Confinement of Reinforced Concrete Columns with Fiber Reinforced Geopolymer Adhesive Jackets

Abstract

Abstract The strengthening and rehabilitation of reinforced concrete structures is an important issue all over the world. Fiber reinforced composites are mainly used for the strengthening and rehabilitation of concrete members. However, its use is limited due to its high price and environmental effects and its adoption of epoxy as an adhesive, where epoxy is considered inefficient at high temperatures and loses most of its properties. This study presents the experimental work on the use of geopolymer compounds as a sustainable adhesive in confinement of RC columns. Where, examined the axial compressive behavior of the circular RC columns confined by fiber reinforced geopolymer adhesive (FRGA) jacket. Totally 15 confined RC columns and one unconfined RC columns with dimensions of 100mm diameter x 600mm height were tested. The parameters of the study were: layers of confining jacket, (1, 2, 3) layer of carbon fiber. To improving the bonding strength of the geopolymer adhesive using discrete fibers, (Carbon fiber, micro steel fiber, Polypropylene fiber) with volumetric ratios of (0.2%, 2%, and 0.4%). Jackets material used (carbon fiber, jute fiber, Steel Wire Mesh, Window Mesh Fabric, (3x3) mm polyethylene mesh and (4x4) mm polyethylene mesh), confinement rate of RC columns (25%, 50%, 75% and 100%). Based on the test results, in the first group found that the confinement by three layer of carbon fiber reinforced geopolymer II adhesive jacket improved the (load enhancement ratio and deformation capacity) by (4.33 and 5.11) respectively, compared with the unconfined RC column. Also in group two noted that adding (micro steel fibers, carbon fibers and polypropylene fibers) to the adhesive led to an improvement in the compressive strength about (16.1%, 8.4%, 7.96%) respectively, Also that the geopolymer paste is an efficient adhesive with the various types of materials used in the formation of the confinement jackets, the confinement jackets consisting of (jute fiber, steel wire mesh) are considered the most efficient in terms of cost and performance compared to other specimens. The use of (jute fiber and steel wire mesh) jackets leads to a significant development in load enhancement by (1.79 and 1.7) and deformation capacity by (2.43 and 1.62) respectively compared to the unconfined RC columns. Also that an increase in the confinement ratio from 25% to 100% led to a significant development in (load enhancement and deformation capacity) by (3.146 and 3.68), respectively. Finally, it is worth noting that it could be considered the geopolymer adhesive as a sustainable and effective alternative to epoxy adhesive in RC columns confinement technology. Whereas, provided a good confinement of RC columns, it has proven its effectiveness as a good adhesive with various jacket materials, allowing the possibility of confined of columns by a low cost with good performance