循环荷载下钢锭铣削型纤维混凝土基本力学性能试验

Test on Basic Mechanical Properties of Steel Ingot Milled Fiber Concrete under Cyclic Loading

摘要:

钢锭铣削型钢纤维凭借其独特的径向扭曲外形、表面粗糙特性和带弯钩的锚尾构造，在混凝土基体中表现出良好的黏结锚固性能。以波浪型钢纤维混凝土和未掺加混凝土试件作为对照组，对钢锭铣削型钢纤维混凝土试件，开展了在循环荷载作用下的三点弯曲梁的试验，测试了荷载-裂缝口张开位移（crack mouth opening displacement，CMOD）曲线等基本力学性能。试验结果表明：在循环加载上限对应的CMOD一定时，混凝土试件的刚度和恢复系数随着加载次数的增加呈现减小趋势；循环加载上限对应的CMOD越大，混凝土试件刚度和恢复系数越小。在正常使用状态下，即当CMOD小于0.5 mm时，相比波浪型钢纤维，钢锭铣削型钢纤维在增益混凝土残余强度、循环刚度上表现更为优异。

Abstract:

Steel ingot milled steel fibers exhibit excellent bonding and anchoring performances in concrete matrices due to their unique radially twisted shape, rough surface characteristics and anchor tail structure with hooks. Taking the wavy steel fiber reinforced concrete specimens and the specimens without concrete addition as the control group, the three-point bent beam test under cyclic loading is conducted on the steel ingot milled steel fiber reinforced concrete specimens to test the basic mechanical properties such as the load - crack mouth opening displacement (CMOP) curve. The test results indicate that when the CMOD corresponding to the upper limit of cyclic loading is fixed, the stiffness and recovery coefficient of concrete specimens show a decreasing trend with the increase of loading times. The larger the CMOD corresponding to the upper limit of cyclic loading, the smaller the stiffness and recovery coefficient of the concrete specimen. Under the normal usage conditions, when CMOD is less than 0.5 mm, compared with the wave-shaped steel fibers, the steel ingot milled steel fibers perform more outstandingly in increasing the residual strength and cyclic stiffness of concrete.