Comparison of Inorganic and Organic Matrices for Strengthening of RC Beams with Carbon Sheets

Abstract

The performance of an inorganic matrix is compared to the performance of an organic matrix when used to externally strengthen reinforced concrete beams with carbon fiber sheets. The experimental study consisted of testing reinforced concrete beams after they were strengthened with carbon fiber sheets that were bonded with an inorganic matrix. This experimental study simulates an earlier study in which beams were strengthened in the same way using an organic matrix. Strength, stiffness, ductility, failure pattern, and cracking of beams strengthened with the two systems are compared. The results indicate that the inorganic matrix is as effective in increasing the strength and stiffness of reinforced concrete beams as the organic matrix, with a minor reduction in ductility. The failure mechanism changed from sheet delamination for the organic system to sheet rupture for the inorganic system. This change in mechanism is attributed to the brittleness of the inorganic matrix that results in crack formation in the composite and a minimum buildup of strain along the interface of the composite and concrete.