Study On Durability Of High Performance Concrete For Pile Of Power Transmission Projects In Coastal Areas

The rusting damage of pile foundation of transmission engineering in coastal areas is very serious,which has caused huge economic loss to the country,this problem has attracted wide attention in recent years.The paper relies on the issues of the China Southern Power Grid Company Limit(CSG210002-2016B4).It carried out relevant research on the durability damage of transmission engineering pile foundation,caused by chloride ion in coastal environment.The main research contents of this paper are as follows:(1)Based on the total volume model,the design of high-performance concrete was carried out,and the working performance and mechanical performance tests were carried out for different mix ratios and comparative analysis was conducted.Finally,a concrete mix ratio that meets the technical requirements of pile foundation construction in transmission engineering was selected.(2)Chlorine ion diffusion experiment was carried out for high-performance concrete.The time-varying equations of surface chloride ion concentration and chloride ion diffusion coefficient of HPC were calculated.The high durability of HPC is proved by comparing the chloride diffusion coefficient of HPC with that of ordinary concrete.(3)Taking the erosion time and concentration of chlorine salt as the influencing factors,the chloride ion diffusion model of high-performance concrete was established by using Comsol Multiphysics software,and the numerical simulation results were compared with the artificial environment,and the results were found to be consistent with each other.(4)the combination of coastal geological conditions and high performance concrete chloride ion diffusion model,probes into the coastal areas of steel bar diameter and the thickness of protection layer for transmission project the influence of the durability of high performance concrete pile foundation,the coastal area transmission engineering pile foundation of high performance concrete chloride ion erosion model,and puts forward the protective layer thickness design value is 70 mm.(5)Based on the analysis of the characteristic parameters of the cracks in the transmission engineering pile foundation in coastal areas,a chloride ion erosion model considering the cracks on the transmission engineering high-performance concrete pile foundation was established.Finally,the durability evaluation model of transmission engineering HPC pile foundation under the coupling of multiple factors is obtained,which provides references for future application of transmission engineering HPC pile foundation in coastal areas.