钢纤维轻骨料混凝土梁抗剪性能试验

Experiments on Shear Resistance of Steel Fiber Reinforced Lightweight Aggregate Concrete Beams

采用建筑结构加载设施,对混凝土强度等级为LC30~LC50,钢纤维体积率为0~1.5%,配箍率为0.16%~0.475%的28根钢纤维轻骨料混凝土(SFRLC)梁进行斜截面抗剪承载力试验,研究钢纤维体积率、剪跨比、配箍率及混凝土强度等级等因素对梁开裂荷载和抗剪承载力的影响。试验结果表明:加入钢纤维可以显著提高梁的抗剪承载力和剪切韧性,随着配箍率和混凝土强度等级提高,SFRLC梁的抗剪强度逐渐增高;随着剪跨比增大,SFRLC梁的抗剪强度有所减弱。在试验结果基础上,通过数据回归分析,建立了SFRLC梁的斜截面抗剪承载力计算公式,并另外加工8根SFRLC梁,用于验证抗剪公式的准确性,验证试验表明,实测值与本文公式计算值吻合良好。

By building structures loading devices, diagonal shear strength of 28 SFRLC （Steel fiber reinforced lightweight aggregate concrete） beams were tested, the strength grade of concrete of SFRLC ranges from LC30 to LC50, the volume fraction of steel fibers of SFRLC ranges from 0 tol.5%, the stirrup ratio of steel fibers of SFRLC beams range from 0.16 to 0.475%.The effects of fiber volume fraction, shear span ratio, stirrup ratio and concrete strength on the cracking load and ultimate shear strength of beams were studied. The experiment results show that steel fiber can obviously improve the ultimate shear strength and shear toughness of the beams, and ultimate shear strength gradually improve with the increase of stirrup ratio and concrete strength, ultimate shear strength is weakened with the shear span ratio increases. Based on the experimental results, by data regression analysis method, the formulas of calculating the ultimate shear resistances of the SFRLC beams were put forward. The additional 8 SFRLC beams were used to validate the accuracy of the ultimate shear resistance formula. The results show that the experimental results match well with the calculated results from the formula.