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...

This study investigates a new concept of producing precipitated calcium carbonate (PCC) from steelmaking slag and carbon dioxide via a spray carbonation process. The presented laboratory-scale spray carbonation test reactor uses a spray nozzle to disperse fine droplets of a Ca-rich solution into a spray tower, where calcium carbonate precipitates as a result of the reaction between calcium and ...

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...

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...

In this study, the treatment of fly ash and steel making slag in aqueous ammonia chloride has been conducted. These zero-value wastes have distinctively high concentrations of magnesium, calcium and iron. The ammonium chloride has been employed as the leaching reagent to extract MgO out of fly ash and slag, and the dissolved cations in the leachate were subsequently precipitated by carbonation....

Objective The purpose of this study was to determine the effects of carbonated water on etched or sealed enamel according to the carbonation level and the presence of calcium ions. Methods Carbonated water with different carbonation levels was manufactured by a soda carbonator. Seventy-five premolar teeth were randomly divided into a control group and 4 experimental groups in accordance with ...

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...

The objective of this paper is to examine the possible use of new blended cements containing calcareous fly ash in structural concrete, potentially adequate for structural elements of nuclear power plants. The investigation included five new cements made with different contents of non-clinker constituents: calcareous fly ash, siliceous fly ash, ground granulated blastfurnace slag, and a referen...

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...