钢丝网或纤维网增强超高性能混凝土双向板弯曲性能  

Flexural properties of ultra high performance concrete reinforced with steel wire mesh or fiber mesh

作　　者：邓宗才[1] 鹿宇浩 桂营金 DENG Zongcai;LU Yuhao;GUI Yingjin(Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学城市与工程安全减灾省部共建教育部重点实验室,北京100124

出　　处：《复合材料学报》2022年第10期4757-4768,共12页Acta Materiae Compositae Sinica

基　　金：北京市教委科技重点资助项目(KZ201810005008)。

摘　　要：为研究钢丝网或纤维网对混杂纤维超高性能混凝土(Ultra-high performance concrete,UHPC)板弯曲性能的影响,进行了四边简支双向板弯曲试验。UHPC中短切纤维为:单掺钢纤维、钢纤维分别与聚乙烯醇纤维、玻璃纤维、玄武岩纤维混掺等。研究参数为:钢丝网与玻璃纤维网层数、孔径、混掺纤维比例等。结果表明,单掺体积分数为1.5vol%的钢纤维时,铺设3层和4层钢丝网的UHPC板的极限承载力和25 mm挠度处的能量吸收值较2层分别提升14.9%、32.3%和14.1%、25.2%;孔径较小的钢丝网对UHPC板承载力和韧性提升明显。当混杂纤维总体积分数为1.5vol%且钢丝网2层时,混掺1.0vol%钢纤维和0.5vol%聚乙烯醇纤维对UHPC板增强增韧效果更好,0.5vol%钢纤维与1.0vol%玻璃纤维或玄武岩纤维混掺较0.5vol%钢纤维与1.0vol%聚乙烯醇纤维混掺对改善板峰后持荷能力更有利,即钢纤维与较高弹性模量非金属纤维混掺有利于提高裂后承载力。与玻璃纤维网相比,铺设钢丝网的UHPC板在峰后延性更好。提出了以素UHPC板峰值荷载挠度作为初裂挠度的韧性指标评定方法,该方法可表征网格和纤维对UHPC板裂后韧性的贡献。基于网格有效利用率概念,建立了板抗弯承载力计算方法,理论值与试验值吻合良好。To study the influence of steel wire mesh on the bending properties of ultra-high performance concrete(UHPC) slabs, a bending test of simply supported two-way slabs with four sides was carried out. The chopped fibers in UHPC ware: Steel fiber and steel fiber were mixed with polyvinyl alcohol fiber, glass fiber and basalt fiber, respectively. The research parameters were: Number of layers of wire mesh and glass fiber mesh, pore size and proportion of blended fibers. The results show that when UHPC is single-doped with 1.5vol% steel fiber, the ultimate bearing capacity and energy absorption at 25 mm deflection of UHPC slabs with 3 layers and 4 layers are increased by 14.9%,32.3% and 14.1%, 25.2%, respectively compared with UHPC slabs with 2 layers of steel wire mesh. When the total volume fraction of hybrid fibers is 1.5vol% and the steel wire mesh is 2 layers, the blending of 1.0vol% steel fiber and0.5vol% polyvinyl alcohol fiber has better reinforcing and toughening effect on UHPC slabs, and the UHPC slab mixed with 0.5vol% steel fiber and 1.0vol% glass fiber or basalt fiber has a stronger ability to maintain load after peak load than 1.0vol% polyvinyl alcohol fiber, namely the mixing of steel fiber with higher modulus of elasticity nonmetallic fiber is advantageous to increase the post-cracking bearing capacity. Compared with glass fiber mesh, UHPC slabs with steel mesh have better ductility after peak load. A method for evaluating the flexibility of UHPC slabs with peak load deflection as initial cracking parameter was proposed, which can characterize the contribution of mesh and fibers to the post-crack toughness of UHPC slabs. Based on the concept of effective utilization of mesh,the theoretical value is in good agreement with the experimental value by calculating the bending capacity.

关 键 词：钢丝网 双向板 混杂纤维 硬化指数 韧性指数 抗弯承载力 

分 类 号：TU376[建筑科学—结构工程]