Title: Durability of Repaired Reinforced Concrete in Marine Environment

Author(s): T. Uomoto, H. Ohga, T. Yonezawa, and H. Ibe

Publication: Symposium Paper

Volume: 145

Issue:

Appears on pages(s): 445-468

Keywords: coatings; corrosion; durability; exposure; marine atmospheres; reinforced concrete; repairs; tests; Structural Research

DOI: 10.14359/4470

Date: 5/1/1994

Abstract:
To evaluate repaired method of damaged concrete, the Japan Concrete Institute had set up the research committee on Repair of Concrete Structures in 1990. The research committee consists of three task groups, marine exposure test group, state-of-the-art report task group, and theoretical analysis task group. The effect of coating, repair materials, and repair method on corrosion of reinforcement embedded in the concrete is evaluated by both experimental and theoretical manner in the committee. In this paper, the results of marine exposure tests up to 18 months are reported. The chloride-damage simulated specimens are repaired by 26 companies using different materials and methods, and the same type of nine specimens are also prepared with different types of repair materials and different thickness of coating to evaluate the effect of these factors. These specimens are exposed on the Izu coast in Shizuoka, Japan. Brightness, color change, and cracks on coating, and electrochemical properties of reinforcements are measured at the ages of 6,12, and 18 months. Cracks and corrosion stains are observed for specimens without coatings, independent of the existence of internal chloride, while there are no cracks and corrosion stains on the coated specimens. Appearance of coating on the specimens depends on the type of the coating applied. Also swelling, peeling, and cracking of the coating are observed for several specimens. The electrochemical properties of reinforcement depend on the type of coating, and a new method to evaluate deterioration of coating using an electrochemical method is proposed.