摘要
网格增强超高性能混凝土(ultra-high performance concrete,UHPC)具有轻质、高强、耐久性好等特性,已应用于薄壁结构和工程加固领域,但单一网格很难实现高效的增强增韧效应.为研究混杂网格增强UHPC双向板的抗弯性能,对3个钢丝网格与玻璃纤维网格混杂增强UHPC板、3个钢丝网格与玄武岩纤维网格混杂增强UHPC板、6个单一网格增强UHPC板和1个无网格UHPC对照板进行弯曲试验,研究网格种类、总层数及铺层方式对其破坏形态、承载能力和弯曲韧性的影响.结果表明:与单一钢丝网格板和单一玻璃纤维网格板相比,钢-玻璃纤维网格混杂板开裂后表现更显著的硬化现象,在连续网格与混杂短纤维协同效应下,板呈现多裂缝破坏模式,延性较理想.铺设2层网格时,钢-玻璃纤维网格混杂板的承载能力较单一钢丝网格板提升23.7%,且其在20 mm挠度处的残余承载力较单一玻璃纤维网格板提升28.2%;钢-玄武岩纤维网格混杂板峰前阶段的能量吸收值和20 mm挠度处的残余承载力均优于单一玄武岩纤维网格板.网格总层数为3层时,与单一玄武岩纤维网格板相比,2层钢丝网格与1层玄武岩纤维网格混杂增强板在峰前挠度为2 mm时的能量吸收值提高了21.6%,20 mm挠度处的残余承载力提高了42.6%.钢-玻璃纤维网格混杂板的网格强度利用率最理想,其承载能力、能量吸收值及弯曲韧性指标均高于钢-玄武岩纤维网格混杂板.最后,考虑网格强度有效利用率建立了混杂网格增强UHPC双向板抗弯承载力理论公式,适用性良好.
Ultra-high performance concrete(UHPC)reinforced with meshes has the advantages of light weight,high strength,and good durability.UHPC has been applied in the fields of thin-walled structures and engineering reinforcement.However,it is difficult to achieve efficient reinforcement and toughening effects with a single mesh.To study the bending properties of the UHPC two-way slabs reinforced with hybrid meshes,three hybrid UHPC slabs of steel wire mesh and glass fiber mesh,three hybrid UHPC slabs of steel wire mesh and basalt fiber mesh,six UHPC slabs of single mesh,and a non-mesh UHPC control slab were subjected to the bending test.The effects of mesh types,layers,and laying methods on the failure mode,bearing capacity,and bending toughness of UHPC slabs were discussed.The results show that compared with the single steel wire mesh and single glass fiber mesh slabs,the steel-glass fiber mesh hybrid slabs exhibited a more significant hardening phenomenon after cracking.Under the synergistic effect of continuous meshes and hybrid short fibers,the slabs have multiple crack propagation modes and good ductility.In the case of two mesh layers,the bearing capacity of the steel-glass fiber mesh hybrid slab is 23.7%higher than that of the slab of single steel wire mesh.Additionally,the residual bearing capacity at 20 mm deflection is 28.2%higher than that of the slab of single glass fiber mesh.The pre-peak energy absorption values and residual bearing capacity at 20 mm deflection of the hybrid slabs of steel wire mesh and basalt fiber mesh are better than the slabs of single basalt fiber mesh.In the case of three mesh layers,compared with the slab of a single basalt fiber mesh,the energy absorption value of the hybrid slab with two layers of steel wire mesh and one layer of basalt fiber mesh at 2 mm deflection is increased by 21.6%,and the residual bearing capacity at 20 mm deflection is increased by 42.6%.The utilization rate of the steel-glass fiber meshes hybrid slab is the most ideal,and its bearing capacity,energy absorption values,and bending toughness index are higher than those of the steel-basalt fiber mesh hybrid slab.Finally,considering the effective utilization rate of mesh strength,the bending capacity calculation method of meshes reinforced UHPC two-way slabs was established,which had good applicability.
作者
邓宗才
李倩
Deng Zongcai;Li Qian(Key Laboratory of Urban Security and Disaster Engineering,Ministry of Education,Beijing University of Technology,Beijing 100124,China)
出处
《天津大学学报（自然科学与工程技术版）》
EI
CSCD
北大核心
2024年第3期301-310,共10页
Journal of Tianjin University：Science and Technology
基金
北京市教委科技重点资助项目(KZ201810005008).
