The frost resistance performance of basalt fiber-reinforced concrete (BFRC) subjected to fatigue loads coupled with hydrodynamic pressure

Abstract

In this work, the effects of different stress levels, exposure conditions and freeze‒thaw (F-T) cycles on the mechanical properties of base concrete (BC) and basalt fiber-reinforced pavement concrete (BFRC) were studied. The concrete mass loss, relative dynamic elastic modulus (RDEM) and fracture energy under various loading conditions and F-T cycles were analyzed to characterize its damage evolution. Additionally, through mercury intrusion porosimetry and scanning electron microscopy (SEM), the pore structure characteristics and micromorphology were investigated to explore the mechanism controlling the increase in concrete performance with basalt fiber (BF). Finally, the relationship between the pore structure and damage variable was investigated, and the frost resistance of concrete was evaluated by using gray correlation analysis and rough set theory (RST). The concrete deterioration under coupling actions and F-T cycles could be divided into stages of (i) slow and (ii) rapid increases. The stress level played a decisive role in Stage I, while the effect of hydrodynamic pressure was more obvious in Stage II. The addition of BF significantly decreased the concrete damage degree throughout testing. After 300 F-T cycles, the RDEM and fracture energy of the BFRC under coupling actions were 1.41 and 2.20 times those of the BC, respectively. Moreover, the addition of BF notably lowered the porosity and most probable pore diameter of the concrete under coupling actions and F-T cycles and thus greatly influenced the increase in pore fractal dimension. The RST indicated that the frost resistance of concrete was closely related to the mixture and stress level.