Understanding the Process of Carbonation in Concrete using Numerical Modeling

Abstract

The objective of the study is to develop a model that will help in understanding the process of carbonation. This study investigates the influence of different physical, chemical and environmental parameters on the carbonation process in concrete. The model incorporates the influence of change in porosity on carbonation and the variations in the internal relative humidity of concrete due to drying on the rate of carbonation. The pore saturation and porosity were found to control the rate of carbonation in concrete. The model demonstrates the preconditioning duration and amount of water released on carbonation have an insignificant effect on the extent of carbonation in the long-term. Increased tortuosity and higher alkalinity could help in improving the carbonation resistance of system.

Extraction of Carbonation Rate from Depth Profile of Concrete Carbonation by using Pseudo-analytical Solution of Two-component Reaction-diffusion Equation

“…Although Shah and Bishnoi (2021) took the diffusion of Ca 2+ ions into account in their reaction-diffusion equation, the diffusion of Ca 2+ is not important because the dissolved Ca 2+ converts to CaCO 3 near the mother CH.…”

Synergistic Effects between Carbonation and Cracks in the Hardened Cement Paste

“…It depends on the parameters related to the cement composition (e.g., the amount of reactive Ca-based constituents), curing duration and conditions, internal saturation degree, aggressivity of the environment (e.g., external relative humidity, CO 2 concentration and temperature) and pore structure [7][8][9][10]. The effect of environmental conditions such as CO 2 concentration and relative humidity on carbonation have been thoroughly investigated before [7,9,11,12] and is well known [13,14]. However, often it is described separately from other HCP properties, such as microstructure and hydrated phase composition, leaving coupled effects less investigated.…”