In the most service life models of reinforced concrete structures the initiation phase is the most crucial, because according to models, service life of the structure will end underestimation on conservative side when carbonation achieves the reinforcement for the first time. The square root model is widely used in predicting carbonation depth of reinforced concrete. The model is based on diffusion laws and thereby arguable for inhomogeneous concrete. The model was evaluated by field measurements from one existing concrete building by conducting condition investigation twice at a time interval of 20 years. Samples were taken from exposed aggregate concrete sandwich panels and balcony side panels. Compared to the data collected from large number of buildings, the measured carbonation rates were very common for Finnish concrete buildings made during the 1960s and 1970s. According to this study, in solid concrete the progress of carbonation of concrete can be predicted reliably with Fick’s second law. This model, however, gives too pessimistic predictions for concrete suffering from freeze-thaw damage. Therefore, a new model has been presented for damaged concrete.
If the inline PDF is not rendering correctly, you can download the PDF file here.
1. Lahdensivu J: “Durability properties and actual deterioration of Finnish concrete facades and balconies”. Tampere Tampere University of Technology Publication 1028 2012 117 p + app. 37 p.
2. Page C. L: “Basic Principles of Corrosion”. In: Schiessl P (editor): Corrosion of Steel in Concrete London Chapman and Hall 1988 pp. 3–21.
3. Schiessl P: “Corrosion of Steel in Concrete”. London Chapman and Hall 1988 101 p.
4. Liu Y & Weyers R E: “Modelling the Time-to-Corrosion Cracking in Chloride Contaminated Reinforced Concrete Structures”. ACI Materials Journal Vol. 95 No. 6 1998 pp. 675 – 681.
5. Tuutti K: “Corrosion of steel in concrete”. Stockholm Swedish Cement and Concrete Research Institute CBI Research 4:82 1982 304 p.
6. Li C Q: “Reliability service life prediction of corrosion affected concrete structures”. ASCE Journal of Structural Engineering Vol. 130(10) 2004 pp. 1570–1577.
7. Concrete Association of Finland: “Concrete codes”. Helsinki The Concrete Association of Finland BY 65 2016 164 p. (in Finnish)
8. Concrete Association of Finland: “Selection of concrete and service life design – guideline for construction designers”. Helsinki The Concrete Association of Finland BY 68 2016 95 p. (in Finnish)
9. Pentti M. Huopainen J. Lahdensivu J. Mäkelä K. “Condition investigation of concrete facades and balconies in Jakomäki”. Tampere University of Technology Research report 274 1994 93 p. (in Finnish)
10. Parrott L J: “A review of carbonation in reinforced concrete”. Cement and Concrete Association Slough UK 1987 42 p.
11. Huopainen J: “Carbonation of concrete facades – a field study”. Tampere University of Technology MSc thesis 1997. (in Finnish)
12. Neves R Branco F A & de Brito J: “A method for the use of accelerated carbonation tests in durability design”. Construction and Building Materials Vol. 36 2012 pp. 585-591.
13. fib Bulletin No. 34. “Model Code for Service Life Design”. International Federation for Structural Concrete Lausanne 2006 116 p.
14. Concrete Association of Finland: “Condition assessment manual of concrete facades and balconies”. Helsinki The Concrete Association of Finland BY 42 2013 163 p. (in Finnish)
15. Lahdensivu J Varjonen S Pakkala T & Köliö A: „Systematic condition assessment of concrete facades and balconies exposed to outdoor climate”. International Journal of Sustainable Building Technology and Urban Development Vol. 4:3 2013 pp. 199-209.
16. Concrete Association of Finland: “Durability of concrete structures”. Helsinki The Concrete Association of Finland BY 9 1976 44 p. (in Finnish)