Numerical Study on Diffusion of Chloride and Induced Rebar Corrosion by Two-Dimensional Multiscale Approach

Abstract

<jats:p>Modeling approach for mesoscopic model of concrete depicting mass transportation and physicochemical reaction is important since there is growing demand for accuracy and computational efficiency of numerical simulation. Mesoscopic numerical simulation considering binder, aggregate, and interfacial transition zone (ITZ) generally produces huge number of DOFs, which is inapplicable for full structure. In this paper, a two-dimensional multiscale approach describing three-phase structure of concrete was discussed numerically. An effective approach generating random aggregate in polygon based on checking centroid distance and intersection of line segment was introduced. Moreover, ITZ elements were built by parallel expanding the edge of aggregates on inner side. By combining mesoscopic model including full-graded aggregate and macroscopic model, cases related to diffusivity and width of ITZ, volume fraction, and grade of aggregate were studied regarding the consideration of multiscale compensation. Result clearly showed that larger analysis model in multiscale model expanded the diffusion space of chloride ion and decreased chloride content in front of rebar. Finally, this paper addressed some noteworthy conclusions about the chloride distribution and rebar corrosion regarding the configuration of rebar diameter, concrete cover, and exposure period.</jats:p>

Non-uniform Model of Relationship Between Surface Strain and Rust Expansion Force of Reinforced Concrete

“…While corrosion courses and behaviors attributed to chloride corrosives can dramatically vary due to diverse service environments and different rebar sections, in general, when rebar corrosion occurs, the bond strength between concrete and steel bars often decreases significantly when a certain level of rust accumulation reaches. Meanwhile, volume expansion as a consequence of rust accumulation, can result in serious rupture failure of concrete elements [2] . After concrete cracks, rebar corrosion will be exacerbated due to the increased exposure of more reinforcements to surrounding humid conditions.…”