Experiment Study On Impact Resistance Performance Of Shrinkage-compensating Steel Fiber Reinforced Shotcrete

Shrinkage-compensating steel fiber reinforced concrete is one of the current rapid development new type composite materials at home and abroad. In this paper, use expansive agent content0%,6%,8%,10%and steel fiber volume rate0%,0.8%,1.2%,1.6%for basic variables, research the impact resistance and compression strength in restriction state of this new type composite material. In the last, compare analysis the limit state compression strength and free state compression strength.For the test of limit state compression strength. First, through variance analysis and poor analysis, determined the optimal combination when the steel fiber volume ratio was1.6%and expansion agent mixing6%.Second,study the relationship between steel fiber volume ratio(expansion agent mixing)and compression strength of shrinkage-compensating steel fiber reinforced shotcrete. The research results show that with the increase of steel fiber volume ratio, compression strength gradually increase. Along with the increase of the admixture of expansive agent, compression strength first increase and then reduce, when the steel fiber volume rate is1.6%and expansive agent content is8%,the compression strength reach maximum. Finally, compare analyzed the limit state compression strength and free state compression strength.The research results show that the more expansive agent mixing content and the larger steel fiber volume rate, the greater the limit state compression strength improve ratio. When expansion agent mixing content is10%, steel fiber volume rate is1.6%; the compression strength improved ratio is17.9%.For the test of impact resistance performance. According to the American ACI544committee recommend the size of impact resistance specimen and the test method of drop weight, a set of steel mold and free-fall hammer impact test device were designed. The research result indicate that with the increase of the admixture of expansive agent, shrinkage-compensating steel fiber reinforced shotcrete initial crack (failure) impact resistance times first increase and then decrease, when the admixture of expansive agent content is6%reach maximum; Impact resistance energy difference between failure and initial crack increased gradually, when the admixture of expansive agent content is10%reach maximum; Distribution characteristics of initial crack (failure) impact resistance times meet the form of quadratic curve. Shrinkage-compensating shotcrete initial crack and failure crack numbers first increase and then decrease, when the admixture of expansive agent content is8%reach minimum; With steel fiber volume ratio increased, shrinkage-compensating steel fiber reinforced shotcrete initial crack and failure impact resistance times increased gradually, when the volume rate of steel fiber is1.6%reach maximum; Impact resistance energy difference between failure and initial crack increase gradually, when the volume rate of steel fiber is1.6%reach maximum; Distribution characteristics of initial crack (failure) impact resistance times meet the form of quadratic curve.Steel fiber reinforced shotcrete initial crack numbers decrease gradually, when the volume rate of steel fiber is0%reach maximum, failure crack numbers increase gradually, when the volume rate of steel fiber is1.6%reach maximum.