碳纤维聚氨酯水泥复合材料压敏特性试验研究

近年来,一种新兴的结构补强加固材料聚氨酯水泥(polyurethane-cement,PUC)中掺入适量碳纤维,制成导电聚氨酯水泥复合材料(conductive polyurethane-cement,CPUC)。讨论了其静态电阻率与固化龄期之间的关系,及静态电阻率的渗流阈值;并采用WDW-500型万能试验机、直流稳压电源和UT61E数字万用表系统测试了CPUC的压敏特性。研究结果表明,CPUC试块的电阻率随固化龄期的增加而增加;并逐渐趋于平缓。碳纤维掺量在2%左右达到渗滤阈值。可通过CPUC电阻率的变化,表征其弹性变形、裂缝稳定扩展及非稳定扩展的三个破坏过程。CPUC试块的这种特性,使其可作为一种本征智能加固材料,用于混凝土梁、墩柱加固后的无损检测。

Experimental Study on Pressure Sensitive Characteristics of Carbon Fiber Reinforced Polyurethane Cement Composites

In recent years, the new kind of structural reinforcement polyurethane cement (PUC) adding proper carbon fiber made of conductive polyurethane cement (CPUC). In this study, we aimed to explore the percolation threshold of static resistivity and the relationship between static resistivity and curing age. We measured the pressure-sensitive properties of CPUC by WDW-500 universal testing machine, DC regulated power supply and UT61E digital multimeter system. The results demonstrated that the resistivity of CPUC test block positive correlate with curing age, then gradually tended to be gentle and reached the percolation threshold at carbon fiber content up to 2%. Detection of changes in electrical resistivity CPUC, characterized the three processes of elastic deformation, stable crack propagation and unstable extension. This CPUC test block can be used as a kind of intrinsic intelligent strengthening material for nondestructive testing of reinforced engineering.