摘要
为研究一种新型超高性能混凝土锚固接头的黏结性能,对19组共57个UHPC锚固接头中心拉拔试件进行研究试验,通过钢筋拔出试验分析UHPC外裹厚度、混凝土接触层表面处理,黏结长度、以及钢筋直径对该形式锚固接头黏结性能的影响,对试件破坏形态以及黏结滑移曲线进行了分析研究。研究结果表明:该新型锚固接头的破坏类型有钢筋屈服后拔出、钢筋未屈服拔出以及外裹混凝土块劈裂后钢筋拔出3种破坏形式;钢筋屈服后拔出破坏的组别需要满足黏结长度不小于4d或者不小于1.5d的UHPC外裹厚度,且UHPC外裹厚度最小值应不小于1d。凹槽处理相对于凿毛处理略为优越的前提是保证凹槽处UHPC外裹厚度不小于1d,但适当的增加黏结长度可以弥补UHPC外裹厚度不足的问题,故建议黏结长度不小于4d。以及大直径锚固接头需要更大的普通混凝土保护层厚度。
In order to study the bonding performance of a new type of ultra-high performance concrete anchoring joint,a total of 57UHPC anchoring joint center drawing specimens in 19 groups were studied and tested,the influence of UHPC coating thickness,concrete contact layer surface treatment,bond length,and steel bar diameter on the bond performance of this type of anchoring joint was analyzed through the steel pull-out test.The failure form of the specimen and the τ-s curve were analyzed and studied.The research results show that the failure types of the new anchoring joint include three failure modes,steel bar pull-out after yielding,steel bar unyield pull-out,and steel bar pull-out after the outer concrete block splits.The group of pull-out failure after steel bar yields needs to be satisfied the bond length is not less than 4d or the UHPC coating thickness is not less than 1.5d,and the minimum UHPC coating thickness should not be less than 1d.The premise that the groove treatment is slightly superior to the chipping treatment is to ensure that the UHPC coating thickness at the groove is not less than 1d,but an appropriate increase in the bond length can make up for the insufficient thickness of the UHPC coating,so it is recommended that the bond length is not less than 4d.And large diameter anchoring joints require greater thickness of ordinary concrete protective layer.
作者
吴越
黄靓
WU Yue;HUANG Liang(School of Civil Engineering,Hunan University,Changsha 410082,China)
出处
《混凝土》
CAS
北大核心
2022年第11期183-187,共5页
Concrete
基金
国家重点研发计划(2019YFC1904700)
长沙市科技局-重点研发计划-重点项目(kq1901025)。
