Experimental investigation and multiscale modeling of reactive powder cement pastes subject to triaxial compressive stresses

• Published in: Construction & building materials Vol. 224; pp. 242 - 254
• Main Authors: Zhang, Kun, Zhao, Lun-Yang, Ni, Tao, Zhu, Qi-Zhi, Shen, Jie, Fan, Yun-Hui
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.11.2019
• Subjects: Alcohol-based shrink-reducing admixture (ASRA); Multiscale model; Reactive powder cement (RPC) pastes; Triaxial compression tests; Triaxial strength nonlinearity; Triaxial compression tests; Reactive powder cement (RPC) pastes; Alcohol-based shrink-reducing admixture (ASRA); Multiscale model; Triaxial strength nonlinearity
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2019.07.049

•High performance RPC was prepared with a new procedure.•A series conventional triaxial compression tests for RPC pastes was carried out.•The effects of porosity on mechanical behaviors of RPC pastes were investigated.•A multiscale constitutive model for RPC pastes under compression was presented. This paper presents experimental and numerical studies on the triaxial mechanical behaviors of reactive powder cement (RPC) pastes prepared with an alcohol-based shrink-reducing admixture (ASRA) and ice-replaced mixing procedure. Standard cylindrical samples were cored from three kinds of high strength RPC pastes. For each kind of RPC pastes, a series of triaxial compression tests were performed under different confining pressures. It is shown that the RPC pastes under consideration present a typical quasi-brittle behaviours, including nonlinearity of stress-strain curves, strain hardening/softening, pressure sensitivity, volumetric dilatancy, triaxial strength nonlinearity, etc.For completeness, triaxial cyclic tests with two different confining pressure were conducted to analyse the mechanical damage characteristics of RPC pastes. Based on the experimental investigations and considering the mircostructure evolution of RPC pastes, a two-step homogenization-based multiscale constitutive model was developed. The model allows to take into account the influence of porosity on elastic constants, material damage induced by mesocracking as well as plastic deformation caused by frictional sliding. There is a good agreement between numerical simulations and experimental data.