Three concrete mix proportions were designed and prepared, respectively, such as fly ash concrete (abbreviated as “FAC”) with 30% fly ash replacement ratio of cement, fly ash, and slag concrete (abbreviated as “FSC”) with each of 20% fly ash and slag replacement ratio and ordinary Portland cement concrete (abbreviated as “OPC”) for the research of carbonation and chloride resistance of concrete...

The initial microscale mechanisms and materials interfacial process responsible for hydration of calcium silicates are poorly understood even in model systems. The lack of a measured microscale chemical signature has confounded understanding of growth mechanisms and kinetics for microreaction volumes. Here, we use Raman and optical spectroscopies to quantify hydration and environmental carbonat...

Moisture diffusion and carbonation influence the behavior of multiple-leaf ancient masonry walls, producing during centuries a redistribution of stresses from the core of lime mortar concrete to the external cladding of stiff masonry. This is likely one of the causes of long-time damage of some ancient masonry towers. With these motivations, coupled processes of moisture diffusion, carbon dioxi...

Bayerite is one of the phases of aluminum hydroxide which is precipitated by the carbonation of aluminate solutions obtained from sintered nepheline syenite leaching. In this study, the conditions for the bayerite formation were predicted by thermodynamic modeling of the carbonation process and the Bromley- Zemaitis model was used for this purpose. Carbonation experiments were carried out a...

This paper explores, for the first time, the possibility of carbonating waste metallic iron powder to develop sustainable binder systems for concrete. The fundamental premise of this work is that metallic iron will react with aqueous CO2 under controlled conditions to form complex iron carbonates which have binding capabilities. Chosen additives containing silica and alumina are added to facili...

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....

Chemical processes like carbonation of concrete structures are driven by slow diffusion processes and fast reactions. This leads to the formation of relatively sharp reaction fronts, which move slowly through the material. Self-adaptive finite element methods provide a tool to automatically generate meshes locally fine enough to capture the reaction, while coarser meshes are sufficient in the b...

We discuss the error analysis for a moving-boundary system in two phases arising from modeling the penetration of a sharp carbonation front into unsaturated cement-based materials. The special feature of this problem is that the moving boundary is driven by a kinetic condition proportional to the rate of a fast carbonation reaction concentrated on the moving boundary. We prove a priori error es...

Alcohol dispersions of Ca(OH)2 nanoparticles, the so-called nanolimes, are emerging as an effective conservation material for the consolidation of stone, mortars, and plasters present in old masonry and/or mural paintings. To better understand how this treatment operates, to optimize its performance and broaden its applications, here we study the nano and microstructural characteristics, carbon...

In Flanders, the northern part of Belgium, about 31% of the produced amount of MSWI bottom ash is recycled as secondary raw material. In view of recycling a higher percentage of bottom ash, a particular bottom ash fraction (Ø 0.1-2mm) was studied. As the leaching of this bottom ash fraction exceeds some of the Flemish limit values for heavy metals (with Cu being the most critical), treatment is...