Deficiency of natural resources in construction industry is one of the major issues in today's construction era. Another major problem, which not only construction industry, but the entire world is facing, is the management of construction and demolition (C&D) waste. Therefore, it becomes inevitable to recycle the C&D waste and to replace it partially with natural aggregate so as to reduce the strain on natural resources. Recycled concrete aggregates (RCAs) cannot be directly reused as it possesses poor quality in terms of physical and mechanical properties. The objective of this experimental work is to improve the properties of RCAs by using pretreatments such as mechanical abrasion, water soaking, acid soaking, and heating. It is found that using mechanical abrasion, weak acid soaking and moderate heating, the micro structure of the RCA is improved. Water absorption and porosity are improved by 20% and 17.75% respectively. Using pre-treated RCAs, with partial and complete replacement for natural aggregates, concrete cubes were cast and tested for evaluation of compressive, split tensile and flexural strengths. Compressive strength for 40% replacement is improved by 17.41% as compared with the M25 grade concrete made using natural aggregates. Also, replacement by 100% is possible and compressive strengths are comparable. Thus, using the pre-treatments, C&D waste utilization, reduction in consumption of natural aggregates (NA) is possible in medium grade applications leading to sustainable construction.

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