Research on the creep properties of cement paste after microwave pre-curing based on indentation test

Abstract

This article researched the influence of microwave pre-curing on the creep properties of cement pastes. Microwave pre-curing with different durations was performed on cement paste specimens after standard cured for 3 d. Subsequently, the creep performance of the cement paste and the phase was acquired using indentation tests. The quantitative analysis of the phase was performed on the cement paste specimens after microwave pre-curing. The reasons for the variation of creep properties of the specimens affected by microwave pre-curing were also analyzed based on the pore characteristics, gel structure, and dielectric properties. The results indicated that the creep modulus of cement paste samples gradually increased with the increase of microwave pre-curing time. Microwave pre-curing significantly enhanced the contact creep modulus (CCM) of low-density (LD) C–S–H gel and high-density (HD) C–S–H gel. With the increase of microwave pre-curing time, the porosity in the samples decreased and the pore structure was significantly improved. Microwave pre-curing decreased the percentage of LD C–S–H gel and significantly increased the percentage of HD C–S–H gel, and also increased the complex structure of C–S–H gel. Microwave pre-curing enhanced the dielectric performance of paste specimens and increased their ability to store and absorb electromagnetic waves.