A new meta-model to calculate carbonation front depth within concrete structures. (30th December 2016)

• Record Type: Journal Article
• Authors: Ta, Van-Loc; Bonnet, Stéphanie; Senga Kiesse, Tristan; Ventura, Anne
• Is Part Of: Construction & building materials. Volume 129(2016)
• Page Start: 172
• Page End: 181
• Publication Date: 2016-12-30
• Subjects: Natural carbonation -- Reinforced concrete -- Fick's first law -- Meta-model; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2016.10.103
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: The carbonation rate obtained with accelerated carbonation is lower than the natural carbonation one. New meta-model to predict the carbonation depth of concrete is developed for the natural carbonation condition. The model developed take into account many parameters readily available in the case of new reinforced structures. Abstract: Carbonation processes cannot be ignored as regards durability and service-life of new concrete structures, and their correct understanding and quantification are essential for maintenance and repair works on existing structures. This paper initially presents a new meta-model developed to calculate carbonation front depth based on the analytic solution of Fick's first law. The only input data required by this non numerical model are: (i) material variables (concrete mix design, maximum nominal aggregate size, cement type, and chemical composition of cement type CEM I and cement density); (ii) technological parameters (initial curing period ( tc )); (iii) environmental parameters (ambient temperature ( T ), relative external humidity ( RH ) and CO2 concentration in the air ([ CO 2 ] ext )). Consequently, this model is fully suitable for the prediction of carbonation depth in the case of new reinforced concrete structures, for which these required parameters are well-known. The meta-model is validated using data from the literature on short and long-term natural carbonation exposure conditions. Most of the experimental data concern CEM I, CEM II, CEM III cement types, and CEM I additives (fly ash (FA)) with various water to cement ( W / C ) ratios and tc . The meta-model is also compared with two already available models: Papadakis' model and Yang's model. The three model predictions are compared with the corresponding values found in the literature. The results confirm that the prediction of the new meta-model proposed here for estimation of carbonation depth is the most accurate in every case.