考虑灌浆缺陷的大直径灌浆套筒黏结性能分析

Analysis of Bond Performance of Large Diameter Grouting Sleeve Considering Grouting Defect

针对装配式建筑实际施工过程中出现的各种灌浆缺陷情况,对带灌浆缺陷的连接钢筋直径为40 mm的新型灌浆套筒进行单向拉伸试验。在已有的黏结强度计算理论的基础上,引用Mander模型对筒壁约束下的灌浆料抗压强度进行优化,并提出不同缺陷形式下灌浆料强度的影响系数,得出黏结强度修正公式。结果表明:修正公式计算的黏结强度值更接近试验值;根据理论公式计算出大直径新型灌浆套筒端部缺陷试件的锚固长度最低要求为5.2d,内部缺陷试件的锚固长度最低要求较端部缺陷试件大1倍钢筋直径,为实际工程中新型灌浆套筒的制作和质量评估提供参考;引入了受筒壁约束下灌浆料抗压强度影响系数α,为内部或其他形式灌浆缺陷的黏结强度理论计算提供思路。

In view of various grouting defects in the actual construction of prefabricated buildings,an unidirectional tensile test was conducted on a new type of grouting sleeve with 40 mm diameter of connecting reinforcing bars with grouting defects.On the basis of the existing bond strength calculation theory,the Mander model is used to optimize the compressive strength of grouting materials under the constraint of tube wall.The results show that the bond strength calculated by the optimized formula is closer to the experimental value.According to the theoretical formula,the minimum anchorage length of the new grouting sleeve end defect specimen with large diameter is 5.2d,and the minimum anchorage length of the internal defect specimen is one steel bar diameter larger than the end defect specimen,which provides reference for the fabrication and quality evaluation of the new grouting sleeve in the practical project.The influence coefficient α about compressive strength of grouting material under the constraint of tube wall is introduced to provide an idea for theoretical calculation of bond strength of internal or other grouting defects.