The Effect of Polypropylene Fiber and Glass Fiber on the Frost Resistance of Desert Sand Concrete

To study the influence of polypropylene (PP) fibers and glass fibers on the frost resistance of desert sand concrete (DSC), the fast-freezing tests were carried out to investigate the freeze-thaw damage law using the apparent damage, mass loss, and relative dynamic elastic modulus as indicators; Based on the mercury intrusion method (MIP) and scanning electron microscopy (SEM), the microstructure evolution was analyzed to reveal the mechanism of fiber frost resistance enhancement. Fit the freeze-thaw damage process of fiber reinforced DSC (FRDSC) and predict the frost resistance life. The results show that fibers can greatly improve the freezing resistance of DSC. The hybrid fiber had the highest enhancing effect, followed by PP fiber and glass fiber. The dynamic elastic modulus of the DSC with 0.15% PP fiber and 0.05% glass fiber is as high as 95%. The pore distribution ratio of FRDSC changes faster, but it is still better than that of reference DSC after freeze-thaw. PP fiber and glass fiber can play a full role in the micro and macro stages of crack development of DSC respectively. The freeze-thaw damage model has high fitting accuracy and the DSC mixed with fibers can significantly improve the service life of buildings in northern China.