Investigation of chloride ingress in cracked concrete treated with water repellent agents

In this paper, results of a test are presented in which reinforced concrete (RC) prisms treated with different water repellent agents have been exposed to cyclic seawater shower for one year. Purpose of the test was to investigate how the water repellent treatment influences the water absorption and chloride ingress into reinforced concrete with and without the existence of cracks. Uncracked RC prisms, some cracked before the water repellent treatment, and some cracked after the water repellent treatment were prepared for comparison. Four types of water repellent agents, ie, liquid silane, liquid silane/oligomeric siloxane, silane-based cream and silane-based gel were applied to treat the concrete surface. Time-dependent water absorption of all the un-cracked and cracked RC prisms was monitored. After one-year exposure, all the specimens were broken open. The penetration depths of water repellent agents in the treated specimens were measured and corrosion areas of the inner steel reinforcement were quantitatively evaluated. The chloride ingress profiles in the cracked and un-cracked RC prisms were evaluated using electron probe microscopy analysis (EPMA). Based on the test results, effectiveness of water repellent treatment as a water and chloride barrier of cracked concrete under marine environment is discussed.