Journal Article

Natural carbonation of aged alkali-activated slag concretes

Mejía de Gutiérrez, Ruby, Bernal, Susan A., van Deventer, Jannie S. J., San Nicolas, Rackel, Provis, John L.

2014

Overview

Alkali-activated slag concretes stored for 7 years under atmospheric conditions are assessed, and the structural characteristics of naturally carbonated regions are determined. Concretes formulated with a 400 kg/m 3 and water/binder (w/b) ratio between 0.42 and 0.48 present similar natural carbonation depths, although these concretes report different permeabilities after 28 days of curing. The inclusion of increased contents of binder leads to a substantial reduction of the CO 2 penetration in these concretes, so that negligible carbonation depth values (2 mm) are identified in concretes formulated with 500 kg/m 3 of binder. Calcite, vaterite, and natron are identified as the main carbonation products formed in these concretes. These observations differ from the trends which would be expected in comparable ordinary Portland cement-based concretes, which is attributable to the physical (permeability) and chemical properties of alkali-activated slag concretes promoting high long-term stability and acceptably slow carbonation progress under natural atmospheric conditions.

• Publisher: Springer Netherlands,Springer,Springer Nature B.V
• Subject: Applied sciences / Atmospherics / Binders / Building construction / Building Materials / Buildings. Public works / Calcite / Carbon dioxide / Carbonation / Civil Engineering / Concretes / Concretes. Mortars. Grouts / Durability of constructions / Durability. Pathology. Repairing. Maintenance / Engineering / Exact sciences and technology / General (composition, classification, performance, standards, patents, etc.) / Machines / Manufacturing / Materials / Materials Science / Original Article / Permeability / Processes / Slags / Solid Mechanics / Strength of materials (elasticity, plasticity, buckling, etc.) / Structural analysis. Stresses / Theoretical and Applied Mechanics