High Sulfate-resistant Portland Cement Concrete Sulfate Attack Resistance

The water-binder ratio of0.3,0.3, dosage of fly ash were0%,15%,25%and15%of high sulfur cementconcrete compressive strength test specimens; The water cement ratio0.30,0.35,0.40,0.45,0.5, highsulfate-resistant Portland cement mortar specimen and water-binder ratio of0.4, the dosage of fly ash were0%,15%,25%and15%of high sulfate-resistant Portland cement mortar specimen resistance to sulfateerosion tests are carried out; And the different water cement ratio and different dosage of fly ash highsulfate-resistant cement specimens microstructure were observed, by test study found that:(1) the influence high sulfur cement concrete compressive strength is the main factor of water/cementratio, dosage of fly ash and ages. Age stage, the compressive strength of concrete, decrease withwater-binder ratio and fly ash content increased; As the extension of curing age, the compressive strengthof concrete increase gradually. For mixing fly ash concrete, its compressive strength before28daysstrength of low and slow growth, but after28days and60days in the process of rapid growth in thecompressive strength of concrete.(2) the water cement ratio, dosage of fly ash and curing age on high sulfur has a great influence on thecorrosion resistance of cement concrete. To reduce the water cement ratio of concrete, can strengthen itsability to resist erosion; Mixed with large dosage of fly ash to improve its ability to resist erosion. Erosionin the same concentration in the solution, the corrosion resistance of curing28days specimen wasobviously higher than that of specimen curing for3days. For curing28specimens, the sulfuric acid rootion concentration of10000mg/L or less erosion solution, reduce the water cement ratio of concrete (0.4) orless, can strengthen its ability to resist erosion; In a high concentration (10000mg/L~20250mg/L) sulfateenvironment water, reducing water-binder ratio (0.4) or less, at the same time mixed with larger dosage(25%or higher) of fly ash can strengthen its ability to resist erosion.(3) high sulfur corrosion resistance of cement concrete has limitations. For curing28days specimen,when the concentration of sulfuric acid root ion or20250mg/L, even reduce the water cement ratio, alsodifficult to guarantee its long-term resistance to sulfate erosion ability;3days for maintenance specimen,when the concentration of sulfuric acid root ion or4000mg/L, water cement ratio of0.4or more specimensare hard to resist the erosion of sulfate solution for a long time.(4) high sulfur cement concrete long-term erosion resistance ability of erosion in a certainconcentration solution, takes a long time of soaking to emerge. Laboratory tests show that the sulfate ionconcentration higher erosion solution soak within six months, most of the specimens with larger resistancecoefficient, however, when the immersion time after more than six months, water-cement larger specimenerosion damage happen first, water cement smaller specimens also lose resistance to erosion ability.Therefore, short-term erosion test is difficult to reflect the reality of the high sulfur cement concrete erosionresistance.(5) the microstructure observation showed that the high sulfur cement concrete under sulfate erosionsurface was the main types of gypsum crystal damage, erosion degree of the performance for the size of thespecimen surface loose layer thickness, the thick loose layer, the greater the coefficient of corrosionresistance of the specimens is smaller, the degree of erosion damage is more serious; As the water cementratio or the increase of dosage of fly ash, porous layer on the surface of the specimen thickness thinning,specimen within the maximum porosity of aperture, the internal structure more compact.