A new electrochemical model has been carefully established to explain the carbonation behavior of cement mortar, and the model has been validated by the experimental results. In fact, it is shown by this study that the electrochemical impedance behavior of mortars varies in the process of carbonation. With the cement/sand ratio reduced, the carbonation rate reveals more remarkable. The carbonat...

Carbonation is one of the major deteriorations that accelerate steel corrosion in reinforced concrete structures. Many mathematical/numerical models of the carbonation process, primarily diffusion-reaction models, have been established to predict the carbonation depth. However, the mass transfer of carbon dioxide in porous concrete includes molecular diffusion and convection mass transfer. In p...

Concrete carbonation damages the passive film that surrounds reinforcement bars, resulting in their exposure to corrosion. Studies on the prediction of concrete carbonation are thus of great significance. The repair of pre-built reinforced concrete (RC) structures by methods such as remodeling was recently introduced. While many studies have been conducted on the progress of carbonation in newl...

Concretes used in marine environment are generally under the cyclic effect of CO2 and chloride ions (Cl -). To date, the influence of carbonation on ingress of chloride ions in concretes has been widely studied; in comparison, study on the influence of Clon the progress of carbonation is limited. During the study, concretes were exposed to independent and combined mechanisms of carbonation and ...

Coal, in particular, and fossil fuels, in general, are well positioned to supply the world’s energy needs for centuries to come if the environmental challenges associated with anthropogenic carbon dioxide emissions can be overcome. Carbon dioxide sequestration is being actively pursued as an option to reduce CO2 emissions, while still enjoying the advantages of low-cost fossil fuel energy. Mine...

Naturally occurring carbonation of cement-based materials is a slow phenomenon. Many factors control the rate of carbonation process in cement-based products. A comprehensive knowledge of the major factors controlling the rate of carbonation, and their effects on the properties of the materials subjected to it, is necessary for using this technology for CO2 sequestration. Most of the studies re...

Concrete carbonation, i.e. the reaction of alkaline species (inside the concrete) with atmospheric carbon dioxide, is one of the major physicochemical processes compromising the service life of concrete structures. While the main carbonation reaction is that of calcium hydroxide, other constituents such as calcium silicates or calcium-silcate hydrates in the concrete can also carbonate. Many au...

Corrosion of concrete reinforcing steel in highway structures has traditionally been related to chloride ions. However, another cause of reinforcing steel corrosion is concrete carbonation which decreases the pH of the pore solution, Carbonation-induced corrosion tends to develop later and proceeds at slower rates than chloride-induced corrosion. Since very long service life goals are currently...

Two new pre-treatment methods (water-washing/carbonation and carbonation/phosphate stabilisation) of municipal solid waste (MSW) incinerator residues were evaluated by column leaching tests under aerobic conditions and anaerobic conditions (which were changed to aerobic conditions after 10 months). A mixture of bottom ash and fly ash (5:1 ratio) was pre-treated using each method. Shredded incom...

Bayesian inference of model parameters for the time dependent carbonation depth of concrete is presented. The statistical model is assumed to have a form of where implies the carbonation coefficient and stands for the modeling error which is assumed to have a normal distribution with zero mean and unknown variance. By the use of existing data for the natural outdoor exposed concrete, the poster...