RC beams strengthened with hemp-FRCM and cotton-FRCM under cyclic bending loads

Abstract

Fiber Reinforced Cementitious Matrices (FRCM) is an interesting solution to retrofit structures, due its compatibility with the substrate and its versatility. This paper presents the application of vegetal-FRCM for strengthening RC beams. Two types of vegetal fibers, cotton and hemp, were coated with epoxy and polyester resin and were embedded into a mortar matrix to retrofit RC-beams subjected to cyclic bending loads. Additionally, FEA simulation analyses of the cyclic bending tests were conducted. Modal analysis was performed on both pre- and post-strengthened RC beams to assess the impact of FRCM on their vibrational modes. The application of FRCM increased the frequency of the 1st bending vibrational mode, enhanced the maximum load-bearing capacity of the specimens between a 4 and a 22%, and delayed the appearance of cracking in the substrate. The numerical simulation proved to be reliable until the yield point, therefore it is suitable for determining design parameters.