Study On The Law Of Deterioration Strength And Freeze-thaw Loss Layer Of High Ductility Fiber Concrete In Long Brine

ECC(Engineered Cementitious Composite)is the abbreviation of the designed cement-based composite material.It was proposed by Professor Victor C.Li of the University of Michigan in the early 1990s.It is based on cement slurry or mortar and PVA fiber as reinforcing material.,through the system optimization design,participate in the quantitative fiber(volume volume ? 2%).At present,the research focus of domestic scholars mainly focuses on the mechanical properties,interface properties and applications of high ductility fiber reinforced cement-based composites,High ductility fiber concrete(ECC)has good tensile strain-hardening characteristics and crack control ability,which makes the high ductility fiber concrete reduce the strength of the high ductility fiber concrete and damage the structure under the conditions of environmental impact and chemical erosion.Less than ordinary concrete.In This paper,use the study the experimental design method to significant influence of the main factors affecting the performance of fiber concrete.The cubic concrete freeze-thaw compression test was carried out on the fiber concrete,and the axial compression test and the flexural test were performed for a long time.The factors affecting the mechanical properties of fiber concrete were compared and analyzed.The main research contents:(1)According to the ultrasonic flat test method,the variation law of the damage layer thickness of high ductility fiber concrete under the environment of sulfate freeze-thaw erosion was studied,and the damage deterioration law of concrete was analyzed from the angle of damage layer.A concrete damage layer thickness prediction model and a concrete damage rate prediction model under the action of freeze-thaw cycles were established*(2)According to the analysis of the mechanical properties of the damaged layer high ductility fiber concrete,the average compressive strength of the damaged layer concrete is calculated by using the linear constitutive relation of the concrete.And the strength model of high ductility fiber concrete damaged by damage layer is deduced.(3)According to the durability test of high ductility fiber concrete under salt erosion,four different solutions(0%Cl-+0%SO42-,5%Cl-+5%SO42-,5%Cl-+10%SO42-)were used.10/%Cl-+5%SO42-)The long-term immersion test of high ductility fiber concrete was carried out,and the variation of basic mechanical properties with the immersion time and brine concentration was found.The compressive strength of uniform high ductility fiber concrete with different Cl-and SO42-concentration values is obtained.