogeneity of concrete.

It can be concluded that it is possible to develop ternary mix normal strength concrete better than OPC concrete

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especially with reference to performance in terms of durability. Within the limits of the experimental investigation it is concluded that the ternary mix consisting of combination of 5% SF and LCFA up to 30% demonstrated high performance.

Acknowledgments

The authors gratefully acknowledge and thank the Central Soil and Materials Research Station, New Delhi for giving the opportunity for conducting the experimental work. The authors also gratefully acknowledge and thank GITAM University, Vishakhapatnam. The authors are also acknowledged the thanks to the researchers and writers whose literature was used here for supporting this research paper.

References

Jones, M.R.; Dhir, R.K.; Magee, B.J. Concrete Containing Ternary Blended Binders: Resistance to Chloride Ingress and Carbonation. Cement and Concrete Research. 1997, 27, 825-831.

Khan M.I, Lyndsdale C.J and Waldron P. (2000). Porosity and Strength of PFA/SF/OPC/Ternary Blended Paste. Cement and Concrete Research. 30: 1225-1229.

Mehta P.K. (1989) Pozzolanic and Cementitious by-products in Concrete another Look, In V.M. Malhotra ed. Fly Ash, Silica Fume, Slag, and Natural Pozzolans in Concrete, Sp 114, Vol. 1, ACI, Detroit: 1-45.

Toutanji H. et al. (2004). Effect of Supplementary Cementitious Materials on the Compressive Strength and Durability of Short-Term Cured Concrete. Cement and Concrete Research. 34: 311-319.

Bagel L. (1998).Strength and Pore Structure of Ternary Blended Cement Mortars Containing Blast Furnace Slag and Silica Fume. Cement and Concrete Research. 28: 1011-1020.

Pandey S.P. and Sharma R.L (2000). The Influence of Mineral Additives on the Strength and Porosity of OPC Mortar, Cement and Concrete Research, 30:19-23.

Khan M.I, Lyndsdale C.J, Strength, permeability, and carbonation of high-performance concrete, Cement and Concrete Research, 32 (2002) 123-131.

IS: 10262-2009, Concrete Mix proportioning guidelines.

IS: 8112- 1989 “43 Grade Ordinary Portland Cement – Specification” Bureau of Indian Standards.

IS: 2386-1963 (I, III) (Reaffirmed 2004), Indian Standard for Method of Tests for aggregates for concrete.

Mehta, P. Kumar. 1993. Concrete Structure, Properties and Materials, Prentice- Hall, Inc., Englewood Cliffs, N.J.07632.

IS: 3812 (Part I) (2003): Specification for Pulverized Fuel Ash, for Use as Pozzolana in Cement, Cement Mortar and Concrete.

ASTM C 618-94 (1994) Standard Specification for Fly Ash and Raw or Calcined Natural Pozzolan for Use as Mineral Admixture in Portland cement Concrete.

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

ASTM C 1240, Standard Specification for Silica Fume used in Cementitious mixtures.

ASTM C 494-92 (1992) Specification for Chemical Admixtures for Concrete.

IS: 1199-1959 Methods of sampling and analysis of concrete

IS: 10086-1982, (Reaffirmed 1999), Indian Standard for specification for moulds for use in tests of cement and concrete.

IS: 13311 (part 1):1992, Non-destructive testing of concrete methods of test, part 1, Ultrasonic pulse velocity, revised 1996.

IS: 516-1959 (Reaffirmed 2004) Edition 1.2 (1991-07), Indian Standard for Method of Tests for strength of concrete.

ASTM C1202-97: standard test method for electrical indication of concrete’s ability to resist chloride ion penetration. Annual book of ASTM standards, vol. 04.02, Philadelphia, 2001. p. 646–51.

ASTM C1138-97, standard test method for abrasion resistance of concrete (underwater method), in: Annual Book of ASTM Standards, vol. 04.02, ASTM.

Mehta, P.K.: In: Khayat, I.H., Aitcin, P.C. (eds.) Symposium on durability of concrete, pp. 99–118. Nice, France, (1994)

Vagelis G. Papadakis (1999). Effect of fly ash on Portland cement systems Part I. Low-calcium fly ash, Cement and Concrete Research 29 (1999) 1727–1736.

M.A. Megat Johari et al.: Influence of supplementary cementitious materials on engineering properties of high strength concrete. Construction and Building Materials 25 (2011) 2639–2648.

Chindaprasirt, P., Chotithanorm, C., Cao, H.T., Sirivivatnanon, V.: Influence of fly ash fineness on the chloride penetration of concrete. Construct. Build. Mater. 21(2), pp.356–361 (2007).

Tikalsky, P.J., Carrasquillo, P.M., Carrasquillo, R.L.: Strength and durability considerations affecting mix proportions of concrete containing fly ash. ACI Mater. J. 85(6), pp. 505–511 (1988).

Naik, T.R., Singh, S.S., Hossain, and M.M.: Abrasion resistance of high-strength concrete made with class C fly ash. ACI Mater. J. 92(6), 649–659 (1995)

Tahir Kemal Erdem. et al. (2008). Use of binary and ternary blends in high strength concrete. Construction and Building Materials 22 (2008). Pp. 1477–1483.

Ozyildirim, C., Halstead, W.J.: Improved concrete quality with combinations of fly ash and silica fume. ACI Mater. J. 91(6), pp. 587–594 (1994).

M. Sharfuddin Ahmed et.al 2008. Chloride penetration in binary and ternary blended cement concretes as measured by two different rapid methods, Cement & Concrete Composites 30 (2008). Pp. 576–582.

Singh Rajbal, Sthapak A.K., Vishnoi R.K., Joshi N.G., Hasbi S.A. and Jones C.S. (2003) “Abrasion and Erosion Resistant Concrete with Silica Fume”, Int. Conf. on Accelerated Construction of Hydro Power Projects, Gedu, Bhutan, 15-17 Oct., Vol. II, pp. VI 78-87.

Yu-Wen Liu “Improving the abrasion resistance of hydraulic-concrete containing surface crack by adding silica fume”, Journal of Construction and Building Materials 21 (2007) 972-977.

Oh, B. H., Cha, S. W., Jang, B. S., and Jang, S. Y. (2002). “Development of high performance concrete having high resistance to chloride penetration.” Nuclear Engineering & Design, 212(1-3 March), pp.221-231.

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POINT OF VIEW

G.V. Ramana holds a B.Tech and M.Tech. degrees from Andhra University, Visakhapatnam, Andhra Pradesh; pursuing PhD at the Department of Civil Engineering, GITAM University, Visakhapatnam. He is working as Scientist-C at Central Soil and Materials Research Station (CSMRS), Hauz Khas, New Delhi. He has an experience of 10 years in execution of rock mechanics investigations for hydro electric projects and other civil engineering projects. His primary area of interests are rock mechanics and concrete technology.

Dr. M. Potharaju holds a M.tech from JNTU, Hyderabad and PhD from Andhra University. He is a Professor and Registrar in GITAM University, Visakhapatnam. His research interest includes fire resistant concrete, geopolymer concrete, recycled aggregate concrete and ternary mixed concrete.

N.V. Mahure holds a BE from Govt. College of Engineering, Amravati, Nagpur University, Maharashtra. He is a Scientist ‘D’ in Central Soil and Materials Research Station, New Delhi. He has an experience of 24 years in different concretes, diagnostics investigations and health monitoring of concrete structures, review of detailed project reports of hydro-electric projects.

Murari Ratnam holds an MSc. from Delhi University; M.Tech from Indian Institute of Technology, Delhi. He is a Director at Central Soil and Materials Research Station, New Delhi. He has an experience of 36 years in chemistry of construction materials, durability of concrete, water quality, polymer concrete, diagnostic investigation of old structures and promotion of utilization of fly ash in concrete.



Effect of mineral and chemical admixtures on the properties of mortar and concrete – A review

Rahul Singh, S.M. Gupta and Babita Saini

Since many decades, construction work is being carried out on a large scale all over the world. To make concrete able to adjust in different environment, the use of admixtures came in lime light. Construction without affecting the strength of concrete is the need of the hour. In this context different admixtures have been used in concrete. This article provides a detailed review of various studies on concrete with admixtures over the years.

IntRoductIonConstruction plays an important role in the welfare and development of Nation’s economy. Exposure to different environmental conditions for construction is one of the major challenge faced by both the under developed and developing countries all over the world. The majority of the constructional issues are related to making amendments in properties of concrete so that it can be used according to the need. Concrete is a composition of materials which is made up of filler (fine and coarse aggregate) and binder constituents (cement and water). The binder constituents glue the filler together to form a synthetic conglomerate. Concrete is strong in compression but weak in tension. In order to make desirable changes in properties of concrete various studies have been carried out with the use of admixtures. Admixtures are the ingredients other than the key ones that are being added during the process of mixing. They make

concrete to adjust to different atmospheres and at different steps of construction to make the process convenient. Adequate precaution during the use of admixtures should be taken as they should not affect the strength of concrete. They should be environment friendly and easily degradable. Some of them are available in natural state and few are being obtained through scientific processes. Admixtures can be classified into following categories.

Mineral admixtures

Chemical admixtures

Mineral admixtures

Mineral admixtures are inorganic in nature that has pozzolanic or hydraulic properties. These fine grained materials are added to the mixture to improve concrete properties or as replacement of cement. Various types of mineral admixtures are fly ash, ground granulated blast furnace slag, silica fume, high reactivity metakaolin, rice husk ash, etc.

Fly ash is byproduct of coal fired electricity generating thermal power plants. It used to replace cement partially up to 60%. Its properties depend on type of coal burnt. Siliceous fly ash and calcareous fly ash are mainly two types of fly ash. Former one is pozzolanic while later has latent hydraulic

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POINT OF VIEW

Table 2. Properties of mortar with fly ash as partial replacement of cementAuthor Mortar % Used

(fly ash)Admixture or Additive

usedProperties studied Results reported

( for fly ash)

(Heinz, 2009)[6] 1 : 3 : 0.5(c:sand:w) 25 TEA Dissolution of Ca, Fe and

early age strength. Strength increased

(Nochaiya, 2009) [7] water/(PC+FA) ratio of 0.5 5,10,20,30 Silica fume (2.5, 5,10)%

by wt of cement

Normal consistency, setting time, workability and compressive strength

water requirement decreased, initial and final setting time increased, workability and compressive strength increased

(Yilmaz, 2007) [8] Cement to sand (1 : 3) , w/c 0.5

(5,10,20) of clinker

Gypsum (5%), Limestone(5,10,15)%and dolomistic limestone (5,10,15)% with fly ash

Compressive strength, setting time, soundness

Strength decreased and setting time prolonged

(Vahid, 2012) [9] w/c =0.45 20, 60 Case of slag also studied at 60 %

Indentation modulus, hardness

degradation of mechanical properties on exposed to heat

(Xianming, 2011) [5] Water cement ratio -0.45 20 ,25 One case with metakaoilin

(5%)

Compressive Strength, young’s modulus, modulus of rigidity

1 and 7 day’s strength reduced but 28 day strength improved.

Table 1. Properties of concrete with fly ash as partial replacement of cementAuthor Concrete

mix% Used (fly ash)

Admixture or Additive used

Properties studied Results reported (for fly ash)

(Limbachiya, 2012) [1] 20,30,35 30Recycled concrete aggregates(0,30,50,100) %

Compressive, flexural and elastic modulus

Decrease in flexural , elastic modulus but increase in compressive strength

(Gudmundur, 2011) [2] 70 20,40,60, 80,100 Study of slag at same percent of replacement

Setting time, Compressive strength (CS)

Less early age compressive strength, setting time close to control mix

(Boga, 2012) [3] 30 15,30,45 -

Hardness, split tensile strength (ST), compressive strength, chloride ion permeability

Max S.T. at 15%, C.S. increased with 15% fly ash but decreased with 30%, 45% fly ash

(Katherine, 2012) [4] 65 (60, 80,90)Study of slag as well as their combination at same value in different ratios

Compressive strength, elastic modulus

At 60% and 80% compressive strength increased, elastic modulus increased and after that no change was observed

(Xianming, 2011) [5] 35 20 ,25 One case with metakaoilin (5%)

Compressive strength, youngs modulus, modulus of rigidity

1 and 7 day’s strength reduced but 28 day strength improved.

properties. The research work done in previous years using fly ash as replacement of cement has been discussed in Tables 1 and 2.

Above table depicts that the optimum replacement to cement by fly ash in the case of mortar was 15%. Also in case

of concrete optimum replacement to cement by fly ash was found to be near 15%. The study also analyzed that it was better to use fly ash with components like lime stone and TEA (Triethanol Amine).



Table 3. Properties of concrete with ground granulated slag as partial replacement of cementAuthors Concrete

MixReplacement

by GGBFS (%)Additive or Condition

Properties studied Results

(Shariq, 2009) [10] 25,35,45 20,40,60 _ Compressive strength in (cubes and

cylinders)

Increase in strength was observed with 40% replacement of cement

(Xianming, 2011)

35 50 _

Comparison of Compressive strength, young’s modulus, modulus of rigidity with replacement of cement by Ultra fine fly ash, fly ash, metakaolin and Silica fume

1st and 28th days strength improved with GGBFS but young’s modulus and modulus of toughness reduced

Gengying Li et al (2001) [11] 80 15

Combined with fly ash( 25,40) in presence of super plasticizer

Compressive strength, sulfate attack Compared to HFAC high-volume FA high-strength concrete at 40% replacement of cement

23.3% greater strength achieved, Superior to HFAC

(Latha, 2012) [12] 20,40,60 10, 20, 30, 40,

50,60,70

HVFA (high volume fly ash) (at same percent ) for comparison of results

Strength efficiency factor (S.E.F.),compressive strength

Increased performance in strength and durability, S.E.F. higher in case of GGBS.

(Nazari, 2010) [13]

Cement450kg/ m3 15,30,45,60

SiO2 nanoparticlesas binder ( 1, 2,3,4)%

Split tensile strength

The split tensile strength (STS) of concrete increased upto 45% replacement of cement by GGBFS where as when greater % was used ie 60% then STS decreased.

Table 4. Properties of mortar with GGBFS as partial replacement of cementAuthors Mortar Replacement by

GGBFS (%)Additive or Condition Properties studied Results

Hwang [14] w/(c+s) ratios [0.35,0.47, 0.59] 0,10,20, 30,40 fly ash

Comparison with fly ash, Penetration resistance, setting time

Longer setting time, slag increased penetration resistance

(Xianming, 2011) [5]

Water cement ratio 0.45 50 -

Comparison of Compressive strength, young’s modulus, modulus of rigidity with replacement of cement by Ultra fine fly ash, fly ash, metakaolin and Silica fume

1st and 28th days strength improved with GGBFS but young’s modulus and modulus of toughness reduced

( Wang, 2007) [15]

w/c ratio( 0.23, 0.47,0.71) 5, 10,20,50,80,100

Tested at different temperatures( 25, 105, 200, 440, 580, 800, 1080)oC

Compressive strength, elastic modulus

Compressivestrength is more susceptible to temperature rise effect

(Boukendakdji, 2011) [16]

Six test for each super plasticizer with 1.2, 1.4, 1.6, 1.8, 2.0, 2.2( w/c 0.4)

10,15,20,25

Poly carboxylate (PC) based and naphthalene sulphonate based super plasticize

Workability and compressive strength

Workability improved up to 20 % of slag, p.c. based super plasticizer gave higher compressive strength

(Alhozaimy, 2012) [17] 1 : 3 : 0.5 10,20, 30,40, Ground dune sand

(GDS) ( 10, 20, 30, 40)Setting time , compressive strength

Compressive strength decreased by increasing GDS and GGBS, initial and final setting time increased

(Nataraja, 2013) [18]

mortar mix 1:3, w/c= 0.5

0, 25, 50,75 and 100%

sulphonated napthalene polymers based super plasticizer

Flow characteristic, compressive strength

Flow decreased with replacement, compressive strength decreased


POINT OF VIEW

Ground granulated blast furnace slag (GGBFS) -

Is a by-product of steel production and having latent

hydraulic properties. It is used to replace cement up to 80%

by mass. The research study done in previous years using

ground granulated blast furnace slag as replacement of

cement has been shown in Tables 3 and 4.

From the previous research work it was found that in both

cases (mortar and concrete) cement replacement by GGBFS

lies between 40-50%. It was also seen that Poly carboxylate

base super plasticizer was better option to be used with

GGBFS.

High reactivity metakaolin HRM is a processed aluminosilicatic pozzolan that is quite reactive. It is a finely ground material that reacts with slaked lime at low temperature and moisture to form strong but slowly hardening cement. It is manufactured by calcinations of purified kaolinite between 650-700oC in a kiln. It produces concrete with durability and strength as with silica fume. It is bright white in color. So it is preferred for architectural concrete. Table 5 gives a general overview about the work done with HRM in previous years.

It has been observed that optimum replacement of cement by HRM lies in the range of 8-10%. It was also observed that very less work has been done to study effect of HRM on mortar.

Table 5. Properties of concrete with HRM as partial replacement of cementAuthors Or References

Concrete mix

Replacement % by HRM

Additive or Condition

used

Properties studied Results ( for HRM)

(Boddy, 2001) [19] 25

0, 8, 12With w/c = 0.30 or 0.40

SPN super plasticizer

Early age Strength, bulk diffusion, rapid chloride permeability, ResistivityLong term- chloride propagation

Strength increased with decrease in w/c and increasing metakaolin. High metakaolin and lower w/c decreased diffusion, permeability conductivity and increased resistivity

(Erhan Guneyisi , 2012) [20]

75 to 86 MPaw/c =

(0.25,0.35) (5 and 15)%

A separate case was studied at same % replacement of cement by silica fume

Compressive and split tensile strength (S.T.S.), Water sorptivity, gas permeability

Strength increased with increase in silica fume and metakaolin. S.T.S. had same strength pattern as C.S., sorptivity coefficient decreased.

Gruber et al ( 2001) [21]

w/c = 0.30or 0.40

(5,10,15, 20)% SPN super

plasticizerChloride ion diffusion, bulk diffusion, expansion

HRM reduced chloride ion diffusion; bulk diffusion reduced with increase in HRM.

(Shelorkar, 2013) [22]

M60( w/c=0.29) ( 0, 4,6, 8) %

A high performance Superplacticizer (1% by mass)

Compressive strength (CS.), chloride permeability test (CPT)

CS increased,CPT decreased

(Patil, 2012) [23] M 50, (5,7.5,

10,12.5,15) %Polycarboxylic ether polymer

CompressiveStrength, chloride and sulfate attack

CS sulfate and chloride resistance increased upto 7.5% then decreased for 10, 12.5 and 15%.

Guneyisi et al (2007) [24] M 60

w/c =( 0.35,0.55) (0, 10,20)%

High-range water-reducing admixture(Sulphonated naphthalene)

Compressive and split tensile strength, water absorption, drying shrinkage and weight loss

CS increased max for w/c 10%, STS increased, water absorption decreased, shrinkage decreased with increase in metakaolin

(Jian-Tong Ding ,2002) [25]

M 40

(0, 5 10,15)%w/ binder ratio= 0.35

In presence of High-range water reducingAdmixture( 4.63) and Retarder ( 1.16)

Slump, compressive strength, free shrinkage, restrained shrinkage cracking (RSC), Chloride diffusivity

MK increases compressive strength at same pace as SF. Shrinkage decreased in both cases. RSC was less than control in both cases.



Silica fumeIt is a byproduct of production of silicon and ferrosilicon alloy. It is similar to fly ash but has size 100 times smaller resulting in high surface to volume ratio and much faster pozzolanic reaction. It is used to increase the strength and durability of concrete but often it requires the use of super

plasticizers for workability. Many authors carried out their investigation on various properties of concrete and mortars with silica fume (SF).

The previous research work by different authors using SF as replacement of cement has been shown in Tables 6 and 7.

Table 6. Properties of concrete with silica fume as partial replacement of cementAuthors or Reference

Concrete mix Replacement by SF ( %)

Additive / ConditionUsed

Properties studied Results ( for SF)

Ganesh Babu et al ( 1994) [26] 20- 100 MPa 5,10,16,20,30,40 Super plasticizer

(0-2)% Compressive strength As SF and w/c increased the strength decreased

Bhanja et al (2002) [27]

w/ binder ratio (0.26, 0.30,0.34,

0.38, 0.42)

0, 5, 10,15,2025 Super plasticizer3.5% by wt of cement

Flexural strength (FS), split tensile strength (S.T.S.)

S.T.S. increases with replacement, F.S. has more effect than S.T.S.

Lam et al (1997) [28] w/c 0.3, 0.4, 0.5 5%

Fly ash ( 0, 20,40)%In combination with S.F. (0, 15, 25,45,55)%separately

Tensile and compressive strength

Increased effect on tensile and compressive strength of cylinders

Jianyong et al (1997) [29] M 50 15, 10, 5

Slag at 10,15,20% respectively to each % of SF, Super plasticizer (1%)

Compressive strength, split tensile strength, rupture strength

Lower compressive strength, high split tensile strength, rupture strength improved

Duval et al (1997) [30] w/ binder 0.25,

0.30, 0.35, 0.45 0,10,20, 30

Naphthalene Sulphonated super plasticizer

Workability, compressive strength

Workability loss increased with increase in SF content. Compressive strength depends on w/c more than on % replacement.

Mustafa Saridemir (2013) [31]

70 to 105 MPaw/c 0.25

5,10,15,20, 25

polycarboxylic ether based super plasticizer,Ground pumice (GP) alone and with combination to SF at same %

Compressive strength, Ec

SF gives higher compressive strength than GP and control.Ec is higher for SF relatively to GP.

Shannag (2000) [32] 69- 110 MPa,

w/c =0.350, 5, 10 , 15,

20, 25

Natural pozzolana( 15)%Super plasticizer( 0.03)%

Workability, compressive strength, Ec , Split tensile strength

High workability achieved, rate of increase of Ec was less than compressive strength. S.T.S. showed inconsistency

J. M. R. etal (2004) [33] w/binder ratio

0.50,0.65, 0.80 0, 16,12 _ Compressive strength, electrical resistivity

CS and electrical resistance increased with increase in % of SF.,

Table 7. Properties of mortar with silica fume as partial replacement of cement

Authors or Reference Mortar Replacement

by SF ( %)Additive / Condition

used Properties studied Results ( for SF)

(Rodriguez, 2012) [34]

w / binder =0.30,Sand / binder =2.0

5,10,20For both SSF

and DSF.

Super plasticizer(1.1 to 2.0)%

Compressive strength, permeability

Compressive strength greater in SSF, permeability reduced.

Appa .Rao (2001) [35]

w/c (0.35, 0.40, 0.45, 0.50)

(c/ sand) 1:30 to 30 - Compressive

strength

Compressive strength increased as SF increased on 0.35 and 0.40 up to optimum % in early ages (3 and 7). At 0.50, increase in SF increases strength at 7, 28 and 90 days also.


POINT OF VIEW

Table 8. Properties of concrete with Rice Husk Ash as partial replacement of cementAuthors or Reference Mix Replacement by

RH (%)Additional condition Properties studied Results ( for RHA)

(Rodriguez de Sensale, 2005) [36]

w/c 0.50, 0.40,0.32 0, 10, 20 At low %

Compressive strength, split tensile strength, air permeability

C.S. with RHA increased but S.T.S. and air permeability decreased.

Rodriguez de Sensale, 2010) [37]

Agg./ binder 2.75 0, 5, 10, 15 Super plasticizer

for 0.32- 0.52, 0.40- 0.10

Air permeability, chloride ion penetration, sulfate resistance

A.P. reduced with RHA, CL penetration value decreased, rise in sulfate resistance.

(Sakr, 2006) [38] w/ c 0.40 0, 5, 10, 15, 20 SP (max -15%),

Compressive strength , sulfate resistance, Separate test with SF at same % for comparison

After 15% increase in RHA, CS reduced , SF showed better sulfate resistance

(Muthadhi ,2013) [39] W binder = 0.30, 0.33, 0.36, 0.44 10, 15, 20, 30 Poly carboxylic ether

polymer based SP

Compressive strength, chloride permeability, water absorption

CS improved, chloride permeability reduced, water absorption reduced

(Shoaib, 1996) [40] 70 MPaw/c = 0.25 to 0.3 10 to 30% Plasticizer

( 25 ml/ kg of cement)

Rate of hydration (R.O.H.), compressive strength

R.O.H decreased, max strength at 15%

(Alireza Naji, 2010)[41] M 35 5, 10, 15, 20Two types of RHA( 5 micron and 95 micron)

Water absorption( w.a.), compressive strength, workability

RHA increased CS,w.a. decreased,workability improved

(Hwang Chao Lung, 2011) [42]

M 55w/b 0.25, 0.35,

0.470, 10, 20, 30 Super plasticizer

Compressive strength, electrical resistance (e.r.), ultra sonic pulse velocity (U.P.V.)

CS increased at later stages ,e.r. increases, U.P.V. reduced

(Ramasamy, 2011) [43] M30, M60 5, 10, 15, 20 Super plasticizer Water absorption, rapidchloride permeability

Water absorption reduced, R.C.P. reduced,

Table 9. Properties of mortar with RHA as partial replacement of cementAuthors or Reference Mortar Replacement by

RH (%)Additional condition Properties studied Results (for RHA)

Rodriguez de Sensale, 2010) [37]

w/c 0.50, 0.40,0.32 0, 5, 10, 15 Super plasticizer

for 0.32- 0.52, 0.40- 0.10

Air permeability, chloride ion penetration, sulfate resistance

A.P. reduced with RHA, CL penetration value decreased, rise in sulfate resistance.

With mortar more stress was laid on w/c, as a result it was seen that SF resulted better at w/c= 0.50. For both mortar and concrete, optimum replacement range of cement by SF lies between 10-25%.

Rice husk ash It is generated during the milling process on the accumulated covering of rice grain. It is the agro waste in which appropriate amount of silica is present. Highly reactive RHA (Rice Husk Ash) is obtained when RHA is burnt under controlled condition. Residual RHA is produced with a lower quality

due to high carbon content. High carbon content increases water demand and introduce dark color to mortar and concrete. It has a considerable amount of carbon which can have adverse effect on its pozzolanic activity. Tables 8 and 9 provide an overview about some work done with Rice Husk.

From the above study, in case of mortar it was observed that RHA resulted better at w/c = 0.32 with replacement range of cement by RHA between 10-15%. In case of concrete the optimum replacement range of cement by RHA was found between 10-20%.



Table 10. Effect of accelerators on properties of concreteAuthors Concrete mix Admixture

(% of concentration)

Additional condition Properties studied Results

(Arunakanthi, 2013) [44]

1:0.76:1.8w/binder

0.3

(0.2, 0.5,1, 2)g/l of CaCl2

Metakaolin (20%) in presence of a High performance superplasticiser (1%)

Compressive strength (CS) and Split tensile strength ( STS)

CS and STS increases with conc. of CaCl2

Devi et al, 2012) [45]

(1:1.517:3.38)w/c = 0.45

TEA (1,2,3,4) % By wt of cement Quarry dust as fine aggregate

Compressive strength (CS), split tensile strength (TS), flexural strength (FS)

Increase in CS, STS, FS till 2%

(Aggoun, 2006) [46]

For Normal C3S( M10 to M15)

Low C3S(M20 to M25)

w/c 0.3

TEA (0.05%)Wt of cement

Compared with[CN(1%)+TEA] Compressive strength CS increases for

both cement

(Aggoun, 2006) [46]

For Normal C3S ( M10 to M15)

Low C3S (M20 to M25)

w/c=0.3

CN (1%)Compared with [CN (1%) +TEA (0.05%)] and [CN (1%) + TIPA (0.05%)]

Compressive strength CS increases for both cements

(Aggoun, 2006) [46]

For Normal C3S ( M10 to M15)

Low C3S(M20 to M25)

w/c=0.3

TIPA (0.05%)by wt of cement

compared with[TIPA (0.05%)+ CN (1%)] Compressive strength CS increases for

both cements

(Venkatesh Reddy,2005) [47]

M20 to M50 Na2CO3(1,2,4,6,10, 15 ) g/l

NaHCO3 used at same concentration

Setting time, compressiveStrength, tensile strength

Setting time reduced, strength also reduced

(Smaoui , 2004) [48]

Fine: coarse agg = 0.41

Fine: coarse agg. = 40: 60

Na2Oe 0.6% to 1.25% _

Compressive strength,Tensile strength

Reduction incompressive , And tensile strength

(Yong–Soo Lee, 2013) [49] w/c 0.52

Sodium AlluminatePowder and Tablet form0.5, 1.0, 1.5%, 2%

_ Setting time, compressionstrength Both get reduced

chemical admixtures

Chemical admixtures are mainly in five categories i.e. accelerators, retarders, air entrainers, super plasticizers, pigments. Accelerators cause early strength gain and speeds setting time. Retarders delay the setting time. Air entrainers increase workability, durability and reduce bleeding. Super plasticizers increase the strength, workability by decreasing water. Pigments add colors.

Accelerators Are the admixtures which reduces setting time of mortar and concrete. They also allow the concrete to be placed in winter in order to avoid any damage. Some of the accelerators are CaCl2, Triethanol amine (TEA), Triisopropanol amine ( TIPA), Calcium Nitrate(CN), Sodium Thiocynate, Oxalic acid, Calcium formate, Sodium carbonate, Sodium aluminates etc. Various research studies carried out about these accelerators have been discussed in Tables 10 and 11.


POINT OF VIEW

Tables 12. Effect of retarders on properties of concrete Authors Concrete mix Admixture

(% of concentration)Additional condition Properties studied Results

(Weerachart Tangchirapat, 2006) [56]

Ratio of fine to coarse 45:55

POFA (Palm OilFuel ASH)

(10, 20, 30, 40)% by wt of binder

Three size of POFA were tested OP, MP and SP

Initial and final setting time

Ordinary size POFA delayed initial and final time

(F. O. Okafor, 2008) [57]

1:2:4w/c 0.4

Cassava flour(CF)

(1, 2, 3, 5, 7, 10)% wt of cement

_ Initial and final setting time

Initial and final setting time was delayed up to 3%

Table 11. Effect of accelerators on properties of mortar Authors Mortar Admixture


(Kyle Riding, 2010) [50]

w/c =0.5,agg:c 2.75

0.06% to wt of cement( CaCl2)

Diethanol- isopropanol amine(0.02%) alone and combined

strength Combination of both increases the early age strength

(D. Heinz, 2009) [6]

1:3:0.5 (c:sand:w)

TEA(0.01 and 0.2 )

% by wt of cement

Fly ash (25%)As cement replacement Early age strength

TEA effective in case of fly ash,For O.P.C. TEA showed no considerable effect

(Justane, 1995) [51] w/c =0.40

Calcium Nitrate( CN)(0, 1.55,2.32, 3.10,

3.86,7.73)%Of cement wt

At two temp 50 and 7oC Early strength CN had accelerating effect

(Paul J. Sanderberg, 2003) [52]

w/ c=0.42 TIPA (200ppm) _ Early age strength Significant strength gain (9%)

(Wise, 1995) [53]

For cement paste w/c

=0.25

Calciumthiocynate(0,1.5,3)%

Compared with Sodium, potassium, Calcium ,lithium at same %

Early age strength Gain in early age strength was seen

(Singh, 2003) [54] c/sand =1:3

Oxalic acid(0.05, 0.1,0.25,

0.5,1,2,3,4)In ratio with

HEC as 1:1, 2:1, 3:1,4:1

HEC ( hydroxyethyl cellulose)

Setting time, early age strength

Setting time decreased, early age strength increased

(Mohamed Heikal ,2003) [55]

w/c for each cement

0.245, 0.325,0.320-0.265

Calcium Formate0, 0.25, 0.50, 0.75

3 types of cement was used i.e. opc,Pozzolanic ( 20% SF), 20% groun clay brick

Compressive strength Early and later strength increased

(Yong–Soo Lee, 2013) [49]

w/c = 0.5

Sodium AlluminatePowder and Tablet

form0.5, 1.0, 1.5%, 2%

_ Setting time, compression strength Both get reduced

CaCl2 - it was observed from the table that for CaCl2, w/c ratio was kept between 0.3 to 0.5, for both mortar and concrete. It was concluded from the table that 1g/l was the optimum value for CaCl2.

TEA - Previous literature reveals that for TEA, w/c was kept in the range of 0.45 to 0.5 for both mortar and concrete. The most optimum range of TEA for replacement of cement lies between 0.05%- 0.2%.

Retarders Are the admixtures which are added in order to slow down the reaction and rate of setting down of concrete. By doing so concrete can remain in fresh mix condition before getting hardened. Some of the retarders are sugar, sodium gluconate, citric acid, lignosulfonate and polysaccharide. Following gives an idea about the work done with retarders has been provided in Tables 12 and 13.



Table 13. Effect of retarders on properties of mortarAuthors Mortar Admixture


( Singh, 1976) [58] Cement pastew/c 0.5

Sodium gluconate(0.055, 0.110, 0.165 ,

0.220, 0.275)% by wt of cement

Temperature was 25oC Setting time Cement hydrationreaction was retarded.

(Thomas, 1983) [59] Cement Pastew/c 0.2

Sugar 15 mM and50 mM _ Setting time Cement hydration

retarded

(Singh, 1986) [60] Cement pastew/c 0.2, 0.25

Citric acid(0, 0.1, 0.2, 0.3, 0.4 )

% by wt_ Setting time

At (0.2, 0.3, 0.4)%By wt of cementretarded the hydration of cement

(Singh, 2001) [61]10 wt%

RHA blendedPortland cement

1 wt % lignosulphonate

(LS)

2% wt CaCl2Alone and combination of both at same concentrations to compare

Setting time andCompressive strength

1% LS prolonged the setting time compressive strengthwas lower to control

(Maria C. Garci Juenger, 2001) [62]

Cement pastew/c 0.45

Sugar 1% by wtof cement

At differenttemperatures Setting time

Hydration reactionIs delayed

(Moschner, 2009) [63]

Cement Paste1 kg cement + 400

gmdistill water

w/c 0.4

Citric acid(0.1, 0.4, 0.5)

% by wtff cement

_ Setting timeSlow down of hydration product formation

(Peschard, 2005) [64] p/ c 0.5% by wt of cement

Polysaccharides(P)

Cellulose ether, starch ether , native Starch, white dextrin, yellow dextrin were also tested

Setting time

Yellow dextrin retarded hydration to max p/c ratio increment lead to extend delay in hydration

dIScuSSIon and concLuSIon The presence of admixtures affect as well as change the fresh and hardened properties of concrete and the change in properties depends upon types of admixtures as well as on their proportion in which they are being used . As mentioned above, admixtures can be classified into categories of mineral as well as chemical admixtures. It has been observed from previous research studies that mineral admixture were used alone and also in combination.

The use of mineral admixtures was large as compared to the chemical admixtures in past. But in recent years chemical admixtures have gained demand. Selection of admixtures is up to the priority of designer and may vary according to quality of cement and ingredient materials of concrete. From the result of researchers it was found that different combinations of admixtures yielded different results.

Research work regarding chemical admixtures is yet to be explored as mineral admixture have been centre of interest since many years and in present time too. The combination of mineral and chemical admixture can create new field for work.

References

Limbachiya Mukesh, Mohammed Seddik Meddah, Youssef Ouchagour , ‘Use of recycled concrete aggregate in fly ash concrete,” Construction and Building Materials,2012,vol.27,pp.439-449.Hanneson Gudmundur, Katherine Kuder, Shogren Rob, Lehman Dawn, “The influence of high volume of fly ash and slag on the compressive strength of self consolidating concrete “, Construction and Building Materials, 2011,vol.30,pp.161-168. Boga Ahmet Raif, Bekir Topcu Ilker, “Influence of fly ash on corrosion resistance and chloride ion permeability of concrete,” Construction and Building Materials, 2012,vol.31,pp.258-264.[4] Kuder Katherine , Lehman Down , Berman Jeffrey , Hannesson Gudmunder , Shogen Rob , “ Mechanical Property of self consolidating concrete blended with high volume of fly ash and slag,” Construction and Building Materials, 2012,vol.34,pp.285-295.

1.

2.

3.

4.


POINT OF VIEW

Shi Xianming , Yang Zhengxian , Lin Yajun , Cross Doug ,” Strength and corrosion properties of Portland cement mortar and concrete with minerals admixtures,” 2011,vol.25,pp. 3245-3256.Heinz D., Globel M., Hilbig M., Urbonas L., Bujanskaite G. , “ Effect of TEA on fly ash solubility and early age strength of mortar,” Cement and Concrete Research, 2009,vol.40,pp.392-397.Nochaiya Thanongsak , Wangkeo Watcharapang , Chaipanich Arnan , “ Utilization of fly ash with silica fume and properties of Portland cement fly ash –silica fume concrete,” Fuel, 2009,vol.89,pp.768-774.Yilmaz Bulent , Olgum Asim , “ Studies on cement and mortar containing Low calcium fly ash, lime stone and dolomistic lime stone ,” Cement and concrete composite, 2007,vol.30, pp.194-201. Zadeh, Zanjani Vahid, Bobko Christopher P. ,” Nanoscale mechanical properties of concrete containing blast furnace sag and fly ash before and after thermal damage”, Cement And Concrete Composites, 2012,vol.37,pp.215-221.Shariq Mohd, Prashad Jagdish, Hasood Amjad, “Effect of GGBFS on time dependent compressive strength of concrete,”Construction and Building Materials, 2010, vol.24, pp.1469-1478.[Li Gengying , Xiaohua Zhao,” Properties of concrete incorporating fly ash and ground blast furnace slag,” cement and concrete composite , 2003,vol.25,pp. 293-299.Suvarna Latha K. , Seshagiri Rao M.V. , Srinivasa Reddy V, “ Estimation of GGBFS and HVFA Strength efficiencies in Concrete with age”, International Journal of Engineering and Advance Technology, 2012, vol-2. Nazari Ali, Riahi, “Splitting tensile Strength of concrete using Ground Granulated Blast Furnace Slag and Sio2 nano particals as binders,” 2010,vol.43, pp.864-872. Hwang Chao –lung , Der-Hsien Shen ,”The Effect of Blast Furnace Slag and fly ash on the hydration of Portland cement,” Cement and concrete research,1991,vol.21,pp.410-425.Wang H.Y., “Effect of elevated temperature on cement paste containing GGBFS,”Cement and Concrete Composite, 2007, vol.30, pp.992-999.Boukendakdji Othmane, Kadri El- hadj ,Kadri Said,” Effect of Granulated Blast Furnace Slag and superplasticizer type on the fresh properties and compressive strength of self- compacting concrete,” Cement & Concrete Composite, 2011,vol.34,pp.583-590. Alhozaimy A., AL-Negheimish A.,Alawad O.A. ,Jaafer M.S., Noorzaei J.,” Binary and Ternary effects of ground dune sand and blast furnace slag on the compressive strength of mortar,” Cement and Concrete composite, 2012,vol.34,pp.734-738.Nataraja M C, Kumar P G Dileep , Manu A S , Sanjay M C ,” Use Of Granulated Blast Furnace Slag As Fine Aggregate In Cement Mortar ,” IJSCER, 2013, vol.2.Boddy Andrea ,Hooton R.D. ,Grubber K.A., “ Long term testing of the Chloride- penetration resistance of concrete containing High Reactivity Metakaolin,” cement and concrete research , 2001,vol.31,pp.759-765. Guneyisi Erhan , Mehmet- Gesoglu, Karaoglu Seda , Mermerdas Kasim , “ Strength , permeability and shrinkage cracking of silica fume and metakaolin concrete,” Construction & Building Materials, 2012,vol.34,pp.120-130.Grubber K.A., Lochan Terry Ram, Body Andrea, Hootan R.D., Thomas M.D.A. ,” Increasing Concrete durability with high reactivity metakaolin, “Cement & concrete composite, 2001,vol.23,pp.479-484.Ajay P. Shelorkar, Dr.D. Jadhao Pradip, “Strength appraisal of High Grade Concrete by using High Reactive Metakaolin,” IJIRSET, 2013, vol.2,pp.657-663. Patil B.B., Kumbhar P.D.,” Strength and durability properties of High Performance Concrete in corporating High Reactivity Metakaolin” IJMER, vol2,pp.1099-1104. Guneyisi Erhan , Mehmet- Gesoglu, Mermerdas Kasim ,” Improving strength , drying shrinkage and pore structure of concrete using Metakaolin,” Materials and structures , 2007.Ding Jian –Tong, Zong jin li,” Effects of Metakaolin and Silica fume on properties of concrete, “ACI MATERIALS JOURNALS, 2002, vol.99, pp.393-398.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

Babu K.Ganesh, Surya Prakash P.V.,” Efficiency of silica fume in Concrete,” cement and concrete research, 1995, vol25, pp-1273-1283.Bhanja S.,Sengupta B.,” Influence of silica fume on the tensile strength of concrete,” Cement and concrete research, 2004,vol.35,pp.743-747. Lam L., Wang Y.L. , Poon C.S. ,” Effect of Fly ash and Silica fume on compressive and fracture behaviors of concrete” cement and Concrete research, 1997,vol.28, pp.271-283.Jianyaong li, Pei Tian ,” Effect of slag and silica fume on the mechanical properties of High strength concrete ,” cement and concrete research , 1997,vol.27,pp.833-837.Duval R., Kadri E.H.,” Influence of silica fumes on the workability and the compressive strength of High Performance concrete,” cement and concrete research.1998,vol.28,pp. 533-547.Suri demir Mustafa,” Effect of silica fumes and ground pumice on compressive strength and modulous of elasticity of high strength concrete,” Construction and Building materials, 2013, vol.49, pp.484-489. Shannag M.J.,” High strength concrete containing natural pozolonna and silica fume,” cement and silica fume,” cement and concrete composite, 2000,vol.22,pp.399-406. Dotto J.M.R., Abreu A.G. de, D.C.C. Dal molin, Influence of silica fume addition on concrete physical properties and on corrosion behavior of reinforce bar,” 2004,vol.26,pp.31-39.Rodriguez Erich D, Bernal Sudan A. , Provis John L. , Paya Jondi , Monzo Jose M. and Borrachero Maria Victoria,” Structure of Portland cement pastes blended with sonicated silica fume,” Journal of materials in civil engineering,” 2012,vol.24, pp.1295-1304.Rao G. Appa,” Development of strength with age of mortars containing silica fume,” cement and concrete research, 2001, vol.31, pp.1141-1146.Sensale Gemma Rodriguez de,” Strength development of concrete with Rice Husk Ash “Cement and Concrete Composite, 2005, vol.32,pp.158-160. Sensale Gemma Rodriguez de,” Effect of rice husk ash on durability of cementitious materials,” 2010, 718-775. Sakr K., “Effect of silica fume and Rice Husk Ash on the properties of Heavy Weight Concrete,” Journal of Materials in Civil Engineering, 2006, vol.18, pp.367-376.Muthadhi A., Kothandaraman S., “Experimental investigations of Performance characteristic of Rice Husk Ash- Blended Concrete” JOURNAL OF MATERIALS IN CIVIL ENGINEERING, 2013, vol.25, pp.1115-1118. Shoaib Ismail Muhammed,” Effect of rice husk ash on high strength concrete,” Construction and Building Materials, 1996, vol.10, pp.521-526. Givi Alireza Naji, Rashid Surya Abdul , Naa Farah ,Aziz A. , Salleh Mohammed Amran Mohd,” Assessment of the effects of Rice Husk ash particle size strength , water permeability and workability of binary blended concrete ,” Construction and Building Materials ,” 2010,vol.24,pp. 2145-2150. Chao- Lung Hwang, Anh- Tuan Buile, Chen Chun-Tsun, “Effect of rice husk ash on the strength and durability characteristics of concrete,” Construction and Building Materials, 2011, vol.25, pp. 3768-3772. Ramaswamy V., “Compressive strength and durability properties of Rice Husk Ash Concrete,” KSCE Journal of Civil Engineering, 2012, 93-102.Arunakanthi E. , Sudarsang Rao H.,” Effect of calcium chloride in mixing and curing water on strength of High Performance Metakaolin Concrete” Indian Journal of Research , 2013, vol.2,pp.91-94.Devi M., Kannon K.,” Inhibitory Effect of Triethanolamine in Quarry Dust Concrete,” Coromandal Journal of Science, 2012, vol.1, pp.10-16. Aggoun S., Cheikh – Zouaoui M. ,Chikh N. , Duval R. ,” Effect of same admixture on the setting time and strength evolution of cement paste at early age,” Construction And Building Material, 2006,vol.22,pp.106-110.

26.

27.

28.

29.

30.

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33.

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36.

37.

38.

39.

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41.

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POINT OF VIEW

Reddy V. Venkateshvara, Rao H. Sudarsana , Jayaveera K N , “ Influence of strong alkaline substance ( sodiumcarbonate) & ( sodium bicarbonate) in mixing water on strength and setting properties of concrete ,” Indian Journal of Engineering & Materials Science, 2005,vol.13,pp. 123-128.Smaoui. N., Berube M. A. , Fournier B. , Bissonnette B. , Durand B. ,”Effect of alkaline addition on the mechanical properties and durability of concrete,” Cement and Concrete Research, 2005, vol.35,pp.203-212. Lee Yong –Soo, Dae – Sung Lim, Byung –Sik Chun, Jae Suk Ryou , “ Characterisation of a sodium alluminate ( NaAlO2) based accelerator , made via a table processing method ,” Journal of Ceramic Processing Research , 2013,vol.14,pp.87-91. Riding Kyle, Denise A. Silva, Scrivener Karen,” Early age strength enhancement of blended cement system by CaCl2 and diethanol – isopropanolamine,” Cement and Concrete Research, 2010,vol.40,pp.935-946. Justane Harold,” Technical Calcium Nitrate as set accelerator for cement at low temperature,” Cement and Concrete Research, 1995, vol.25, pp.1766-1774.Sandberg Paul J., Doncaster F. ,” On the mechanism of strength enhancement of cement paste and mortar with triisopropanolamine,” Cement and Concrete Research, 2004, vol.34, pp.973-976.Wise T., Ramachandran V.S., Polomark G.M.,” The effect of thiocynates on the hydration of Portland cement at low temperature,” thermochemica acta, 1995,vol.264,pp.157-171.Singh N.K., Misra P.C., Singh V.K., Narang K.K. , “ Effect of hydroxyethyl cellulose and oxalic acid on the properties of cement ,” cement and concrete research, 2003,vol.33,pp.1319-1329.

47.

48.

49.

50.

51.

52.

53.

54.

Heikal Mohammed ,” Effect of Calcium Formate as a set accelerator on the physiochemical and mechanical properties of pozzolanic cement pastes ,” Cement And Concrete Research, 2004,vol.34,pp.1051-1056. Tangchirapat Weerachart , Sacting Tirasit , Chai Jatmapitakkul, Kiattikornol Kraiwood , Ahek Siripanichgerm,” Use of waste ash from palm oil industry in concrete ,” waste management , 2006,vol.27,pp.81-88. Okafor F.O.,”The potential of cassava flour as a set retarding admixture in concrete,” Nigerian Journal of Technology, 2002, vol. 27, 5-12. Singh N.B., “Effect of Gluconates on the hydration of cement,” Cement and Concrete Research, 1976, vol.6, 455-460. Thomas N.L., Birchall J.D., “The retardation action of sugars on cement hydration “Cement and Concrete Research, 1983, vol. 13, pp.830-842. Singh N.B. , Singh A.K. , Smt. Singh S. Pabha ,” Effect of citric acid on the hydration of Portland cement ,” Cement And Concrete Research,” 1986, vol16, pp.911-920.Singh N.B. , Singh V.D. , Singh Sarita , Rai Sarita , Chaturvedi Shivani , “ Effect of lignosulfonate , calcium chloride and their mixture on the hydration of RHA- Blended Portland cement ,” Cement And Concrete Research, 2001,vol.32,pp.387-392. Juenger Maria C. Garei, Jennings Hamlin M.,” New insights into the effects of sugar on the hydration and microstructure of cement paste,” Cement and Concrete Research, 2001, vol.32, pp.393-399. Moschner Goril , Lothenbach Barbara , Figi Renato , Ruben Kretz- Schmar,” Influence of citric acid on the hydration of Portland cement ,” Cement And Concrete Research , 2009, vol.39,pp.275-282.Peschard A., Govin A. , Pourchez J., Fredan E. , Bertrace L., S. Maximilien , Guilhot B. ,” Effect of Polysaccharides on the hydration of cement suspension ,” ECERS ,2006,vol.26,pp. 1439-1445.

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Dr. S.M. Gupta holds a B.Sc. Civil (Hons.), an M.Tech. and PhD, all from Kurukshetra University, Kurukshetra, Haryana. He is a Professor in the Civil Engineering Department, National Institute of Technology, Kurukshetra. His fields of interest are structural engineering, high strength concrete and self compacting concrete.

Babita Saini holds a B.E. Civil (Hons.) from Punjab University, Chandigarh; M.Tech. and PhD degrees from Kurukshetra University, Kurukshetra, Haryana. She is an Associate Professor in the Civil Engineering Department, National Institute of Technology, Kurukshetra. Her fields of interest are concrete technology, design of concrete and steel structures.

Rahul Singh holds an M.Tech degree from NIT Kurukshetra, Haryana. He is an Assistant Professor in the Civil Engineering Department of Ajay Kumar Garg Engineering College, Ghaziabad (UP). He has presented and published few research papers in national conferences. His fields of interest are recent developments in concrete technology, use of daily waste materials in enhancing concrete properties and design of concrete structures.

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