套筒内锈蚀钢筋与灌浆料黏结性能试验研究

Experimental Study on Bonding Performance of Corroded Steel Bars and Grout in Sleeve

为了研究钢筋锈蚀对灌浆套筒接头连接性能的影响,通过对20个进行人工锈蚀的试件开展拉拔试验,获得灌浆套筒内不同直径的钢筋在不同锈蚀率情况下的破坏形态、锚固内部钢筋应变和荷载滑移曲线.对比分析不同直径钢筋在不同锈蚀率情况下的黏结应力分布曲线、相对滑移曲线和不同锚固位置处的黏结滑移曲线.通过试验结果和理论分析,发现随着锈蚀率的增加,钢筋的抗拔能力均有不同程度的衰减,当锈蚀率达到12%时,灌浆套筒内钢筋的抗拔能力降低约50%;分析得出灌浆套筒内锈蚀钢筋的黏结应力衰减机理;建立钢筋锈蚀前后黏结锚固位置函数模型,并确定参数取值;建立钢筋锈蚀前后与灌浆料间考虑黏结锚固位置函数的黏结滑移本构关系,为锈蚀前后钢筋与灌浆料的有限元分析提供参考依据.

In order to study the influence of the corrosion of steel bars on the connection performance of grouting sleeve joints,a pull-out test was carried out on 20 specimens subjected to artificial corrosion.The test obtained the failure modes of the steel bars of different diameters in the grouting sleeves under different corrosion rates,the strain of the anchoring internal steel bars vs the load slip curves.The bond stress distribution curves,relative slip curves,and bond-slip curves at different anchorage positions with different diameter steel bars under different corrosion rates are compared and analyzed.Through the test results and theoretical analysis,it is found that as the corrosion rate increases,the pull-out ability of the steel bars is attenuated to varying degrees.When the corrosion rate reaches 12%,the pull-out ability of the steel bars in the grouting sleeve is reduced by about 50%.The bond stress attenua⁃tion mechanism of corroded steel bars in the grouting sleeve is obtained.A function model of the bonding and anchor⁃ing position of the steel bars before and after corrosion is established,and the parameter values are determined.The bond-slip constitutive relationship between the steel bars before and after corrosion and the grouting material is es⁃tablished considering the bond and anchor position function,which provides a reference for the finite element analy⁃sis of steel bars and the grouting material before and after corrosion.