We investigate the fast-reaction asymptotics for a one-dimensional reaction-diffusion system describing the penetration of the carbonation reaction in concrete. The technique of matchedasymptotics is used to show that the reaction-diffusion system leads to two distinct classes of sharpinterface models. These correspond to different scalings of a small parameter representing the fast-reaction an...

A consolidating product based on nanoparticles of slaked lime (Ca(OH)2) dispersed in isopropyl alcohol was exposed under different relative humidities (RH), 33%, 54%, 75% and 90% during 7, 14, 21 and 28 days. The characterization of the calcium hydroxide nanoparticles and the formed calcium carbonate polymorphs has been performed by Micro-Raman spectroscopy, Transmission Electron Microscopy (TE...

The development of new or modified cementitious materials is an important part of existing strategies to improve performance and minimize life-cycle costs and to eliminate the CO2’s impact on durability. The high anion exchange capacity of layered double hydroxides (LDHs) materials makes their interlayer ion exchange by organic and inorganic anions versatile and easily achieved. LDH-like materi...

One of the primary problems related to reinforced concrete structures is carbonation concrete. In many cases, depth on used evaluate service life. Factors that can substantially affect resistance are temperature, relative humidity, cement composition, concentration external aggressive agents, quality concrete, and cover. This paper investigates effect varying proportions blended Portland (ordin...

s and Publications: Johnson, N. C., Thomas B. Maher, K., Bird, D. K., Rosenbauer, R. Brown, G. E. Jr. (2011) Adsorption of organic ligands on silicate mineral surfaces in the presence of CO2 and water: Insight into olivine dissolution rates. Goldschmidt Conference, Prague, Czech Republic. Johnson N. C., Thomas B., Maher K., Bird D. K., Rosenbauer R. J., Brown G. E. Jr. (2011) Kinetics of olivin...

This study proposes a simple and novel synthesis route for rhombohedral single crystals (<2µm) of magnesite. This synthesis can be summarized by two main sequential reactions: (1) aqueous carbonation of synthetic brucite (Mg(OH) 2) by injection of CO 2 in a highly alkaline medium (2Molal of NaOH) at ambient temperature (∼20°C), leading to precipitation of platy-compacted aggregates of dypingite...

Precipitated calcium carbonate (PCC) was prepared by means of semicontinuous carbonation of Ca(OH)2 suspension, at 35 and 45 °C and in the presence of non-ionic dextran and dextran sulfate. The carbonation process was regulated at different predetermined values of electrical conductivity, that corresponded to different concentrations of dissolved Ca(OH)2: 0.5 mS cm < κ25 < 5.0 mS cm. The result...