Bond Strength Behaviour Of Zinc Rich Paint Coating On Concrete Surface

Durability issues associated with concrete structures are the major problems the civil engineering community is facing today around the world. Concrete can suffer chemical damage from contaminants added during manufacturing and/or by action of external aggressive agents such as chlorides, carbon dioxide and moisture. Deterioration can occur in different ways in concrete like sulphate attack, alkali silica reaction, efflorescence and corrosion of reinforcing steel. Application of surface coatings and treatment on concrete surface provides a cost-effective and relatively simple approach for protecting reinforced concrete and is recommended by BS 1504-9:2008. However, they are more beneficial if corrosion is due to carbonation. Moreover, these coatings have low adhesion strength and is one of the main reason for its failure. This research aims on application of Zinc Rich Paint (ZRP) as a concrete coating and focuses on its pull-off strength behaviour for different quality concrete mix designs and under the influence of different factors such as variable concrete substrate roughness, amount of compaction and different environmental conditions. Both failure load and failure mode were recorded and observed. Medium surface roughness showed highest pull-off strength between coating and substrate i.e. 3.35 MPa which is greater than the required value of 1.5 MPa (for flexible systems with trafficking) and 2.0 MPa (for rigid systems with trafficking) recommended by BS EN 1504-2:2004. Alternatively, ZRP coatings may also provide some corrosion protection to reinforcement and the same is under study.