Influence of mixed recycled aggregate on the physical e mechanical properties of recycled concrete

摘要

This article discusses the findings of a feasibility study on the partial replacement of natural coarseudaggregate with a poor quality recycled aggregate from construction and demolition waste in theudmanufacture of concrete of 30 MPa strength grade. The mixed recycled aggregate used had a high asphaltudand floating material content. Workability, density, compressive and tensile strength, water absorptionudand sorptivity were studied in a series of concretes containing 25 or 50% of the recycled aggregate withudand without floating materials. The results showed that using up to 50% of the recycled aggregate had noudadverse effects on fresh concrete workability. Most of the physical and mechanical properties of hardenedudconcrete (strength, density, sorptivity and water absorption) were observed to decline with risingudrecycled aggregate replacement ratios and floating particle content. Overall, considering the strength andudother properties achieved, the concretes containing the mixed recycled aggregates studied were found toudbe apt for housing construction. The technical, economic and environmental improvements stemmingudfrom the potential replacement of natural coarse aggregate with such recycled construction and demolitionudwaste would contributed to the sustainability of the construction industry.