弯曲荷载与酸雨侵蚀共同作用下钢纤维混凝土的耐久性能

Durability of Steel Fiber Reinforced Concrete Under Combined Effect of Flexural Loading and Acid Rain Erosion

利用拉杆加载系统对钢纤维混凝土试件施加弯曲荷载,开展弯曲荷载作用下钢纤维混凝土的酸雨干湿循环试验,研究钢纤维掺量以及应力状态、应力水平对钢纤维混凝土酸雨侵蚀作用下中性化深度的影响规律。结果显示:弯曲拉应力加速了混凝土的中性化速度,一定水平下的弯曲压应力对于混凝土的中性化起到了抑制作用。钢纤维混凝土在承受弯曲荷载作用下的中性化弯曲应力影响系数与应力水平之间的关系符合二次多项式。钢纤维能够降低弯曲拉应力对基体混凝土酸雨侵蚀速度的影响,在本实验所选用的几种掺量中,当钢纤维掺量为1.5%时,这种降低效果最明显。但是钢纤维对弯曲压应力引起的混凝土酸雨侵蚀中性化深度变化无显著影响。

Flexural loading was applied on steel fiber reinforced concrete using the tie beam loading system.The erosion simulation tests of acid rain on steel fiber reinforced concrete under flexural loading were carried out.Effects of steel fiber content,stress state,and stress level on steel fiber reinforced concrete neutralization depth were studied.Test results indicated that the flexural tensile stress could accelerate the concrete neutralization speed,while a certain level of flexural compressive stress could retard the concrete neutralization speed.Under flexural loading,the relationship between influence coefficient of flexural loading on neutralization of steel fiber reinforced concrete and the stress level was accorded with quadratic polynomial.Steel fiber could reduce the influence of flexural tensile stress on matrix concrete neutralization depth.According to the varied mixing proportions in the test,the SFRC with the steel fiber content of 1.5 ％ has the best effect.But steel fiber has no significant effect on influence of flexural compressive loading on matrix concrete neutralization depth.