Life cycle assessment of a bridge column made of concrete and biochar

Within construction materials, research is moving towards the use of recycled waste for the production of more sustainable concretes. Some of these studies regard the addition of biochar, a solid carbonaceous by-product obtained from the thermochemical conversion of biomass, into concrete admixtures, and have shown that biochar can improve some physical and mechanical performances of concrete. Furthermore its “carbon-sink” property allows to fix carbon in a stable form in buildings for decades. In this work, an environmental analysis was conducted, using the Life Cycle Assessment methodology, of a hypothetical bridge column consisting of a concrete matrix containing biochar, which is characterized by an environmental damage principally caused by the production phase, mainly due to the steel rebars. In order to evaluate possible environmental advantages, the results obtained were compared with those relating to a bridge column composed of a traditional concrete matrix. The comparative analysis carried out by assuming the same mechanical performances has shown that the traditional scenario is characterized by slightly higher environmental damage.