Limit state modelling for carbonation induced corrosion: the effect of climate change and low CO2-binders on the service life
J.H.M. Visser
TNO, the Netherlands
Carbonation of concrete is strongly affected by the climate conditions but degradation models do not take this into account. Based on historic data of the Dutch weather stations, it was found that in addition to increasing CO2 concentrations, the relative humidity is decreasing. Both effects have been added to the carbonation model. In addition, the resistance against carbonation has been modelled in more detail to include the principal concrete composition parameters and the effect of the relative humidity. The climate effects have been demonstrate by mean values calculations for three type of cement, indicating a significant increase in carbonation depth for binders that already dry out under the current relative humidity but the change is dramatic for those cements that are currently are saturated at the prevailing relative humidity, but will dry out due to the lower RH as a consequence of climate change. Their carbonation rate increases so much that the service life in many cases will be compromised. This first assessment of the climate change effects on carbonation, couples to the drive towards low or no clinker-based binders warrants urgent further research towards the effect of these binders at the current and climate change.
Key words: Service life, carbonation, environmental load, material resistance, climate change