Analysis of the Effect of Porosity in Concrete under Compression Based on DIP Technology

Abstract

On a mesoscopic scale, concrete is considered to be a heterogeneous composite material which is composed mainly of cement mortar, aggregate, an interface transition zone (ITZ), and pores. The mesoscopic model of concrete was established by applying digital image processing (DIP). To study the impact of porosity on the compressive strength of concrete, the pore equivalent model was introduced to build concrete with different pore contents. The base force element method (BFEM) based on the complementary energy principle was used in the numerical simulation of concrete. This paper investigated the effect of porosity on the strength of concrete under uniaxial compression. The results showed that the mesoscopic model of concrete based on DIP technology can better simulate the strength test and failure mechanism of concrete by using BFEM. As the porosity in the ITZ increases, the peak strength of concrete under compression decreases. The compressive strength of concrete also decreases with the growth of porosity in the mortar matrix. The ITZ porosity has a greater effect on the compressive strength of concrete than the mortar porosity.