The effect of gravel content on fluidity and mechanical properties of reactive powder concrete

Abstract

Reactive powder concrete (RPC) is one kind of ultra-high performance concrete (UHPC), which has ultra-high strength, high toughness and high durability. However, its high cost and specific curing regime limit its extensive application. To reduce cost and simplify curing regime, cement-silica fume-fly ash ternary cementitious system, natural medium sand with well gradation for totally replacing the quartz sand and normal curing regime for specimens were used. Then six types of mix proportions for RPC were designed, and the gravel content that replaced natural medium sand were 0%, 20%, 25%, 30%, 35% and 40%, respectively. The fluidity and mechanical properties of the specimens, such as compressive, flexural, and splitting tensile strength, were investigated. Results show that the fluidity always increase with the gravel content and slump-flow is more apparent than that of the slump, while the compressive, flexural, and splitting tensile strength increase until reach the peak value when the gravel content is about 35%, and these strengths are 20%, 90% and 65% higher than that of RPC without gravel, respectively. Therefore, RPC incorporated with gravel can not only improve its fluidity and mechanical properties, but also reduce the engineering cost. The conclusions obtained in the study are of important theoretical value to direct the similar engineering practice.