Ceramics-Silikáty 66, (1) 36 - 42 (2022)

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.