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The purpose of this paper is to highlight the sustainability benefits of using demolition and industrial wastes as a replacement for aggregates and cement in traditional concrete mixes.

Crushed concrete from demolition sites served as a replacement for fine and coarse aggregate in some of the mixes at various ratios. In addition, ground granulated blast furnace slag, metakaolin, silica fume, and fly ash each served as a cement replacement for cement content in the mixes tested in this research at various rates. Compression strength tests, permeability, and thermal expansion tests were performed on various mixes to compare their performance to that of traditional mixes with natural aggregate, and with no cement replacement.

The compressive strength results indicated the suitability of using such demolition wastes as replacements in producing green concrete (GC) without hindering its mechanical characteristics significantly. In addition, the results indicated an enhancement in the mechanical characteristics of GC when replacing cement with pozzolanic industrial wastes and byproducts.

The research assesses the utilization of sustainable GC using recycled waste aggregate and byproducts.

Using coconut shell aggregates (CSA) in concrete benefits agricultural waste management and reduces the demand for mineral resources. Several studies have found that concrete containing CSA can achieve strengths that are comparable to regular concrete. The purpose of the present work is to evaluate the concrete’s durability-related properties to supplement these earlier findings.

Cylindrical specimens were prepared with a constant water–cement ratio of 0.50 and CSA content ranging from 0% to 50% (at 10% increment) by volume of the total coarse aggregates. The specimens were cured for 28 days and then tested for density, surface hardness, electrical resistivity and water sorptivity. The surface hardness was measured to describe the concrete resistance to surface wearing, while the resistivity and sorptivity were evaluated to describe the material’s resistance to fluid penetration.

The results showed that the surface hardness of concrete remained on average at 325 Leeb and did not change significantly with CSA addition. The distribution of surface hardness was also similar across all CSA groups, with the interquartile range averaging 59 Leeb. These results suggest that the cement paste and gravel stiffness had a more pronounced influence on the surface hardness than CSA. On the other hand, concrete became lighter by about 9%, had lower resistivity by 80% and had significantly higher initial sorptivity by up to 110%, when 50% of its natural gravel was replaced with CSA. Future work may be done to improve the durability of CSA when used as coarse aggregate.

The present study is the first to show the lack of correlation between CSA content and surface hardness. It would mean that the surface hardness test may not completely capture the porous nature of CSA-added concrete. The paper concludes that without additional treatment prior to mixing, CSA may be limited only to applications where concrete is not in constant contact with water or deleterious substances.

The majority of previous studies made on Recycled Concrete Aggregates (RCA) are limited to the utilisation of non-structural grade concrete due to unfavourable physical characteristics of RCA including the higher absorption of water, tending to increased water requirement of concrete. This seriously limits its applicability and as a result it reduces the usage of RCA in structural members. In the present study, the impact of hybrid fibres on cracking behaviour of RCA concrete beams along with the inclusion of reinforcing steel bars under two-point loading system exposed to different sustained elevated temperatures are being investigated.

RCA is substituted for Natural Coarse Aggregates (NCA) at 0, 50 and 100 percentages. The study involves testing of 150 mm cubes and beams of size (700 × 150 × 150) mm, i.e. with steel reinforcing bars along with the addition of 0.35% Steel fibres+ 0.15% polypropylene fibres. The specimens are being exposed to temperatures from 100° to 500°C with 100° interval for 2 h. Studies were made on the post crack analysis, which includes the measurement of crack width, crack length and load at first crack. The crack patterns were analysed in order to understand the effect of fibres and RCA at sustained elevated temperatures.

The result shows that ultimate load carrying capacity of reinforced concrete beams and load at first crack decreases with the raise in temperatures and increased percentage of RCA content in the mix. Further that 100% RCA replacement specimens showed lesser cracks when compared to the other mixes and the inclusion of fibres enhances the flexural capacity of members highlighting the importance of fibres.

RCA can be used for structural purposes and the study can be projected for assessing the performance of real structures with the extent of fire damage when recycled aggregates are used.

Most of recycled materials can be used in the regular concrete which solves two problems namely avoiding the dumping of C&D waste and preventing the usage of natural aggregates. Hence the study provides sustainable option for the production of concrete.

The reduction in capacity of flexural members due to the utilisation of recycled aggregates can be negated by the usage of fibres. Hence improved flexural performance is observed for specimens with fibres at sustained elevated temperatures.

At present Glass Reinforced Plastic (GRP) waste recycling is very limited due to its intrinsic thermoset composite nature and non‐availability of viable recovery options. The purpose of this paper is to assess the recycling potential of GRP waste powder and fibre in concrete, cement and rubber composites.

Extensive laboratory experiments were conducted to examine the suitability of GRP waste in concrete, cement, and rubber composites. GRP waste samples were processed and suitable tests were performed to measure the mechanical properties of the resulting three composites.

The findings of this experimental investigation confirmed that GRP waste can be used as a partial replacement for virgin and raw materials in composites. Furthermore, the addition of GRP waste powder and fibre to composites has the potential to improve their mechanical properties.

Results show that the use of GRP waste powder in concrete and rubber composites and GRP waste fibre in architectural cladding panels has technical, economic and environmental benefits. As such, the findings of this research pave the way for viable technological options for substituting quality raw materials by GRP waste in pan‐industry composites and improving their mechanical properties. However, resulting recycled composites depend upon the consistency and quality of GRP waste powder and fibre, and the access to specialised composite material manufacturing facilities. Furthermore, full compliance tests including durability studies and requirements, which may depend upon specific applications, are recommended.

The adopted methodological approach of this research and subsequent experimental results pave the way for viable technological options for substituting quality raw materials by GRP waste in pan‐industry composites. It is anticipated that the results of this research would help diverting GRP waste from landfill to more useful industrial applications.

Growing technological innovations, ample market value and demand for GRP composites all over the world has trigged interest in optimising GRP waste recovery. However, few solutions for GRP waste recycling into value‐added industrial products are being explored. The work reported so far is very limited and did not show viable applications for GRP waste composites. Hence, this research sets out to examine the suitability of GRP waste powder and fibre in concrete, cement, and rubber composites.

When products are differentiated, applying the standard critical loss formula to assess whether it is profitable for a hypothetical monopolist to impose a common price increase can lead to delineating an antitrust market that is too broad by setting a critical loss threshold that is too low. This error is particularly likely to occur when the products exhibit very different per-unit profits, own price elasticities, and cross price elasticities. In particular, different per-unit profits are a necessary condition for this error to occur and this difference is more likely to be driven by an asymmetry in prices than by an asymmetry in costs when own price elasticities are moderate in magnitude. In contrast, differences in the quantity sold of each product do not tend to lead to errors in market definition. Given the issues associated with the standard critical loss analysis, critical loss analysis with asymmetric price increases and the gross upward pricing pressure index are practical alternative approaches for conducting market definition analysis when products in a candidate market are differentiated.

The purpose of this paper is to concern with using municipal solid waste incineration bottom ash (MSWI-BA) in concrete application.

In this paper, the performance of reinforced concrete (RC) beams containing MSWI-BA was investigated. Four concrete mixes were used in this study. The control mix had a proportion of 1 (cement): 2 (fine aggregates): 4 (coarse aggregates) by weight. In the other three mixes, the fine aggregates were partially replaced with 20%, 40% and 60% MSWI-BA (by weight). The water to cement ratio was kept constant at 0.5 in all mixes. Concrete cubes and cylinders were prepared to determine some physical and mechanical properties of concrete, whereas RC beams were used for determining the structural performance.

There was an increase in compressive strength, tensile strength and the modulus of elasticity when 20% of fine aggregates were replaced with MSWI-BA. However, beyond 20% these properties were reduced. The load bearing capacity and deflection were the highest for the control beam and the beam with 20% MSWI-BA.

The research conducted in this investigation used a specific type of MSWI-BA. The composition of the waste can vary from one plant to another and this presents one of the limitations.

The findings of this research indicate that MSWI-BA can partially substitute fine aggregate, thus reducing the impact of construction on the environment.

The MSWI-BA used in this research differs from other types as the waste papers and cartons are removed from the waste and used to produce other products. Therefore, this study is considered original as it examines MSWI-BA with different properties for use in construction.

The purpose of this research is to evaluate construction and industrial waste materials in concrete using different additives.

The experimental study investigated the effect of waste foundry sand (WFS), waste glass (GW) as partial substituent to natural sand and addition of waste glass fibers (GFs) and silica fume (SF) in natural/construction waste aggregate concrete on mechanical properties, durability and microstructure using.

The results reveal significant strength enhancement on using two admixtures, the maximum increase in compressive strength was obtained on using 20% WFS and 0.75% GF for both natural (75% increment) and construction waste (72% increment) coarse aggregates. Using three admixtures simultaneously, the maximum enhancement in compressive strength was found for (WFS(20%) + GW(10%) + GF(0.75%)) for both natural aggregates (122% increment) and construction waste (114% increment) coarse aggregates as compared to control mix. The 28 days split tensile and flexural strength of natural/construction waste aggregate concrete improve with age appreciably for optimal contents of single, two or three admixtures and the maximum tensile and flexural strength increment was 135 and 97% for mix (WFS(20%) + GW(10%) + GF(0.75%)) with natural aggregates as compared to control mix. The microstructural analysis results indicate improved microstructure upon partial substitution of sand with WFS, GW and SF along with addition of waste GFs.

The use of construction and industrial waste as a substituent to natural aggregate/sand will provide far reaching benefits for the green construction and the environment at large.

The purpose of this paper is to investigate the effect of elevated temperature on mechanical and physical properties of concrete specimens obtained by substituting the river sand with copper slag (CS) at proportions of 25%, 50%, 75% and 100%. The specimens were heated in an electric furnace up to 100, 200, 300, 400, 500 and 600 C and kept at these temperatures for 2 h duration. After the specimens were cooled in the furnace, mass loss, ultrasonic pulse velocity (UPV), compressive strength, split tensile strength (STS), flexural strength (FS) and modulus of elasticity (MOE) values were determined. No spalling occurred in the specimens after subjected to elevated temperature. The surface cracks were observed only in specimens exposed to 600 C. The maximum reduction in compressive strength and STS at 600C is 50.3% and 36.39% for referral mix (NC), 18% and 16% for specimens with 100% CS (MCS4). The reduction in MOE of specimens is observed to be high as copper slag content increases with increasing temperature. Scanning electron microscopy (SEM) studies are carried out to examine the changes in micro-structures of specimens after exposed to elevated temperatures.

After casting of concrete specimens, it is cured for 28 days. After attainment of 28 days age, the concrete specimens is taken out from the curing tank and allowed to dry for 2 days to remove any moisture content in the specimens to prevent explosive spalling during the time of heating. The prepared concrete specimen is subjected to temperatures of 100^°C, 200^°C, 300^°C, 400^°C, 500^°C and 600^°C up to 2 h duration. The physical test, mechanical test and SEM studies are carried out after cooling of specimens to room temperature (RT). The quality of concrete specimens is measured by conducting UPV test after cooling to RT.

The post-thermal strength properties of concrete specimens with copper slag contents are higher than referral mix concrete. The reduction of MOE of concrete specimens is more with incremental in copper slag content with increase in temperatures. Furthermore, the quality of concrete specimens is ranging from “good to medium” up to 500C temperatures based on UPV test.

In this research work, the natural sand is fully replaced with copper slag materials in the concrete mixes. The post-thermal strength properties like residual compressive strength, residual STS, residual FS and residual MOE is higher than referral mix after subjected to elevated temperature conditions. Higher density and toughness properties of copper slag materials will contribute to concrete strength. The effect of elevated temperature is more on MOE of concrete specimens having higher copper slag contents when comparing to specimens compressive strength.