Confinement of Square Reinforced Concrete Columns by Fiber Reinforced Geopolymer Adhesive Jackets

Abstract

Abstract Strengthening process for old and damaged reinforced concrete structure have become sources of interest to researchers in recent times. Therefor, there are many techniques used for this purpose including the use of fiber reinforced polymers, but the undesirable properties of polymers such as high cost, emission of gases, toxic fumes and global warming, made it necessary to find an alternative materials with high efficiency and ability to withstand high temperature (Salman et al, 2021). The geopolymer adhesive is a sustainable and environment friendly material. This work considered experimental study to confinement square reinforced concrete columns using geopolymer as a sustainable adhesive material. The experimental program includes testing of fourteen square reinforced concrete columns with dimensions of 10cm width x 60cm height. The axial compressive behavior of all columns was tested. The variables of the study were: the effect of the number of jacket layers by carbon fiber reinforced with geopolymers adhesive (1, 2, and 3) layers, effect of jackets material which are (carbon fiber, steel mesh, plastic mesh, and glass mesh), the confinement ratio (25%, 50%, 75% and 100%) of the length of RC columns and distribution of strips confinement (1.5, 2.5 and 3.5)cm with 50% confinement ratio. Through the test result, it was found in the confinement by three layer of carbon fiber reinforced geopolymer adhesive jacket development the (load enhancement ratio and deformation capacity) by (1.86 and 2.52) respectively, compared with the reference RC column (unconfined). Also, it was noted that, the use of (plastic mesh and steel wire mesh) jackets led to significant development in load enhancement ratio by (1.41 and 1.27) and deformation capacity by (1.86 and 1.50) respectively. Also, the increase in confinement ratio from 25% to 100% show significant development in (load enhancement ratio and deformation capacity) by (1.59 and 1.86), respectively. Finally, it was found the use of carbon fiber with distribution 1.5cm led to improvement in (load enhancement ratio and deformation capacity) by (1.40 and 1.43), respectively. The test result showed that the geopolymer used in the confinement square reinforced concrete columns is an effective material with high efficient and has good adhesion strength with different types of material, therefor it considered sustainable material and its use led to reduce the cost and improvement columns behavior. In conclusion, comparing test result to analytical calculations, the ratio of experimental to theoretical calculation for concrete columns confined with two layers of carbon fiber in the first and second suggested equations was (1.00 and 0.99), respectively, while the ratio of experimental to theoretical calculation in the concrete columns confined by two layers of jute fiber in the first and second suggested equations, was (1.09 and 1.19), respectively. Finally, it was found the ratio of experimental to theoretical calculation in the concrete columns confined with 50%