Effects-of-waste-PET-as-coarse-aggregate-on-the-fr_2016_Construction-and-Bui.pdf

Construction and Building Materials 125 (2016) 946–951

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Effects of waste PET as coarse aggregate on the fresh and harden properties of concrete Md. Jahidul Islam a, , Md. Salamah Meherier b, A.K.M. Rakinul Islam a ⇑

a b

Department of Civil & Environmental Engineering, Islamic University of Technology, Gazipur 1704, Bangladesh School of Engineering, University of British Columbia, 3333 University Way, EME 4222, Kelowna, BC V1V1VV7, Canada

h i g h l i g h t s

  PET

aggregate concrete has better workability compare to natural aggregate concrete. of density is achievable with PET coarse aggregate in concrete.   Relatively high compressive strength is attainable with PET aggregate concrete.

  Reduction

a r t i c l e

i n f o

 Article history: Received 23 February 2015 Received in revised form 22 August 2016 Accepted 28 August 2016 Available online 3 September 2016 Keywords: Polyethylene terephthalate Coarse aggregate Compressive strength Unit weight Workability

a b s t r a c t

This This study study invest investiga igates tes the effect effect of plasti plastic c as an altern alternati ative ve coarse coarse aggreg aggregate ate on variou variouss fresh fresh and harden harden properties of concrete. Polyethylene terephthalate (PET), a thermoplastic polymer, is considered as an alternative aggregate and replaced with natural coarse aggregate, such as brick chips. The PET aggregate is obtained by shredding, melting and crushing the collected waste PET bottles. The primary focus of the work work is to observ observe e compr compress essive ive streng strength th and unit unit weight weight of PET aggreg aggregate ate concre concrete te (PAC) (PAC) along along with with their their workability in comparison with the natural aggregate concrete (NAC). With the increase in PET replacement ratio and w/c ratio lower unit weights and compressive strengths are observed for PAC compare to NAC. Compressi Compressive ve strength for 20% PET replaced replaced PAC at 0.42 w/c ratio is 30.3 MPa which which is only 9% less than the NAC. However, PAC has significantly significantly high workability as 1.8 cm slump value is observed for 20% PET replace replaced d PAC at 0.42 0.42 w/c w/c ratio. ratio. Therefor Therefore, e, PET PET replac replaced ed concre concrete te with with low w/c ratio ratio and high workability can be used for structural concrete member.   2016 Elsevier Ltd. All rights reserved.

1. Introduction Due Due to increa increase se in produc productio tion n of day to day disposal disposal goods, goods, waste disposal management has become a major environmental issue in the world. Lack of proper proper waste waste disposal disposal managemen managementt causes environmental pollution and may cause detrimental effects on soil. soil. Among Among all of the waste waste mater material ials, s, plasti plastic c based based waste waste materials are filling a significant portion of landfill spaces as they are not easily degraded or decomposed [1] decomposed  [1].. Plastic materials consumption sumption around around the world world increased increased from 5 million tons to about 100 million tons during the year 1950–2001 [2] 1950–2001  [2].. In Western Europe, about 23 million tons of waste plastic materials are generated ina year [3] where whereas as the Unite United d States States produc produced ed approx approxima imatel tely y 11 million tons [4] tons  [4].. In Asia, China and India consume the maximum numbe numberr of plasti plastic c mater material ialss [5] [5].. During ring the the fiscal cal yea year of  Corresponding author. E-mail addresses:  [email protected]  [email protected] (M.J.  (M.J. Islam),  [email protected]. ca (M.S. ca  (M.S. Meherier), [email protected] Meherier),  [email protected] (A.K.M.  (A.K.M. Rakinul Islam). ⇑

http://dx.doi.org/10.1016/j.conbuildmat.2016.08.128 0950-0618/   2016 Elsevier Ltd. All rights reserved.

2010–20 2010–2011, 11, Banglade Bangladesh sh consumed consumed 0.75 million million tons of polymer polymer and recycl recycled ed plasti plastic c waste. waste. Per capita capita consum consumpti ption on of plasti plastic c produc products ts of the nation nation is 3.6 kg/ye kg/year ar which which is lower lower than than the global global average average of 20 kg/year. kg/year. Plastics based on polymers can be broadly classified into two categories, thermoplastic and thermosetting plastic. Thermoplastics, such as polyethyle polyethylene ne (PE), polystyre polystyrene ne (PS), polypropy polypropylene lene (PP), polyethylene terephthalate (PET), and high density polyethylene lene (HDPE (HDPE), ), can be melte melted d throug through h heatin heating g and harden hardened ed by cooling [6] [6].. On the other hand, thermosetting plastics cannot be melted or softened through heating [7] heating [7].. Polyethylene terephthalate (PET) is a semi crystalline polymer with with high high mecha mechanic nical al strengt strength h and and toughn toughness ess as well well as hydro hydrolyt lytic, ic, chemical chemical and solvent solvent resistance. resistance. It is widely widely used in packagin packaging g industrie industriess (i.e. pharmaceu pharmaceutical ticalss and food products) products) and drinking drinking bottles production. It is also used as precision moldings for office and domestic appliances, automobile parts and electronic devices in the manufac manufacturing turing process [8] [8].. Becau Because se of the conven convenien ience ce of using using PET bottle bottles, s, the demand demand is ever ever increa increasin sing. g. Howe However ver,,

M.J. Islam et al. / Construction and Building Materials 125 (2016) 946–951  Table 1

 Table 2

Chemical composition of PCC.

Material properties of aggregates.

Components

Percent (%)

Calcium oxide (CaO) Silicon dioxide (SiO2) Aluminium oxide (Al2O3) Ferric oxide (Fe2O3) Sulphur trioxide (SO3) Magnesium oxide (MgO) Loss on ignition

55.17 22.14 6.36 3.44 2.56 1.60 2.31

Description

Materials

Specific gravity Water absorption capacity (%) Fineness modulus

managing these large amounts of plastic wastes becomes a major concern for the environment. As such, it has become a significant issue of minimizing and/or reusing these waste products in various applications. Application of waste PET bottles as various forms of filler materials in concrete have been explored, thus creating the opportunities for reusing these waste materials in concrete. Researches have been conducted for using recycled PET as a binder in concrete, also known as polyester concrete or polymer concrete [9]. The polymer concrete showed better resistance in compression and flexure compared to Portland cement concrete  [10,11]. Fiber reinforced concrete with PET fibers from waste PET bottles has better control on the plastic shrinkage cracking in concrete  [12,13], as well as increases the resistance to durability properties, such as rapid freeze-thaw and salt or sodium sulphate environment [14]. Plastic shrinkage cracking is the dominant cause for reducing performance in cement-based composites [15–17]. Other options have been developed and adopted in reusing waste PET bottles as aggregates in mortars and concrete composites [18,19]. The majority of these studies related to reusing waste PET bottles as a partial and/or full replacement of fine aggregate (sand) in both mortar and concrete  [1,20–29]. Vaverka [30]  used both high density polyethylene (HDPE) and PET in preparing mortar having different sand (5–20% of the total sand volume) replacement ratio. On the other hand, very few studies have been incorporated waste PET bottles as a partial replacement of coarse aggregate in concrete mixtures   [29,31,32]. Besides waste PET, other plastic wastes such as HDPE, PE and PS have been used as aggregates in preparing various concrete composites [33].

Coarse aggregate–PET

Fine aggregate– sand

2.33 9.75

1.58 0.43

2.43 7.00

6.86

6.70

1.74

2. Materials  2.1. Portland composite cement  Portland composite cement (PCC) is the most commonly used cementitious material for the concrete in Bangladesh, and hence, it has been used in the concrete mix design. It has a density of  3.15 kg/m3 and 28 days compressive strength of 42.9 MPa. Chemical analysis of the PCC was performed according to the ASTM C114 [34]   standard test method and the percentage (weight basis) of  major components are shown in Table 1.  2.2. Sand Natural river sand was used as fine aggregate (FA) in the concrete mix. The sand was first washed to remove the dirt in it and

100

   )    %    ( 80   g   n    i   s   s   a    P 60    t   n   e   c   r   e    P   e 40   v    i    t   a    l   u   m 20   u    C

   )    %    ( 80   g   n    i   s   s   a    P 60    t   n   e   c   r   e    P   e 40   v    i    t   a    l   u   m   u 20    C

0

Coarse aggregate–brick

All of these studies concluded that the increase in volume replacement of PET aggregates showed a declining trend in the compressive strength of the concrete regardless the consistency of the water-cement ratio. The major advantage of using waste PET bottles as aggregates is the reduction of the self-weight of  the concrete because of its low unit weight. This study will examine the physical and mechanical properties of concrete with melted waste PET bottles as coarse aggregates. The novelty of this study is to use modified melted waste PET aggregates instead of using untreated waste materials. As such, this research will attempt to suggest an option that not only stands to improve or maintain the characteristics of the resulting concrete but also provides a reusing option for the waste PET bottles.

100

FA ASTM-Upper Limit ASTM-Lower Limit

947

PCA Brick CA ASTM-Upper Limit ASTM-Lower Limit

0 0.1

1

10

1

10

Sieve Size (mm)

Sieve Size (mm)

(a)

(b)

Fig. 1.   Grading size distribution of aggregates along with ASTM limits for (a) fine aggregate and (b) coarse aggregates.

100

M.J. Islam et al. / Construction and Building Materials 125 (2016) 946–951

948

 2.4. PET aggregate Preparation of PET aggregates requires several steps. Firstly, used PET bottles are collected through local vendor. These bottles then pre-washed before passing through a shredder and transformed into granular particles also known as post-consumer PET flakes. PET flakes can also be directly collected from local recycling plants. PET flakes are put into an oven with temperature ranging between 280 C and 320 C, and melted PET are collected and cooled to achieve solidified PET. The piles of PET are crushed using a crushing machine to obtain desired size. The acquired aggregates were relatively rounder in shape with smoother surface compare to the crushed brick aggregates as shown in Fig. 2. Following the ASTM C127 [37] and C136 [36] different tests were done to obtain the physical properties of PET aggregate and these results are tabulated in   Table 2. The grade size distribution of the PET coarse aggregates (PCA) was found to be similar to the brick coarse aggregates as described in  Fig. 1(b). Fig. 2.   PET coarse aggregate.

3. Mix design then dried in an oven. Specific gravity, water absorption capacity and fineness modulus of the sand was determined according to standard testing procedures (ASTM C128  [35]   and ASTM C136 [36]) and is given in Table 2. The grading size distribution analysis of the sand, as shown in Fig. 1(a), reveals the material to be particularly fine. Furthermore, it had high water absorption capacity of  7%.  2.3. Brick coarse aggregate Bricks were obtained from local brick fields and crushed into brick chips which were used as natural coarse aggregates in the samples. These aggregates were angular in shape with rough surfaces. Physical properties, like specific gravity, water absorption and fineness modulus of the brick chips were tested according to ASTM C127 [37] and ASTM C136 [36] and summarized in Table 2. As shown in   Fig. 1(b), the grading size distribution of the brick chips is closer to the lower limit of the ASTM standard. Water absorption capacity of the brick coarse aggregate was significantly high at 9.75%.

To investigate the performance of PET aggregate on fresh and harden properties of concrete, five mixture types were selected where the natural coarse aggregates (brick chips) with PET coarse aggregates (PCA) by 0%, 20%, 30%, 40% and 50% volume of coarse aggregates. All the mixtures had same type of Portland composite cement (PCC) and river sand as fine aggregate in the concrete mix design. Concrete mix design was carried out for three different water-cement (w/c) ratios, and they were 0.42, 0.48, and 0.57. The mix proportion for the concrete was conducted based on the ACI Standard Practice ACI 291.1 for mixture proportioning (volume basis)   [38]. The resultant mix proportions of all the mixes by weight for one cubic meter volume of concrete are tabulated in the Table 3. 4. Testing methods Slump tests were also conducted for each category of the samples in order to measure the workability of the fresh concrete. Six cylindrical specimens of 300 mm  150 mm dimensions were prepared from fresh concrete mixtures for each mixture types.

 Table 3

Mix design for 1 m 3 of concrete.

y

Mixture

Designationy

Cement (kg/m3)

Water (kg/m3)

Fine aggregate (kg/m3)

Brick coarse aggregate (kg/m3)

PET coarse aggregate (kg/m3)

W/C

NAC 20% PAC 30% PAC 40% PAC 50% PAC

WC42P0 WC42P2 WC42P3 WC42P4 WC42P5

461.5 461.5 461.5 461.5 461.5

193.8 193.8 193.8 193.8 193.8

534.2 534.2 534.2 534.2 534.2

1024.0 819.2 716.8 614.4 512.0

0.0 138.9 208.3 277.8 347.2

0.42 0.42 0.42 0.42 0.42

NAC 20% PAC 30% PAC 40% PAC 50% PAC

WC48P0 WC48P2 WC48P3 WC48P4 WC48P5

449.0 449.0 449.0 449.0 449.0

215.5 215.5 215.5 215.5 215.5

519.8 519.8 519.8 519.8 519.8

996.4 797.1 697.5 597.8 498.2

0.0 135.1 202.7 270.3 337.8

0.48 0.48 0.48 0.48 0.48

NAC 20% PAC 30% PAC 40% PAC 50% PAC

WC57P0 WC57P2 WC57P3 WC57P4 WC57P5

431.6 431.6 431.6 431.6 431.6

246.0 246.0 246.0 246.0 246.0

499.6 499.6 499.6 499.6 499.6

957.7 766.2 670.4 574.6 478.8

0.0 129.9 194.8 259.8 324.7

0.57 0.57 0.57 0.57 0.57

WC42P0= water-cement ratio 0.42, PCA replacement 0%; WC42P20 = water-cement ratio 0.42, PCA replacement 20%; WC42P30 = water-cement ratio 0.42, PCAreplacement 30%; WC42P40 = PCA water-cement ratio 0.42, replacement 40%; WC42P50 = PCA water-cement ratio 0.42, replacement 50%; WC48P0 = water-cement ratio 0.48, PCA replacement 0%; WC48P20 = water-cement ratio 0.48, PCAreplacement20%; WC48P30 = water-cement ratio 0.48, PCAreplacement30%; WC48P40 = PCAwater-cement ratio 0.48, replacement 40%; WC48P50 = PCAwater-cement ratio 0.48, replacement 50%.; WC57P0= water-cement ratio 0.57, PCAreplacement0%; WC57P20 = water-cement ratio 0.57, PCA replacement 20%; WC57P30= water-cement ratio 0.57, PCA replacement 30%; WC57P40 = PCA water-cement ratio 0.57, replacement 40%; WC57P50 = PCA watercement ratio 0.57, replacement 50%.

M.J. Islam et al. / Construction and Building Materials 125 (2016) 946–951

20

949

36

Concrete Type 50% PAC 40% PAC 30% PAC 20% PAC  NAC

16

32

   ) 12   m   c    (   p   m   u    l    S 8

   )   a    P    M    (    h    t 28   g   n   e   r    t    S   e   v    i   s   s 24   e   r   p   m   o    C

4

20

0

Concrete Type 50% PAC 40% PAC 30% PAC 20% PAC  NAC

16 0.4

0.44

0.48

0.52

0.56

0.6

0.4

0.44

W/C Ratio

50% PAC 40% PAC 30% PAC 20% PAC  NAC

  m    /   g    k    (   y    t    i   s   n   e    D

5.2. Density

2000

1900 0.4

0.44

0.48

0.52

0.6

resistance than the rough textured brick aggregates. Furthermore, the round shape of PCA provides less surface area and fewer voids compare to the brick aggregates which leads to better workability. Almost negligible water absorption capacity of PCA also contributes in improving the workability of fresh concrete mixtures. In the case of highest w/c ratio (= 0.57) for PAC, bleeding was observed. Despite having this little drawback, it is expected that for a desired slump value PCA will reduce the amount of used water content and eliminate the use of water reducing agents. Thus it will help to achieve permissible compressive strength.

Concrete Type 2100

0.56

Fig. 5.   Variation in compressive strength of concrete with w/c ratio.

2200

   )

0.52

W/C Ratio

Fig. 3.   Slump values for various concrete type.

   3

0.48

0.56

0.6

W/C Ratio Fig. 4.   Variation of density with w/c ratio for various concrete.

Molds were removed after 24 h and then cured in water at room temperature of 25 ± 2 C for 21 days. Samples were tested for compressive strength after 28 days using a 1000 kN servo hydraulic universal testing machine. In addition, the unit weights of the samples were measured. 5. Results and discussions 5.1. Workability The workability of PET Aggregate Concrete (PAC) increases with the percentage of PET Coarse Aggregate (PCA) as well as the increase in w/c ratio, as shown in   Fig. 3. The relatively smooth and glassy texture of PCA provides less inter particle frictional

Densities of the samples were measured at dry condition just before the compressive strength test and results are shown in Fig. 4. The test data indicates a gradual reduction in density of  PAC compared to natural aggregate concrete (NAC) and the variation ranges between 4% and 10%. As the water cement ratio increases, the density for PAC decreased while the density of NAC remained almost the same. This can be contributed to the low unit weight of PCA compared to regular coarse aggregate (brick chips). The density reduction rate of cylinder is higher for 50% PAC with 0.57 w/c ratio. 5.3. Compressive strength The compressive strength tests are carried out after 28 days of  casting. The results illustrate a declining trend in compressive strength for PAC compared to NAC (Fig. 5). Further decrease in strength is also observed for concrete with increased PCA content and water cement ratio. The inter-face between the cement paste and aggregate known as ‘transitionzone’ and its integrity influences thecompressive strengthof concrete. Bleedingcaused by higher w/c ratio in concrete promotes the accumulation of water in the transition zone of concrete resulting decrease in compressive strength of  concrete. As from the properties of PCA we know that its water absorption capacity is almost zero in comparison to the absorption capacity of brick aggregates. This causes more accumulation of  water in thetransition zone. This extra water remaining in the transition zone results in poor paste structure and gel bond in the PAC which greatly reduces its compressive strength.

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950

- PCA had smooth surface which results in weak bonding between the PCA and cement matrix. Surface modification or chemical treatment of PCA could make its surface rough and thereby ensure better bonding. Moreover, restricting the PCA substitution by 20% would ensure comparable compressive strength compared to the NAC.

16

Concrete Type 50% PAC

   )    3   m    /   g    k    / 12   a    P    k    (   y    t    i   s   n   e    D    / 8    h    t   g   n   e   r    t    S   e   v    i   s   s 4   e   r   p   m   o    C

40% PAC 30% PAC 20% PAC  NAC

References

0 0.3

0.4

0.5

0.6

W/C Ratio Fig. 6.   Variation in compressive strength/density of concrete with w/c ratio.

Along with the bleeding water, the smooth surface of the PCA also contributes to the low compressive strength of PAC. Rough aggregate surface of brick chips develop strong bondage between the aggregates and the cement paste but smooth surface of PCA is unable to develop strong bond results in a lower compressive strength than NAC. The failure pattern of the PAC cylinders confirms the weak bondage between the PCA and cement paste. All the PAC cylinders in the experiment showed mortar failure cracks around the PCA. Fig. 6 demonstrates the variation of compressive strength/density ratio with the w/c ratio. For higher w/c ratios NAC showed a significant increase in compressive strength/density ratio compare to PAC. However, for w/c ratio of 0.42 this variation is insignificant especially for PAC with 20% PCA. Furthermore, 28 days compressive strength for 20% PCA replaced concrete was 30.3 MPa compare to 33.4 MPa for NAC when w/c ratio was 0.42. This leads to the conclusion that small amount of PCA replaced concrete with low w/c ratio can produce concrete similar to the traditional concrete with natural aggregates. 6. Conclusions The use of 20%, 30%, 40% and 50% PCA replaced concrete mixture results in following conclusions:

[1]  M. Frigione, Recycling of PET bottles as fine aggregate in concrete, Waste Manage. 30 (6) (2010) 1101–1106. [2] Plastic recycling information sheet, UK. Waste Online, 2006. [3]  A. Adrados, I. de Marco, B.M. Caballero, A. López, M.F. Laresgoiti, A. Torres, Pyrolysis of plastic packaging waste: a comparison of plastic residuals from material recovery facilities with simulated plastic waste, Waste Manage. 32 (5) (2012) 826–832. [4] EPA, Plastics, Environmental Protection Agency, 2010. [5]  S.B. Kim, N.H. Yi, H.Y. Kim, J-H.J. Kim, Y-C. Song, Material and structural performance evaluation of recycled PET fiber reinforced concrete, Cem. Concr. Compos. 32 (3) (2010) 232–240. [6]  P. Panyakapo, M. Panyakapo, Reuse of thermosetting plastic waste for lightweight concrete, Waste Manage. 28 (9) (2008) 1581–1588. [7]  R. Siddique, J. Khatib, I. Kaur, Use of recycled plastic in concrete: a review, Waste Manage. 28 (10) (2008) 1835–1852. [8] P.M. Subramanian, Plastics recyclingand waste management in theUS, Resour. Conserv. Recycl. 28 (3–4) (2000) 253–263. [9] B.-W. Jo, S.-K. Park, J.-C. Park, Mechanical properties of polymer concrete made with recycled PET and recycled concrete aggregates, Constr. Build. Mater. 22 (12) (2008) 2281–2291. [10]   K.S. Rebeiz, Time-temperature properties of polymer concrete using recycled PET, Cement Concr. Compos. 17 (2) (1995) 119–124. [11]  K. Rebeiz, S. Serhal, D. Fowler, Shear strength of reinforced polyester concrete using recycled PET, J. Struct. Eng. 121 (9) (1995) 1370–1375. [12]   T. Ochi, S. Okubo, K. Fukui, Development of recycled PET fiber and its application as concrete-reinforcing fiber, Cem. Concr. Compos. 29 (6) (2007) 448–455. [13]  D.A. Silva, A.M. Betioli, P.J.P. Gleize, H.R. Roman, L.A. Gómeza, J.L.D. Ribeiro, Degradation of recycled PET fibers in Portland cement-based materials, Cem. Concr. Res. 35 (9) (2005) 1741–1746. [14]  J.-P. Won, C.-I. Jang, S.-W. Lee, S.-J. Lee, H.-Y. Kim, Long-term performance of  recycled PET fibre-reinforced cement composites, Constr. Build. Mater. 24 (5) (2010) 660–665. [15]   P.N. Balaguru, S.P. Shah, Fiber-Reinforced Cement Composites, McGraw-Hill, 1992. [16]   A. Bentur, S. Mindess, Fibre Reinforced Cementitious Composites, second ed., CRC Press, 2006. [17] J.-H.J. Kim, C.-G. Park, S.-W. Lee, S.-W. Lee, J.-P. Won, Effects of the geometry of  recycled PET fiber reinforcement on shrinkage cracking of cement-based composites, Composites Part B 39 (3) (2008) 442–450. [18]   V.T. Breslin, U. Senturk, C.C. Berndt, Long-term engineering properties of  recycled plastic lumber used in pier construction, Resour. Conserv. Recycl. 23 (4) (1998) 243–258. [19] K. Flaga, Advances in materials applied in civil engineering, J. Mater. Process. Technol. 106 (1–3) (2000) 173–183. [20]   O.Y. Marzouk, R.M. Dheilly, M. Queneudec, Valorization of post-consumer waste plastic in cementitious concrete composites, Waste Manage. 27 (2) (2007) 310–318. [21]   Y.W. Choi, D.J. Moon, Y.J. Kim, M. Lachemi, Characteristics of mortar and concrete containing fine aggregate manufactured from recycled waste polyethylene terephthalate bottles, Constr. Build. Mater. 23 (8) (2009) 2829– 2835. ˘ lu, C.D. Atis, K. Akçaözog ˘ lu, An investigation on theuse of shredded [22]   S. Akçaözog waste PET bottles as aggregate in lightweight concrete, Waste Manage. 30 (2) (2010) 285–290. [23]  K. Hannawi, S. Kamali-Bernard, W. Prince, Physical and mechanical properties of mortars containing PET and PC waste aggregates, Waste Manage. 30 (11) (2010) 2312–2320. [24]   J.M.L. Reis, E.P. Carneiro, Evaluation of PET waste aggregates in polymer mortars, Constr. Build. Mater. 27 (1) (2012) 107–111. [25]   S.-J. Liu, Recycled Plastics as Fillers in Polymer Cement Concrete Composites, New Jersey Institute Technology, New Jersey, 1988. [26]  C. Albano, N. Camacho, M. Hernández, A. Matheus, A. Gutiérrez, Influence of  content and particle size of waste pet bottles on concrete behavior at different w/c ratios, Waste Manage. 29 (10) (2009) 2707–2716. [27]   Y.-W. Choi, D.-J. Moon, J.-S. Chung, S.-K. Cho, Effects of waste PET bottles aggregate on the properties of concrete, Cem. Concr. Res. 35 (4) (2005) 776– 781. [28]   Z.Z. Ismail, E.A. Al-Hashmi, Use of waste plastic in concrete mixture as aggregate replacement, Waste Manage. 28 (11) (2008) 2041–2047. [29] R.V. Silva, J. de Brito, N. Saikia, Influenceof curing conditions on the durabilityrelated performance of concrete made with selected plastic waste aggregates, Cem. Concr. Compos. 35 (1) (2013) 23–31. 

- PAC offered much better workability than the regular concrete aggregate while using same w/c ratio. This provides the opportunity to work with low w/c ratio and get the desired concrete strength. - A 4–10% reduction in density was achieved with the PAC compare to the NAC. Although it could not be classified as a lightweight concrete still it provides a substantial advantage over the NAC by reducing the self-weight of the structure. - High strength concrete is achievable with the PCA, especially for concrete with low w/c ratio and small amount of PCA replacement. With 20% PCA replaced concrete at w/c ratio of 0.42, 30.3 MPa compressive strength was achieved. Since PAC has a high workability incorporating low w/c ratio in concrete mix design is not big issue, and thus, PAC can be adopted for structural concrete with confidence.

M.J. Islam et al. / Construction and Building Materials 125 (2016) 946–951 [30] J.V. Vaverka, An Analysis of Reinforced Concrete Composites Utilizing Recycled Polyethylene Terephthalate Thermoplastic, University of Northern Iowa, 1991. [31]   A. Ghaly, M. Gill, Compression and deformation performance of concrete containing postconsumer plastics, J. Mater. Civ. Eng. 16 (4) (2004) 289–296. [32] N. Saikia, J. de Brito, Mechanical properties and abrasion behaviour of concrete containing shredded PET bottle waste as a partial substitution of natural aggregate, Constr. Build. Mater. 52 (2014) 236–244. [33]  T.R. Naik, S.S. Singh, C.O. Huber, B.S. Brodersen, Use of post-consumer waste plastics in cement-based composites, Cem. Concr. Res. 26 (10) (1996) 1489– 1492. [34] ASTM C 114-04, Standard Test Methods for Chemical Analysis of Hydraulic Cement, ASTM International, West Conshohocken, PA, 2004. www.astm.org.

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[35] ASTM C 128-01, Standard Test Method for Density, Relative Density (Specific Gravity), and Absorption of Fine Aggregate, ASTM International, West Conshohocken, PA, 2001. www.astm.org. [36] ASTM C 136-01, Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates, ASTM International, West Conshohocken, PA, 2001.  www.astm. org. [37] ASTM C 127-01, Standard Test Method for Density, Relative Density (Specific Gravity), and Absorption of Coarse Aggregate, ASTM International, West Conshohocken, PA, 2001. www.astm.org. [38] ACI 211.1-91, Standard Practice of Selecting Proportions for Normal, Heavyweight, and Mass Concrete, ACI Manual of Concrete Practice, Part 1: Materials and General Properties of Concrete, Detroit, Michigan, 1994