Experimental Study on Resistance of Hybrid Fiber Reinforced Concrete to Freezing and Thawing
Experiments were conducted to study the resistance of steel-polypropylene hybrid fiber reinforced concrete (HFRC) to freezing and tharwing. The mix proportions of concrete in strength grade CF40 were designed according to the superposition mix design method, where five mass contents of polypropylene fiber changing in range of 0.3~1.5kg/m3 with 0.3kg/m3 increment while the fraction of steel fiber by volume was constant as 1.0%, and four fractions of steel fiber by volume changing in range of 0.5~2.0% with 0.5% increment while the mass content of polypropylene fiber was kept as 0.9kg/m3. The results show that the steel-polypropylene hybrid fiber can significantly increase the resistance of HFRC to freezing and thawing, the losses of dynamic elasticity modulus and flexural strength of HFRC decrease with the increasing mass content of polypropylene fiber and fraction of steel fiber by volume, there is the coupling effect of enhancing on resistance of HFRC to freezing and thawing by hybrid fibers.