钢管轻集料混凝土组合界面黏结滑移性能

Mechanical behaviors of bond slip at interface of lightweight aggregate concrete for steel tubes

通过对27根钢管轻集料混凝土试件的推出试验,研究了钢管轻集料混凝土黏结滑移的发展过程及破坏机理,考察了影响钢管轻集料混凝土黏结强度的因素;并对其中的4个试件进行了反复推出试验,研究了循环荷载对黏结强度的影响.初次推出试验表明:养护方式和浇筑方式对钢管轻集料混凝土组合界面的黏结强度有一定的影响;钢管内壁越粗糙,黏结强度也越大;轻集料混凝土强度对黏结强度影响不大;在试件的参数范围内,黏结强度随长细比和径厚比增长而降低.反复推出试验的结果表明:初次推出的承载力最大;同一方向推出次数增加,钢管轻集料混凝土的黏结破坏荷载和黏结强度均会降低.

Based on the push-out tests on 27 lightweight aggregate concrete-filled steel tubes （LACFST）, the development of bond slip and the failure mechanism of the lightweight aggregate concrete were studied, and the factors affecting its bond strength were investigated. The repeated push-out tests of four of the specimens were conducted, and the effect of the cyclic load on the bond strength was studied. The first time push-out test results indicate that the curing and concrete-pouring ways have a certain effect on the bond strength of the lightweight aggregate concrete-filled steel tube interfaces： the rougher the inner surface condition of the steel tubes is, the larger the bond strength is. The strength of the lightweight aggregate concrete has little effect on the bond strength. Within the specifications of test specimens, the larger the slenderness ratio and the diameter-thickness ratio are, the lower the bond strength is. The repeated push-out test results show that the bearing capacity of the first time push-out tests is the largest. The failure load and bond strength of the lightweight aggregate concrete for steel tubes will decrease with the increase of the push-out time in the same direction.