Component Four: Carbonation of Lime

Work Completed

The initial work was carried out at the GCI by Koenraad van Balen as a Conservation Guest Scholar and published as "Carbonation Reaction of Lime, Kinetics at Ambient Temperature," Cement and Concrete Research 34 (2004).

Abstract

"The uptake of carbon dioxide due to the carbonation reaction of Ca(OH)₂, in ambient temperature of approximately 20° C has been studied. Different types of lime have been used and the CO₂-concentration has been varied to identify the influence of different variables on the kinetics of the reaction. A closed loop system has been developed and validated that allows measuring the carbonation progress directly from monitoring CO₂ uptake. Thermal analysis was used to verify the degree of carbonation that reached up to 83%. Factor analysis on the dataset has demonstrated that reaction speed is not dependent on CO₂-concentration with the limits tested. Carbonation speed is depending on the specific surface of the lime. The results of this study contribute to research carried out on modeling lime mortar carbonation and on the carbonation process in general." (© 2004 Elsevier Publishers, Ltd.)

Further work

At the GCI, the composition of natural hydraulic limes is being characterized by XRD and TGA to identify important differences in the materials. A grant was obtained by the Department of Engineering, Catholic University, Leuven, to study the competition between carbonation and hydration of calcium hydroxide and calcium silicate binders. The ongoing project in Leuven on competition between carbonation and hydration builds on previous methodologies and results. Different types of hydraulic lime binders and mortars samples are subjected to different curing conditions that influence the carbonation and hydration processes. Curing conditions favoring one of the processes can impede optimum bonding of the mortar resulting in a reduction of its durability. Research on lime-based hydraulic mortars and grouts have revealed that the bond strength can also diminish, even after 90 or more days of hardening. The research profits from the existing collaboration at Leuven between the Engineering Department and the research group of physical-chemical geology. The combined expertise will contribute to understanding of material properties from the engineering to the microstructural scale. It strengthens the ongoing research and expertise on the study of hydration and carbonation of mineral binders (with or without organic binders).

Last updated: October 2007