Utilization of Recycled Fines Obtained From Construction and Demolition Waste in Concrete and Mortar

Abstract

Construction activities are inevitable and indispensable for the overall development of society. Also, the environmental degradation associated with constructions is conspicuous. Thus, sustainability in infrastructural development is prime and has to be acknowledged on a priority basis to avoid further damage to the must be acknowledged on the environment and natural resources. newline Construction and demolition waste (CD-W) being the massive of all wastes, has endless potential to alternate construction materials. The utility of CD-W for components of structural stability is still irresolute. An approach for productive recycling of CD-W has to be developed, in order to serve needs of fine aggregate and cement, simultaneously. Thus, this dissertation accounted utilization of CD-W to as fine aggregate and cement in mortar and concrete. newlineThe major portion of CD-W is used as recycled coarse aggregate (RCA) as coarse aggregate in concrete. RCA was found to be underperforming as coarse aggregate due to porous texture, adhered mortar, lower abrasion resistance, and light weightiness. Thus, it was hypothesized, that crushed RCA gives recycled fines (RF), which would be better as crushed recycled coarse aggregate (CRCA) for fine aggregate and satisfactory as residual cement paste (RCP) for cement replacement, respectively. newline The comparable chemical composition RF to that of cement (OPC/ PPC) made it suitable for cement replacement. However, the RF particles were found to be heavier and more water absorbing as compared to natural fine aggregate (NFA), which has made it good, but difficult choice for sand replacement. newline As RF is a known high water absorbing material, the variation in mechanical strengths and durability of mortar and concrete are bound to it. Thus, the study on mortar and concrete was decisive to their behavior with RF in them under two conditions: first when the slump was kept constant and second when the slump was allowed to vary. newline newline