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Article

Exploring the Effect of Different Waste Fillers in Manufactured Sustainable Plastic Aggregates Matrix on the Structural Lightweight Green Concrete

by
Fahad K. Alqahtani
1,* and
Idrees Zafar
2
1
Department of Civil Engineering, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia
2
Cathodic Protection Department, Saith Limited, ICM, Yeoman Road, Ringwood, Hampshire BH24 3FA, UK
*
Author to whom correspondence should be addressed.
Sustainability 2023, 15(3), 2311; https://doi.org/10.3390/su15032311
Submission received: 1 November 2022 / Revised: 9 January 2023 / Accepted: 17 January 2023 / Published: 27 January 2023
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Abstract

:
The infrastructure demands for mega cities, urbanization and environmental concerns are pushing for smart and sustainable solutions. Structural lightweight concrete is gaining popularity in the concrete industry because of its intrinsic properties of resisting the load and being lighter in weight. Therefore, in this study, a green structural lightweight concrete was targeted by fabricating a plastic-based aggregate incorporating different industrial by-products to reduce the carbon tracks along with an alternate lightweight structural material. Thus, the compatibility of the different industrially by-products (dune dust, fly ash, and quarry dust) with plastic to produce a sustainable structural lightweight aggregate was evaluated in this study. The major physical characteristics of manufactured aggregates along with fresh, hardened, and durability properties of concretes were studied. Results revealed that altering the filler type had altered the texture and size of the developed aggregate. The aggregates developed with dune dust showed the largest particle size, bulk specific gravity, and strength while the ones with fly ash had the smallest size and water absorption. The decrease in the strength was found to be 24.7, 43.6, and 29% for dune dust, fly ash, and quarry dust respectively, once the filler percentage was increased from 50 to 70%. Additionally, all the concretes incorporating developed aggregates have evidently demonstrated their likely usage in structural lightweight applications by complying with ASTM C330/C330M-14 for compressive, flexural, and splitting tensile strength values, in addition to the improved durability behavior.

1. Introduction

Today, in various applications, concrete is the most broadly used construction material in the world with a yearly demand reaching 30 billion ton [1].The increase in urbanization adds to this production volume as the requirement for adequate infrastructure becomes vital for sustainable cities. The importance of lightweight concrete becomes more significant as it provides obvious advantages that are mainly associated with reducing the overall weight of the structure [2]. In addition, the increased thermal insulation of lightweight concrete also provides an excellent opportunity to make energy-efficient structures [2]. It should be noted that lightweight concrete coupled with its ability to take structural loads is one of the promising construction materials in coming decades. Several methods have been adopted to develop lightweight concrete, however, one of the most successful approaches is by using lightweight construction materials, mainly coarse aggregates [3,4]. The materials such as the waste material from metal slush, mining remainders, the shell of coconut and palms, steel slag, used tyre rubber, bottom ash, crushed concrete, fly ash, clay manufactured aggregates and plastic aggregates have been used as coarse aggregates to develop lightweight concrete in the past. However, the use of plastic-based aggregates in concrete is the focal point for the current study mainly because of two reasons, the production of plastic waste has substantially increased in the last few decades and secondly the traditional way of dumping plastic products, is now resulting in a reduction of landfill capacities day by day (100 million tons in 2001) [5,6]. Therefore, effective plastic waste management is the key concern for all developed and developing countries. In this scenario, the concrete industry offers a tentatively effective approach of consuming plastic waste (such as Polyethylene Terephthalate (PET) or High-Density Polyethylene (HDPE) plastic bottles) as a possible substitute for coarse or fine aggregates as they constitute more than 60% of the volume in the traditional concrete formulation. One of the targeted areas is to maximize plastic waste utilization and help to reduce the landfilling and dumping of these wastes, as potentially targeted in the current study. The low density of plastic makes it one of the appropriate candidates especially for developing light weight concrete. For example, a number of studies had used shredded PET bottles (see Figure 1 and Figure 2) as replacement for fine aggregate (from 5 to 75%) [7,8,9,10,11] and coarse aggregate (up to 15%) [12,13,14,15].
It was observed that, replacing 20% of fine aggregate by waste plastic resulted in a 95% slump reduction [17]; however, a similar replacement percentage by PET caused the slump of the resulting concrete to reduce by 42 to 73% [7]. The researchers commented on the higher friction and non-uniform shape of the shredded PET plastic for this decrease [9,17,18,19]. However, when fine aggregate was replaced by synthetic aggregates, which had less friction because of smooth and even surface, ultimately increased the slump values [20,21]. The fresh density was also found to decrease when the coarse aggregate was replaced with expanded polystyrene [18,22,23].The researchers have mentioned the decreased density of plastic in comparison to normal aggregates being the major cause for the reduced values of fresh density [9,12,13,15,18,19,24]. Similar to the fresh properties, the hardened properties of the concretes made with plastic waste and plastic-based aggregates were also found to be affected. The replacement of coarse aggregates with plastic particles by 40 to 80% resulted in the lessening of dry density by 11 to 65% [22,25,26,27,28,29,30]. While the replacement of coarse aggregate with synthetic plastic aggregates also reduced the dry density of concrete [21,22,31,32,33]. In addition, the compressive strength of the concrete containing the synthetic plastic aggregates also declined. The maximum reduction varied between 62 and 82% due to replacing normal coarse aggregates with plastic particles at different levels (15–80%) [15,22,24,25,26,27,28,29]. Similarly, replacing coarse aggregate totally with synthetic lightweight aggregate resulted in a reduction ranging from 43–72% [32,33,34]. The researchers commented on the feeble bond between the cement and plastic particles which ultimately weakened the interfacial transition zone to be the probable cause of reduced compressive strength [9,10,14,15,18,19,28,29,35]. Similarly, the splitting tensile strength and flexural strength of the concretes formed with plastic waste were found to decrease [9,15,35,36]. In addition, the durability properties of concretes made with plastic particles or plastic-based aggregates were less investigated. Moreover, it was also noticed that the majority of the researchers have focused on integrating the recycled plastic particles in concrete while limited trials have been made to manufacture a lightweight plastic-based aggregate using different fillers types [20,21,32,33,34,37,38,39,40]. In addition, recently, a few researchers have also tried to incorporate different types of plastic aggregates in concretes [6,41,42,43]. It was noticed that the production process and filler types had a significant effect on the physical and mechanical properties of the plastic-manufactured aggregates. In addition, the concrete industry contributes around 7% of the global carbon dioxide gas emissions, although cement is the primary source, however, the other ingredients of concrete including coarse aggregates also contribute. Therefore, replacing the natural coarse aggregates in concrete with fabricated plastic aggregates (as in this study) will not only help in plastic waste utilization but will also help to conserve natural resources, which are the main source for ordinary coarse aggregates. In addition, the two fillers, i.e., fly ash and quarry dust are mainly the by-product of the industrial process while dune dust is available in huge quantities is desserts and imposes environment hazard, therefore the utilization of these fillers will help to reduce the carbon footprints of concrete industry. Therefore, in light of the above literature review, the present study was conducted to manufacture the synthetic aggregate using recycled plastic and different filler types with an aim to optimize the filler type for producing the structural lightweight concrete to increase its applications as the majority of the studies before have shown the lessening of mechanical properties with the incorporation of plastic based aggregates. All the physical and mechanical characteristics of the manufactured aggregates were studied. In addition, a detailed investigation of the physical, mechanical, and durability properties of concrete containing 100% plastic manufactured aggregates as coarse aggregate with different filler types will also be carried out and comparisons will be made with lightweight and normal-weight concretes.

2. Materials, Experimental Plan, and Procedures

2.1. Ingredient Properties

To prepare the green lightweight concrete including the plastic waste, various other ingredients were also added. Ordinary Portland cement which is manufactured locally and complies with the standard specifications was used. In the current study four aggregate series were used i.e., normal weight aggregate (NW), naturally occurring lightweight aggregate (NLW), commercially available lightweight aggregate (CLW), and green manufactured plastic aggregate (GMPA). The details of the manufacturing of green plastic aggregates and their properties will be discussed in the following section. The NW, NLW, and CLW aggregates as shown in Figure 3 were used as references, to compare the properties of the GMPA. The NW and NLW were also used to prepare two reference concrete series to compare the properties of concrete containing GMPA. NW and NLW were obtained from a local trader while Lytag Limited delivered the CLW. The sieve analysis results for NW and NLW are shown in Figure 4. The red sand and crushed sand were used in this study as fine aggregates. To optimize the particle size distribution as per the [44,45], the red sand and crushed sand were added in a percentage of 65% and 35% respectively. The sieve analysis result for optimized fine aggregate is shown in Figure 5.
The key physical properties of the coarse and fine aggregates used in the current study are shown in Table 1.

2.2. Concrete Mix Formulation and Test Methods

Eight concrete mixes were prepared as per the methods mentioned in [46]. The water-to-cement ratio was kept constant for all the mixes at 0.5. The complete mix design quantities for all the mixes are shown in Table 2. The total water was calculated by taking into account the water absorption capacities of respective plastic fabricated aggregates. Two reference concrete mixes i.e., normal weight concrete and lightweight concrete were prepared using NW and NLW aggregates series respectively. The other six concrete series were prepared using the six different types of GMPA as discussed in the following section.
All the concrete series were investigated for their fresh, hardened, and durability-related properties. The test details along with the age of the tested specimen and respective standard are shown in Table 3. According to [47], usually, an average of three samples is taken for each test age in order to ensure good repeatability of concrete results.

3. Results and Discussion

3.1. Manufacturing of Green Plastic Aggregate

The plastic waste used for the current experimental study was provided by a resident recycling company that accumulates different types of plastic waste from the surrounding areas. After gathering the plastic waste, it is purified, shredded, melted, pelletized, and disintegrated into fragments or fine powder. In the current study, disposable PET water bottles were used as a primary source of plastic. Three different filler types were also selected i.e., dune sand, quarry fines, and fly ash. All three of the filler materials were selected to make the plastic aggregate environmentally friendly as they represent either the by-product (quarry fines and fly ash) or the abundantly occur cheap material (dune sand). As discussed in the Section 1, different filler types lead to different physical and mechanical properties of the resulting manufactured aggregate. Therefore, to optimize the filler type and percentage of plastic waste, six different types of aggregate series were produced. The detailed mixing proportions are tabulated below in Table 4. All the aggregates series were manufactured using the experimental procedure patented by [55]. All the Green Manufactured Plastic Aggregate (GMPA) series are shown in Figure 6. It was observed that the different filler types have resulted in different colors of produced GMPA series. The GMPA series manufactured using quarry fines, fly ash and dune sand appeared to be yellow, grey and brown respectively.

3.2. Green Synthetic Lightweight Aggregate Investigation

3.2.1. Shape and Texture

The shape and surface textures of the manufactured aggregate particles were evaluated based on descriptive examination using optical microscopic investigation. It was observed that the majority of the GMPA series had sharp edges irrespective of the filler type as the aggregate was observed to crush instead of being shredded. It was also noticed that different filler types have resulted in the different textures of the developed aggregate. The aggregates were found to have rough, partially rough, and partially smooth textures developed with dune dust, quarry fines, and fly ash, respectively. It was noticed that, the GMPA series in shape and texture were closer to NW aggregates rather than NLW and CLW. The plastic-based synthetic aggregates manufactured by [21,32] were found to be spherical /smooth and angular/smooth respectively which are different from the ones developed in the current study. From the shape and texture, it appeared that the GMPA series manufactured using fly ash (GMPA 2 and 5) might improve the slump of the concrete as compared to the dune dust and quarry fines series. On the other hand, the improvement of the cement aggregate matrix bonding is expected more with dune dust and quarry fine incorporated GMPA series as compared to that of the ones developed fly ash as fillers.

3.2.2. Sieve Analysis

The particle size distribution for the manufactured aggregates was studied using sieve analysis and the results were compared with standard limits for normal and lightweight aggregates as per [45,56]. In addition, the results were compared with NW and NLW reference aggregates used in the current study. The sieve analysis results for all the GMPA series are shown in Figure 7 and Figure 8 with standard limits for lightweight and normal-weight aggregates respectively.
It was observed from the above graphs that the GMPA series have exhibited different behaviors. GMPA1 series have been found to comply fully with the [56] conditions while GMPA2, GMPA3, GMPA5, and GMPA6 series diverged by23, 16, 19 and 8%, respectively from the upper limit of sieve no. 4. However, GMPA4 series deviated by 3.5%, while NLW significantly diverged by 39% from the lower limits of sieve no. 3/8. It was determined from these results that the GMPA series developed by using dune dust were coarser as compared to the GMPA series developed by quarry dust/fines or fly ash fillers. The least coarse particles were the ones developed by using fly ash as they had the smallest size amongst all three fillers. On the contrary, it was observed from Figure 8 that the developed GMPA series do not fulfill the grading requirements of the normal weight aggregates.

3.2.3. Fineness Modulus

The fineness modulus (FM) values strongly correlate with the identification of the coarse material and vice versa [57]. The FM values help in estimating the coarseness and comparative analysis between particle sizes. The results for the fineness modulus FM for the GMPA series are shown in Figure 9 along with the two-reference series of NW and NLW.
The fineness modulus for the GMPA series showed a marginal reduction varying from 0.6 to 4.5%, as compared to NW; with exception of GMPA4, which was slightly higher by 0.7%. Similarly, a comparison with NLW revealed a decreasing trend ranging from 10 to 14%. These results indicate that the GMPA series developed with dune dust (i.e., GMPA1 and GMPA4) were the coarsest, since they had the largest value of fineness modulus (i.e., 5.79, 5.87). In contrast, GMPA2 and GMPA5 were the finest among the GMPA series since they had the smallest values of FM (i.e., 5.56, 5.64). In addition, these results show that the fineness modulus values have marginally increased with an increase in the filler percentage (50 to 70%). These results are in accordance with the sieve analysis results.

3.2.4. Bulk Specific Gravity

The bulk specific gravity (BSG) is the ratio of the weight of a given volume of aggregate, including the permeable and impermeable voids in the particles, equated to the weight of an equal volume of water [58]. The variation of oven dry bulk specific gravity BSG (OD) values for GMPA series along with NW, NLW, and CLW is shown in Figure 10. It was noticed that the specific gravity of the GMPA series increased for both percentages of plastic and all types of fillers when compared with NLW and CLW. The maximum percentage increase for the GMPA series was noted to be 38% and 35% with regard to NLW and CLW respectively. However, the specific gravity of GMPA was 25 to 35% less than that of the NW series.
It was noticed that for a constant plastic percentage, the highest bulk-specific gravity values were shown by the aggregate particles manufactured using dune dust as filler, followed by quarry dust and fly ash. In addition, the increase in the filler percentage by 20% has caused an increase of an average of 7% in the bulk-specific gravity values. It was also noticed that the aggregate particles prepared in the current study appeared to be heavier as compared to the prior studies [31,32,59,60].

3.2.5. Water Absorption

The variation of water absorption (WA) values for the GMPA series along with NW, NLW, and CLW are shown in Figure 11. It was observed that the GMPA series displayed lower values of water absorption in comparison with NW, NLW, and CLW; with the exception of GMPA6, which had a 13% increase compared to NW. The observed reductions varied from 91 to 97%, from 90 to 96.7%, and from 7 to 62% as compared to NLW, CLW, and NW respectively. The impermeable nature of plastic present in the manufactured aggregate is thought of as the decreasing trend in water absorption values.
It was observed that among all the filler types for a given percentage of plastic, the aggregates manufactured using fly ash fillers have shown the least water absorption. In addition, it was also noted that an increased percentage of fillers, has resulted in an increase of 55, 116, and 77% for dune dust, fly ash, and quarry dust respectively. In the author’s opinion, the decrease in the plastic content having the impermeable nature is probably associated with the increase in the water absorption values, in addition to the increase in the porosity of the matrix as reported in a previous study [31,32]. It was also noticed that the water absorption values for the current study are on the higher side as compared to the previous studies [32,33,59,60]. In those works, the maximum water absorption of aggregates varied between 4.2 and 19.3%.

3.2.6. Unit Weight

The results of dry unit weight (DUW) for the GMPA series along with NW, NLW, and CLW are shown in Figure 12. It was observed that the dry unit weight of the GMPA series showed a decreasing trend in comparison with NW while the values were found to increase with respect to NLW and CLW series. The dry unit weight of the GMPA series decreased by 8 to 22% in comparison to NW while the increase in GMPA dry unit weight varied between 52 to 80% and 19 to 42% with respect to NLW and CLW aggregate series. In addition, it was also noticed that an increase in the percentages of filler percentage in the aggregate matrix caused an increase in the dry unit weight of the manufactured aggregate irrespective of filler type. The highest values of dry unit weight at each percentage of plastic are shown by the dune dust filler while fly ash fillers had shown the lowest values. The increase was found to be 11, 7, and 9% for dune dust, fly ash, and quarry dust respectively. The major reason is that higher-density materials (fillers) have replaced the lower-density material (recycled plastic) in the aggregate matrix. The same trend was observed as reported in a previous study [31,32].
It was observed that the density values of the GMPA aggregate series are comparable to the densities of aggregates developed in the previous studies [20,21,61]. The values of dry unit weight for the GMPA series have exceeded the limit of [56] for structural lightweight aggregate (i.e., 880 kg/m3) by 20–43%.

3.2.7. Aggregate Void Content

The comparisons between the voids’ percentages for the GMPA series along NW, NLW, and CLW are shown in Figure 13. It was observed that the GMPA series have shown a decreasing trend for the void percentage as compared to all three reference aggregate series. The decrease was found to vary between 25 to 45.5%, 4 to 36%, and 1 to 34% with respect to NLW, CLW, and NW series respectively. In addition, it was also noticed that the increase in the filler percentage for a given plastic content reduced the void content for all types of fillers. The decrease in the void percentage varied between 11 to 18% to increase the filler percentage from 50 to 70%. This reduction is mainly because of the increase in packing density with an increase in the percentage of more fine material instead of plastic particles.

3.2.8. Strength

The results of the impact value test for the GMPA series along with NW, NLW, and CLW are shown in Figure 14. The impact values for NW, NLW and CLW were found to be were 9.7, 39 and 21.6% respectively. The GMPA series have shown the ability to be crushed upon impact and have shown a decrease in the values by 43 to 61% with reference to NLW. Similarly, in comparison with CLW, a reduction ranging from 1.1 to 28.5% was observed; except for GMPA5, which had a marginal increase (i.e., 5%). However, in comparison with NW, substantial increases in the aggregate impact value, varying from 60 to 135%, were also observed.
It was also observed that the increase in the filler percentage has increased the impact values. A decrease of 24.7, 43.6, and 29% in the strength was found when the percentage of fillers was increased from 50 to 70% for dune dust, fly ash, and quarry dust respectively. In the author’s opinion, this decrease was mainly because of less binder which yielded less bonding between the filler particles. Furthermore, the impact value observed for the GMPA series was less than the maximum allowable limit (i.e., 30%) given by [62].

3.3. Green Lightweight Concrete Investigation

3.3.1. Fresh Properties of Green-Manufactured Plastic Aggregates Concrete

The slump and fresh densities of the concrete containing green manufactured plastic aggregates were determined to evaluate the fresh behavior of the aforementioned concrete and a comparison was made with concrete having normal weight and naturally light weight aggregates. The slump results for concrete containing six different types of GMPA series along with NC and NLWC are shown in Figure 15. It was noticed that the slump values increased with reference to NC; whereas fluctuating results were seen as compared with NLWC, as shown in Figure 15. The increase in slump varied between 25 and 150% as compared to NC. The reported values of slump were found to be in line with existing studies which observed a similar increasing trend ranging from 51 to 123% at 75% replacement of NA with plastic-based aggregate [20,21]. However, with respect to NLWC, the slump of GMPC1 and GMPC4 increased by 10 and 19%; while that of GMPC2, GMPC3, and GMPC5 decreased by 52, 10, and 40% respectively. It was noticed that the slump variation was found to have an inverse relation with the size of the aggregates as GMPC1 and GMPC4 have shown the highest slump values correspondingly their respective aggregates had the maximum size. Accordingly, the packing level reduces with the coarser aggregates, which would decrease the demand for cement paste, which ultimately increases the workability of the mix.
Overall, GMPC2 has not satisfied the workability requirements of structural lightweight concrete (i.e., 75–125 mm) specified in [63]; while all the other mixes have shown slump values within the specified limits.
The fresh densities for concrete containing six different types of GMPA series along with NC and NLWC are shown in Figure 16. The fresh densities of GMPC had an average reduction of 15% as compared to NC, while a marginal variation of ±3% was found with respect to NLWC. The maximum and minimum fresh density was attained by GMPC4 and GMPC2 respectively corresponding to the densities of the respectively manufactured aggregates as discussed previously.

3.3.2. Hardened Properties of Green-Manufactured Plastic Aggregates Concrete

Dry Density

Tests were carried out on GMPA concrete to evaluate its fulfillment of density requirements specified for lightweight concrete. The 28 days dry density results for the GMPC series; in comparison with NC and NLWC are shown in Figure 17. The findings in Figure 17 revealed that there was a marginal variation (i.e., from −2 to 5%) between the dry density of GMPC and NLWC. On the other hand, the density of the GMPC series was found to be 14–20% lower than that of the NC series. In addition, these results showed that the minimum dry density of GMPC was achieved by GMPC2, since GMPA2 has the lowest specific gravity/density amongst GMPA series, as observed previously with fresh density. The decrease in dry density values is well in accordance with the previous research where the decrease of about 15–31% was reported at a replacement of 75 to 100% for coarse aggregates or fine aggregates by manufactured plastic [20,21,31,32,33].
Overall, it was noticed that the dry density values of the concrete containing six different types of GMPA were found to be inside the boundaries (i.e., 1400–1900 kg/m3) specified in [63] with a marginal increase (6%).

Compressive Strength

The 28 days cube compressive strength results for the GMPC series; in comparison with NC and NLWC are shown in Figure 18. It was observed that with age the compressive strength of all the series has improved. During the curing period of 7 to 14 days, the compressive strength was found to increase by 3 to 19%, 18% and 16% for GMPC, NLWC and NC respectively. Likewise, during the curing period of 14 to 28 days, the compressive strength was found to increase by 7 to 34%, 19% and 13% for GMPC, NLWC and NC respectively. It was noticed that, for 28 days, the GMPC series observed a significant increase ranging between 13 and 39.7%, as compared to LWC, except for GMPC4 and GMPC5, which demonstrated a marginal decrease (8%). The strength trend was found to vary according to the strength of aggregates as reported in the previous section. In addition, the strength of the GMPC series had shown a trend of decreasing strength with respect to NC. The decrease was found to be between 7 to 39 %. However, the reported values of decrease in strength are on the lower side as compared to the strength values reported in previous studies, where the decrease varied between 31 to 66% at replacement percentage varying between 75 to 100% [20,21,32,33,34]. Furthermore, it was observed that the highest value of 28 days compressive strength was attained by since its aggregate (i.e., GMPA3) attained the highest strength among all the GMPAs. In addition, the reduction in the compressive strength was also observed when the percentage of filler was increased in the aggregate matrix.
To estimate the compressive strength of the concrete prepared in the current study based on cylindrical specimens, the relation proposed by [64,65], i.e, cylindrical compressive strength is 0.8 times the cubical compressive strength for the same concrete. An increase of 17 to 82% with respect to the lowest boundary value set by [56], i.e., 17 MPa, was found for the 28-day cylinder compressive strength of GMPC series highlighting its possible lightweight structural uses.

Flexural Strength

The flexural strength results of GMPC, in comparison with NC and NLWC are presented in Figure 19. An improvement in the values of flexural strength for all the concrete mixes was noticed with age. During the curing period of 7 to 14 days, the flexural strength was found to increase by 5 to 18%, 53% and 6% for GMPC, NLWC and NC respectively. Likewise, during the curing period of 14 to 28 days, the compressive strength was found to increase by 3 to 27%, 25% and 13% for GMPC, NLWC and NC respectively
Interestingly, Figure 19 indicates that the RPAC-2 achieved a higher flexural strength (i.e., 7–21%) at 7 days; except for GMPC4, which had 15% lower strength compared to LWC. On the other hand, with an increase in the curing period i.e., at 14 and 28 days GMPA had shown lessened flexural strength values in comparison to NC and NLWC. It was noticed that the lowest lessening in 28-day flexural strength was found to be 39 and 23%, as compared to NC and LWC respectively, for GMPC3 and GMPC6. While, the highest reduction was observed in GMPC3, which was 53 and 41% lower with respect to NC and LWC. This trend can be because of the increased aggregate strength of the GMPA3 and GMPA4 series. In addition, a reduction varying from 15 to 20% was found for the GMPC series when the percentage of filler was increased in the aggregate matrix, as observed with compressive strength
Overall, the present study’s results reveal that the 28-day flexural strength of GMPC was less strong than conventional concrete (NLWC and NC). Nonetheless, these reductions are less compared to those reported in other studies i.e., the lessening of flexural strength was observed to vary from 50 to 59% at the replacement level of manufactured plastic aggregates of 15–50% [15,27]. To make an assessment compared to [56] criteria, which specifies the lowest boundary value for splitting tensile strength as 2.1 MPa, the flexural stresses will be converted to equivalent splitting tensile strength for the current concrete results by using the relation proposed [65,66], i.e., the splitting tensile strength is equal to 0.75 times the flexural strength for the given concrete. Thus, the estimated 28-day splitting tensile strength for GMPC ranged from 2.3 to 3.03 MPa, which is clearly greater than the limit described in [56].

Splitting Tensile Strength

The splitting tensile strength results of GMPC, in comparison with NC and NLWC are presented in Figure 20. Like compressive and flexural strength, an increase was observed in the splitting tensile values for all the concrete mixes with age (curing period). In addition, it was noticed that the splitting tensile strength for the GMPC series decreased with respect to NC for all ages, however, in comparison with NLWC, at 7 days the splitting tensile strength of GMPC showed an increase while at 14 and 28 days, the opposite trend was observed. GMPC3 had shown a maximum increase of about 40% with respect to NLWC and a minimum reduction of 28% with respect to NC. In addition, the lessening in the splitting tensile strength of GMPC at 14 and 28 days was noticed to be 3 to 28.5% and 11 to 31% respectively with respect to NLWC. On the other hand, the average lessening in the splitting tensile strength of GMPC at 14 and 28 days was noticed to be 36% and 41% respectively with respect to NC. The results of splitting tensile strength were in line with the previous studies, where the decrease in the splitting tensile strength was observed to be 31% o 39% at replacement levels of 75 to 100% [20,21,32]. Furthermore, a decrease in the splitting tensile strength values of 16, 15, and 3% was observed with an increase in the filler percentage (50 to 70%) in the manufactured aggregate matrix for Dune sand, fly ash, and quarry waste, respectively.
Generally, it was perceived that all the concretes made in the current study by using the green manufactured plastic aggregates have satisfied the splitting tensile strength criteria mentioned in the [56], i.e., minimum value as 2.1 MPa, excluding GMPC4 and GMPC5.

Microscopic Investigations

To study the physical internal characteristics of the concrete made by using NLWA and GMPA series, the microscopic images corresponding to the same age, i.e., 28 days were studied as shown in Figure 21.
It was noticed that GMPC concretes have exhibited a distinct and demarcated boundary between the aggregate particles and cement as compared to NLWC. In addition, the optical microscopic images of NLWC have shown the presence of pores in the structure of NLWA aggregates making it as a spongy structure in comparison with GMPC concrete where GMPA aggregates have shown relatively solid aggregate particles. This behavior ultimately affects the overall strength of the concrete as observed in the compressive strength results for all the concrete series, i.e., NLWC had shown lower strength as compared to GMPC concretes because of its porous aggregate structure. The same explanation has also been described in another study by [67]. In addition, the GMPC series have relatively shown higher voids in the cement paste as compared to NLWC which might have also resulted in the reduction of the strength values for GMPC.

3.3.3. Durability-Related Properties of Green Manufactured Plastic Aggregates Concrete

In the current study, the resistance to chloride penetration was chosen as the durability indicator for all the concrete series. The resistance of concrete containing GMPA towards ingressive soluble (i.e., chloride) was evaluated using a chloride ion penetration test. The results for the GMPC series are presented in Figure 22, in comparison with NC and NLWC. A decreasing trend was observed in the chloride penetration for the GMPC series as compared to NC and NLWC. A decrease of 32 to 70% and 38 to 73% was observed in the GPMC series with respect to NC and NLWC series respectively. The prime reason for this decrease is the impervious nature of plastic particles which do not allow the penetration of solution through them reduce the higher flow through concrete. A reduction in the chloride permeability of about 36% was observed in a comparable study where 45% of the fine aggregates were replaced with polyvinyl chloride-based aggregates [35].
In addition, GMPC2 and GMPC5 have shown the minimum values of chloride permeability among the GMPC series. GMPC2 and GMPC4 have yielded a significant reduction varying from 67 to 70% and from 70 to 73%, in comparison with NC and LWC respectively. However, the highest permeability was found in GMPC1 and GMPC4. The percentage decrease varied between 32 to 38% and 38 to 44% with respect to NC and NLWC respectively. The change in the permeability values for the GMPC series is mainly linked to the packing percentage of the concrete. The coarser aggregates generally yield less dense structure leading to higher permeability values as is the case of GMPA1 and GMPA4.
Moreover, it was also noticed that the increase in the filler percentage (50 to 70%) of the aggregate matrix resulted in a slight decrease of 5 to 8% in the values of chloride permeability values for the resulting concrete. Furthermore, as per the [54], the concrete containing GMPA can be classified in the low to moderate chloride penetration zone, therefore, the present results advocate the use of GMPC for mild chloride exposure lightweight structures.

4. Conclusions

The current research study was undertaken to explore the effects of various filler types on the properties of green manufactured plastic aggregates and at a second stage, incorporate the manufactured aggregates in concrete to investigate its fresh, hardened, and durability-related properties. The following major conclusions were drawn from the above results and discussions:
  • The addition of different filler has modified the properties of the developed aggregate. The dune dust addition caused the aggregates to be rougher as compared to quarry fines and fly ash. The manufactured aggregates developed by using dune dust were coarser and had the highest bulk specific gravity among the three filler types.
  • The water absorption values were found to be lowest for the aggregates manufactured using fly ash fillers as compared to quarry fines and dune dust. Furthermore, the increase in the percentage of fillers in the aggregate matrix (50 to 70%) caused the water absorption to increase by 55, 116, and 77% for dune dust, fly ash, and quarry dust respectively. Furthermore, the results of the impact test have demonstrated a decrease of 24.7, 43.6, and 29% in the strength values when the percentage of fillers was increased from 50 to 70% for dune dust, fly ash, and quarry dust respectively.
  • The addition of different fillers in the aggregate matrix has altered the slump and dry density results of resulting concrete, however, except GMPA2 (manufactured aggregates composed of 50% fly ash and 50% plastic) satisfied the workability (i.e., 75–125 mm) and density (i.e., 1400–1900 kg/m3) requirements of structural lightweight concrete specified in [63].
  • The compressive, flexural, and splitting tensile strength of concrete containing green manufactured plastic aggregates have shown a decrease with reference to normal as well as natural lightweight concrete, irrespective of the filler type. Furthermore, the chloride permeability test results have shown the increased durability of concretes made with green manufactured plastic aggregates as compared to normal as well as natural lightweight concrete. The durability increased with an increase in the filler percentage for all filler types.
  • Although, the majority of the concrete made in the current study by using green manufactured plastic aggregates have satisfied the criteria mentioned in [56] demonstrating its ability for lightweight structural uses, GMPA3 (manufactured aggregates composed of 50% quarry dust and 50% plastic) appeared to be the best choice. Overall, the green manufactured plastic aggregates have demonstrated their capacity for structural lightweight construction projects with effective utilization of plastic waste and industrial by-products.

Author Contributions

Conceptualization, F.K.A.; Methodology, F.K.A.; Formal analysis, I.Z.; Data curation, F.K.A.; Writing—original draft, I.Z.; Writing—review & editing, F.K.A.; Project administration, F.K.A.; Funding acquisition, F.K.A. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Researchers Supporting Project number (RSP2023R264), King Saud University, Riyadh, Saudi Arabia.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The authors can be contacted for research data, if needed.

Acknowledgments

The authors extend their appreciation to the Researchers Supporting Project number (RSP2023R264), King Saud University, Riyadh, Saudi Arabia for funding this work.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Zafar, I. Sustainable Alternatives for Green Mortar: Quarry Waste and Ultra high fly ash utilization. IOP Conf. Series: Earth Environ. Sci. 2022, 1026, 012034. [Google Scholar] [CrossRef]
  2. Mouli, M.; Khelafi, H. Performance characteristics of lightweight aggregate concrete containing natural pozzolan. Build. Environ. 2008, 43, 31–36. [Google Scholar] [CrossRef]
  3. Shi, J.; Liu, B.; Liu, Y.; Wang, E.; He, Z.; Xu, H.; Ren, X. Preparation and characterization of lightweight aggregate foamed geopolymer concretes aerated using hydrogen peroxide. Constr. Build. Mater. 2020, 256, 119442. [Google Scholar] [CrossRef]
  4. Shi, J.; Tan, J.; Liu, B.; Liu, Y.; Xu, H.; Wang, Z.; Xiong, T.; Shi, J. Thermal and mechanical properties of thermal energy storage light-weight aggregate mortar incorporated with phase change material. J. Energy Storage 2020, 32, 101719. [Google Scholar] [CrossRef]
  5. Siddique, R.; Khatib, J.; Kaur, I. Use of recycled plastic in concrete: A review. Waste Manag. 2008, 28, 1835–1852. [Google Scholar] [CrossRef]
  6. Abu-Saleem, M.; Zhuge, Y.; Hassanli, R.; Ellis, M.; Rahman, M.; Levett, P. Evaluation of concrete performance with different types of recycled plastic waste for kerb application. Constr. Build. Mater. 2021, 293, 123477. [Google Scholar] [CrossRef]
  7. Albano, C.; Camacho, N.; Hernández, M.; Matheus, A.; Gutiérrez, A. Influence of content and particle size of waste pet bottles on concrete behavior at different w/c ratios. Waste Manag. 2009, 29, 2707–2716. [Google Scholar] [CrossRef]
  8. Remadnia, A.; Dheilly, R.; Laidoudi, B.; Quéneudec, M. Use of animal proteins as foaming agent in cementitious concrete composites manufactured with recycled PET aggregates. Constr. Build. Mater. 2009, 23, 3118–3123. [Google Scholar] [CrossRef]
  9. Rahmani, E.; Dehestani, M.; Beygi, M.H.A.; Allahyari, H.; Nikbin, I.M. On the mechanical properties of concrete containing waste PET particles. Constr. Build. Mater. 2013, 47, 1302–1308. [Google Scholar] [CrossRef]
  10. Juki, M.I.; Awang, M.; Annas, M.M.K.; Boon, K.H.; Othman, N.; Kadir, A.B.A.; Roslan, M.A.; Khalid, F.S. Relationship between Compressive, Splitting Tensile and Flexural Strength of Concrete Containing Granulated Waste Polyethylene Terephthalate (PET) Bottles as Fine Aggregate. Adv. Mater. Res. 2013, 795, 356–359. [Google Scholar] [CrossRef]
  11. Frigione, M. Recycling of PET bottles as fine aggregate in concrete. Waste Manag. 2010, 30, 1101–1106. [Google Scholar] [CrossRef] [PubMed]
  12. Ferreira, L.; de Brito, J.; Saikia, N. Influence of curing conditions on the mechanical performance of concrete containing recycled plastic aggregate. Constr. Build. Mater. 2012, 36, 196–204. [Google Scholar] [CrossRef]
  13. Silva, R.V.; de Brito, J.; Saikia, N. Influence of curing conditions on the durability-related performance of concrete made with selected plastic waste aggregates. Cem. Concr. Compos. 2013, 35, 23–31. [Google Scholar] [CrossRef]
  14. Saikia, N.; de Brito, J. Waste polyethylene terephthalate as an aggregate in concrete. Mater. Res. 2013, 16, 341–350. [Google Scholar] [CrossRef] [Green Version]
  15. Saikia, N.; de Brito, J. Mechanical properties and abrasion behaviour of concrete containing shredded PET bottle waste as a partial substitution of natural aggregate. Constr. Build. Mater. 2014, 52, 236–244. [Google Scholar] [CrossRef]
  16. Hannawi, K.; Kamali-Bernard, S.; Prince, W. Physical and mechanical properties of mortars containing PET and PC waste aggregates. Waste Manag. 2010, 30, 2312–2320. [Google Scholar] [CrossRef] [PubMed]
  17. Batayneh, M.; Marie, I.; Asi, I. Use of selected waste materials in concrete mixes. Waste Manag. 2007, 27, 1870–1876. [Google Scholar] [CrossRef]
  18. Ismail, Z.Z.; Al-Hashmi, E.A. Use of waste plastic in concrete mixture as aggregate replacement. Waste Manag. 2008, 28, 2041–2047. [Google Scholar] [CrossRef]
  19. Rai, B.; Rushad, S.T.; Kr, B.; Duggal, S.K. Study of Waste Plastic Mix Concrete with Plasticizer. ISRN Civ. Eng. 2012, 2012, 29–32. [Google Scholar] [CrossRef] [Green Version]
  20. Choi, Y.-W.; Moon, D.-J.; Chung, J.-S.; Cho, S.-K. Effects of waste PET bottles aggregate on the properties of concrete. Cem. Concr. Res. 2005, 35, 776–781. [Google Scholar] [CrossRef]
  21. Choi, Y.W.; Moon, D.J.; Kim, Y.J.; Lachemi, M. Characteristics of mortar and concrete containing fine aggregate manufactured from recycled waste polyethylene terephthalate bottles. Constr. Build. Mater. 2009, 23, 2829–2835. [Google Scholar] [CrossRef]
  22. Tang, W.; Lo, Y.; Nadeem, A. Mechanical and drying shrinkage properties of structural-graded polystyrene aggregate concrete. Cem. Concr. Compos. 2008, 30, 403–409. [Google Scholar] [CrossRef]
  23. Chen, B.; Liu, J. Properties of lightweight expanded polystyrene concrete reinforced with steel fiber. Cem. Concr. Res. 2004, 34, 1259–1263. [Google Scholar] [CrossRef]
  24. Ben Fraj, A.; Kismi, M.; Mounanga, P. Valorization of coarse rigid polyurethane foam waste in lightweight aggregate concrete. Constr. Build. Mater. 2010, 24, 1069–1077. [Google Scholar] [CrossRef] [Green Version]
  25. Sabaa, B.; Ravindrarajah, R.S. Engineering properties of lightweight concrete containing crushed expanded poly-styrene waste. In Proceedings of the Symposium MM: Advances in Materials for Cementitious Composites, Boston, MA, USA, 1–5 December 1997; pp. 1–3. [Google Scholar]
  26. Ravindrarajah, R.S. Bearing strength of concrete containing polystyrene aggregate. In Proceedings of the RILEM 8th International Confrence: Durability of Building Materials and Components, Vancouver, BC, Canada, 30 May–3 June 1999; Volume 1, pp. 505–514. [Google Scholar]
  27. Lima, P.; Leite, M.; Santiago, E.Q.R. Recycled lightweight concrete made from footwear industry waste and CDW. Waste Manag. 2010, 30, 1107–1113. [Google Scholar] [CrossRef] [PubMed]
  28. Rahman, M.M.; Islam, M.A.; Ahmed, M. Recycling of waste polymeric materials as a partial replacement for aggregate in concrete. In Proceedings of the International Conference on Chemical, Environmental and Biological Sciences, Hong Kong, China, 29–30 December 2012. [Google Scholar]
  29. Al-Manaseer, A.; Dalal, T. Concrete containing plastic aggregates. Concr. Int. 1997, 19, 47–52. [Google Scholar]
  30. Haghi, A.K.; Arabani, M.; Ahmadi, H. Applications of expanded polystyrene (EPS) beads and polyamide-66 in civil engineering, Part One: Lightweight polymeric concrete. Compos. Interfaces 2006, 13, 441–450. [Google Scholar] [CrossRef]
  31. Kashi, M.; Swan, C.; Holmstrom, O.; Malloy, R. Innovative lightweight synthetic aggregates developed from coal Flyash. In Proceedings of the 13th International Symposium on Management and Use of Coal Combustion Products, Orlando, FL, USA, 11–15 January 1999; Volume 1, pp. 1–5. [Google Scholar]
  32. Jansen, D.; Kiggins, M.; Swan, C.; Malloy, R.; Kashi, M.; Chan, R.; Javdekar, C.; Siegal, C.; Weingram, J. Lightweight fly ash-plastic aggregates in concrete. Transportation Research Record: J. Transp. Res. Board 2001, 1175, 44–52. [Google Scholar] [CrossRef]
  33. Slabaugh, S.; Swan, C.; Malloy, R. Development and properties of Foamed synthetic Lightweight Aggregates. In Proceedings of the World of Coal Ash (WOCA) Conference, Covington, KY, USA, 7–10 May 2007. [Google Scholar]
  34. Malloy, R.; Desai, N.; Wilson, C.; Swan, C.; Jansen, D.; Kashi, M. High Carbon Fly Ash/Mixed Thermoplastic Aggregate for Use in Lightweight Concrete (859). Tech. Pap. Annu. Tech. Conf.-Soc. Plast. Eng. Inc. 2001, 3, 2743–2752. [Google Scholar]
  35. Kou, S.C.; Lee, G.; Poon, C.S.; Lai, W.-L. Properties of lightweight aggregate concrete prepared with PVC granules derived from scraped PVC pipes. Waste Manag. 2009, 29, 621–628. [Google Scholar] [CrossRef]
  36. Sakr, K.; El-Hakim, E. Effect of high temperature or fire on heavy weight concrete properties. Cem. Concr. Res. 2005, 35, 590–596. [Google Scholar] [CrossRef]
  37. Alqahtani, F.K.; Khan, M.I.; Ghataora, G.; Dirar, S. Production of Recycled Plastic Aggregates and Its Utilization in Concrete. J. Mater. Civ. Eng. 2016, 29, 04016248. [Google Scholar] [CrossRef]
  38. Alqahtani, F.K.; Ghataora, G.; Khan, M.I.; Dirar, S. Novel lightweight concrete containing manufactured plastic aggregate. Constr. Build. Mater. 2017, 148, 386–397. [Google Scholar] [CrossRef]
  39. Alqahtani, F.K.; Ghataora, G.; Dirar, S.; Khan, M.I.; Zafar, I. Experimental study to investigate the engineering and durability performance of concrete using synthetic aggregates. Constr. Build. Mater. 2018, 173, 350–358. [Google Scholar] [CrossRef] [Green Version]
  40. Alqahtani, F.K.; Zafar, I. Characterization of processed lightweight aggregate and its effect on physical properties of concrete. Constr. Build. Mater. 2020, 230, 116992. [Google Scholar] [CrossRef]
  41. Islam, M.J.; Shahjalal, M. Effect of polypropylene plastic on concrete properties as a partial replacement of stone and brick aggregate. Case Stud. Constr. Mater. 2021, 15, e00627. [Google Scholar] [CrossRef]
  42. Tayeh, B.A.; Almeshal, I.; Magbool, H.M.; Alabduljabbar, H.; Alyousef, R. Performance of sustainable concrete containing different types of recycled plastic. J. Clean. Prod. 2021, 328, 129517. [Google Scholar] [CrossRef]
  43. Bamigboye, G.O.; Tarverdi, K.; Umoren, A.; Bassey, D.E.; Okorie, U.; Adediran, J. Evaluation of eco-friendly concrete having waste PET as fine aggregates. Clean. Mater. 2021, 2, 100026. [Google Scholar] [CrossRef]
  44. ASTM C33/C33M-16; Standard Specification for Concrete Aggregates. ASTM International: West Conshohocken, PA, USA, 2016.
  45. ASTM C136/C136M-14; Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. ASTM International: West Conshohocken, PA, USA, 2014.
  46. ACI 211.2-98; Standard Practice for Selecting Proportions for Structural Lightweight Concrete (Reapproved 2004). American Concrete-ACI Committee 211: Farmington Hills, MI, USA, 1998.
  47. ASTM C192/C192M-16; Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory. ASTM International: West Conshohocken, PA, USA, 2016.
  48. ASTM C143/C143M-15; Standard Test Method for Slump of Hydraulic-Cement Concrete. ASTM International: West Conshohocken, PA, USA, 2015.
  49. ASTM C138/C138M-16; Standard Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete. ASTM International: West Conshohocken, PA, USA, 2016.
  50. BS EN 12390-7:2009; Testing Hardened Concrete: Density of Hardened Concrete. British Standards Institution: London, UK, 2009.
  51. ASTM C579-02; Standard Test Methods for Compressive Strength of Chemical-Resistant Mortars, Grouts, Monolithic Surfacings, and Polymer Concretes. ASTM International: West Conshohocken, PA, USA, 2012.
  52. ASTM C496/C496M-11; Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens. ASTM International: West Conshohocken, PA, USA, 2011.
  53. ASTM C580-02; Standard Test Method for Flexural Strength and Modulus of Elasticity of Chemical-Resistant Mortars, Grouts, Monolithic Surfacings, and Polymer Concretes. ASTM International: West Conshohocken, PA, USA, 2012.
  54. ASTM C1202-12; Standard Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration. ASTM International: West Conshohocken, PA, USA, 2012.
  55. Alqahtani, F.K. Recycled Plastic Aggregate for Use in Concrete. U.S. Patent No. 10,294,155, 21 May 2019. [Google Scholar]
  56. ASTM C330/C330M-14; Standard Specification for Lightweight Aggregates for Structural Concrete. ASTM International: West Conshohocken, PA, USA, 2014.
  57. Domone, P.; Illston, J. Construction Materials: Their Nature and Behaviour; CRC Press: Boca Raton, FL, USA, 2010. [Google Scholar]
  58. Prowell, B.D.; Baker, N.V. Evaluation of New Test Procedures for Determining Bulk Specific Gravity of Fine Aggregate by Automated Methods. Transp. Res. Rec. J. Transp. Res. Board 2004, 1874, 11–18. [Google Scholar] [CrossRef]
  59. Phillips, P.; Richards, G. The use of mixed polymer waste products to produce paving grade asphalt. In Proceedings of the 3rd Eurasphalt and Eurobitume Congress, Vienna, Austria, 12–14 May 2004. [Google Scholar]
  60. Swan, C.; Sacks, A. Properties of Synthetic Lightweight Aggregates for use in Pavement Systems. In Advances in Pavement Engineering; ASCE: Reston, VA, USA, 2005; pp. 1–12. [Google Scholar] [CrossRef]
  61. Koide, H.; Tomon, M.; Sasaki, T. Investigation of the use of waste plastic as an aggregate for lightweight concrete. Sustainable Concrete Construction. In Proceedings of the International Conference at the University of Dundee, Scotland, UK, 9–11 September 2002; Volume 5, pp. 177–185. [Google Scholar]
  62. BS 812-112:1990; Methods for Determination of Aggregate Impact Value (AIV). British Standards Institution: London, UK, 1990.
  63. ACI 213R-03; Guide for Structural Lightweight-Aggregate Concrete-ACI Committee 213. American Concrete-ACI Committee 211: Farmington Hills, MI, USA, 2003.
  64. Hamad, A.J. Size and shape effect of specimen on the compressive strength of HPLWFC reinforced with glass fibres. J. King Saud Univ.-Eng. Sci. 2015, 29, 373–380. [Google Scholar] [CrossRef] [Green Version]
  65. Neville, A.M. Properties of Concrete; Pearson Education Limited: Essex, UK, 1995. [Google Scholar]
  66. Raphael, J.M. Tensile strength of concrete. ACI J. Proc. 1984, 81, 158–165. [Google Scholar]
  67. Marzouk, O.Y.; Dheilly, R.; Queneudec, M. Valorization of post-consumer waste plastic in cementitious concrete composites. Waste Manag. 2007, 27, 310–318. [Google Scholar] [CrossRef] [PubMed]
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Figure 1. PET aggregates [16].
Figure 1. PET aggregates [16].
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Figure 2. Type of PET particles [9].
Figure 2. Type of PET particles [9].
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Figure 3. Different types of aggregates used in the current research.
Figure 3. Different types of aggregates used in the current research.
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Figure 4. Sieve analysis for NW and NLW aggregate used in the current study.
Figure 4. Sieve analysis for NW and NLW aggregate used in the current study.
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Figure 5. Sieve analysis for the fine aggregates used in the current study.
Figure 5. Sieve analysis for the fine aggregates used in the current study.
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Figure 6. Various types of Green Manufactured Plastic Aggregate series produced in the current study.
Figure 6. Various types of Green Manufactured Plastic Aggregate series produced in the current study.
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Figure 7. Sieve analysis results for GMPA series in comparison with NLW.
Figure 7. Sieve analysis results for GMPA series in comparison with NLW.
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Figure 8. Sieve analysis results for GMPA series in comparison with NW.
Figure 8. Sieve analysis results for GMPA series in comparison with NW.
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Figure 9. Fineness modulus of GMPA series along with NW and NLW.
Figure 9. Fineness modulus of GMPA series along with NW and NLW.
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Figure 10. Bulk specific gravity of GMPA series along with NW, NLW, and CLW series.
Figure 10. Bulk specific gravity of GMPA series along with NW, NLW, and CLW series.
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Figure 11. Water absorption values of GMPA series along with NW, NLW, and CLW series.
Figure 11. Water absorption values of GMPA series along with NW, NLW, and CLW series.
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Figure 12. Dry unit weight of GMPA series along with NW, NLW, and CLW series.
Figure 12. Dry unit weight of GMPA series along with NW, NLW, and CLW series.
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Figure 13. Void percentage of GMPA series along with NW, NLW, and CLW series.
Figure 13. Void percentage of GMPA series along with NW, NLW, and CLW series.
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Figure 14. Impact values of GMPA series along with NW, NLW, and CLW series.
Figure 14. Impact values of GMPA series along with NW, NLW, and CLW series.
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Figure 15. Slump values of GMPC series along with NC and NLWC.
Figure 15. Slump values of GMPC series along with NC and NLWC.
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Figure 16. Fresh density values of GMPC series along with NC and NLWC.
Figure 16. Fresh density values of GMPC series along with NC and NLWC.
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Figure 17. 28-day dry density of GMPC series along with NC and NLWC.
Figure 17. 28-day dry density of GMPC series along with NC and NLWC.
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Figure 18. 28-Compressive strength of GMPC series along with NC and NLWC.
Figure 18. 28-Compressive strength of GMPC series along with NC and NLWC.
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Figure 19. Flexural strength of GMPC series along with NC and NLWC.
Figure 19. Flexural strength of GMPC series along with NC and NLWC.
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Figure 20. Splitting tensile strength of GMPC series along with NC and NLWC.
Figure 20. Splitting tensile strength of GMPC series along with NC and NLWC.
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Figure 21. Optical microscopic images of (a) NLWC, (b) GMPC4, (c) GMPC 5, and (d) GMPC6.
Figure 21. Optical microscopic images of (a) NLWC, (b) GMPC4, (c) GMPC 5, and (d) GMPC6.
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Figure 22. 28-day chloride permeability of GMPC, NC, and NLWC.
Figure 22. 28-day chloride permeability of GMPC, NC, and NLWC.
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Table
Table 1. Key Physical properties of coarse and fine aggregates used for this study.
Table 1. Key Physical properties of coarse and fine aggregates used for this study.
Specific PropertyCoarse AggregateFine Aggregate
NWNLWCLWRed SandCrushed Sand
TypeCrushedUncrushedPelletizedUncrushedCrushed
Apparent Specific Gravity2.691.411.912.642.77
Nominal Maximum Size (mm)1010101.184.75
Fineness Modulus5.836.5-1.543.89
Dry Unit weight (kg/m3)155469788915891599
Absorption (%)1.4818.616.820.281.67
Table
Table 2. Mix design for eight different concrete series prepared in this study.
Table 2. Mix design for eight different concrete series prepared in this study.
Concrete TypeTotal WaterFree WaterCementFine AggregatesCoarse Aggregate
NWNLWGMPA
kg/m3
NC243.9228456770784--
NLWC299228456909-352-
GMPC1237.4228456735--572
GMPC2235.3228456729--535
GMPC3237.7228456737--565
GMPC4240.8228456708--637
GMPC5239.2228456729--570
GMPC6242.6228456729--618
Table
Table 3. Investigation types and their details for concretes.
Table 3. Investigation types and their details for concretes.
Property TypeTestTesting Age (Day)Standard Used
FreshSlump-[48]
Fresh density-[49]
Hardened/MechanicalDry density28[50]
Compressive strength7, 14, 28[51]
Splitting tensile strength7, 14, 28[52]
Flexural strength7, 14, 28[53]
DurabilityChloride ion penetration28[54]
Table
Table 4. Composition of manufactured RPA.
Table 4. Composition of manufactured RPA.
Sr. No.DesignationPlastic Waste %Filler TypeFiller %
1GMPA150Dune Dust50
2GMPA250Fly Ash50
3GMPA350Quarry Dust50
4GMPA430Dune Dust70
5GMPA530Fly Ash70
6GMPA630Quarry Dust70
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Alqahtani, F.K.; Zafar, I. Exploring the Effect of Different Waste Fillers in Manufactured Sustainable Plastic Aggregates Matrix on the Structural Lightweight Green Concrete. Sustainability 2023, 15, 2311. https://doi.org/10.3390/su15032311

AMA Style

Alqahtani FK, Zafar I. Exploring the Effect of Different Waste Fillers in Manufactured Sustainable Plastic Aggregates Matrix on the Structural Lightweight Green Concrete. Sustainability. 2023; 15(3):2311. https://doi.org/10.3390/su15032311

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Alqahtani, Fahad K., and Idrees Zafar. 2023. "Exploring the Effect of Different Waste Fillers in Manufactured Sustainable Plastic Aggregates Matrix on the Structural Lightweight Green Concrete" Sustainability 15, no. 3: 2311. https://doi.org/10.3390/su15032311

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