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为研究圆钢管再生混凝土界面黏结的失效机理,以再生粗骨料取代率、混凝土强度等级及长径比为变化参数,设计了4组共15个圆钢管再生混凝土试件进行推出试验。通过试验获取了界面黏结的荷载-滑移曲线、黏结应变和黏结力分布规律。运用相关计算模型对圆钢管再生混凝土的黏结强度进行对比计算,回归得到圆钢管再生混凝土的黏结强度计算式。研究结果表明:加载端首先出现滑移,此后滑移发展至自由端;在加载初期和加载后期的圆钢管纵向应变分别呈负指数分布和线性分布;长径比较大试件的峰值荷载均大于长径比较小的试件;界面黏结损伤的发展随再生粗骨料取代率的增加而提前;界面埋置长度的增加有利于其黏结滑移能量耗散。
In order to study the failure mechanism of interfacial adhesion of recycled concrete with round steel tube, four groups of 15 specimens of recycled concrete with round steel tube were designed and tested with the replacement rate of recycled coarse aggregate, the strength grade of concrete and the aspect ratio. The load-slip curve, bond strain and cohesive force distribution of interfacial bond were obtained through experiments. The correlation calculation model was used to calculate the bond strength of the reclaimed concrete filled circular steel tube. The formula for calculating the bond strength of the reclaimed concrete filled circular steel tube was obtained by regression. The results show that the slip occurs first at the loading end, and then develops to the free end. The longitudinal strain of the round steel tube at the initial stage of loading and the later stage of loading is respectively negative exponential distribution and linear distribution. The peak load of larger diameter- The results show that the development of interfacial bond damage advances with the increase of replacement rate of reclaimed coarse aggregate. The increase of interfacial embedding length is favorable for the dissipation of bond slip energy.