Mechanical and Durability Properties of Concrete Containing Recycled Concrete Aggregates

This study examines the mechanical and durability properties of five different concrete mixes using the construction and demolition waste as partial replacement of coarse aggregate. In the concrete mixes, a constant water-cement (w/c) ratio of 0.43 was used. In contrast, the natural coarse aggregates were replaced by recycled coarse aggregate using five different replacement percentages, i.e. 0 (R0), 30% (R30), 50% (R50), 70% (R70) and 100% (R100). The durability of recycled aggregate concrete (RAC) was investigated for 28, 90, 180, 365 and 720 days. The standard procedures were adopted for durability tests such as half-cell potential (ASTM C876), hydraulic permeability (DIN 1048) after exposure in salt spray machine, pull-out test (ASTM C900) and carbonation (CEN test). The results showed that the mechanical and durability properties of concrete with a replacement percentage of 0% and 30% are approximately similar. The comparative study of different replacement percentages showed that concrete with a 30% replacement percentage of natural coarse aggregate by recycled concrete aggregate can be used as structural concrete in the construction sector of Pakistan.