Deterioration Index Analysis of Cemented Sand and Gravel Materials under Freeze–Thaw Action

Abstract

The freeze–thaw cycle test, uniaxial compressive strength test, dynamic elastic modulus test, and nuclear magnetic resonance (NMR) scanning test were carried out to study the freeze–thaw resistance of cemented sand and gravel materials in cold areas. The compressive strength, relative dynamic elastic modulus, porosity, and the most probable pore size of macroscopic degradation indexes before and after freezing and thawing were analyzed. The results show that: (1) both the compressive strength and relative elastic modulus gradually decrease with the increase of the number of freeze–thaw cycles, the porosity increases with the rise of the number of processes, and the growth rate gradually accelerates; (2) with the increase in freeze–thaw cycles, the spectral peak shifts to the larger aperture, the harmful aperture accounts for the most significant proportion, and the most probable pore size and minimum aperture increase; and (3) according to the gray entropy correlation method, the deterioration index that significantly influences the compressive strength and elastic modulus of cemented sand and gravel materials is the total porosity, and the most influential pore size range is 50–200 nm.