STATIC AND DYNAMIC BEHAVIOR OF CONCRETE STRUCTURES REINFORCED WITH NANOTUBES MODIFIED COMPOSITES

The use of composites for the reinforcement of concrete structures, sometimes poses the problem of the detachment of the composite plates/fibers from the surface of the concrete support, especially in arid or dry climates. This phenomenon of disbonding, due to the poor performance of the matrix (adhesive glue), affects nearly 8% of the structures reinforced with FRP in Algeria and negatively influences the durability and bearing capacity of the reinforced structure over time. This article presents the results of a study on reinforced concrete structures. It concerns the insertion of carbon nanotubes (CNT) in epoxy resin, used as an adhesive for CFRP composites. The objective is to evaluate the improvement of the mechanical performances of the resin used and to contribute to reduce the phenomenon of disbonding. An experimental work carried out on a set of reinforced concrete beams, strengthened by CFRP plates, with the insertion of carbon nanotube powders (CNT) in the resin used, with percentages varying from 0 to 2%, has been performed. To validate the results obtained, a numerical work based on the finite element method was developed taking the case of a concrete bridge requiring repairs. The results showed that the nano-composites (CNTs) improve the mechanical performance of the epoxy resin and bring an appreciable gain of the order of 50 to 170% to the constraints. Moreover, this technique of moderation of composites by adding nanotubes (CNTs), gives an appreciable gain at vibration frequencies. This was confirmed by the results of the modal analysis of the bridge structure repaired with 2% addition of CNTs.