Experimental Study On Resistance Of Steel Fiber Reinforced Lightweight Aggregate Concrete To Permeability And Frost

Lightweight aggregate concrete has superior performances on seismic, impermeability,fire-resistance and heat insulation, which has wide application prospect to the high-rise andlarge-span engineering structures as bridges, high-rise buildings. At present the research onthe mechanical properties of lightweight aggregate concrete is relative mature, but less ofthe research for its long-term durability. To ensure the long-term use of lightweightaggregate concrete structure, the study on durability of lightweight aggregate concrete is aprofound significance.The lightweight aggregates have more pores themselves which can improve thecompactness of concrete and the bonding properties of interface between aggregates andcement mortar, and reduce the influence of materials’ heterogeneity. They show a greaterinfluence on frost resistance and impermeability of the concrete. Therefore, this article willfocus on researching the frost resistance and permeability resistance of lightweightaggregate concrete.The content of this research mainly includes:(1) Fixed dosage of air-entraining agent, conducting the tests to study the effect ofsteel fiber content on impermeability and frost resistance of lightweight aggregateconcrete.(2) Fixed steel fiber content, conducting the tests to to study the effect of air-entrainingagent dosage on impermeability and frost resistance of lightweight aggregateconcrete.(3) Changing the fine aggregate from light sand to mechanism sand and keeping thesame dosages of air-entraining agent and steel fiber content to study the effect onimpermeability and frost resistance of lightweight aggregate concrete. (4) Verifying the synchronicity of the influence on impermeability and frostresistance of the concrete by analyzing the microscopic view.Results of the test indicated that the frost resistance and impermeability of the concreteare improved with the increase of air-entraining agent dosage from0to0.12‰, but thetrend is gradually smooth. Steel fiber has no apparent effect on the impermeability oflightweight aggregate concrete. When mixed with1.2%steel fiber by volume, theimpermeability of the concrete will be a reduction. In terms of the frost resistance oflightweight aggregate concrete, the negative effect is more apparent when the fraction ofsteel fiber by volume is0.4%, and the frost resistance of the concrete increases in turn whenthe fractions of steel fiber by volume are0.8%and1.2%. When the fine aggregate ismachine-made sand, the frost resistance and impermeability of concrete is better than thesteel fiber reinforced full-lightweight concrete.