Experimental Study and Theoretical Models on Compressive Properties of Ultrahigh Toughness Cementitious Composites

摘要

Ultrahigh toughness cementitious composite (UHTCC) is a new class of high performance fiber-reinforced cementitious composites which exhibits pseudostrain hardening and multiple cracking phenomena. The main objectives of this paper are to investigate the compressive properties of UHTCC and to develop the constitutive models to describe it. The complete study includes an experimental phase and an analytical phase. In the experimental phase, the stress-strain curves were directly obtained, and the compressive parameters, i.e., strength, average strain at maximum stress, elastic modulus, and Poisson's ratio, were calculated. The relationships of compressive parameters as a function of compressive strength were proposed according to the test results. The comparisons between UHTCC and matrix were carried out to understand the fiber effect on the compressive parameters. In the theoretical phase, comparisons were conducted between experimental results and existing models. As a result, two analytical relationships were proposed for design purpose under ultimate limit state conditions and nonlinear analysis of UHTCC structures. The research should lead to better understand the compressive properties of UHTCC and the mechanisms of fiber reinforcement for UHTCC and to provide analysis models for design or analysis of UHTCC structural members.