混凝土化学植筋粘结锚固性能的试验研究

Experimental Research on the Bonding Properties of Chemically Post-installed Bar in Concrete

通过对102个化学植筋和18个预埋钢筋组成的120个混凝土植筋试样进行了详细的拉拔试验对比分析,研究结果表明混凝土强度、钢筋直径、锚固长度、植筋孔径和方式是影响钢筋平均极限拉拔力与胶-混界面极限平均粘结力的重要因素,采用混凝土预埋筋和后植筋时钢筋平均极限拉拔力基本相同,表明2种方式可以达到补强混凝土的相同效果,且试件主要呈现钢筋拉断、胶-混界面破坏和混凝土劈裂破坏形式。基于理论分析建立了混凝土劈裂破坏时钢筋极限拉拔承载力计算式和植筋界限孔径。

Comparative analysis for 120 specimens of installed bar,including 102 specimen of post-installed bar and 18 specimen of embedded bar are carried out by pullout tests.Based on the experimental results,it is shown that the bonding properties of post-installed bar are significantly influenced by steel bar,tensile strength of concrete,anchoring depth of steel bar and diameter of hole.The ultimate average pullout forces of steels in specimen of post-installed bar and specimen of embedded bar are nearly equal.Three kinds of failure models,installed bar pulled out from concrete,tensile failure of installed bar and concrete split,are obtained in this paper.Furthermore,on the basis of analyzing failure mechanics of concrete split,empirical formulae for determining ultimate pullout force and limit hole diameter are established.