Effect of fine aggregate on rheological properties of ultra-high performance concrete（UHPC)

Abstract

In this paper, four kinds of ecological fine aggregates (manufactured sand, recycled sand, aeolian sand and river sand) were used to prepared UHPC, the effects of the fine aggregates on the workability, rheological properties and mechanical properties of UHPC were studied. The results reveal that the type and content of fine aggregate have an effect on the rheological properties and mechanical strength of UHPC. Under the same mix proportion, the yield stress and plastic viscosity of recycled sand UHPC are higher than those of river sand UHPC, manufactured sand UHPC and aeolian sand UHPC, mainly due to its high water absorption. The high intergranular porosity, high surface area and low fineness modulus of aeolian sand contributes to an increase in yield stress, and high rate into thin and irregular shapes of manufactured sand are the major ingredients which affect the workability of UHPC. The yield stress and plastic viscosity of UHPC decrease with the increase of water-binder ratio, and the gap between the four fine aggregate systems is gradually narrowed. The effects of different fine aggregates on the mechanical properties of UHPC are arranged according to the improvement effect: recycled sand > manufactured sand > river sand > aeolian sand.