Influence of fly ash and stress level on permeability of concrete

In order to analyze the relationship between fly ash replacement, stress level and permeation time, the chloride ion concentration in anode chamber was measured during the accelerated chloride penetration test. The results showed that the fly ash concrete exhibits high rate of chloride ion penetration when the specimens are cured in water for 28 days; a long curing period can decrease the chloride ion penetration of fly ash concrete. The application of 5 times of 0.4 f_cy (axial compressive strength) increases the chloride penetration of concrete obviously. The chloride ion penetration of concrete has a further increment when the stress level rises from 0.4 f_cy to 0.8 f_cy. The long curing period is better for the strength grade design of fly ash concrete.