受火后混凝土黏钢界面的剪切性能研究

针对不同的受火温度(250,350,450和550℃)和不同的混凝土强度(C25,C30和C35),进行了混凝土高温受火后黏钢界面剪切性能的试验研究.结果表明,当混凝土受火温度相同时,随着混凝土强度的提高,黏钢界面黏结剪切强度逐渐增大,平均增大幅度在3%左右,最大增大幅度近8%.当混凝土强度等级相同时,界面的黏结剪切强度随着受火温度的升高逐渐降低.当受火温度为450℃时,黏结剪切强度为常温的50%;当受火温度为550℃时,黏结剪切强度仅为常温的38%左右.得到了钢-混凝土黏结剪切强度与混凝土强度的比值随混凝土受火温度升高的退化规律.

Shear Behavior at the Interface Between Concrete and Steel Plate Exposed to Fire

The shear behavior at the interface of concrete bonded to steel plate was examined after exposure of the structure to different temperatures (250, 350, 450 and 550 ℃). Three different strengths of concrete were used in the tests (C25, C30 and C35). The interfacial shear strength was observed to increase with an increase in concrete strength for a given temperature. The average increase was about 3% but the largest was nearly 8%. For a given strength of concrete the interfacial bond decreased in strength as the temperature increased. The bond strength was 50% of the un-heated strength after heating to 450 'C. After heating to 550 ℃ the strength was only 38% of the original strength. An expression relating the bond strength to the strength of the concrete and the heating temperature was derived from the test results.