A full-scale pilot project has been conducted to demonstrate the use of fine recycled concrete aggregates (RCA) for two different concrete qualities with high replacement of natural aggregates. The fine RCA replaced the crushed stone sand fraction in the grade slab (M20) and in the lean concrete (M10) at replacement levels of 50 and 100, respectively. The RCA concrete was used in the newly constructed precast concrete factory for the affordable housing project of the City and Industrial Development Corporation of Maharashtra Limited (CIDCO). Concrete rubble was recycled into RCA 0/2 mm by a wet recycling process. The aggregate properties complied with IS: 383 (2016) and the grading achieved was Zone II. The obtained fresh and hardened concrete properties were fully comparable with the reference concrete. The site engineers expressed satisfaction on their experience of using RCA as replacement for CSS, as no placement and finishability issues were encountered. The pilot project has created a desire to continue exploring future opportunities for the use of RCA in concrete. The price of the fine RCA was competitive even with significant longer transport distance to the construction site than for the CSS aggregates. Hence, there is a potential for significant cost savings in the Mumbai region.
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