玄武岩纤维-橡胶混凝土性能研究OA北大核心CSTPCD

In order to solve the problems of easy shrinkage cracking and freeze-thaw failure of concrete on the pavement of plateau airport,the mechanical properties,early shrinkage and frost resistance of concrete with different volumes of basalt fibers and different substitution rates rubber powder were studied.The mechanism of action of basalt fibers and rubber powder was explained by nuclear magnetic resonance and scanning electron microscopy,and an early shrinkage model of concrete considering the content of basalt fibers and rubber particles was established.The results show that compared with the baseline concrete,the 7 and 28 d flexural strength of the concrete with 0.3％(volume fraction,the same below)basalt fibers and 10％(volume substitution rate of sand,the same below)rubber particles increases by 13.6％and 11.8％,the 7 and 28 d compressive strength increases by 26.7％and 18.1％,the shrinkage rate reduces by 54.7％in 72 h.The mass loss rate reduces by 67.0％,and the loss rate of dynamic elastic modulus reduces by 10.4％after 300 freeze-thaw cycles.Basalt fibers can inhibit the expansion of microcracks in the concrete matrix,bear part of the shrinkage stress.The effects of filling,water storage and air entrainment of elastomer rubber particles optimize the pore structure of the matrix,delay the evaporation of water,relieve the frost heave pressure,improve the mechanical properties and frost resistance,and decrease the early shrinkage of concrete.The established shrinkage model can better reflect the early shrinkage characteristics of basalt fiber-rubber concrete.