粉煤灰对UHPC性能及微观结构的影响

Effect of Fly Ash on Property and Microstructure of UHPC

研究了粉煤灰取代量对超高性能混凝土(UHPC)的流动度、抗压强度、抗折强度、微观结构以及钢纤维与基体黏结界面的影响。结果表明:粉煤灰取代量与混凝土流动度呈正相关;UHPC的抗压强度随粉煤灰取代量的增加呈先降低后升高的趋势;UHPC的抗折强度随粉煤灰取代量的增加呈先升高后降低的趋势;通过SEM结果发现,随粉煤灰取代量的增加,混凝土微观结构的密实度呈先减小后增大的趋势;UHPC基体与钢纤维的黏结性能呈先增大后减小的趋势。

The effect of the replacecement amount of fly ash on fluidity,compressive strength,flexural strength,microstructure of UHPC and the bonding interface between steel fiber and UHPC matrix was studied.The results show that the replacement amount of fly ash is positively correlated with the fluidity of UHPC.The compressive strength of UHPC decreases first and then increases with the increase of the replacement amount of fly ash.The flexural strength of UHPC tends to increase first and then decrease with the increase of the replacement amount of fly ash.Through SEM scanning,it is found that the density of UHPC microstructure shows a decreasing trend with the increase of the replacement amount of fly ash and then increases.The bonding performance of UHPC matrix and steel fiber increases first and then decreases.