Study on the Effect of Bentonite on the Resistance to Corrosion of Plastic Concrete

Objective: To study the effect of bentonite on the corrosion resistance of concrete. Methods: Using the direct immersion method, the chloride ion solution and sulphate ion solution were prepared to simulate the corrosive water environment, and the test blocks were placed in the corrosive solution for corrosion. The cube compressive strength of plastic concrete with different bentonite admixtures was tested under standard curing conditions, after immersion in chloride ion solution and after immersion insulfate ion solution immersion curing. The relationship between the amount of bentonite admixture and the strength of the test block after dissolution in ambient water was analyzed in comparison with the reference group. The microstructure of the internally doped bentonite was studied using SEM (scanning electron microscopy) , and its corrosion mechanism was discussed. Results: As the proportion of bentonite in the cementitious material increases, the cube compressive strength of plastic concrete gradually decreases. In the range of 0~30%, the corrosion degree of chloride ion solution on the concrete strength first decreases and then increases. When the content of bentonite is 20%, the corrosion effect is the smallest; the effect of corrosion of sulfate ion solution on concrete strength continues to decrease, and is minimized at 30%. Conclusion: A certain amount of bentonite can effectively reduce the strength loss of plastic concrete after corrosion.