seismic performance of hybrid fibre reinforced beam ... representing an exterior beam column joint...

INTERNATIONAL JOURNAL OF CIVIL AND STRUCTURAL ENGINEERING Volume 1, No 3, 2010

© Copyright 2010 All rights reserved Integrated Publishing services Research article ISSN 0976 – 4399

749

Seismic performance of hybrid fibre reinforced Beam Column joint Perumal.P 1 , Thanukumari.B 2

1 Professor and Head, Department of Civil Engineering, Government College of Engineering, Salem, TamilNadu, India

2 Research Scholar, Assistant Professor and Head, Department of Civil Engineering, Cape Institute of Technology, Levengipuram, Tirunelveli District,amil Nadu, India.

[email protected]

ABSTRACT

High Strength Concrete has become a very popular construction material which is directly related to recent development in concrete technology. The brittle nature of this High Strength Concrete results in sudden unpredictable failure. By using special hybrid fibre combinations of steel and polypropylene fibres, the explosive failure behaviour of High Strength Concrete (HSC) may be avoided. The main objective of this study is to investigate the effect of different proportions of hybrid fibre combinations (1.5% of steel fibre and 0 to 0.4% of polypropylene fibre) at the joint of exterior beamcolumn connections subjected to earthquake loading using M60 concrete. The hybrid fibre combinations of 1.5% of steel fibre and 0.2% of polypropylene fibre have best performance considering the strength, energy dissipation capacity and ductility factor. An attempt has been made to develop a new model by slightly modifying the previous models available in the literature for the joint shear strength. The proposed model was found to compare satisfactorily with the test results.

Keywords: High strength concrete, hysteresis, hybrid, energy absorption and beam column joint.

1. Introduction

The recent earthquakes revealed the importance of the design of reinforced concrete (RC) structures with ductile behaviour. Ductility can be described as the ability of reinforced concrete cross sections, elements and structures to absorb the large energy released during earthquakes without losing their strength under large amplitude and reversible deformations. Generally, the beamcolumn joints of a RC frame structure subjected to cyclic loads such as earthquakes experience large internal forces. Conventional concrete looses its tensile resistance after formation of cracks. However, fibre concrete can sustain a portion of its resistance following cracking to resist more cycles of loading. Development of HSC is directly related to a number of recent technological developments. HSC is developed by using superplasticizer, micro fillers like silica fume and flyash and fibres of different types. The specific use of these micro fillers leads to a strengthening of the cement matrix as well as an improvement of density and surface abrasion resistance. Unfortunately the behaviour of the HSC is very brittle. The improvement of compressive strength is followed by a very strong bond in the interaction zone of aggregate and cement matrix. The weakest components in the high strength



750

concrete structure are the aggregate, while these are the interaction zones in the normal strength concrete. The HSC structures fall suddenly without an announcement by cracks and the fracture zone is very smooth. This leads to a wellknown steep descending branch of the stressstrain curve. In practice only few methods are known to improve the ductility of HSC structural members under compressive forces. The closely spaced ties are one of the examples. Instead of using this method the main aim of the present research programme is to strengthen the material itself to avoid disadvantageous concerning costs and workability. In this article, the experimental study is made by using the fibres to increase the ductility in the beamcolumn joint, which is the most critical region during earthquake.

2. Research Objectives

This paper reports experimental study carried out to investigate the behaviour of exterior beam column joint made of hybrid fibre (combinations of steel and polypropylene fibres) reinforced concrete. In the previous investigations the amount of steel fibres, type and aspect ratio, amount of synthetic fibers have been separately taken into consideration as experimental parameters. In the present study five sets of high strength concrete specimens representing an exterior beam column joint subjected to reversed cyclic loading were tested under displacement controlled loading. The specimens were designated as per the Table 1. The first specimen was cast without seismic detailing (designed as per IS 4562000).

Figure 1: Seismic Joint

The second specimen was cast as per seismic detailing as per the requirements of IS Code 13920:1993. Figure 1 shows the beamcolumn joint with seismic detailing. The



751

remaining three specimens were designed as like the first one but incorporating hybrid fibre in the joint region. Figure 2 shows the beamcolumn joint without seismic detailing with hybrid fibre reinforced concrete in the joint region. Hybrid fibre combination was mixed in the range of 1.5% of steel fibre and 0 to 0.4% of polypropylene fibre with an increment of 0.2 %.

Figure 2: Fibre Joint

Table 1: Details of the Test specimens

Specimen Idetification III O2 III S2 III F12 III F 22 III F32 Detailing of Lateral

Reinforcement

Without Seismic Detailing

With Seismic Detailing




% of Steel fibre 1.5 1.5 1.5

% of Polypropylene

Fibre 0 0.2 0.4



752

2.1 Material Properties and Concrete Mixes

Two different concrete mixes were used and they were given in Table 2. HPC mix proportion for M 60 concrete was obtained based on the guidelines given in modified ACI 211method. Table 2 presents the proportions of the two different concrete mixes used to cast the test specimens. OPC 53 grade cement, river sand passing through 4.75mm IS sieve and coarse aggregate less than 10 mm size were used for the investigation. Corrugated steel fibres of diameter 0.5mm, length 30mm and aspect ratio 60 were used. The polypropylene fibre used has a diameter of 0.008mm, length 20mm and of aspect ratio 2500. Part of the cement was replaced by micro fillers such as silica fume (10 %) and flyash (15%). In this study the cement was replaced by 10% of silica fume and 15% of flyash. Superplasticizer was added to increase the workability of the concrete.

Table 2: Mix Proportions of High Strength Concrete (kg/m 3 )

Mix Cement Fly Ash

Silica fume

Sand Coarse Aggre Gate

Water Super Plasti siser

Steel Fibre

Polypropylene fibre

HPC 463 88 36 656 962 209 10 lit HPFRC 463 88 36 608 891 207 11.75 lit 117.5 0,1.82&3.64

3. Experimental Setup and Procedure

Each specimen was tested under reversed cyclic loading in the loading frame. The general arrangement of the experimental setup is shown in Figure 3. The reversed cyclic load was applied by using one screw jack for giving downward displacement and one hydraulic jack for giving upward displacement at the end of the beam at a distance of 50mm from the beam end.

Figure 3: Schematic Diagram of Reverse Cyclic Loading Test setup



753

The loading programme consisted of a simple history of reversed symmetric displacement amplitudes of 5mm, 10mm, 15mm, 30mm and 45mm. The test was done with displacement control and the specimen was subjected to an increasing reversed cyclic displacement up to failure. By using proving ring the load was precisely recorded and the beam displacement using dial gauge.

4. Results and Discussions

4.1 Ultimate load

Table 3 shows the ultimate load for all the specimens. Figure 4 shows the envelope curve of the displacement load cycles for all the specimens. From this figure it is evident that the specimen III F 22 has maximum ultimate load of 37.6 kN. It is 77.5% higher than the specimen cast without fibre (III O2) and 9.5% higher than the specimen cast by using steel fibre only (III F 12).

Table 3: Ultimate Load, Maximum Deflection at failure and Energy Dissipation Capacity

Ultimate load (pu) kN

Deflection at Failure (mm) (δu)

Sl.No Specimen Id Positive Negative Positive Negative

Energy Dissipation Capacity(Ecu)

KNm 1 III O2 22 21.2 30 30 522 2 III S2 23.4 26 45 30 866 3 III F12 30.6 34.4 45 30 1455 4 III F 22 32.7 37.6 45 45 1781 5 III F32 28.4 30.4 45 30 1207

Figure 4: Overall Load Displacement curve for all test specimens



754

4.2 Energy Dissipation Capacity

Table 3 shows the energy dissipation capacity of all the specimens. Figure 5 shows the hysteresis loop for the specimen III F22. Figure 6 shows the energy dissipation capacity of all the specimens. From this figure it is noted that the specimen III F22 has the maximum energy dissipating capacity. It is 241% higher than the specimen without fibre (III O2) and 22.5% higher than the specimen with steel fibre only (III F12).

Figure 5: Load Displacement Plot For III F 22

Figure 6: Energy Dissipation Capacity

4.3 Experimental Joint Shear stress

For the exterior beamcolumn joint the horizontal and vertical joint shear stresses (τjh, τjv) can be calculated using the following formula (Murty et al. 2003)

τjh = h A core H b b b

b c

L L 0.5D d L

+ −

and (1)



755

τjv = b c b v

c c

L 0.5D L D 1 A core L d

c H + − −

(2)

ACI 318 specifies the limit of joint shear stress as k√ ' c f Mpa, where ' c f is the cylinder compressive strength, in Mpa. The factor k depends on the confinement provided by the members framing into the joint; k is taken as 1.67, 1.25 and 1.0 for interior, exterior and corner joints respectively.

Table 4: Ultimate Shear capacity of the Joint using M60 Concrete

Sl. No

Specimen Id ' c f

N/mm 2

Ultimate Load kN

Horizontal Shear stress

τjh, in kN/mm 2

Vertical Shear stress τjv in kN/mm 2

Limiting Shear stress as per

ACI= 1.0 ' c f kN/mm 2

τjh, / τACI

1 III O2 61.2 22 13.2 11.70 7.82 1.69 2 III S2 61.2 26 15.6 13.83 7.82 1.99 3 III F12 66.9 34.4 20.64 18.29 8.18 2.52 4 III F 22 69.3 37.6 22.56 20.00 8.32 2.71 5 III F32 62.8 30.4 18.24 16.17 7.92 2.30

Table 4 shows the horizontal and vertical shear stresses induced in the joint region, and code prescribed limiting shear stress. From this table it is observed that the specimen III F22 has maximum horizontal and vertical shear stresses compared to all the other specimens. The value of factor k is 1.69 and 1.99 for ordinary and seismic specimen respectively and ranges from 2.3 to 2.71 for specimen cast by using fibre in the joint region.

This value is greater than the code prescribed value. The code prescribed value is only for normal concrete without fibre. Murthy et al., (2003) have reported that the improvements in the joint reinforcement details and longitudinal bar anchorages caused the joints to sustain larger shear stress values (1.25√fc to 1.79√fc) than the code specified limiting values. In another study Kurose et al. (1988) reported that even without joint reinforcement shear stress between 1.16√fc and 1.83√fc Mpa were developed prior to beam hinging. Hence in the present study the increase in limiting shear stress may be due to the addition of fibre in the joint region.

4.4 Theoretical Shear Strength of the Joint

The joint shear strength can be calculated theoretically. It comprises the four components: shear strength of plain concrete, shear strength resisted by longitudinal steel, shear strength of lateral reinforcement and shear strength of fibre reinforced concrete.



756

(th) τ can be calculated by using the following equation

c fib s l (th)

(V +V +V +V ) = j A

τ (3)

VC = τc bb db (4)

' 0.07(1 10 ) c w c f τ ρ = + (Liu, Cong, 2006) (5)

s t w

b b

Ab d

ρ = (6)

( ) sh yt S

A f d V

S

∗ ∗ = (7)

fib V = 2 f f P j

f

l V V A

d

−

(8) This equation was arrived based on the experimental results

l y V =0.87*f *Ast (9)

4.5 Prediction of Joint Shear Strength by developing a Model

An attempt has been made to predict shear strength of joints using the models available in the literature proposed by Tsonos et al., 1992, Jiuru et al., 1992, and Ganesan et al., 2007.

4.5.1 Modification proposed

In order to account for the effect of hybrid fibre in the model, a regression analysis was carried out. A parameter Fc was introduced to account for the combined effect of hybrid fibres compressive strength of concrete, and modulus of rupture of concrete is given by

( ) '

f f p 1+ V *A V c c

cr

f F f

= + (10)

(exp) τ = (th.) τ * ( 0.04 Fc + 1.466) (11)

Where (th.) τ is given by Equation (3)

By replacing (exp) τ by (pre) τ , where (pre) τ indicates the predicted shear strength value, the predicted value of shear strength is given by



757

(pre) τ = (th.) τ *( 0.04 Fc + 1.466) (12)

Figure 7: Relationship Between (exp) τ and (th.) τ and Fibre Factor for HPFRC Specimen

Figure 7 shows the comparison between the (exp) τ / (th.) τ and fibre factor (Fc) for high strength concrete and all the points are close to the line of equality and lie within ± 15% lines of agreement. The formula gives better results for steel fibre reinforced and hybrid fibre reinforced concrete specimens. Hence, the proposed model predicts the shear strength satisfactorily. The proposed model is however only a preliminary model that needs to be improved further with the help of a larger database.

4.6 Moment Curvature Behaviour

An attempt was made to study the moment curvature relationship for all the specimens using the test results. The ductile behaviour of an interior beamcolumn joint induces the formation of plastic hinges in the beams near the column faces. To investigate the flexural behaviour of the beams, various sections of the top and bottom reinforcement were instrumented by strain gauges. The strains measured at 15mm below the extreme compression fibre and 15mm above the extreme tension fibre have been used to calculate the curvature, ф of the beam for every loading stage using the relation (Ganesan and Indira,2000)

Ф = ( )

t b

b

e e d a

+ −

(13)



758

The values of moment M were calculated using the experimental values of load and lever arm. Table 5 shows the moment, curvature ductility at peak load and yield load. These values of M and Ф were used to obtain momentcurvature plots for the joint.

Table 5: Moment and Curvature Ductility Factor

Sl.No Specimen Id

(Curvature at peak load)

2 10 X − 1 m

(Curvature at yield load)

2 10 X − 1 m

Curvature Ductility Factor

Moment at Peak Load kNmm

1 III O2 4.0927 3.0772 1.33 9900 2 III S2 5.4159 3.0772 1.76 11700 3 III F12 9.4373 3.0443 3.1 15480 4 III F22 10.828 3.0416 3.56 16920 5 III F32 11.472 3.0510 3.76 13680

4.7 Curvature Ductility Factor

The capacity of the member to deform beyond its initial yield deformations with minimum loss of strength and stiffness depends upon the ductility factor which is defined as the ratio of the ultimate deformation to its yield deformation at first yield. Ductility may be defined easily in the case of elastoplastic behaviour. Ductility factors in beamcolumn joint have been defined in terms curvature at critical section and is (Ganesan and Indira,2000)

Curvature ductility factor = u

y

Ф Ф

(14)

y Ф =curvature at yield = ( )

y

s b

f

E d x − (15)

The curvature at peak load and curvature ductility factor thus calculated for all M60 concrete specimens are given in Table 5. From the table it may be noted that the hybrid fibre reinforced specimens have better values of ductility factor than the other specimens.

5. Conclusions

1. The hybrid fibre reinforced concrete joints undergo large displacements without developing wider cracks when compared to SFRHPC and HPC joints.

2. The fibres are effective in resisting deformation at all stages of loading from first crack to failure.

u Ф y Ф



759

3. The specimen III F22 which was formed by using hybrid fibre reinforced concrete in the joint region, consisting of 1.5% of steel fibre and 0.2% of polypropylene fibre exhibited excellent strength, deformation capacity, energy dissipation capacity and damage tolerance. It also has minor joint damage.

4. The addition of polypropylene fibre increases the energy dissipation capacity, ultimate load, when the dosage of polypropylene fibre is 0.2 %.

5. The specimen III F32 (1.5% of steel fibre +0.4% of polypropylene fibre) has the maximum curvature ductility factor. The excess polypropylene fibre increases the ductility but at this % the ultimate load and energy dissipation capacity is also reduced.

6. It is possible to reduce the congestion of steel reinforcement in beamcolumn joint by replacing part of ties in columns by steel and synthetic fibres and thereby reducing the cost of construction.

7. For analysing and predicting the joint shear strength, the joint shear strength formula has been developed by considering volume of steel and polypropylene fibre in the previously developed models.

Notations

Lb Length of beam

Lc Length of column

Db Total depth of beam

Dc Total depth of column

db Effective depth of beam

dc Effective depth of column

A h core horizontal cross sectional area of the joint core resisting the

horizontal joint shear

A v core vertical cross sectional area of the joint core resisting the vertical shear

Ast Area of beam longitudinal reinforcement

Ash Area of shear reinforcement

S Spacing of shear reinforcement



760

fyt Characteristics strength of lateral reinforcement

f l length of the steel fibre

f d diameter of the steel fibre

f A Aspect Ratio of the steel fibre

Vf percentage of volume of steel fibre

Vp percentage of volume of polypropylene fibre

j A area of joint core

τc Shear stress in concrete

VC Shear resisted by concrete

VS Shear resisted by strriups

fib V Shear resisted by fibre

Vl Shear resisted by longitudinal reinforcement

' c f Cylindrical compressive strength of concrete

fcr modulus of rupture of concrete

(exp) τ Experimental value of ultimate shear stress

(pre) τ Predicted value of ultimate shear stress

(th.) τ Theoretical value of ultimate shear stress

t e Strain in the top reinforcement

b e Strain in the bottom reinforcement

a Compressive reinforcement cover

u Ф Curvature at peak load



761

y Ф Curvature at yield

y f yield strength of main reinforcement

s E Modulus of elasticity of steel

x depth of neutral axis

6. References

1. Alexandors and Tsonos.G., 2007, Cyclic Load Behavior of Reinforced Concrete BeamColumn Sub Assemblages of Modern Structures. ACI Structural Journal, 104(4), pp 468478.

2. Amir A. Mirsayah and Nemkumar Banthia. 2002. Shear Strength of Steel Fibre Reinforced Concrete. ACI Materials Journal, 99(5), pp 473479.

3. Andre Filatrault, Karim Ladicani, and Bruno Massicotte. 1994. Seismic Performance of Code Designed Fibre Reinforced Concrete Joints. ACI Structural Journal, 91(5), pp 564571.

4. Andre Filiatrault, Sylvain Pineau, and Jules Houde. 1995. Seismic Behaviour of Steel Fibre Reinforced Concrete Interior BeamColumn Joints. ACI Structural Journal, 92(5), 543551.

5. Asha, P. and Sundararajan, R. 2006. Evaluation of seismic resistance of exterior beamcolumn joints with detailing as per IS 13920:1993. The Indian concrete Journal, 80(2), pp 2934.

6. Au, F.T.K., Huang, K. and Pam, H.J., 2005. Diagonally Reinforced Beam Column Joints Reinforced Under Cyclic loading. Structures and Buildings, 158, pp 2140.

7. Ganesan, N. and Indira, P.V., 2000. Latex modified SFRC beamcolumn joints subjected to cyclic loading. The Indian Concrete Journal, 74(7), pp 416420.

8. Ganesan, N., Indira, P.V and Ruby Abraham., 2007. Fibre Reinforced High Performance Concrete BeamColumn Joints Subjected to Cyclic Loading.ISTE Journal of Earthquake Technology, 44(4), pp 445456.

9. Gustavo J. Parra Montesinos. 2005. HighPerformance Fibre Reinforced Cement Composites an Alternative for Seismic Design of Structures. ACI Structural Journal, 102(5), pp 668673.



762

10. Indian Standard Plain and Reinforced Concrete Code of Practice IS 456:2000 Bureau of Indian Standards, New Delhi.

11. Indian Standard Ductile Detailing of reinforced Concrete Structures subjected to Seismic Forces. Code of Practice: IS 139201993 (Part 1):2002. Bureau of Indian Standards, New Delhi.

12. Indian Standard Criteria for Earthquake resistant Design of Structures, Part I Genaral Provisions and Buildings, IS 1893 (Part I) 2002 Bureau of Indian Standards, New Delhi.

13. Jamal Shannag M, Nabeela Abu Dyya and Ghazi Abu Farsakh. 2006. Lateral load Response of HighPerformence Fibre Reinforced Concrete BeamColumn Joints. ELSEVIER Journal of Construction and Building Materials 19, 500508.

14. Lars Kutzing. 1997. Use of Fibre Hybrid to Incerase the ductility of High Performance Concrete (HPC). Institute for Massivbau and Baustoffechnologie i Gr.Universitat Leipzig,LACER No. 2, pp 125134.

15. Liu and Cong. 2006. Seismic Behaviour of BeamColumn Joint Subassemblies Reinforced with Steel fibres. A report submitted in partial fulfilment of the requirements for the degree of Master of Engineering in the University of Canterbury.

16. Murty, C.V.R., Durgesh C. Rai, Bajpai, K.K and. Jain, K. 2003. Effectiveness of Reinforcement Details in Exterior Reinforced Concrete BeamColumn Joints for Earthquake Resistance. ACI Structural Journal, 100(2), pp 149156.

17. Shetty, M. S. “Concrete Technology Theory and Practice”. S.Chand &Company Ltd, New Delhi, 1996.

18. Parviz Soroushian and Ziad Bayasi. 1991. Fibre Type Effects on the Performance of Steel Fibre Reinforced Concrete. ACI Material Journal, 88(2),pp 129134..

19. Paul, R.Gefken and Melvin, R.Ramey. 1989. Increased Joint Hoop Spacing in Type 2 Seismic Joints Using Fibre Reinforced Concrete. ACI Structural Journal, 86(2),pp 168172.

20. Tang Jiuru et al., 1992. Seismic behavior and shear strength of framed joint using steelfiber reinforced concrete. Journal of Structural Engineering, 118(2),pp 341 358.

21. Thanukumari, B. and Perumal, P. 2009. An Experimental Study on the Behaviour of M20 Concrete with Hybrid Fibre in Exterior BeamColumn Joints Subjected to Reversed Cyclic Loading. IETECH Journal of Civil and Structures, 2(2), 065070.



763

22. Thanukumari, B. and Perumal, P. 2010. Behaviour of M60 Concrete Using Fibre Hybrid in Exterior BeamColumn Joint Under Reversed Cyclic Loading. Asian journal of civil engineering (building and housing), 11(2), pp 265275.

23. Tsonos, A.G., Tegos, I.A. and Penelis, G.G. (1992). Seismic Resistance of Type 2 Exterior BeamColumn Joints Reinforced with Inclined Bars. ACI Structural Journal, 89(1),pp 3–12.

********************

In this paper, it is envisaged to create a new composite material which can be derived from the already existing nondegradable and hazardous waste materials. The new composite material is a combination of Ordinary Portland cement and Dyeing Industry Effluent Treatment plant Sludge (DIETPS). It replaces the non availability of natural



764

building materials such as sand and related aggregates. It is the method of extracting wealth from the waste. Various compositions of mixtures are made in Phase I of the research. The test results of different mixtures are analyzed. The economical composite, 1:1.7 having sufficient strength as per IS codes for Bricks was selected. The composite mixture having high quality with low cost is selected for future use as a nonconventional building material named as Synthetic Sludge Aggregate (SSA). This SSA is used to manufacture synthetic fine aggregates. The fine aggregates are then used as replacement of sand in various percentages is M20, M30 and M40 concrete and compressive strength and split tensile strength characteristics are studied as per BIS standards. It is envisaged that this composite material reduces the environmental hazards caused by dyeing industries. There is an abundant scope for the use of this SSA in various construction and development activities.

Keywords: Composite, Cement, Dyeing Industry Effluent Treatment Plant Sludge, Synthetic Sludge Aggregate, Sand & Concrete

1. Introduction

DIETPS is classified as hazardous waste, generated during the primary treatment of textile effluents. Thousands of tonnes of sludge generated in the last ten years are piled up at common and individual effluent treatment plants. The effluents generated are treated at effluent treatment plants. 8.8crore litres of effluents, after primary treatment in effluent treatment plants, are being let out into the Noyyal River every day in Thiruppur alone. One tonne of dewatered sludge is produced for every 5001000 m 3 of wastewater treated. They all generate dried sludge amounting to an estimated 88 tonnes a day in Thiruppur alone. The sludge, a highly hazardous chemical waste, is stored in open yards. The industry also struggles to find a place for a landfill of this sludge. “Landfill is not a solution to pollution” as during rains the DIETPS dissolves in rain water and leaches in to the ground and storm runoff from these yards pollutes streams and rivers. DIETPS consists of dye waste, lime, ferrous sulphate, coagulant aids and polyelectrolyte, etc 1 . DIETPS used in the research contains chlorides of 36.85% and sulphate of 20.63%.

Cement is a widely used binding material in construction industry. It is used in mortar, concrete, precast elements and even for manufacturing bricks. Compared to other binding materials, cement is the cheapest one.

In this paper it is envisaged to create a new composite using ordinary Portland cement and DIETPS. The non dissolving mix having sufficient strength is obtained in phaseI of the research and in phaseII, The composite is used as a replacement for sand in M20, M30& M40 concrete. Concrete mix design is done by using the ACI Committee method.

Concrete 5 is a most widely used material today. The versatility and mouldability of this material, its high compressive strength has largely contributed to its widespread use. Concrete has been in use throughout the civilized history of our mankind. As the



765

technology advances, new ingredients are added to study the alteration in properties of concrete with each ingredient. As each recipe created in kitchen has different tastes, concrete also shows different extraordinary changes in properties with change in ingredients.

The compressive strength of concrete is one of the most important and useful properties of concrete. It is used as a qualitative measure for other properties of hardened concrete. Compressive strength of concrete is generally determined by testing cubes made in Lab or field. When concrete fails under compressive load, the failure is essentially a mixture of crushing and shear failure. The compressive strength of concrete mainly depends on watercement ratio, aggregate strength, etc.

2. Review of literature/Theoretical Background of study

Ramesh Kumar, et al, has done extensive study on dye effluents in Perundurai. He says that, Textile dyeing industries in Erode and Tirupur district of Tamilnadu (India) discharge effluents ranging between 100 and 200m³/t of production. Dyeing is performed by Jigger or advanced Soft Flow reactor process. Coloring of hosiery fabric takes place in the presence of high concentration of sodium sulphate or sodium chloride (30 – 75 kg/m³) in dye solutions.

Hilary Nath has produced block bricks from the primary sludge generated in the garment washing process. The developed sludge brick was tested for the common parameter for a building block. Comparing the test results with normal block brick, a higher compressive strength was recorded in the sludge block brick.

Balasubramanian et al, has studied the potential reuse of textile effluent treatment plant (ETP) sludge in building materials. The physiochemical and engineering properties of a composite textile sludge sample from the southern part of India have been studied.

Jewaratnam, Jegalakshimi did a detailed work on sludge from a waste water treatment plant, the sludge in this work was dried and powdered and added to clay in various proportions. A 8”x31/2”x1/2” size of samples were produced by using manual press operated at 180 psi. The samples were dried in an oven at 105°C for 24 hours before firing in a kiln at 1050°C using specific temperature program to optimize vitrification process. The fired samples were evaluated for the thermal conductivity and sound barrier characteristics were evaluated. The project is under progress.

Reddy Babu G, conducted the feasibility study of usage of sludge from sand beneficiation treatment plant in the production of bricks. At 5% to 10% of replacement, the quality of bricks is superior to the brick made from brick earth alone and can be used for superior work of permanent nature.

Seshadri Sekhar, et al, studied the properties like Compressive Strength, Split Tensile Strength and Flexural Strength of Self compacting concrete mix proportions ranging from



766

M30 to M65 Grades of Concrete. An attempt also has been made to obtain a relationship between the splitting tensile strength, Flexural Strength and Compressive strength by the test results.

3. Research Objectives

• In Phase I, a nondissolving and economical composite is to be obtained. The composite will be cast in bricks blocks and strength will be ascertained as per BIS 3&4 .

• In Phase II, composite will be crushed to obtain SSA . The SSA would be used as a replacement for sand in various ratios viz. 5%, 10%, 15% and 20% in M20, M30 and M40 concretes. Mix design will be as per ACI Committee method. Compressive strength and split tensile strengths will be evaluated as per BIS.

4. PhaseI Research Methodology

The DIETPS was collected from a dyeing industry near Thirumangalam. The chemical composition and properties of DIETPS was found. The DIETPS was mixed with widely available binding material viz. Ordinary Portland Cement (OPC) using watercement ratio as 0.5. The various mix ratios were adopted by trial and error method and the resultant dried samples were examined for dissolving in water. The most economical and non dissolving DIETPS & OPC mix was obtained. The mix was used to manufacture bricks with pure DIETPS & OPC mix and DIETPS & OPC & sand mix. Fly Ash – LimeGypsum (FALG) bricks were also manufactured using various percentages of DIETPS as replacement for fly ash. The bricks were tested as per Indian standard codes for compressive strength & water absorption.

Figure 1: Photo of Briquettes Manufactured

5. Analysis and Interpretation



767

Figure 2: Chart of Percentage Loss of Mass

Table 1: Percentage loss of mass in briquettes

Briquette Mix Percentage Loss of Mass 1:05 17.2 1:04 15.5 1:03 10.3 1:02 7.8

01:01.9 3.1 01:01.8 1.4 01:01.7 0 01:01.6 0 01:01.5 0

a) Inference from dissolution test: Various mixes of OPC & DIETPS were tried viz. 1:5, 1:4, 1:3, 1:2, 1:1.9, 1:1.8, 1:1.7, 1:1.6 & 1:1.5. Out of these 1:1.7, 1:1.6 & 1:1.5 mix briquette samples did not dissolve in water and shape of sample did not disintegrate. The mix 1:1.7 is taken for casting bricks as it is economical.

b) Manufacture of bricks: Bricks were moulded in 9”x 4”x3” moulds. Using various trial mixes with watercement ratio as 0.5. After 28 days curing, the bricks were tested as per BIS. The results are shown in table I



768

Figure 3: Photo of Bricks Manufactured

Table 2: Compressive Strength of Bricks and Cost Comparison

Mix details Cost per Brick (Rs.)

Water absorption

In %

Crushing strength in N/mm 2 (7 days)

Crushing strength in N/mm 2

(28 days)

OPC and DIETPS ratio 1:1.5 7.0 2.97 9.067 13.24

OPC and DIETPS ratio 1:1.7 6.84 2.96 7.463 10.37

OPC ,DIETPS and sand ratio 1:1.7:2.1 4.22 3.22 8.576 11.07

OPC ,DIETPS and sand ratio 1:1.7:3 4.04 3.59 5.487 7.41

OPC ,DIETPS and sand ratio 1:1.7:3.5 3.73 3.41 5.373 7.15

FALG Based bricks 10% DIETP S 4.15 8.81 2.524 3.4

FALG Based bricks 15% DIETPS 4.31 11.50 2.216 2.79

FALG based bricks 20% ETP sludge 4.38 14.80 3.770 5.95



769

Figure 4: Comparison Chart of Bricks

c) Phase I – Results: The compressive strength of the bricks with only OPC – DIETPS mixes gave high strength but cost per brick is quite high and not marketable. The OPC – DIETPS – sand 1:1.7:3 mix showed appreciable reduction in strength when compared to OPC – DIETPS mixes, but the cost per brick is comparable to the cost of other country bricks. It shows 28 days crushing strength as 7.41 N/mm 2 , which is equivalent to second class brick as per IS3495 (part – I)1976.

6. Phase – II Research Methodology

The 1:1.7 mix bricks were broken down to obtain SSA. The SSA is used as replacement for sand in various percentages 5%, 10%, 15% and 20% in concrete mixes M20, M30 and M40. Mix design was done as per ACI Committee method. M20 is 1:2.88:3.16 with w/c ratio 0.60. M30 Mix is 1:2.03:2.48 with w/c ratio 0.47. M40 Mix is 1:1.46:2.0 with w/c ratio 0.38. Concrete cubes were created to study compressive strength for 3 days and 28 days. Cylinders were cast to study split tensile strength of concrete at 28 days. Tests were conducted as per BIS.



770

7. PhaseII Analysis and Interpretation

Table 3: Compressive Strength at 3days in N/mm 2 .

Mix / Mix ratios M20 M30 M40

Plain concrete(PL) 13.52 21.86 29.13 Concrete with 5% sand replacement by SSA (5%) 14.38 19.87 31.73 Concrete with 10% sand replacement by SSA (10%) 12.86 17.52 29.07 Concrete with 15% sand replacement by SSA (15%) 13.82 16.9 28.74 Concrete with 20% sand replacement by SSA (20%) 11.2 16.42 24.85

Table 4: Compressive strength at 28 days in N/mm 2

Mix/ Mix ratios M20 M30 M40 Plain concrete(PL) 20.375 29.37 42.616

Concrete with 5% sand replacement by SSA (5%) 21.544 29.8 38.51 Concrete with 10% sand replacement by SSA (10%) 18.455 27.836 37.305 Concrete with 15% sand replacement by SSA (15%) 13.58 24.862 33.228 Concrete with 20% sand replacement by SSA (20%) 12.36 20.944 32.268

Figure 5: Comparison of 3 days compressive strength



771

Figure 6: Comparison of 28 days compressive strength in N/mm 2

Table 5: Split Tensile Strength at 28 Days in N/mm 2

Mix/ Mix Ratios M20 M30 M40

Plain concrete (PL) 2.270 3.1975 3.2376

Concrete with 5% sand replacement by SSA (5%) 2.085 2.7889 3.68






772

Figure 7: Comparison of 28 days split tensile strength in N/mm 2

From the tables and charts it is evident that the compressive strength of the concrete cubes decreases with increase in percentage of SSA. This may be due to the presence of chlorides of 36.85% and sulphate of 20.63% in DIETPS. Both chloride and sulphate are deleterious to concrete. Hence SSA of 5% may be used in concrete as there is only very mild variation in strength. From the charts we can clearly observe that the strength actually increased at 5% of SSA.

8. Recommendations and findings

• A composite is successfully obtained from the OPC and DIETPS. • Bricks can be manufactured from the composite with strength of second class

bricks and their cost is comparable with bricks available in market. • New composite aggregate SSA is projected as replacement of already scantly

available sand. • SSA can be used only up to 5% as replacement of sand without affecting the

strength of concrete.

9. Limitation of the study

• Only strength characteristics of the composite and concrete is studied. • Durability aspects of the composite will be considered in further research. • Environmental and economical impact of using this composite can be evaluated in

further research.



773

10. Conclusions

A non Dissolving composite of mix 1:1.7 was manufactured successfully. The composite was used for manufacturing bricks in first phase of the research. The bricks were found to be economical and the compressive strength of bricks was similar to second class bricks as per BIS. In phase II of the research, bricks were broken down to obtain SSA and the SSA was used as replacement for sand in concrete mixes M20, M30 and M40. Compressive strength of all the concrete mixes showed decline in strength with increase in percentage of SSA. This may be due to the chloride and sulphates present in SSA. Hence it is advisable to use only 5% of SSA as replacement of sand in concrete. Commercial manufacture of bricks from the composite may also be undertaken after doing durability study on the composite.

References

1 Balasubramaniana J., et al., (2005), “Reuse of textile effluent treatment plant sludge in building materials”, Elsevier Ltd., online paper, 11 January 2005, pp. 1.

2 Hilary Nath (2006), “SludgeBricks Development”, Reach Journal, brandix inspired solutions, Issue 3, pp. 6.

3 IS3495 (part – I)1976 –“Determination of compressive strength, Methods of test of burnt clay bricks”, Bureau of Indian Standards, New Delhi.

4 IS3495 (part – II)1976 “Determination of water absorption, Methods of test of burnt clay bricks”, Bureau of Indian Standards, New Delhi.

5 IS4562000 – Plain and Reinforced concrete Code of practice, Bureau of Indian Standards, New Delhi.

6 Jewaratnam, et al., (2006) “Waste Recovery from Industrial Sludge”. University of Malaya. Engineering eTransaction, 1 (2). ISSN 18236379, pp. 58.

7 Ramesh Kumar M. and K. Saravanan, (2009) “Recycling of Woven Fabric Dyeing Wastewater Practiced in Perundurai Common Effluent Treatment Plant”. CCSE Journal, April 2009, Volume 3, No – 4, pp 146

8 Ranganathan K., et al., (2006)“Recycling of wastewaters of textile dyeing industries using advanced treatment technology and cost analysis”—Case studies”. Conservation and recycling, Volume 50, Issue 3, May 2007, pp 306318

9 Reddy Babu G, Mallikarjuna Rao K, Ramana Reddy IV (2005), “Value addition for sludge generated from sand beneficiation treatment plant”. Dept Civil Engg., SVU Coll Engg, Tirupati. Nature Env. Polln. Techno, , pp 203206



774

10 Renganathan L (2009), “Safe disposal of sludge, a problem”, Online edition of India's National Newspaper, The Hindu.

11 Seshadri Sekhar T. and Srinivasa Rao P., (2008) “Relationship between Compressive, Split Tensile, Flexural Strength of Self Compacted Concrete” International Journal of Mechanics and Solids, © Research India Publications, ISSN 09731881 Vol. 3 No. 2, (2008) pp. 157–168.

12 Shetty M.S. (2005) “Concrete technology theory and practice” S. Chand publications, ISBN 8121903483, pp 257.

seismic performance of hybrid fibre reinforced beam ... representing an exterior beam column joint...

Documents