In last decades significant investigation has been carried out in order to predict the bond strength of externally bonded reinforcement (EBR) systems with carbon fiber reinforced polymer (CFRP) materials in concrete and, as consequence of that, many analytical expressions can be found in the literature, including in standards. However, these expressions do not account for the influence of several parameters on bond behavior such as the type of surface preparation which is a mandatory and critical task in the strengthening application. The present work gives contributions to reduce this lack of knowledge. For this purpose, an experimental program composed of single-lap shear tests was carried out, the main parameters studied being: (i) the type of concrete surface preparation (i.e., grinding and sandblasting) and (ii) the bond length. Prior to the application of the EBR CFRP system, the roughness level provided by the different methods of surface preparation was characterized by a laser sensor. Test results revealed that sandblasting concrete surface preparation yielded higher values, in terms of maximum shear force and fracture energy. Finally, existing expressions in standards were upgraded in order to account for the concrete surface roughness level in the estimation of the bond strength.

Freshwater is an increasingly scarce resource. Its use in the production of concrete is one important contributor to its fast depletion. Alternatively, the use of seawater for reinforced concrete production, combined with the use of glass fibre reinforced polymers (GFRP) as reinforcement, may represent an interesting solution to increase concrete sustainability. The objective of this paper is to explore this promising solution through the development of concrete compositions with seawater. Additionally, it is also an objective to assess the bond behaviour between GFRP rods and concrete, in a design perspective. The influence of concrete age, rod diameter and anchorage length were also investigated. An analytical model capable of determining the local bond stressslip laws was used. Results demonstrated that the use of seawater had no relevant effects on neither concrete mechanical properties nor bond behaviour.

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