Mário Rui Freitas Coelho

Bond between concrete and multi-directional CFRP laminates

Recently, laminates of multi-directional carbon fiber reinforced polymers (MDL-CFRP) have been developed for Civil Engineering applications. A MDL-CFRP laminate has fibers in distinct directions that can be arranged in order to optimize stiffness and/or strength requisites. These laminates can be conceived in order to be fixed to structural elements with anchors, resulting high effective strengthening systems. To evaluate the strengthening potentialities of this type of laminates, pullout tests were carried out. The influence of the number of anchors, their geometric location and the applied pre-stress are analyzed. The present work describes the carried-out tests and presents and analyzes the most significant obtained results.

Bond behavior between concrete and multi-directional CFRP laminates using the MF-EBR strengthening technique

The strengthening technique based on the use of multi-directional laminates of CFRP simultaneously glued and fixed with anchors (MF-EBR) has been recently purposed. An experimental program composed of pullout tests was carried out in order to study the bond behavior between concrete and MF-EBR system. The diameter and number of anchors, the pre-stress level applied to the anchors, and the strengthening procedures were the main analyzed parameters. The present work describes the carried-out tests and presents and analyzes the most significant obtained results.

Advancements in retrofitting reinforced concrete structures by the use of CFRP materials

Reinforced concrete is nowadays one of the major structural materials used in infrastructures’ construction. As the years passed since the beginning of its use, technology has changed and today it is known that a large number of constructions do not verify some of the most recent safety requirements in addition to the durability problems that several structures face. This calls for the need for corrections and/or strengthening activities. Fibre Reinforced Polymer materials (FRP) have been used in Civil Engineering applications due to: lightweight, good mechanical properties (stiffness and strength), corrosion-resistant, good fatigue behaviour, easy application and virtually endless variety of shapes available. Recent advancements in retrofitting reinforced concrete structures by the use of CFRP materials promoted by the authors of the present chapter are herein summarized. Firstly a brief overview on the most common properties of old reinforced concrete constructions those who might need for interventions, is presented. Then, the most common repairing and/or strengthening techniques are addressed. Finally, a deeper look is taken on the new repairing and/or strengthening techniques using FRP reinforcements.