UTILIZATION OF SLAG POWDER AND RECYCLED CONCRETE WASTES IN REACTIVE POWDER CONCRETE

Abstract

Using recycled wastes and industrial by-products in construction materials has become mandatory to conserve the natural resources and manage waste-disposal environmental problems. This experimental work investigates the workability and strength properties of reactive powder concrete (RPC), utilizing slag powder and finely ground recycled concrete waste as the partial substitutes for cement and quartz sand, respectively. The results for the slump flow, flexural strength, compressive strength, split-tensile strength were analysed for varying contents of the recycled concrete waste in RPC, i.e., (0, 5, 10, 15, 20, 25 and 30) % and a constant slag-powder addition of 20 %. Furthermore, water absorption of the hardened specimens of 28 d of curing was also examined. The results indicated a rise in the water absorption and reduced workability with the increase in the content of recycled concrete in RPC. This was due to porous inter-particle voids in recycled concrete wastes. The strength properties of RPC exhibited superior performance for the substitution of 15 % of quartz sand with recycled concrete waste. A low water-cement ratio and a steel-fibre addition to RPC play an important role in the strength development and durability properties of RPC.