Impact of carbonation on the durability of cementitious materials: water transport properties characterization

Abstract

Abstract. Within the context of long-lived intermediate level radioactive waste geological disposal, reinforced concrete would be used. In service life conditions, the concrete structures would be subjected to drying and carbonation. Carbonation relates to the reaction between carbon dioxide (CO 2 ) and the main hydrates of the cement paste (portlandite and C-S-H). Beyond the fall of the pore solution pH, indicative of steel depassivation, carbonation induces mineralogical and microstructural changes (due to portlandite and C-S-H dissolution and calcium carbonate precipitation). This results in the modification of the transport properties, which can impact the structure durability. Because concrete durability depends on water transport, this study focuses on the influence of carbonation on water transport properties. In fact, the transport properties of sound materials are known but they still remain to be assessed for carbonated ones. An experimental program has been designed to investigate the transport properties in carbonated materials. Four hardened cement pastes, differing in mineralogy, are carbonated in an accelerated carbonation device (in controlled environmental conditions) at CO 2 partial pressure of about 3%. Once fully carbonated, all the data needed to describe water transport, using a simplified approach, will be evaluated.

Reactive Transport in Evolving Porous Media

“…This can lead to the deterioration of mechanical properties (Chagneau et al 2015;Li et al 2017). For cement materials, the delayed formation of ettringite (Taylor et al 2001) or atmospheric carbonation (Auroy et al 2013) are typical examples of precipitation processes that can induce fracturing, which can be detrimental in the context of CO 2 sequestration or radioactive waste management. In all the aforementioned cases, precipitation can lead to clogging, which significantly affects flow and solute transport.…”

RTM for Waste Repositories

“…Finally, some important effects of carbonation on the properties of concrete that have been largely observed are not actually taken into account in modeling (Czarnecki and Woyciechowski 2015; Ashraf 2016; Savija and Lukovic 2016): changes in porosity, transport properties, microand macro-mechanical properties, shrinkage and cracking. Experimental data has been recently acquired on changes in water retention properties and permeability (Auroy et al 2013(Auroy et al , 2015(Auroy et al , 2018. The impact of carbonation is not the same for the different types of concrete (Auroy et al 2015), which would also constitute an interesting challenge for RTM.…”