The Research On The Durability Of Cement Matrix Composites Pvafiber Reinforced

In recent years, as people pay more attention to the high performance concrete andfiber concrete, research has entered a stage of rapid development. The preparation ofpolyvinyl alcohol (polyvinyl alcohol, referred to as PVA) fiber reinforced cement basedcomposite material is a composite material with excellent performance, strain hardeningand multiple cracking characteristics. In the recent twenty years at home and abroad, theperformance of fiber reinforced cement based composite materials to do a lot of researchwork, and attempts the application in road engineering, related research is focused on thetheoretical analysis, the mechanical properties and shrinkage cracking, but the study on thedurability of the relatively few.This paper mainly studies the effect of water binder ratio, fly ash, silica fume dosageand PVA fiber content on resistance and diffusion resistance of composite materials. Asingle salt freezing experiment method, determination of mass per unit area of ultrasoniclosses and loss rate of dynamic elasticity modulus of PVA enhance the frost resistance ofcement based composite materials; the rapid chloride migration test method, determinationof PVAenhanced diffusion properties of cement based composite anti chloride ion diffusioncoefficient. The main conclusions are as follows:1.Water binder ratio of PVA enhanced internal porosity, cement based composite holediameter, and the pore space, change the pore structure characteristics of internal, watercement ratio is between0.27~0.4prepared PVA reinforced cement based compositematerial, with water to binder ration creases frost resistance and anti diffusion performance;2.Fly ash filled the internal defects of PVA reinforced cement based compositematerials, make the structure more compact, pore refining. Test the FA content of40%~50%PVA enhanced freezing thaw spalling resistance of cement based compositematerials, the result showed that when the content of fly ash in between45%~50%, withfrost resistance and the diffusion of strong;3.PVA fiber has the ability of high elastic modulus, combined with strong and cementmatrix, homogeneous dispersion of PVA fiber effectively prevent the crack of cement basedcomposite materials, PVA fiber content in between1.5%~2%, cement based compositesPVA fiber reinforced frost resistance of cement based composite materials and proliferationresistance performance is better than not to join the fiber the;4.Filling effect and volcano ash effect of silica fume, make PVA reinforced cement based composite material is more dense, pore size can be reduced,stopped communicatingpores of the. Incorporation of silica fume is5%~20%,cement based composite materials toimprove the anti diffusion.This paper studies the correct evaluation of road concrete in deicing salt environment,frost resistance and diffusion, has important practical significance and broad applicationprospect in engineering to solve the practical problem of concrete pavement in cold area offrozen damage of salt.