An innovative approach to enhancing the strength and durability of recycled aggregate concrete through fly ash-silica fume coating and rice husk ash supplementation

The building industry responded to the growing imperative to reduce the global ecological footprint by developing new inventive methods of utilizing waste materials. Concrete waste is one of the leading contributors to global waste streams and a great opportunity for sustainable reuse. Recent research has demonstrated its potential for structural applications in concrete, although its use for nonstructural component construction has been well established. This study introduces an innovative approach, combining the impact of S-FA (silica fume-fly ash) slurry coated recycled aggregates (RCA) and supplementary cementitious material (Rice husk) simultaneously, for the first time to be evaluated for structural performance. These findings present a major improvement in the reuse of concrete waste for structural applications by overcoming the constraints recognized by the mechanical characteristics of RCA. The study is based on an extensive experimental program which evaluated critical parameters such as compressive and tensile strength, water absorption and acid resistance. The incorporation of 100% treated RCA aggregates improved compressive strength by 23% compared to the control mix of non-treated 100% RCA aggregates. Similarly for the same mix acid resistance strength demonstrated a 7% increase while the Non-destructive test results revealed that the treatment enhanced RCA performance by providing improved results through ultrasonic pulse velocity (UPV) readings that increased by 19% compared to the control mix of non-treated RCA aggregates (100%).