保护层厚度对受拉与受压粘结强度的影响

Influence of concrete covers on tensile and compressive bond strength

针对不同混凝土保护层厚度,分别进行了12个拔出试验和18个推出试验,并对试验结果进行了对比与分析.结果表明:当保护层厚度较小时,无论是拔出试件还是推出试件,均发生劈裂破坏;当保护层厚度较大时,推出试件钢筋被缓缓推出,混凝土没有开裂;增加混凝土保护层厚度既可以提高钢筋的受拉粘结强度,也可以提高钢筋的受压粘结强度;混凝土保护层厚度在一定限值范围内对钢筋受拉粘结强度影响较大.

12 pullout tests and 18 push out tests were carried out under different concrete covers and the test results were compared and analyzed. When the ocncrete cover is thin, the specimens split no mater wehther they are under pullout conditions or push out conditions. While when the concrete cover is thick enough, the bars for the push out specimens would be pushed out slowly and the concrete didn＇t split. Tensile bond strength as well as compressive bond strength of high strength bars increases when the concrete cover becomes larger. In addition, the concrete cover influence much on the ten sile bond strength of the bar under a certain limit value range.