Study on Durability of Concrete with Different Admixtures Under Full Immersion Sulfate Corrosion
In order to study the durability of concrete with different admixtures under full immersion sulfate corrosion,two admixtures of fly ash and silica fume with a substitution rate of 20%were set as cementitious materials to be mixed into concrete,and 5%,10%and 20%concentrations of sodium sulfate solution were carried out.The test of corrosion was up to 168 days under full immersion conditions.The macroscopic durability of concrete was characterized by the macroscopic quality change and compressive strength change of corroded concrete,and the microscopic potential mechanism of concrete corrosion was explored by SEM test.Using the relative quality evaluation parameter index of concrete,the Weibull probability distribution model was established to predict the residual life of concrete to reflect its durability.The results show that the mass change rate and compressive strength increase first and then decrease,and the peak value appears on the 84th day of immersion corrosion.Fly ash has a better effect on reducing the mass change rate of concrete,silica fume has a better effect on improving the early strength of concrete,and the solution concentration has little effect on each test group.Microscopically,the reason for the deterioration of sulfate-corroded concrete is the ettringite formed after secondary hydration;both fly ash and silicon powder have good performance in resisting sulfate corrosion,and fly ash is better.
full immersion corrosion testdurability of concreteWeibull functionlifetime prediction
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