Use of crushed bricks and recycled concrete as replacement for fine and coarse aggregates for sustainable concrete production

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The growing concern over the significant ecological changes requires sustainable developments in all fields. Concrete production is one of the largest consumers of natural resources as it consumes a huge volume of natural fine and coarse aggregates, which constitute 70% - 80% of the concrete volume. It is evident that such large amount of concrete production in the growing construction industry puts significant impact on the use of natural resources and the environment. Hence, investigating the use of recycled materials to replace the finite natural resources became evident and is the focus of researchers. In this research, the use of waste crushed bricks (CB), and crushed recycled concrete (CRC) as a partial replacement of fine and coarse aggregates in concrete was studied. The replacement ratios of 10%, 50%, and 100% by weight of either fine or coarse aggregates were used. Eight concrete mixes with 168 specimens were tested for compressive, splitting tensile as well as, flexural strength. All tests were carried out at ages of 7, 28 and 56 days. The results indicated that there is a feasibility of using bricks and concrete wastes in concrete mix as a partial replacement of course and fine aggregates. It is deduced that a 50% replacement ratio of coarse aggregate with crushed concrete resulted in a 30%, 25%, and 23% increase in compressive, tensile, and flexural strengths, respectively. While 50% replacement ratio of fine aggregate with crushed bricks resulted in a 23%, 28%, and 19% increase in compressive, tensile, and flexural strengths, respectively. The most effective mix was at 50% replacement ratio of coarse aggregate with crushed concrete in combination with 50% replacement ratio of fine aggregate with crushed bricks. The results of this mix showed 32%, 28%, 26% increase in compressive, tensile, and flexural strengths, respectively.