碳-玻混杂纤维网格增强水泥基材料板轴拉性能与力阻响应特性研究

Study on axial tensile properties and piezoresistive response of carbon fibric reinforced cementitious matrix

为研究碳-玻混杂纤维网格增强水泥基材料(carbon-glass hybrid fiber grid reinforced cementitious matrix,C-GFRCM)板的轴拉性能与力阻响应,开展12组C-GFRCM板单轴拉伸试验,分析砂浆类型、预应力水平、黏合剂以及玻璃纤维布粘贴方式对其受拉性能和纤维利用率的影响,研究C-GFRCM板拉伸过程中碳纤维束的电阻变化与试件受力状态的响应机制,以及力阻响应与裂缝发生位置的规律。结果表明:预应力C-GFRCM板多为单裂缝破坏模式,环氧树脂黏合CGFRCM板多为纤维拉断破坏,地聚物黏合C-GFRCM板纤维发生滑移而拉断-拔出破坏;预应力工艺主要提升C-GFRCM板的开裂荷载,且预应力水平越高提升效果越明显,最大可提高267%;采用环氧树脂黏合剂分散粘贴玻璃纤维布可显著增强C-GFRCM板的极限荷载,最大可提高320%;拉伸过程中C-GFRCM板的力阻响应呈现三阶段特征,即弹性阶段电阻无明显变化;裂缝发展阶段在裂缝产生处电阻开始增长与波动;裂缝扩大与破坏阶段在主裂缝处电阻增长显著,采用力阻响应可以准确表征C-GFRCM板的受力状态并判断裂缝发生位置,不同设计参数C-GFRCM板的电阻变化对受力状态的敏感性不同。

To investigate the tensile properties and piezoresistive response of carbon-glass hybrid fiber grid reinforced cementitious matrix(C-GFRCM),12 sets of C-GFRCM plates were subjected to uniaxial tensile tests.The influence of mortar type,prestress level,adhesive,and the arrangement of glass fiber sheet on their tensile properties and fiber utilization rate was analyzed.The changes in electrical resistance of carbon fiber bundles during the tensile process of C-GFRCM plates and the response mechanism of specimen stress state,as well as the law of resistance response and crack occurrence position,were studied.The results showed that prestressed C-GFRCM plates mostly exhibited a single crack failure mode,while epoxy resin adhesive C-GFRCM plates mostly experienced fiber pullout failure,and C-GFRCM plates with geopolymer adhesive saw fiber slip and pullout failure.The prestressing process mainly enhances the cracking load of C-GFRCM plates,and the higher the prestress level,the more significant the enhancement effect,with a maximum increase of 267%.Dispersion pasting of glass fiber cloth using epoxy resin adhesive can significantly enhance the ultimate load of C-GFRCM plates,with a maximum increase of 320%.During the tensile process,the piezoresistive response of C-GFRCM plates exhibited three stages:in the elastic stage,the resistance showed no significant change;in the crack development stage,the resistance began to increase and fluctuate at the crack initiation point;in the crack enlargement and failure stage,the resistance at the main crack increased significantly.The resistance response can accurately characterize the stress state of C-GFRCM plates and determine the occurrence 83 position of cracks.The sensitivity of resistance of C-GFRCM plates to stress state varies changes with different design parameters.