Axial Compressive Performance Of Reinforced Concrete Column Strengthened By BFRP After High Temperature

In recent years,the development of admixtures has enabled concrete to save resources,energy and reduce emissions while maintaining good physical and mechanical properties.At the same time,the iterative update of reinforcement materials has made it possible for buildings to continue to be used safely after being reinforced,except for the reconstruction of buildings after the disaster.At the same time,the iterative update of building materials has made it possible to reuse the post-disaster buildings in addition to being demolished and reconstructed.This article took the basalt fiber and fly ash that make up concrete admixture as starting point to study the working performances and mechanical properties of basalt fiber-fly ash concrete.Based on the above research results,the morphology of reinforced concrete columns experienced ISO-834 standard heating process and after disaster were recorded.And the axial compression performance of columns strengthened by BFRP was studied to explore the optimal reinforcement scheme.The main research contents of the article are as follows:First of all,with the basalt fiber content and the replacement rate of fly ash as variables,the initial slump,initial expansion,compressive strength and flexural strength after 28 days’ standard curing of concrete were studied.The results show that when the basalt fiber content is 0.1% and the fly ash replacement rate is 10%,the working performances and mechanical properties are optimal.Based on the response surface method and the consensus function,the verification of the test results was realized.Based on the above research,the optimized concrete mix ratio was used to make reinforced concrete columns.The burst,collapse phenomena during standing period and phase composition of the specimens analyzed by XRD undergo heating process were studied.Based on the temperature field analysis software,the temperature rises and fall process of the specimen were simulated.Results show that macroscopic burst and collapse of the specimens are closely related to the microscopic phase composition,and the temperature field simulation results can form a good correspondence with the measured data.Then,using BFRP as the reinforcement material,adopt optimized or fully wrapped and 0-4 layers of reinforcement to reinforce the specimen after high temperature.Axial compression test was carried out on the reinforced specimens.The results show that although BFRP can significantly improve the deformation performance of the specimens,the mechanical property damage caused by high temperature is difficult to compensate.Compared with the 3-layer,the 4-layer reinforcement with BFRP has very limited effect.Finally,on the basis of the analysis of the experimental data and the reference of the existing research results,the ultimate stress and ultimate strain models of specimens reinforced with BFRP after high temperature were proposed.The corresponding model provides calculation reference for actual engineering reinforcement designs and calculations.There are 75 pictures,25 tables and 115 references that jointly frame this paper.