Experimental Study On Chloride Ion Eroson Resistance Of Polyvinyl Alcohol Fiber Reinforced Cementitious Composites Under Dry-wet Cycles

Polyvinyl alcohol fiber reinforced cementitious composites (PVA-FRCC for short) asa new composite material, numerous studies have shown that its basic mechanicalproperties are better than traditional concrete material, therefore, it is necessary to furtherstudy on its mechanical properties and durability in all kinds of environment to providebasis for engineering application.In this paper, Strength degradation character and chlorideion penetration character of PVA-FRCC under double environment of dry-wet cycle andChloride corrosion were studied in this paper, by setting differents dry cycle temperaturetests and differents fiber content tests. Strength degeneration mechanism and chloride ionpenetration character of PVA-FRCC, also effect of dry cyele temperature and fiber contentof PVA-FRCC on chloride ion penetration were analyzed under double environment ofdry-wet cycle and Chloride corrosion.Sevral conclusions were obtained as the following：(1) PVA-FRCC has the characteristics of high later strength. Compressive strength for270d corrosion ages under double environment of dry-wet cycle and Chloride corrosiondecreased to some extent, compared with the respective90d compressive strength.Compressive strength of PVA-FRCC with1%PVA fiber decreased most, which is up to15.7%, Compressive strength of PVA-FRCC with2%PVA fiber decreased a minimum of8.5%.(2) Chloride ions erosion maximum depth and average depth of PVA-FRCC with0%,0.5%,1%,1.5%,2%PVA fiber increased with the numbers of wet and dry cycles underdouble environment of dry-wet cycle and Chloride ion penetrated fast after a slow first.Chloride ion penetration depth generally show a reducing trend under double environmentof dry-wet cycle and Chloride corrosion,as the PVAfiber content increasing from0%to2%.(3) Influence of20°C、40°C and60°C dry cycle temperature on Chloride ionpenetration depth is obvious under double environment of dry-wet cycle and Chloridecorrosion. Temperature increasing from20℃to60°C, the maximum erosion depth ofchloride ion and the average erosion depth is increasing. Chloride ion resistance ofPVA-FRCC with2%PVA fiber is better than that with1%.（4）Free chloride ion concentration of PVA-FRCC with0%,0.5%,1%,1.5%,2%PVA fiber increased with the numbers of wet and dry cycles under double environmentof dry-wet cycle. Dry cycle temperature increased from20℃to40℃, free chloride ion concentration increased while free chlorine ion double increased when dry cycletemperature inceased from40℃to60℃.Influence of PVA fiber contant to free chlorideion concentration of PVA-FRCC under double environment of dry-wet cycle is notobvious.(5) Evolution process of classical chloride ion diffusion model was described,Chloride ion diffusion of PVA-FRCC under double environment of dry-wet cycle wasestabished finally by Correcting classical model.