预制键槽式UHPC与后浇混凝土界面粘结抗剪性能
Interface shear resistance of precast keyway UHPC and post-cast normal concrete
王鹏刚 1赵明海 2田砾 1潘崇根 3陈春雷 4傅宁5
作者信息
- 1. 青岛理工大学 土木工程学院,青岛 266033
- 2. 青岛理工大学 土木工程学院,青岛 266033;吕梁市机关事务服务中心,吕梁 033000
- 3. 浙江大学宁波理工学院,宁波 315199
- 4. 浙江省二建建设集团有限公司,宁波 315000
- 5. 宁波蛟川构件有限公司,宁波 315200
- 折叠
摘要
永久性模板的使用可实现混凝土结构的快速施工,缩短工期,提高整体结构的承载能力和耐久性能.其界面粘结抗剪性能是确保永久性模板与混凝土协同工作的关键.本文设计并制作了 3组不同强度混凝土试件和 10组键槽式超高性能混凝土(UHPC)-普通混凝土(NC)复合试件,通过单面剪切试验和理论分析,系统研究了键槽密度、键槽间距、混凝土强度、养护条件等对键槽式UHPC-NC结合面抗剪性能的影响.结果表明:整体试件的裂缝与加载中心轴线呈一定角度,UHPC-NC结合面破坏发生于普通混凝土一侧.UHPC-NC荷载-滑移曲线细分为 4个近似线性阶段,其极限滑移量均在 0.9 mm以内.复合试件UHPC-NC的粘结面总剪切强度由粘结面接触摩擦力、水泥石-骨料相互作用、键槽-骨料互锁机制、剪切膨胀提供.合理的UHPC-NC键槽界面在提高界面粘结抗剪强度的同时,可有效提高界面相对位移.在60℃蒸汽养护条件下,水泥石-骨料界面及UHPC-混凝土界面作用减弱.建立了键槽式UHPC-后浇NC界面抗剪承载力修正公式,其计算值与试验值具有较高的吻合度,大多数结果落在 90%置信区间,置信区间之外的点,受试件养护龄期的影响.因此,要准确计算键槽式UHPC-NC复合试件抗剪强度还需要考虑养护龄期的影响,引入养护龄期修正参数.
Abstract
Use of permanent formwork can achieve rapid construction,shorten the construction period,and improve the bearing capacity and durability of concrete structure.Interfacial bond shear performance is the key to ensure the collaborative work of permanent formwork and concrete.Three groups of concrete specimens with different compressive strengths and ten groups of keyway ultra-high performance concrete(UHPC)-normal concrete(NC)composite specimens were prepared.The effects of keyway density,spacing,concrete strength,and curing condition on the shear property of keyway UHPC-NC were systematically studied through single-side shear tests and theoretical analysis.Results show that the crack of the concrete specimen is at a certain angle to the loading center axis.And the failure of the UHPC-NC joint surface occurs on the side of concrete.The load-displacement curve of UHPC-NC specimens can be subdivided into four approximately linear stages.And all of the displacements are within 0.9 mm.The total shear strength of the UHPC-NC composite specimen was provided by the contact friction of the bonding surface,matrix-aggregate interaction,keyway-aggregate interlocking mechan-ism and shear expansion.A reasonable interface of the UHPC-NC keyway can improve both the shear strength and the interface relative displacement of UHPC-NC specimens.After steam curing at 60℃,the interface of matrix-aggregate and the interface UHPC-NC are weakened.According to the results,a modified equation for the shear strength of the keyway UHPC-NC composite specimen was proposed.The calculated values agree well with the experimental results.Most of the calculated values fall within the 90%confidence interval.The values outside the confidence interval are affected by the curing time of the specimens.Therefore,to accurately calculate the shear strength of the keyway UHPC-NC composite specimen,the influence of curing time should also be considered by the curing time factor.
关键词
永久性模板/超高性能混凝土/剪切试验/键槽参数/界面粘结抗剪性能Key words
permanent template/ultra-high performance concrete(UHPC)/shear test/parameter of keyway joint/interface bonding shear performance引用本文复制引用
基金项目
宁波市科技创新重大专项(2025)(2020Z035)
出版年
2024
NETL
NSTL
万方数据