Corrosion durability of functionally-graded reinforced concrete beams

Abstract

A micromechanical model for the design of strain-hardening engineered cementitious composites containing hybrid fibres is developed. The model is used to guide the design of a hybrid fibre reinforced cement mortar exhibiting strain-hardening and multiple-cracking behaviour under flexural loading. This material, referred to as a Ductile Fibre Reinforced Cementitious Composite (DFRCC), is used to replace part of concrete which surrounds the main flexural reinforcement in RC beams for corrosion protection. The resulting concept is referred as Functionally-Graded Concrete (FGC). The effectiveness of the concept of FGC in retarding the corrosion of steel reinforcement in RC beams and reducing the tendency of the concrete cover to delaminate as measured by a concrete embeddable fibre optic strain sensor (FOSS) is studied. The performance of the FGC concept is also compared with that of another method employing Supplementary Cementing Materials (SCM). Finally, a finite element model is proposed to simulate corrosion induced-damage in FGC beams as well as in ordinary RC beams.