Case Study on the 20 Years Propagation of Carbonation in Existing Concrete Facades and Balconies

Nordic Concrete Research

Lahdensivu Jukka¹  Lahdensivu Elina²  Köliö Arto³ 

[1] Adjunct Professor at Tampere University, Faculty of Built Environment Korkeakoulunkatu 10 FI-33720Tampere, Finland;MSc Student at Tampere University, Faculty of Built Environment Korkeakoulunkatu 10, FI-33720Tampere, Finland;Postdoctoral researcher, Faculty of Built Environment Korkeakoulunkatu 10 FI-33720Tampere, Finland;

关键词: concrete;    carbonation;    corrosion;    field measurement;    service life;    modelling;   

DOI  :  10.2478/ncr-2019-0004

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown