Research on the freeze-thaw cyclic test and damage model of Aeolian sand lightweight aggregate concrete

Abstract

In this study, partial river sand was replaced by Aeolian sand. The Aeolian sand was added in quantities of 0%, 10%, 20%, 30%, and 40%, to replace the river sand with the same mass, and five groups of 100mm×100mm×400mm Aeolian sand pumice lightweight aggregate concrete were created for the purpose of studying the freeze-thaw damage law of the concrete. The damage variable was tested using ultrasonic pulse velocity and resonance frequency. With the aid of the SEM and AFM analyses of the freeze-thaw test from both microscopic and microcosmic perspectives, this study discussed the degradation mechanism of the freeze-thaw damage of the Aeolian sand lightweight aggregate concrete. In addition, based on the discussion, the Weibull probability and damage theories were applied in order to study the freeze-thaw damage model of the concrete. The results showed that the ultrasonic pulse velocity could also reflect the change rule of the internal structure of the lightweight aggregate concrete. The addition of the Aeolian sand both promoted and inhibited the freeze-thaw damage of the concrete. Therefore, the optimal substitution rate of the Aeolian sand set in this study was 20–30% of the river sand. Based on the freeze-thaw damage mechanism of the lightweight aggregate, this study established a damage constitutive model which was able to forecast the freeze-thaw damage of the Aeolian sand lightweight aggregate concrete.