Investigation into compressive property, chloride ion permeability, and pore fractal characteristics of the cement mortar incorporated with zeolite powder

Abstract

As a non-homogeneous porous material, the microstructure of cementitious composites critically affects the mechanical and durability properties. This paper aims to analyze the effect mechanism of cement replacement by zeolite powder on the microscopic pore structure characteristics, macroscopic mechanical behavior, and durability of mortar to reduce cement consumption and improve mortar performance. The compressive strength and chloride ion permeability of mortar incorporated with zeolite powder were experimentally determined, and the effects of zeolite powder content on the composition of cement hydration products and pore structure were further analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and mercury intrusion porosimetry (MIP). The pore structure characteristics were quantitatively analyzed by fractal theory. The results shows that incorporating zeolite powder in cement mortar fills the pores, promotes secondary hydrate formation, reduces the Ca/Si ratio, refines the pore size, and reduces the porosity of large pores. Thus, the internal pore structure of the matrix is significantly improved, reducing the pore fractal dimension and improving the compressive strength and chloride ion penetration resistance. 15% cement replacement zeolite powder has been found optimal in reducing the porosity and chloride ion permeability coefficient while enhancing the compressive strength. The pore structure fractal dimensions calculated by the Menger sponge fractal model can quantitatively describe the pore structure distribution characteristics, which can help ascertain the relationship between zeolite powder content, pore structure quantitative characteristics, and macroscopic mechanical behaviors.