Durability evaluation of concrete sealed with polyurea polyaspartic coatings

Abstract

For this project, the performance of various polyaspartic coating materials was investigated. Motivation for this study was to assess various options for the containment of concrete within bridge parapet walls to prevent the falling of materials on passing vehicles and pedestrians as the bridge's concrete erodes over time. The purpose of the investigation is to identify several acceptable manufacturers of polyaspartic polyuria coating materials that could be used on a scaled concrete surface to inhibit further surface disintegration such as mortar flaking and scaling. To evaluate durability characteristics of these materials, several test methods were performed. ASTM D7234 and D6677 were used to test the adhesion ability of the various coatings to the concrete substrate. Cyclic freezing/thawing, wetting/drying (Hartell and Zeng), and salt ponding were performed in accordance with ASTM C666 and ASTM D7234 to understand the coatings ability to perform and protect concrete over time due to extreme weather conditions. In order to better aid in the adhesion comparative analysis between different coating types, compression/modulus of elasticity testing (ASTM C39/ASTM469) was performed along with flexural testing (ASTM C78). Results demonstrate that the coating systems retained could be used as part of a repair strategy to remediate deteriorated concrete cover for the prevention of further damage caused by moisture transport and to contain minor scaled concrete fragments.