Title: Chloride-Induced Corrosion Deterioration of Bridge Deck with Latex-Modified Concrete Overlay

Author(s): Soundar S. G. Balakumaran, Richard E. Weyers, and Michael C. Brown

Publication: Materials Journal

Volume: 113

Issue: 4

Appears on pages(s): 483-491

Keywords: bridge deck; chloride diffusion; corrosion; latex-modified concrete; low permeability; overlay; service life model

DOI: 10.14359/51688990

Date: 7/1/2016

Abstract:
Overlaying an existing bridge deck with a low-permeability concrete layer would ideally reduce the rate of ingress of chloride, thus delaying the corrosion process. It is essential to study the effect of overlays on the service life of bridge decks. A bridge deck with latex-modified concrete (LMC) overlay was selected, as a part of the Federal Highway Administration’s Long-Term Bridge Performance project, in the state of New Jersey for corrosion testing and modeling. Electrochemical corrosion tests were conducted and samples were collected for laboratory testing. Powdered concrete samples at various depths contained higher chloride contents in the LMC overlay than expected. Although the rapid chloride permeability test showed significantly lower permeability for the LMC layer, chloride diffusion rates and percent saturation were higher than in the original deck concrete. Because the chlorides mainly diffuse through concrete pore water, despite the lower permeability of the LMC layer, 40% of the chloride contents at bar depths were higher than 1 lb/yd3 (0.59 kg/m3).