properties of concrete made with recycled coarse...

3755

www.ijifr.com Copyright © IJIFR 2015

Research Paper

International Journal of Informative & Futuristic Research ISSN (Online): 2347-1697

Volume 2 Issue 10 June 2015

Abstract

Using waste materials for new products is a growing global trend. In the construction field, this trend has gained importance because of natural aggregate depletion and land fill space depletion. This paper gives results of studies undertaken to assess suitability of construction demolition waste as coarse aggregate in new concrete production. In this paper the difference in properties of recycled aggregate (RA) and evaluating the influence of the RAs on the mechanical and durability properties of recycled aggregate concrete (RAC) are presented. While experimenting with fresh and hardened concrete, mixtures

containing RA in amount of 25%, 50%, 75% and 100% were prepared. The experimental results showed that the RAC can be designed to achieve comparable hardened properties, relative to the corresponding properties of natural aggregate concrete (NAC).

1. Introduction

Concrete is a composite material, basically consisting of different constituents such as binding

materials, water, aggregates and admixtures. Among these ingredients, aggregate plays a very

crucial role in concrete which occupy the largest volume of about 60–75% of total concrete volume.

Properties of Concrete Made With

Recycled Coarse Aggregate

Paper ID IJIFR/ V2/ E10/ 064 Page No. 3755-3761 Subject Area Civil

Engineering

Key Words Waste Management, Recycled Aggregate, Recycled Aggregate Concrete,

Mechanical Properties, Durability

Received On 12-06-2015 Reviewed On 25-06-2015 Published On 29-06-2015

Shaikh Mohd. Akib 1

M.Tech. Student

Department of Civil & Environmental Engineering

Veermata Jijabai Technological Institute,

Mumbai-Maharashtra

Sameer U. Sayyad 2

Assistant Professor,

Department of Civil & Environmental Engineering

Veermata Jijabai Technological Institute,

Mumbai-Maharashtra

3756

ISSN (Online): 2347-1697 International Journal of Informative & Futuristic Research (IJIFR)

Volume - 2, Issue - 10, June 2015 22ndEdition, Page No: 3755-3761

Shaikh Mohd. Akib , Sameer U. Sayyad : Properties of Concrete Made With Recycled Coarse Aggregate

It is indispensable for any construction work (Behera et al. 2014). In recent years, the accelerating

urbanization has led to excessive demolition work and construction activities, which consequently,

resulted in the production of large quantities of construction and demolition (C&D) waste,

especially concrete waste. More than 10 billion tons of construction and demolition waste are

produced every year (Mehta 2002). In most cases, this type of waste is incorrectly managed through

illegal deposits causing landfill space depletion.The main problems that industry of construction

materials faces are: natural aggregate depletion, large amount of generated construction and

demolition (C&D) waste and land fill space depletion. Recycling of waste concrete and producing

recycled coarse aggregate (RCA), not only saves landfill space but also reduces the demand for

extraction of natural raw materials for new construction activity (Radonjanin et al. 2013).

Reuse of recycled aggregate (RA) to fully or partially substitute natural aggregate (NA) has

been extensively studied (Limbachiya et al. 2000, Sagoe et. al. 2001, Topcu and Sengel 2004, Zega

and Di Maio 2011, and Duan and Poon 2014). From these studies it is worth noting that the

properties of RA are generally poorer compared with those of NA, which are reflected in higher

water absorption, porosity, aggregate crushing value (ACV), aggregate impact value (AIV) and Los

Angeles abrasion value (LA), and lower specific gravity and 10% fines value (TFV). Limbachiya et

al. (2000) found that recycled concrete aggregate had 7 to 9% lower relative density and 2 times

higher water absorption than natural aggregate. Sagoe et al. (2001), Topcu and Sengel (2004), and

Zega and Di Maio (2011) found that RA drastically lowers the workability of recycled aggregate

concrete (RAC). Literature reports conforms that RAC suffers lower strengths, lower modulus of

elasticity, and significant reductions in the energy of fracture and consequently on the fracture zone

size, compared with natutal aggregate concrete (NAC). The use of RA in practical application is

generally limited to non-structural concrete, and the replacement ratio of NA by RA is

recommended not to exceed 30% (Limbachiya et al. 2000, Topcu and Sengel 2004).

2. Experimental Program

2.1 Materials

Ordinary Portland cement of 53 grade conforming to IS 8112-1989 was used throughout the present

work. As the present study aims to predict the effect of the RA on the performance of RAC, only

conventional fine aggregate (locally available crushed sand) is used.Both NA and RA were used as

the coarse aggregate in this study. Crushed gravel obtained from local quarry was used as NA. RA

was obtained from an old demolished building. The nominal size of the natural and recycled coarse

aggregates was 10 and 20 mm. The properties of NA and RA were determined in accordance with

IS 2386-1963 and presented in Table 1. Superplasticizer conforming to IS 9103-1999 was used in

this study.

Table 1: Properties of Coarse Aggregate

Sr. No. Properties Size

(mm)

Aggregate type

NA RA1

1 Specific gravity

4.75-10 2.76 2.3

10-20 2.76 2.44

2 Water absorption (%) 4.75-10 2.8 6.6

10-20 2.77 4.38

3 Crushing value (%) 10-12.5 22.81 27.68

4 Impact value (%) 10-12.5 12.98 23.59

3757




NA RA 25% RA 50% RA75% RA 100%

(mm) 195 150 130 115 100

0

50

100

150

200

250

Slu

mp

(m

m)

2.2 Concrete mixes and specimens preparation

Mix proportioning was done for M-40 grade concrete with target strength of 48 MPA at 28 days as

per IS 10262-2009. A control mix (NAC) was prepared with 100% NA while RAC were made

with 25, 50, 75 and 100% RA. The details of these concrete mixes are given in Table 2. All the

concrete mixes were designed using absolute volume method with aggregates at saturated surface-

dried (SSD) condition and the actual proportions of the mixes at mixing were adjusted according to

the moisture contents and water absorption capacity of the aggregates. A total of five mixes of

concrete were prepared. For each concrete mix thirteen 150 mm cubes and three 150 mm diameter,

300 mm height were cast. All the test specimens were cured in water curing tank until the age of

testing. The compressive strength was determined at age 3, 7, and 28 days as per IS 516-1959.

Splitting tensile strength (IS 5816-1999), water permeability test (DIN 1048), and rapid chloride

penetration test (ASTM C-1202) was conducted at age 28 days.

Table 2: Mix proportions for various concrete mixes (kg/m3)

Mix series Cement Sand NA RA

Water Admixture 10 mm 20 mm 10 mm 20 mm

NA 450 795 484 592 - - 165 4.95

RA 25% 450 795 363 444 101 131 165 4.95

RA 50% 450 795 242 296 202 262 165 4.95

RA 75% 450 795 121 148 303 393 165 4.95

RA 100% 450 795 - - 404 524 165 4.95

3. Results and discussion

3.1 Properties of aggregate

The physical and mechanical properties of the investigated aggregates are shown in Table 1.

Compared with NA, the RAs had a lower specific gravity and higher water absorption. This is

attributable to the old mortar adhered to the recycled aggregate. The aggregate crushing value and

aggregate impact value of RAs were also lower than NA due to separation and crushing of old

mortar adhered to it (Duan and Poon 2014).

3.2 Properties of concrete

3.2.1 Workability

The workability of fresh

concrete mixes was

determined by slump test and

the results are shown in Fig.1.

The results showed that the

workability of the concretes

was gradually decreasing

when the percentage of RAs

increased. The reason is that

Figure 1: Slump of various concrete mixes

3758




the presence of porous adhered mortar in the RA increases water absorption, thereby reducing the

workability of the fresh mix.

3.2.2 Compressive strength

The compressive strength of concrete made with NA and RA for the different replacement

percentages are shown in Fig. 2. Each of the reported values represents the average of three values.

Figure 2: Compressive strength of various concrete mixes

The general trend observed for 3- and 7-day strength is similar: the strength increases with

increasing RCA content. This phenomenon may be because the free water content required for

cement hydration was partially absorbed by RCA because of its absorptive nature. Consequently,

there was a reduction in the effective W/C ratio. With the reduction in the effective W/C ratio, the

mortar strength of RCA concrete was likely superior to that of the control mixes. Unlike the 3-day

and 7-day strength test results, the 28-day compressive strength of RCA concrete did not show an

upward trend with the increase in RCA content. A reduction in strength was observed when the

RCA replacement level was more than 50%. The 28 days compressive strength of 100% RA was

only 89% of NAC. In summary, the compressive strength of all the concrete mixes with up to 50%

RCA replacement level showed higher strength than that of the control mix.

These trends can be attributed to two factors: effective W/C ratio and ITZ. Analogously, there

was a reduction in the effective W/C ratio of RCA concrete because of its absorptive nature. In

general, the higher the replacement level, the lower the effective W/C ratio. However, there is only

one ITZ for the control mix, whereas RCA concrete has two ITZs, i.e., the interface between NCA

and adhesion mortar (old ITZ) and the interface between the adhesion mortar and new mortar (new

ITZ). Hence, the adhered mortar may play an important role in determining the performance of

RCA concrete, particularly with respect to strength and permeability (Ryu 2002; Otsuki et al.

2003).Neville (1995) also noted that the influence of the type of coarse aggregate on the strength of

concrete varies in magnitude and depends on the W/C ratio of the mix. For a W/C ratio below 0.4,

the strength of the concrete is manipulated by the properties of the aggregate rather than the

strength of the mortar. With an increase in the W/C ratio, the influence of aggregate declines,

presumably because the strength of mortar itself becomes paramount. As the strength of the mortar

NA RA 25% RA 50% RA 75% RA 100%

3 days 26.25 30.38 30.60 30.70 30.78

7 days 33.99 40.71 37.78 37.86 37.92

28 days 51.29 54.56 52.18 48.99 45.76

0.00

10.00

20.00

30.00

40.00

50.00

60.00

Co

mp

ress

ive

stre

ng

th (

MP

a)

3759




depends considerably on the mortar class, a lower effective W/C ratio will produce higher mortar

strength and, consequently, the strength properties of concrete will be enhanced.

3.2.3 Splitting tensile strength

The splitting tensile strength of conventional and recycled aggregate concrete are shown in Fig. 3.

The result indicates that the concrete made with RA had splitting tensile strength similar to that of

the corresponding natural aggregate concrete. This can be attributed to the rough surface of the RA

that might improve the microstructure of the interfacial transition zone (Duan and Poon 2014).

Figure 4: Tensile strength of various concrete mixes

3.2.4 Water penetration test under pressure

The effect of different replacement percentages on the depth of water penetration under

pressure are shown in Fig. 4. The results show that the average values of water penetration of

recycled concretes are similar to, and in some cases better than those of conventional concrete. This

can be attributed to an improvement in the transition zone of mortar-recycled aggregate (Zega and

Di Maio 2011).

Figure 4: Depths of water penetration for various concrete mixes

NA RA 25% RA 50% RA75% RA 100%

Mpa 2.93 3.34 2.90 2.88 2.84

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Ten

sile

str

engt

h (

MP

a)

NA RA 25% RA 50% RA 75% RA 100%

mm 11 9 11 10 9

0

2

4

6

8

10

12

Dep

th o

f w

ate

r p

enet

rati

on

(m

m)

3760




3.2.5 Rapid Chloride penetration test

Figure 5 shows the effect of different replacement percentages on the resistance of chloride ion

penetration of the concrete. The results show that all concrete made with recycled aggregates

generally had better resistance to chloride ion penetrability, and it decreased as the percentage of

recycled aggregate increased.

Figure 5: Chloride ion penetration values for various concrete mixes

4. Conclusion

The following conclusions can be made based on the results of this study:

I. Quality of recycled concrete aggregate is lower than natural aggregate quality, due to the

mortar that remains attached on the surface.

II. The workability of the concrete was gradually decreasing as the amount of replacement of RA

increased.

III. The compressive strength of the concrete mixes with up to 50% RA replacement level showed

higher strength than that of the control mix. But when the percentage of recycled aggregate

used increased, the compressive strength was reducing.

IV. For 100% replacement the compressive strength of recycled aggregate concrete was 11 %

lower than natural aggregate concrete.

V. Despite the increase in the RCA replacement level, the splitting tensile strength, water

penetration and chloride penetration of the various concrete mixes did not show any

significant difference.

VI. Hence, this study recommends the recycling of waste concrete as an aggregate material in

production of new concrete.

VII. In conclusion, recycling coarse aggregates in concrete production may help solve a vital

environmental issue apart from being a solution to the problem of shortage of natural

aggregate in concrete.

NA RA 25% RA 50% RA 75% RA 100%

Coulombs 5524 3836 3856 4165 4430

0

1000

2000

3000

4000

5000

6000

To

tal

Ch

arg

e P

ass

ed (

Co

ulu

mb

s)

3761




References

[1] M. Behera, S.K. Bhattacharyya, A.K. Minocha, R. Deoliya, S. Maiti, “Recycled aggregate from C&D

waste & its use in concrete – A breakthrough towards sustainability in construction sector: A review”,

Construction and Building Materials, Vol 68, pg 501–516 (2014).

[2] V. Radonjanin, M. Malesev , S. Marinkovic, Ali Emhemd Saed Al Malty, “Green recycled aggregate

concrete”, Construction and Building Materials, Vol 47, pg 1503–1511 (2013).

[3] M. C. Limbachiya, T. Leelawat and R. K. Dhir, “Use of recycled concrete aggregate in high-strength

concrete”, Materials and Structures, Vol 33, pg 574 580 (2000).

[4] K.K. Sagoe-Crentsil, T. Brown, A.H. Taylor, “Performance of concrete made with commercially

produced coarse recycled concrete aggregate”, Cement and Concrete Research, Vol 31, pg 707-712

(2001).

[5] I.B. Topcu, S. Sengel, “Properties of concretes produced with waste concrete aggregate”, Cement and

Concrete Research, Vol 34, pg 1307-1312 (2004).

[6] C.J. Zega and A.A. Di Maio, “Recycled Concretes Made with Waste Ready-Mix Concrete as Coarse

Aggregate”, Journal of Materials in Civil Engineering, Vol 23, pg 281-286 (2011).

[7] Z.H. Duan, C.S. Poon, “Properties of recycled aggregate concrete made with recycled aggregates with

different amounts of old adhered mortars”, Materials and Design, Vol 58, pg 19–29 (2014).

[8] Ishtiyaq Gull, “Testing of Strength of Recycled Waste Concrete and Its Applicability”, Journal of

Construction Engineering and Management, Vol 137, pg 1-5 (2011).

[9] N.Y. Ho, Y.P. Kelvin Lee, W.F. Lim, T. Zayed, K.C. Chew, G.L. Low and S.K. Ting, “Efficient

Utilization of Recycled Concrete Aggregate in Structural Concrete”, Journal of Materials in Civil

Engineering, pg 318-327 (2013).

[10] J.S. Ryu, “An experimental study on the effect of recycled aggregate on concrete properties”,

Management Concrete Research, Vol 54, pg 7–12 (2002).

[11] N. Otsuki, S. Miyazato, and W. Yodsudjai, “Influence of recycled aggregate on interfacial transition

zone, strength, chloride penetration and carbonation of concrete”, Journal of Materials in Civil

Engineering, Vol 15, pg 443–451 (2003).

[12] Bureau of Indian Standards, “Indian standard methods of test for aggregate for concrete” IS 2386-1963,

New Delhi, India (1963).

[13] Bureau of Indian Standards, “Guidelines for concrete mix design proportioning.” IS 10262-2009, New

Delhi, India (2009).

properties of concrete made with recycled coarse...

Documents