Evaluation of Workability and Moisture Transport Properties of Recycled Concrete Aggregate

The growing generation of construction and demolition waste has encouraged the use of recycled concrete aggregate (RCA) as a sustainable alternative to natural aggregates in concrete production. However, concerns remain regarding its effect on workability and durability-related properties. This study investigates the influence of partial replacement of natural coarse aggregate with RCA on the workability and moisture transport properties of concrete. Concrete mixes were prepared with varying RCA replacement levels, and fresh concrete behavior was evaluated using slump and slump loss tests. Moisture transport characteristics were assessed through water absorption and sorptivity tests at different curing ages. The results show that increasing RCA content leads to a noticeable reduction in workability and workability retention due to the higher water absorption and rough surface texture of RCA. In addition, water absorption and sorptivity increased with higher RCA replacement, indicating greater susceptibility to moisture ingress. Nevertheless, mixes containing low RCA replacement levels (5–10%) demonstrated performance comparable to conventional concrete. The study concludes that limited RCA usage can be effectively adopted to promote sustainable concrete construction without significantly compromising performance.