Performance assessment of sustainable mortar mixes using recycled fine aggregate obtained from different processing techniques

Increased construction activity around the world to meet rising economic demand depletes natural resources, mainly river sand. River sand remains the first choice for fine aggregate because of its superior quality and the lack of a suitable alternative. This situation resulted in haphazard sand exploration. Also, demolition waste generated by construction industries and its growth rate has become a major issue for many countries. Although the utilization of construction and demolition waste (CDW) has proved as a sustainable option, the inferior properties of CDW limit its utility as a construction material, especially the fine portion of CDW. This study investigates the effects of CDW as a fine aggregate replacement on the workability and mechanical performance of the mortar by using three types of recycled fine aggregate (RFA) derived from the same CDW by applying different processing techniques. Firstly, the effect of different processing techniques in washed and unwashed state of RFA at 0%, 50% and 100% replacement ratios on mechanical properties of mortar was examined. Further, the most appropriate RFA was selected to analyze the effect of moisture conditions on the compressive strength of mortar at 25%, 50%, 75% and 100% replacement levels. Superior results were achieved in the case of a treated aggregate with improved mechanical properties, whereas there was a decrement in properties in saturated moisture conditions than in dry conditions. This study concludes that by adopting suitable processing techniques results in the enhancement of mechanical properties of mortar at all moisture states with respect to unprocessed aggregate. Further, improved results conclude the valid potential of RFA in producing sustainable mortar.