Date of Award

1-1-2019

Publication Type

Master Thesis

Degree Name

M.A.Sc.

Department

Civil and Environmental Engineering

Keywords

corrosion, cyclic, FRCM, monotonic, reinforced concrete, strengthening

Supervisor

Faouzi Ghrib

Rights

info:eu-repo/semantics/embargoedAccess

Abstract

The long-term serviceability of reinforced concrete (RC) structures such as bridges is a growing concern due to the accumulated corrosion damage on the tensile reinforcement caused by de-icing salts and from exposure to seawater coastal environment. This issue coupled with fatigue damage caused by cyclic loading on an aging infrastructure have led to the development of fiber reinforced polymer (FRP) building and strengthening materials since the mid 1990’s. More recently over the past decade fiber reinforced cementitious matrix (FRCM) sheets have been introduced as an alternative to FRP sheets in strengthening RC structures. An experimental program is carried out on large-scale flexure critical reinforced concrete beam specimens subjected to corrosion damage of the tensile reinforcement. The specimens were tested under monotonic and cyclic loading configurations after being rehabilitated with FRCM composite systems. The targeted corrosion mass loss of the tensile reinforcement was moderate (10 %) and severe (20 %). The strengthening consisted of two layers of FRCM sheets applied on the tensile face of the beam along the clear span and partially wrapped 75 mm up the sides of the beam with the primary direction of the fabric being in the longitudinal direction. In addition, 100 mm wide FRCM U-wraps were placed at the loading points and near the supports. Two types of FRCM being C-FRCM and PBO-FRCM were included in this study to compare their overall effectiveness in improving the structural performance of corroded RC beams. Furthermore, one specimen was strengthened with G-FRP sheets to compare its effectiveness to the FRCM strengthening systems under monotonic loading. Longitudinal cracking, rebar mass loss, and reduced structural performance are included based on the damage done by corrosion. The load-deflection response, the strain development in the fabric and concrete, and the mode of failure are presented for the monotonic testing. Fatigue cyclic test results include the fatigue life, stiffness degradation, progression of the longitudinal strains, and the degradation of the specimen up to failure. The results showed the FRCM systems increased the static ultimate capacity and improved the fatigue stiffness and fatigue life of the corrosion damaged RC beams.

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