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Title: Strengthening of Reinforced Concrete Beams Using Embedded Carbon Fiber-Reinforced Polymer with Polyester-Silica

Author(s): Yail J. Kim and Ibrahim Bumadian

Publication: Structural Journal

Volume: 118

Issue: 4

Appears on pages(s): 31-43

Keywords: carbon fiber-reinforced polymer (CFRP); failure; interface; rehabilitation; retrofit; strengthening

DOI: 10.14359/51725906

Date: 7/1/2021

This paper presents the feasibility of a novel anchor system that mitigates the end-peeling of carbon fiber-reinforced polymer (CFRP) sheets used for strengthening reinforced concrete beams. Contrary to conventional anchoring methods, CFRP sheets are embedded inside the pre-grooved concrete and covered by a durable polyester-silica composite. After conducting ancillary tests on material, bond, and interfacial properties, 14 strengthened beams are loaded in flexure to assess the performance of the proposed anchor system, contingent upon embedment angle and local debonding along the bond-line. The polyester-silica matrix shows superior moistureresistance to ordinary cementitious mortar and possesses a fully cured compressive strength of 38 MPa (5500 psi) as well as interfacial capacities comparable to those of an epoxy adhesive. The embedment angle and local debonding of CFRP affect the flexural behavior of the strengthened beams, including sectional rotation and stress distributions. The presence of mechanical fasteners with supplementary epoxy layers in the anchorage substantially enhances the flexural capacity, energy dissipation, and ductility of the beams. Correlation and sensitivity analyses are performed to analytically characterize the load-carrying capacities of the strengthened beams with variable embedment angles and the degree of local debonding.