硅烷改性混凝土防水和抗氯离子性能试验研究

The water repellency and chloride resistance of modified concrete with silane without and with cracks have been investigated through neutron radiography test, water absorption test and chloride penetration test. The results indicate that the process of water penetration into mortar specimens without silane can be visualized distinctly by means of neutron radiography, while water in the modified mortar with silane cannot be observed by naked eyes. The hydrophobic films formed in the capillary pores from the added silane effectively restrain liquid water from penetrating into mortar, and consequently it results in decreasing water absorption to be only 13% of mortar without silane. The hydrolysis and polymerization reaction of silane in cementitious materials do not block the respirability of the capillary pores. Cracks are instantaneously filled with water once specimens without silane crack, and after that water will penetrate into the adjacent areas around the cracks. However, even when the modified specimens with silane crack up to 0.3 mm, there is no obvious water movement observed. The cracks from 0.1 mm to 0.4 mm hardly decrease the integral water repellency of modified concrete with silane. Due to the high water repellency of the modified concrete with silane it thus also has high resistance to chloride penetration with or without cracks. It is an effective method to improve the water repellency and chloride resistance and thus the durability of cement-based materials by modifying concrete with silane.