Application of recycled aggregates and biomass ash in fibre-reinforced green roller compacted concrete pavement-technical and environmental assessment

For both financial and environmental reasons, it is becoming more and more common to investigate recycling waste building materials from construction and demolition (C&D) sites. For the construction of big structures like dams or wide horizontal surfaces like road foundations, roller compacted concrete (RCC) is a unique dry concrete comprised of aggregates, water, and a little amount of cement. A high-volume solid waste-based RCC was prepared in this study, and different contents of recycled aggregate, biomass ash (BA) and polypropylene fibre (PPF) were used. Meanwhile, the mechanical properties, durability, microstructure and environmental benefits of eco-friendly RCCs were evaluated. The results showed that the addition of CRA, FRA and BA resulted in a decrease in the mechanical properties of RCC. When the full volume of recycled aggregate was used, the 90-d compressive strength of RCC reinforced with 1% PPF could reach 41.53 MPa. Although the dry unit weight of RCC was decreased by the addition of recycled aggregate and BA, its sorptivity coefficient was also increased. Meanwhile, the full-volume solid waste-based RCC exhibited high resistance to chemical attack and freeze-thaw. In addition, proper recycling of recycled aggregates and BA can effectively reduce the cost and carbon footprint of RCC.