Sustainable Concrete made of Construction and Demolition Wastes using Recycled Wastewater in the UAE

Abstract

Most of the previous research on the use of recycled materials for concrete examined only the effect of using recycled aggregate in concrete mixes. In this paper, the combined effects of recycled aggregate and recycled water on the strength and durability of recycled concrete are presented and discussed. Three types of mixing water were examined and found to comply with the requirements of EN 1008 and ASTM C94. The test program involved the preparation of a moderate strength concrete made out of recycled water and recycled aggregate obtained from demolition and construction wastes. In the demolition waste series, four mixes of concrete were prepared using different contents of aggregate extracted from demolition waste and recycled water. The effect of the recycled aggregate and recycled water on the axial and flexural strength was found to be moderate but had a significant negative impact on the durability. In the construction waste series, to enhance the durability and to lower the carbon footprint of the recycled concrete mix, the OPC was replaced by GGBS. Four replacement ratios, 60%, 70%, 80%, and 90%, of the OPC were examined. While all the four mixes achieved good strength and durability, the mix with 90% GGBS did not achieve the target strength of 40 MPa even after 56 days. In general, fully recycled concrete mix with 80% GGBS replacement is recommended for any sustainable future construction in the Gulf with an expected carbon footprint of 129.9 kg/m 3 .

Compressive strength and microstructure of alkali-activated mortars with high ceramic waste content

“…As indicated by Behera et al [5] and Silva et al [11], the quality, quantity, size and type of recycled aggregates to be used need to be precisely characterised because they strongly influence the mechanical properties and durability of the concrete being designed. As observed by Elchalakani and Elgaali [12], recycled concrete strength is greatly influenced by the quality of aggregates. This conclusion has been corroborated in different studies where ceramic waste has been used as recycled aggregate in PC systems.…”

Mechanical properties of rubberised concrete for road side barriers

“…These reductions were attributed to: (i) higher level of inter-particle friction that occurs between rubber aggregates and other mix Three tests were made to measure the durability of the recycled rubber concrete; namely: water absorption (WA) test according to BS 1881BS -122 (1983, initial surface absorption of concrete (ISAT) test according to BS 1881BS -208 (1996; and Drying Shrinkage tests on concrete prisms 300 mm long were prepared and tested according to ASTM C157/C (2008). In the Gulf, concrete accepted for the construction of high rise buildings has a minimum 50 years design life with good durability (Elchalakani and Elgaali 2012). For good quality durable concrete, the WA must be less than 2.0% and the ISAT must be less than 0.05 ml/m 2 /sec.…”

“…It is seen that the ISAT values increase proportionally with the increase in rubber concentration in the concrete mix. It is seen that all the measured ISAT values are less than the benchmark value of 0.05 ml/m 2 /s often specified for concreting in hot climates in the GCC (Elchalakani and Elgaali 2012). Figure 5 shows a plot for the best-fit curve for the travel distance against the concentration of the rubber in the mix for the concrete cubes.…”

“…Waste tire management and disposal is a major environmental concern in many countries. Stockpiling is dangerous, not only due to a potential negative environmental impact, but also because it presents a fire hazard and provides a breeding ground for rats, mice, vermin and mosquitoes (Elchalakani and Elgaali 2012;Senouci 1993, 1994;Fedroff, Ahmad, and Savas 1996;Ghaly and Cahill 2005;Güneyisi, Gesoğlu, and Özturan 2004;Khaloo, Dehestani, and Rahmatabadi 2008;Khatib and Bayomy 1999;Li et al 2004;Najim and Hall 2010;Siddique and Naik 2004;Toutanji 1996;Topçu 1995). Aiello and Leuzzi (2010) noted that in the EU-28, stockpiling can reach 600 ton/ year, whereas in the US stockpiling reached 300 million tons in 2004 (Siddique and Naik 2004), whereas in the state of Sharjah in the UAE it reached about 8 million tons in 2011.…”

An Extension of the CODAS Approach Using Interval-Valued Intuitionistic Fuzzy Set for Sustainable Material Selection in Construction Projects with Incomplete Weight Information

“…Radhi [21] performed an experiment on UAE construction and found the impact of UAE construction on global warming. Elchalakani and Elgaali [22] combined the effects of recycled aggregate and recycled water and discussed the strength and durability of recycled concrete. The authors prepared a moderate strength concrete using recycled water and recycled aggregate obtained from construction wastes.…”