钢筋-中高强度再生混凝土黏结滑移性能梁式试验研究

Beam-type experimental study on bond-slip properties between rebars and medium/high strength recycled concrete

为研究钢筋与再生混凝土黏结滑移性能,进行了13个梁式试件的钢筋-中高强度再生混凝土黏结性能试验。研究了钢筋外形、锚固长度、混凝土强度、再生骨料取代率对钢筋-再生混凝土黏结滑移性能的影响。结果表明:再生粗骨料混凝土取代率为33%~66%、细骨料为天然砂时,钢筋-再生混凝土黏结强度与普通混凝土接近;再生粗骨料取代率100%、再生细骨料取代率50%以上时,钢筋-再生混凝土黏结性能明显退化;与普通混凝土相比,再生粗骨料混凝土的相对混凝土强度黏结效率系数有所提高;变形钢筋与再生混凝土的黏结强度明显好于光圆钢筋;钢筋与再生混凝土的黏结强度随钢筋相对锚固长度增大而减小;拟合所得的黏结-滑移本构模型,其计算值与试验值吻合良好。

In order to investigate the bond-slip behavior between steel bars and recycled concrete, the bond-slip properties of 13 reinforced medium/high strength recycled concrete beam-type specimens were tested. The effects of the shape of steel bar, the length of anchorage, the strength of concrete and the replacement ratio of recycled aggregate on the bond-slip behavior between steel bars and recycled concrete were studied. Research shows that： when the recycled coarse aggregate replacement is 33% -66% and the fine aggregate is natural sand, the bond strength between steel bar and recycled concrete is basically coincident with ordinary concrete. When the replacement rate of recycled coarse aggregate is 100% and the fine aggregate is over 50% , the bond behavior between rebars and recycled concrete is degraded distinctly. Compared with the ordinary concrete specimens, the bond efficiency coefficient of the relative concrete strength of the recycled coarse aggregate concrete specimens is higher. The bond strength between deformed bars and recycled concrete is better than plain ones. The bond strength between steel and recycled concrete decreases with the increase of the anchorage length of reinforcement. The calculated values of the fitted bond-slip constitutive model agree with the experimental values well.