Advances in Characterization of Carbonation Behavior in Slag-Based Concrete Using Nanotomography

Abstract

Exposure of concrete to the atmosphere causes absorption of CO2 and carbonation via a chemical reaction between the CO2 and calcium hydroxide and calcium-silicate-hydrate reaction products inside the concrete. A greater understanding of carbonation behavior and its micro- and nanoscale impacts is needed to predict and model concrete durability, cracking potential and steel depassivation behaviors. New and sophisticated techniques have emerged to analyze the microstructural behavior of concrete subjected to carbonation. High-resolution full-field X-ray imaging is providing new insights to nanoscale behavior. Full-field nano-images provide significant insight into 3D structural identification and mapping. Nanotomographic modeling of an accelerated carbonated test specimen can also provide a 3D view of the pore structure that resides inside slag-based concrete. This is critical for better understanding of the capillary porosity and pore solution behaviors of concrete in situ. We investigated the analysis of durability properties, including the carbonation behavior of slag-based concrete, by evaluating microstructural and nanotomographic identification techniques.