钢纤维增强高强轻骨料混凝土的力学性能

Mechanical Properties of Steel Fiber Reinforced High-Strength Lightweight Aggregate Concrete

为提高高强轻骨料混凝土(HLAC)的强度和韧性,在HLAC中分别掺入体积分数为0.5%~2.0%的微细型、端钩型、波纹型钢纤维,研究了钢纤维类型及其体积分数对钢纤维增强高强轻骨料混凝土(SFHLAC)的抗压、劈裂抗拉、抗折和抗剪强度等力学性能的影响,分析了SFHLAC的韧度因子和承载力变化系数等材料韧性指标的变化特点.结果表明:除体积分数为2.0%的波纹型钢纤维增强高强轻骨料混凝土外,SFHLAC的力学强度和韧性指标均随着钢纤维体积分数的增大而增大;微细型钢纤维对HLAC的增强增韧效果最好,端钩型钢纤维对HLAC抗折强度的提高效果与微细型钢纤维接近,但对其他力学强度和韧性的改善均不如微细型钢纤维,波纹型钢纤维对HLAC的增强增韧效果均较差;综合考虑新拌混合料工作性能后,给出了3种典型钢纤维的工程应用建议体积分数.

In order to improve the strength and toughness of high-strength lightweight aggregate concrete(HLAC),0.5%to 2.0%volume fraction of micro-fine,end hook and corrugated steel fibers were mixed into HLAC respectively.The mechanical properties of steel fiber reinforced high-strength lightweight aggregate concrete(SFHLAC)such as compression,splitting tensile,flexural and shear strength were studied.The characteristics of material toughness such as toughness factor and bearing capacity variation coefficient of SFHLAC were also analyzed.The results show that except for the corrugated steel fiber reinforced high-strength lightweight aggregate concrete with 2.0%volume fraction of corrugated steel fiber,the strength and toughness of SFHLAC increase with the increase of the steel fiber volume fraction;the micro-fine steel fiber has the best reinforcement and toughening effect on HLAC;the improvement effect of the end hook steel fiber and the micro-fine steel fiber on flexural strength of the HLAC is similar,but the improvement of other mechanical strength and toughness is not as good as that of micro-fine steel fiber;the effect of corrugated steel fiber on the strength and toughness of HLAC is poor;after comprehensively considering the working performance of the fresh mixture,the recommended volume fraction for engineering applications of three typical steel fibers are given.