Volume 5, Issue 10 (November 2008)
Mechanical Properties of High Strength Concrete with Field-Demolished Concrete as Aggregates
Environmental and economic factors are increasingly encouraging higher value utilization of demolition debris. While the use of recycled concrete aggregate (RCA) is confined mainly to low-grade application, it would be more beneficial if high strength concrete (HSC) can be produced with demolished concrete for new concrete construction. Hence, an experimental study was undertaken to explore the feasibility and potential of using field-demolished concrete as full replacement of natural aggregates to produce HSC, as reported in this paper. The workability of fresh concrete and mechanical properties of hardened concrete made with RCAs were investigated. The preliminary results indicated that HSC with up to 80 MPa of 28-day compressive strength made with field-demolished concrete as coarse aggregate and natural sand as fine aggregate can be obtained with the facilitation of a modified mixing method and the addition of silica fume. By providing a general basis for evaluating demolished concrete as aggregates for HSC, the investigation reported herein should contribute significantly to the understanding of recycled aggregate concrete as a viable option in the HSC construction industry.