Research On The Electrical Conductivity And Mechanical Properties Of CFRCM Under ICCP

The effectiveness of carbon fabric reinforced cementitious matrix（CFRCM）in the ICCP-SS（impressed current cathodic protection-structural strengthening）dual-functional system of reinforced concrete structures for rust prevention and mechanical performance reinforcement has been verified.With the increasing scarcity of freshwater and river sand resources,the research on the ICCP-SS dual-function system with seawater and sea sand-CFRCM as the main body has broad prospects.However,with the influence of ICCP,the electrical conductivity and mechanical properties of CFRCM and carbon fiber will be degraded due to anodic reaction,and the degradation of material performance in seawater and sea sand（chlorinated environment）is still unknown.Moreover,there are few fitting prediction formulas or empirical formulas currently available for performance prediction in material level,also,the direct relationship between charge density and performance has not been established.Research on carbon fiber smart materials shows that the force resistance effect based on carbon fiber can self-monitor its stress state and damage.A lot of theoretical and experimental research is still needed to realize self-monitoring.This paper takes carbon fiber bundles,common mortar-CFRCM and seawater sand-CFRCM as the research objects,focus on the performance degradation and the piezoresistive response during loading,finally establishes the equivalent delamination failure model of CFRCM bundles,the main research content and conclusions as follows:1.Through the ICCP simulation test of saturated Ca（OH）₂ solution and saturated Ca（OH）₂ solution prepared by seawater,common mortar-CFRCM and seawater sea sand-CFRCM with four electrification environments,the influence of ICCP on the electrical conductivity with different electrification environments is proved.Also,electrical conductivity prediction formula related to the charge density was obtained by fitting.2.Through the loading tests of the mechanical properties of two kinds of mortar CFRCM after the ICCP test（pull-out test,tensile test for bundles,and tensile test for CFRCM slabs）,the influence and mechanism of ICCP on the failure mode and mechanical properties were analyzed,and the fitting results were obtained.3.Through the piezoresistive response curve of the CFRCM loading process,the influence of ICCP on the piezoresistive effect at each stage of loading was analyzed,and the relationship between the piezoresistive response and the crack development and fiber fracture during the tensil process of the CFRCM slabs was analyzed,also the influence of ICCP on the piezoresistive effect was realized.The function of crack location and sequence determination based on the piezoresistive e effect is realized,which provides a basis for self-monitoring of structural performance through the force resistance effect of carbon fiber bundles.4.Based on the piezoresistive effect of the CFRCM slabs during tensile test,the equivalent delamination failure model of the CFRCM bandles in pull-out test and tensil test was established,and the mutual conversion of electrical information and load information was realized.And according to the influence mechanism of ICCP on the mechanical properties and electrical conductivity,the correction method of the model with the influence of ICCP is proposed.