Carbonation in concrete infrastructure in the context of global climate change: Part 2 – Canadian urban simulations

In Part 1 of this paper, a carbonation model was developed and experimentally verified which was able to forecast carbonation depth of a concrete specimen considering varying ambient temperature, humidity and CO2 concentrations. Part 2 of the paper applies the carbonation diffusion/reaction model developed in Part 1 to predict the effects of global climate change on the carbonation of concrete. Climate scenarios were formulated and combined with the model for two major Canadian cities, Toronto and Vancouver. Results show that for undamaged and unstressed concrete, climate change will significantly affect carbonation progress. The model showed that for unloaded, non-pozzolanic concrete, ultimate carbonation depths in Toronto and Vancouver could be up to 45% higher. For in-service structures under load, the rates of deterioration are likely to be even faster. This is a cause for concern, and much further effort must be devoted to fully understand these phenomena.