Effect of Cementitious Capillary Crystalline Waterproofing (CCCW) Materials on the Frost Resistance of Panel Concrete (PC): Experiment and Mechanism

Abstract

Cementitious capillary crystalline waterproofing (CCCW) materials are a type of rigid waterproofing materials. In this study, the effect of CCCW materials on the frost resistance of panel concrete (PC) has been investigated to solve the problem of concrete freeze–thaw damage in cold regions. Experiments were conducted to test the influence of different contents of CCCW materials on the apparent damage, compactness, strength and permeability of concrete; Results showed that after freeze–thaw cycles, the mass loss of concrete mixed with CCCW materials was relatively small, and the reduction rate of RDME, ultrasonic velocity, and splitting tensile strength of concrete decreased, indicating that its frost resistance was improved. The improvement effect was most significant when the CCCW materials content was 2%; When the content of CCCW materials becomes larger (> 2%), the microhardness of concrete decreases, and the pore structure becomes looser compared to low content, this phenomenon is consistent with the microstructure shown in the SEM images. Based on the complexation–precipitation reaction, this paper proposed the mechanism of CCCW materials on the frost resistance of concrete in freeze–thaw environment. And used the two parameters Weibull distribution, a freeze–thaw damage model was established with the splitting tensile strength of concrete as the indicator. Furthermore, this study proposed a theoretical model of ultrasonic velocity in concrete with CCCW materials, and the predicted value of this model has a small error compared to test data.