Modelling the Deformation of Steel-bars in Reinforced Concrete Beams Submerged in Lagoon

Abstract

Corrosion of steel and spalling of concrete in reinforced concrete elements have become a common occurrence in structures that are built around marine environment. This research investigated the effect of chloride on the steel in reinforced concrete beams. Mechanical tests such as; compressive, flexural and bond strengths were done on replicate concrete elements which were cast and buried for a maximum of one year in the Lagos lagoon. Twenty-four number of 150 mm x 150 mm x 600 mm sized reinforced concrete beams were cast for the flexural strength test, while forty-eight concrete cubes were cast for both compressive and bond strength tests, samples were cured in both lagoon and fresh water (The fresh water is for the control). A finite element program, ANSYS was used to model the deformation (deflection) of the steel reinforcement in the beams. Results showed a general reduction in compressive, flexural and bond strengths for the concrete samples buried in the lagoon, while those buried in freshwater showed an increase in strength as the concrete ages. The modelled results of the reinforcement showed a one-year deformation rate (r = 0.0181) in the steel of concrete buried in lagoon water. This value was used to estimate the future and past deformation values of these reinforcements due to chloride attack.

Keywords

• chloride
• lagoon water
• steel
• reinforced concrete
• deformation