钢纤维高强混凝土断裂韧度及影响因素

Fracture Toughness of Steel Fiber Reinforced High Strength Concrete and Influencing Factors

通过钢纤维高强混凝土切口梁三点弯曲试验,探讨了相对切口深度(a0/h)、粗骨料最大粒径(dmax)、水灰比(W/C)和钢纤维体积率(ρf)等因素对钢纤维高强混凝土断裂韧度(KfIC)和断裂韧度增益比(KfIC/KIC)的影响。结果表明:ρf一定时,KfIC随a0/h的增加逐渐减小,随dmax的增加呈增大趋势,随W/C的减小逐渐增加;a0/h一定时,KfIC随ρf的增加逐渐增大;钢纤维能够显著提高高强混凝土断裂韧度,KfIC/KIC大于1;影响因素不同,KfIC/KIC变化趋势不同。在分析试验结果的基础上,建立了钢纤维高强混凝土断裂韧度计算模式。

Through the three-point bending test on the specimens of steel fiber reinforced high strength concrete（SFHSC）,the effects of influencing factors such as relative notch depth（a0/h）,maximum particle diameter of coarse aggregate（dmax）,water cement ratio（W/C） and fiber volume fraction（ρf） on the fracture toughness（KfIC） of SFHSC and the fracture toughness increment ratio（KfIC/KIC） were investigated.The results show that for the same ρf,KfIC decreases with increasing a0/h.KfIC increased as dmax increased,and KfIC increased as W/C decreased.For the same a0/h,KfIC increases as ρf increases.Steel fiber significantly improved the fracture toughness（KIC） of high strength concrete,leading to KfIC/KIC of 1.The variation of KfIC/KIC was different at different influencing factors.Based on the experimental results,a model was proposed to calculate the fracture toughness of SFHSC.