55 / 2022-03-31 10:39:20

Multi-scale study on creep of hardened cement paste under different relative humidity

creep；hardened cement paste；relative humidity；multi-scale homogenization；discrete retardation spectra

This paper studied the multi-scale creep mechanism of irreversible creep of hardened cement paste under different relative humidity conditions and the multi-scale prediction of creep. Firstly, the uniaxial compression creep test of hardened cement paste for 360 days and the creep recovery test for 21 days were carried out. Based on ¹H NMR, ²⁹Si NMR, nanoindentation and N₂ adsorption-desorption tests, the microscale occurrence sites of irreversible creep of hardened cement paste were determined. Subsequently, the hardened cement paste was divided into two scales, and the creep multi-scale homogenization calculation was carried out by the Mori-Tanaka (MT) method and the self-consistent (SC) method. The long-term creep kinetics characteristics of the hardened cement paste were predicted, and the creep properties of the paste obtained by the direct test of microindentation were compared to analyze the accuracy of the two creep prediction methods. Finally, based on the discrete retardation spectra analysis, the time corresponding relationship between the macroscopic creep test of cement paste and the indentation creep test was analyzed.