Properties evaluation of double silane system compound gel as a protective coating on concrete

Inhibiting moisture transfer at the surface of concrete plays a vital role on the durability of concrete, and permeable protective coating can effectively resist the intrusion of external moisture into concrete. A double silane system compound gel was prepared through sol-gel synthesis method by using isobutyl triethoxy silane and tetraethyl orthosilicate, solving the problems of volatility and poor adhesion of traditional silane-based penetrating protective materials. The performance of the compound gel was verified through static contact angle, capillary water absorption of concrete with cracks, electrochemical accelerated ion penetration, and rapid carbonation tests. The test results showed that the capillary water absorption coefficient for concrete with cracks up to 0.5 mm and coating compound gel was reduced by more than 70% compared to blank; the corrosion time of inserted reinforcement in concrete treated with the compound gel was extended by more than two times compared to blank. The research of compound gel can expand the application market of silane-based protective materials, especially for some longitudinal concrete structural parts that need higher durability requirements.