Local compression capacity of ultra-high performance concrete containing coarse aggregate: Testing and calculation method

Abstract

The introduction of coarse aggregate (CA) into conventional ultra-high performance concrete (UHPC) can greatly reduce cost and shrinkage without significant sacrifice in strength. Ultra-high performance concrete containing coarse aggregate (UHPC-CA) possesses excellent lightweight characteristics, which is suitable for prestressed concrete structures. Nevertheless, many knowledge need to be explored to promote the engineering application of UHPC-CA structures, including anchorage zone behaviors, effects of key parameters on local bearing capacity, and the lack of reasonable calculating method of UHPC-CA. Thus, 23 groups of UHPC-CA specimens were tested, with varying local area aspect ratio, duct size and concrete compressive strength. The performance of UHPC-CA under the limited area load was analyzed, including feature loads, load-deformation relationships, failure features, cracking patterns and wedge features. Besides, the stress change and damage mechanism of UHPC-CA under the limited area load were investigated by finite element simulation. The results showed that UHPC-CA specimens still followed the wedge cleaving theory. Eventually, a special calculation method for evaluating the local bearing capacity was developed and validated with experimental data and existing normative models.