砌块灌孔混凝土与钢筋粘结性能试验

为进一步研究灌孔混凝土与钢筋粘结锚固机理和锚固长度的可靠性,笔者进行了12组36个试件的拉拔试验,建立粘结应力与滑移(τ-S)关系曲线,确定了锚固钢筋受力破坏的各个阶段(微滑移、内裂滑移、劈裂、下降和残余5个阶段),综合分析了灌孔混凝土强度、锚固长度、钢筋直径和横向配筋对粘结性能的影响.试验结果表明:在给定的l/d的条件下,粘结强度随灌孔混凝土强度增加而提高,随相对锚固长度增大而降低,但钢筋直径对粘结强度影响较小.最后,考虑灌孔混凝土的劈拉强度和相对锚长,利用最小二乘法,通过统计回归提出了粘结特征强度的统计公式.

Tests and Research on the Bond Behavior of Reinforcement and Grout Concrete

Based on the result of 12 groups of cube specimens' pullout test and considered the four parameters of anchorage length,strength of grout concrete,bar diameter and horizontal reinforce,a curve of bond stress vs.slip is obtained and every phase of the bond behavior is identified in this paper.The result of the test indicates that,under the condition of l/d is determinate,the higher grout strength with the higher bond strength,and bond strength will be lower with the increasing of anchorage length,but the influence of bar diameter is much smaller.At last,it establishes the formula of the characteristic bond strength applying regressive equation that provides some proof for the further study.