Selection of adhesives and quality control of structural repairs by bonding on site

Abstract

Bonding on site has been used successfully for many years in the repair and strengthening of timber structures. However, there is still a lack of knowledge about its service durability, especially under high service temperature conditions. Not only the performance and durability of epoxy adhesives depend on their thermal stability but also on the preparation and application procedures followed on site, as confirmed by tests conducted by the authors to evaluate the effects of mixture ratios and curing conditions. This paper discusses a number of test methods that can be used for quality control of structural repair jobs involving bonding on site. Two studies conducted at LNEC where these methods were applied are presented: one concerning a structural intervention on a decorative suspended ceiling, the other concerning the selection of adhesives suitable for high service temperature conditions as expected in some roofs. DMA and FTIR analysis results are presented and their high potential for quality control during and after adhesive application is discussed.