ABSTRACT
The use of externally bonded Fibre Reinforced Polymer (FRP) composites has become a popular means to strengthen and repair bridge and building infrastructure in recent years. The use of FRP composites as an alternative to steel plates presents a more sustainable option for structures such as concrete, steel or timber bridges subjected to aggressive environments. However, the long-term service life and durability of FRP strengthened structures is of importance and in Australia alone it is estimated that 70% of concrete bridge infrastructure are in need of repair or strengthening due to material degradation over time and increased traffic loading. This paper reviews work done to date on the long-term durability of the critical bond between the FRP and concrete considering environmental conditions and material durability.
Considering the type of exposure, conditioning regime and performance of the joint under monotonic testing, durability refers to the ability of the joint to resist permanent damage. Since Karbhari et al. (2003) first identified gaps in the durability of a variety of FRP-to-concrete systems, a considerable amount of literature has been published on FRP-to-concrete joints subjected to a wide range of simulated environmental conditions and is recently summarized by Aydin et al. (2016). Geometric, material and conditioning regime differences in test procedures have been widely explored with the general outcome being that the degradation of joint strength is dependent on the change in shear strength of the adhesive relative to the concrete shear strength with prolonged exposure.
A regression analysis is performed to quantitatively assess the parameters influencing the change in strength of environmentally degraded adhesively bonded joints. This analysis will return a conservative lower bound prediction of joint strength degradation over a number of commonly occurring in-service environmental conditions. Studies conducted in the presence of moisture are only be presented here Figure 1. Regression analysis of moisture bond tests. <italic>T =</italic> 20° C. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig59_1.tif"/>
