BONDING BEHAVIOUR and FAILURE MECHANISM of DAMAGED CEMENT CONCRETE REPAIRED USING EPOXY-BASED CONCRETE

Abstract

In this paper, the strength grade and surface roughness of damaged concrete are used as controlling factors to explore their influence on the bonding behaviour of concrete repaired using epoxy-based concrete. Using X-ray photoelectron spectroscopy (XPS) analyses and phenomenological methods, the essence of the bonding force and the mechanism for bonding failure between the epoxy-based concrete and damaged concrete are revealed. As shown by the results, the bonding strength of the repaired concrete increases with an increase in the average sand-filling depth and the strength grade of the damaged concrete. However, when the sand-filling depth exceeds 17 mm, the bonding strength no longer increases. The chemical bonding force between the epoxy-based concrete and damaged concrete essentially comes from coordination bonds formed at the bonding surface. Based on the experimental phenomena and test results, a bonding strength model is established for the repaired concrete, and it provides a basis for predicting the interface bond strength in practical repair engineering.