A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Effect of surface preparation on corrosion of steel rebars coated with cement-polymer-composites (CPC) and embedded in concrete
Highlights First paper on performance of CPC coated steel rebars considering the possible quality issues at construction sites. Paper covers from microstructure aspects of corrosion to the service life of a bridge structure. Possible corrosion mechanism for inadequately applied CPC coated steel is proposed. When CPC coatings are used, sandblasting of steel rebar can enhance the service life by twice.
Abstract Nowadays, Cement-Polymer-Composites are widely used to coat steel rebars to delay the initiation of corrosion in reinforced concrete (RC) structures. However, Cement-Polymer-Composite (CPC) coating is sometimes inadequately applied on rusted steel and can lead to premature under film/crevice corrosion. This paper investigates the effect of such inadequate applications of CPC coating and premature corrosion on the service life of RC structures. For this, maximum surface chloride concentrations, diffusion coefficients, and chloride thresholds were determined by a one-year-long laboratory study on the specimens obtained from a 6-year-old bridge and prepared in the laboratory. Studies found that the chloride threshold of inadequately coated steel rebar (i.e., coating on ‘as received’ surface) is significantly lower than that of the adequately coated steel rebars (i.e., coating on ‘sandblasted’ surface). Also, the corrosion initiation time for systems with inadequately coated steel rebar was about 50% less than that of the systems with adequately coated steel rebars. The corrosion mechanisms were justified with micrographs. It is recommended not to use CPC coated steel rebars if adequate surface preparation (say, cleaning/sandblasting) is not implemented.
Effect of surface preparation on corrosion of steel rebars coated with cement-polymer-composites (CPC) and embedded in concrete
Highlights First paper on performance of CPC coated steel rebars considering the possible quality issues at construction sites. Paper covers from microstructure aspects of corrosion to the service life of a bridge structure. Possible corrosion mechanism for inadequately applied CPC coated steel is proposed. When CPC coatings are used, sandblasting of steel rebar can enhance the service life by twice.
Abstract Nowadays, Cement-Polymer-Composites are widely used to coat steel rebars to delay the initiation of corrosion in reinforced concrete (RC) structures. However, Cement-Polymer-Composite (CPC) coating is sometimes inadequately applied on rusted steel and can lead to premature under film/crevice corrosion. This paper investigates the effect of such inadequate applications of CPC coating and premature corrosion on the service life of RC structures. For this, maximum surface chloride concentrations, diffusion coefficients, and chloride thresholds were determined by a one-year-long laboratory study on the specimens obtained from a 6-year-old bridge and prepared in the laboratory. Studies found that the chloride threshold of inadequately coated steel rebar (i.e., coating on ‘as received’ surface) is significantly lower than that of the adequately coated steel rebars (i.e., coating on ‘sandblasted’ surface). Also, the corrosion initiation time for systems with inadequately coated steel rebar was about 50% less than that of the systems with adequately coated steel rebars. The corrosion mechanisms were justified with micrographs. It is recommended not to use CPC coated steel rebars if adequate surface preparation (say, cleaning/sandblasting) is not implemented.
Effect of surface preparation on corrosion of steel rebars coated with cement-polymer-composites (CPC) and embedded in concrete
Kamde, Deepak K. (author) / Pillai, Radhakrishna G. (author)
2019-11-12
Article (Journal)
Electronic Resource
English
%bwob , % by weight of binder , AR , As-received , <italic>C</italic> (<italic>x</italic> , <italic>t</italic>), Chloride concentration at depth ‘<italic>x</italic>’ after exposure for ‘<italic>t</italic>’ seconds , CDF , Cumulative distribution function , <italic>C<inf>max</inf></italic> , Maximum chloride concentration at the exposed concrete surface , CPC , Cement-Polymer-Composite , <italic>C<inf>s</inf></italic> , Surface chloride concentration , <italic>Cl<inf>th</inf></italic> , Critical chloride threshold of steel-concrete interface , <italic>D<inf>cl</inf></italic> , Diffusion coefficient of concrete , <italic>erf</italic> , Error function , <italic>m</italic> , Decay constant , RC , Reinforced Concrete , SB , Sand-blasted , SC , Steel-Cementitious , <italic>t</italic> , Exposure time , <italic>t<inf>i</inf></italic> , Time to corrosion initiation , wC , With coating , woC , Without coating , <italic>x</italic> , Depth from the exposed surface of concrete , Reinforced concrete , Surface preparation , Chloride threshold , Cement polymer composite coating
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