Prediction of Carbonation-induced Corrosion Initiation of Steel in RC Structures Exposed to Natural Inland Environment of South Africa

Author(s): Jacob O. Ikotun, Mike B. Otieno and Yunus Ballim
Paper category: Proceedings
Book title: Proceedings of International Conferences (ICACMS) Advances in Construction Materials and systems Vol 2
Editor(s): Manu Santhanam, Ravindra Gettu, Radhakrishna G. Pillai, Sunitha K. Nayar
ISBN: 978-2-35158-194-0
e-ISBN: 978-2-35158-191-9
Publisher: RILEM Publications SARL
Publication year: 2017
Pages: 472-481
Total Pages: 10
Language : English

Abstract: While there are many empirical and analytical models to predict carbonation-induced corrosion initiation period in concrete with extensive data presented in literature, most do not capture the necessary parameters to allow their application to steel RC structures exposed to the natural inland environment. In this paper, an empirical model to predict time to carbonation-induced corrosion initiation in concrete is developed based on the 28-day oxygen permeability index (OPI) and the 2-year natural carbonation data of concretes containing 100% PC, 35% fly ash (FA), 50% ground granulated blast-furnace slag (BS), 10% silica fume (SF) and (30% BS + 10% SF) exposed to the Johannesburg natural weather. The concretes were made using 0.40, 0.60 and 0.95 water/binder ratios and initially cured in water for 7 and 28 days. The 28-day OPI was used to characterise and quantify the quality of the concretes. Multiple linear regression analysis using the least squares method is used to develop a model that can be used to predict time to carbonation-induced corrosion initiation in concrete exposed to inland weather conditions. The proposed model showed the combined influence of concrete quality, cover depth and exposure conditions on the predicted carbonation-induced steel corrosion initiation time of the different concretes.

Online publication : 2017
Publication type : full_text
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