镀铜钢纤维增强废弃陶瓷粉超高性能混凝土的压敏性研究

Piezoresistivity properties of copper-plated steel fiberreinforced ultra high performance concrete with ceramic waste powders

镀铜钢纤维具有良好的电学性能、力学性能和电导率,而废弃陶瓷粉具有内养护作用和低碳属性。在镀铜钢纤维分散良好的情况下,两者的协同作用易在混凝土基体中形成良好且化学稳定的增强、增韧和导电网络。采用均匀筛入法分散镀铜钢纤维,制备了镀铜钢纤维增强废弃陶瓷粉超高性能混凝土并研究了其压敏性能。研究结果表明,在不同镀铜钢纤维掺量、不同加载幅值和不同加载速率下,镀铜钢纤维均可提高废弃陶瓷粉超高性能混凝土的压敏性能,2.50%(体积分数)的镀铜钢纤维增强废弃陶瓷粉超高性能混凝土的电阻率变化率和应力/应变灵敏度相比于对照组分别提升了650.0%、614.3%和1223.0%。相比纤维掺量和加载速率,加载幅值对压敏性能的影响最大。且由力-电模型表明,废弃陶瓷粉超高性能混凝土在循环荷载的电阻率变化率和应力/应变之间均服从指数函数关系,拟合度均在0.90以上。因此,通过测试镀铜钢纤维增强废弃陶瓷粉超高性能混凝土的电阻率即可实现混凝土结构的应力/应变监测。

The copper-plated steel fiber has the characteristics of good electrical,mechanical and high conductivity,and the ceramic waste powders has the advantages of pozzolanic internal curing and low carbon properties.It is easy to form a good andchemically stable strengthening,toughening and conductive network by synergistic action.Therefore,the piezoresistivity properties of copper-plated steel fiber content and loading conditions on copper-plated steel reinforced fiber ultra high performance concrete with ceramic waste powders were studied by using uniform sieving method.The research shows that the copper-plated steel fiber can improve the piezoresistivity of ultra high performance concrete with ceramic tile waste powders with different content of copper-plated steel fibers under different load amplitudes and different loading rates.Compared with plain samples,the fractional change in resistivity and stress/strain sensitivity of 2.50 vol% content of copper-plated steel fibers reinforced ultra high performance concrete with ceramic waste powders are increased by 650.0%,614.3% and 1223.0%,respectively.Moreover,it can be seen that the loading amplitude has the greatest influence on the piezoresistivity performance among copper-plated steel fibers and loading rates.The stress-electricity model shows that the relationship between the fractional change in resistivity and stress/strain sensitivity of ultra high performance concrete with ceramic waste powders is exponential function under cyclic load,and the fitting degree is above 0.90.Therefore,the stress/strain monitoring of concrete structures can be realized by testing the resistivity of copper-plated steel fiber reinforced ultra high performance concrete with ceramic waste powders.