Performance of Recycled Aggregate Concrete after Washing Treatment of Aggregates

Abstract

Retrieval and reuse of crushed concrete aggregates (CCA) in the concrete industry is a common practice that has gained popularity due to environmental concerns that identify the saturation of landfill areas as a harmful and costly by-product of construction, and has therefore become a necessity for a sustainable, more well-coordinated effort towards improving concrete preparation. This research examines a natural method of CCA-washing that aims to effectively segregate contaminants from healthy material by allowing CCAs to sit outdoors for a period of time thus being subjected to several rain-washing cycles. Eleven mixes were prepared, a control mix with 100% natural/virgin concrete aggregates (NCA/VCA) and ten mixes with CCA content varying between 10-100% replacement. Findings showed that even up to 100% substitution a remarkable reduction of only 15% in compressive strength was observed, with no significant change or effect on the consistency; thus conferring potentially significant sustainability implications.