Experimental Study on the Corrosion Resistance and Self-Healing Performance of Cementitious Capillary Crystalline Waterproofing(CCCW)Materials Under Sulfate Environment
Full immersion tests on cementitious capillary crystalline waterproofing(CCCW)materials mortar specimens and non CCCW bonded sand specimens were conducted in clear water and 5%Na2 SO4 solution respectively.By comparing the mass loss rate and compressive strength changes of two types of mortar specimens in different solutions,their resistance to sulfate corrosion can be evaluated.By introducing cracks and observing their self-healing,the healing effect of CCCW material on cracks was characterized by the secondary compressive strength repair rate.Simultaneously,techniques such as mercury intrusion testing,scanning electron microscopy,and X-ray diffraction analysis were used to analyze the pore structure,appearance,and phase composition of the specimens.The results showed that the addition of CCCW material reduces the quality loss rate under sulfate erosion,improves the compressive strength of CCCW mortar,delays the occurrence of erosion damage,which has exhibited good sulfate resistance.Compared to a clear water environment,the healing effect of cracks is more significant in a 5%Na2 SO4 solution.CCCW material could stabilize hydration products,promote the formation of a network structure of healing products,and accelerate crack healing.CCCW material can effectively reduce the proportion of harmful pores,improve the compactness of mortar,and shift the dominant pore size of cement slurry from the large pore range of 77.14 nm to the small pore range of 40.27 nm.
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