钢筋-超高性能混凝土界面黏结性能试验

为研究轻薄UHPC构件内钢筋-UHPC界面间的黏结性能，以钢筋直径、黏结长度和保护层厚度为变量设计了多组配筋UHPC拉拔试验，并探讨各设计变量对钢筋-UHPC界面黏结性能的影响.基于试验结果，分析各设计参数对配筋UHPC试件破坏形式、黏结应力-滑移曲线、黏结锚固强度及其对应滑移量等因素的影响.研究表明：钢筋直径、黏结长度和保护层厚度的变化对配筋UHPC界面黏结性能影响较大；极限黏结强度及滑移量随黏结长度的减小而增加，随钢筋直径增加而先增加后降低；随保护层厚度变薄，极限黏结强度降低而滑移量增加.钢筋直径为12 mm和16 mm时，配筋保护层厚度和黏结锚固长度分别不宜小于1.5倍和4倍直径；直径为8 mm的钢筋黏结锚固长度不宜小于3.5倍直径.基于数理统计法归纳的配筋UHPC界面极限黏结强度及临界锚固长度计算式与试验结果误差较小.

Test on Interface Bonding Behavior between Steel Rebar and Ultra-high Performance Concrete

To study the bonding behaviors of the interface between steel rebar and ultra-high performance concrete (UHPC) for the thin and light reinforced UHPC members, several pull-out tests of reinforced UHPC specimens with different design variables, such as the diameter and cover thickness of steel rebar, and bonding length, were tested in this paper, and their influences of design variables on the bonding properties of the interface between steel rebar and UHPC are investigated. Based on the test results, the effect of each design parameter on the failure types, bond stress-slip curves, bond anchoring strength, and corresponding slip of the reinforced UHPC specimens is analyzed. The obtained results show that the changes in the rebar diameter, bonding length, and cover thickness have a great influence on the bonding behaviors of the interface between the steel rebar and UHPC. The ultimate bond strength and corresponding slip increase with the decrease in bond length, while it first increases and then decreases with the increase of the rebar diameter. The ultimate bond strength decreases with a reducing rebar cover thickness, while the corresponding slip increases. When the diameter is 12 mm and 16 mm, the cover thickness and the bonding anchor length of steel rebar should not be less than 1.5 times and 4 times of rebar diameter, respectively, while the bonding anchor length of the steel bar with a diameter of 8 mm should not be less than 3.5 times of the diameter. The calculation formulas of ultimate bond strength and critical anchorage length for the interface of reinforced UHPC are derived from mathematical statistics method, and they agree well with the test results.