Effect of key design parameters on the physical / mechanical properties of coarse aggregated UHPC and its structural response subjected to bending

Abstract

This study experimentally investigates the effect of key design parameters on the physical, mechanical and structural performance of coarse aggregated ultra-high performance concrete (CA-UHPC), with an aim to provide design guidance for on-site engineering applications. The variables of maximum aggregate size, aggregate content, fiber dosage and curing condition are selected for investigation. The results showed that increasing aggregate size does not significantly affect the compressive strength, but somewhat increases the elastic modulus and fracture energy; the increase of aggregate content results in a reasonable increase of compressive strength and elastic modulus. In particular, the 480 kg/m3 coarse aggregated UHPC shows a compressive strength of ∼150 MPa, elastic modulus of ∼50 GPa, autogenous shrinkage of <200 µε, and outstanding durability. The structural specimens fabricated with coarse aggregated UHPC exhibit excellent load-carrying capacity and ductility when subjected to four-point bending. More importantly, it was found that the effect of curing condition on the structural performance is insignificant. The results of this study can provide insights into the development of advanced UHPC materials and structures and promote their applications in practice.