Evaluation of degradation of structural adhesives used for the strengthening of reinforced concrete structures

• Grant number: 16/20025-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2016
• End date: November 30, 2017
• Field of knowledge: Engineering - Civil Engineering - Structural Engineering
• Principal Investigator: Gláucia Maria Dalfré
• Grantee: Amanda Duarte Escobal Mazzú
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

This research project is based on experimental analysis of the degradation of the mechanical properties of structural adhesives, in this case, epoxy resins used in the external reinforcement of structures according to the Externally Bonded Reinforcement technique (EBR). In this reinforcement technique, the overall performance of a structure externally reinforced with FRPs (Fiber Reinforced Polymer) mainly depends on the efficacy of the bond between the FRPs and the concrete substrata. However, this external structural reinforcement is exposed to environmental conditions (freeze-thaw cycles, temperature, carbonation, ultraviolet radiation, humidity-drying cycles). Also, the strengthening technique is directly exposed to the action of fire and vandalism too. The durability of the epoxy resin, the bond to the concrete substrata of the structural element to be reinforced and, especially, its performance when exposed to long-term aging are poorly understood. Recently, an exploratory experimental program was carried out in order to verify the degradation of the epoxy resin exposure to constant moisture. The results of the experimental program show a reduction of the tensile stress and of the elastic modulus of the epoxy resin when exposed to constant moisture. Thus, based on the results obtained in exploratory program, a new campaign of tests to evaluate the degradation of epoxy resins is herein proposed in order to evaluate the mechanical properties of resins commonly used in external reinforcement systems when exposed to weathering, humidity cycles, constant humidity and accelerated aging. (AU)