On bonding repairing steel fibre reinforced concrete to hardened concrete

In the last years an emerging repair and strengthening technique for concrete slabs has been used, consisting of applying a thin layer of steel fibre reinforced concrete (SFRC) onto the existent concrete slab. The performance of the structural system depends on the bonding behaviour between old and new concretes. Adhesives based on epoxy resins currently make this liaison. The prices of these adhesives are quite different depending, mainly, on the percentage of pure resin that they include. In the present paper, three commercial adhesive compounds of distinct prices and properties were selected to bond concrete base and repairing SFRC overlay. The bond behaviour was assessed from pull-off tests and the influence of the strength class of concrete base and repairing SFRC was analysed. Finally, the performance of the adhesives was evaluated, considering both the bond strength and their prices.Fundação para a Ciência e a Tecnologia (FCT) - PhD grant SFRH/BD/11232/2002