Impact of climate change on the carbonation in concrete due to Carbon Dioxide ingress: Experimental Investigation and Modelling  

Greenhouse gases (GHG), in terms of CO2 emissions, cause a greenhouse impact leading to changes in the planet’s temperature and relative humidity (RH). These changes in CO2, temperature and RH (leading to changes in the internal moisture content) have considerable impacts on the depth of carbonation (DoC) in existing concrete structures. However, the models to forecast the DoC as a function of time in the cracked and uncracked concrete members are scarce and have limitations in terms of incorporating key variables relevant to the climate change. This study aims to develop an integrated deterioration model of carbonation in concrete. The combined impacts of variations in the internal factors (such as mechanical properties of concrete, porosity and crack width) and external factors (such as %CO2, %RH and temperature), on chemical reaction rates due to carbonation in concrete were considered. This model is based on simultaneous solutions of the diffusivity and reaction activites of CO2(aq) and Ca(OH)2(aq). The proposed model was validated using the accelerated carbonation experiments involving different properties of concrete and cracks widths. Finally, this model was employed to forecast the DoC in order to identify corrosion state owing to impact of climate change scenarios of the Inter-governmental Panel of Climate Change (IPCC 2014) and the UKCP'09 climate projections.