粉煤灰和石英粉对超高性能混凝土性能的影响

Effect of fly ash and quartz powder on properties of ultra-high performance concrete

为研究粉煤灰部分取代硅灰、石英粉部分取代石英砂对超高性能混凝土(UHPC)性能的影响,进行了UHPC抗压强度、抗折强度、抗拉强度和流动性试验。结果表明:随着粉煤灰取代硅灰比例的增加,UHPC的抗折强度和抗拉强度提高,流动性降低,但当粉煤灰取代率超过10%时,UHPC的抗压强度降低;UHPC的抗折强度和抗拉强度随着石英粉取代石英砂比例的增加而提高,当石英粉取代率为10%时,UHPC的抗压强度最大;当石英粉取代率为30%时,抗折强度和抗拉强度分别提高了56.5%和24.4%;UHPC的流动性随着石英粉取代率的增加而降低;当粉煤灰取代率为30%、石英粉取代率为15%、水胶比为0.18时,UHPC的力学性能和工作性最佳。

In order to study the effect of fly ash partial replacement of silica fume and quartz powder partial replacement of quartz sand on the properties of ultra-high performance concrete(UHPC),the compressive strength,flexural strength,tensile strength and fluidity tests of UHPC were carried out.The results show that the flexural strength and tensile strength of UHPC increase with the increase of the proportion of silica fume,and the fluidity decreases.When the replacement rate of fly ash exceeds 10%,the compressive strength of UHPC decreases.The flexural strength and tensile strength of UHPC increase with the increase of quartz powder replacement rate.When the quartz powder replacement rate is 10%,the compressive strength of UHPC is the highest.When the replacement rate of quartz powder is 30%,the flexural strength and tensile strength are increased by 56.5%and 24.4%respectively.The fluidity of UHPC decreases with the increase of quartz powder replacement rate.When the replacement rate of fly ash is 30%,the replacement rate of quartz powder is 15%and the water-binder ratio is 0.18,UHPC has the best mechanical properties and workability.