高强钢筋与超高性能混凝土黏结性能试验研究  

Experimental study on bond performance between high strength steel rebar and ultra-high performance concrete

作　　者：梁芮 黄远[1,2] LIANG Rui;HUANG Yuan(College of Civil Engineering,Hunan University,Changsha 410082,China;Hunan Provincial Key Laboratory on Damage Diagnosis for Engineering Structures,Hunan University,Changsha 410082,China)

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]湖南大学工程结构损伤诊断湖南省重点实验室,湖南长沙410082

出　　处：《建筑结构学报》2022年第9期294-302,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(51890901);湖南省自然科学基金项目(2020 JJ2003);湖南创新型省份建设专项(2020RC5005)。

摘　　要：为研究超高性能混凝土(UHPC)与高强钢筋的黏结性能,设计并制作69个试件,通过拔出试验研究UHPC强度、纤维体积率、纤维尺寸形状、保护层厚度、黏结长度、加载方式和黏结段位置对黏结性能的影响。结果表明:试件的主要破坏形态包括拔出破坏、钢筋拉断和劈裂破坏,高强钢筋与UHPC界面的黏结强度随UHPC抗压强度、纤维体积率和长径比以及保护层厚度的增加而增大;纤维的掺入对高强钢筋与UHPC黏结强度提高作用明显;当纤维体积率从1%增长至3%,长径比从35增加到100时,黏结强度分别提高了23%和16%;但纤维形状的变化对黏结强度没有明显影响;黏结强度随着UHPC抗压强度和保护层厚度的增大而显著增加,随着黏结长度增大而降低,当保护层厚度超过4倍钢筋直径时,增幅基本不变;当黏结段位于加载端时,受拉拔出加载试件黏结强度仅为受压加载的77%,黏结段越靠近试件中部,加载方式对黏结强度影响越小。基于试验结果,确定临界锚固长度计算式,提出高强钢筋与UHPC的黏结强度计算式,同时建立黏结应力-滑移本构关系模型。通过试验结果及公式计算结果对比可得,现有的普通混凝土黏结强度公式低估了高强钢筋与UHPC的黏结强度,建议的简化公式预测结果与试验结果吻合良好。To investigate the bonding properties of high-strength steel rebar in ultra-high performance concrete(UHPC), 69 specimens were designed and produced. The effects of UHPC strength, fiber volume ratio, fiber size and shape, concrete cover thickness, bonding length, loading condition, and bonding segment condition on bonding properties were studied through pull-out tests. The results show that the specimens fail in three modes: pull-out, rebar fracture, and splitting failure. The main factors affecting the bond strength between high strength steel bar and UHPC are UHPC compressive strength, fiber volume content, aspect ratio, and cover thickness.The incorporation of fiber has a significant effect on improving the bonding strength. When the fiber volume ratio increases from 1% to 3% and the aspect ratio increases from 35 to 100, the bonding strength increases by 23% and 16%, respectively. However, the change of fiber shape has no pronounced effect on bonding strength. The bonding strength increases significantly with the compressive strength of UHPC and concrete cover thickness but decreases with the bonding length. When the concrete cover thickness exceeds four times the rebar diameter, the increment is hardly changed. When the bonding segment is located at the loading end, the bonding strength of the specimens under pull-out loading is only 77% of that under compression loading. The closer the bonding segment is to the middle of the specimen, the less influence the loading condition has on the bonding strength. Based on the experiment results, the formula for calculating critical anchorage length was established, and the formula of bonding strength between high-strength steel rebar and UHPC interface was proposed, and the bond-slip constitutive model was established. The existing equations for the bonding strength of ordinary concrete underestimate the bonding strength of high-strength steel rebar to UHPC. The simplified equations in this paper predict the results in good agreement with the experimental results.

关 键 词：超高性能混凝土 高强钢筋 拔出试验 黏结强度 黏结应力-滑移本构模型 

分 类 号：TU375[建筑科学—结构工程] TU317.1