In order to reduce the carbon footprint of concrete by accelerated carbonation, the FastCarb project will apply two approaches, one directed upstream and the other directed downstream. The goal of the downstream approach will be to design an accelerated carbonation process and implement it at the pre-industrial scale, to verify that the concretes manufactured with the treated aggregate have the required properties and to characterize the environmental and economic viability of the considered industrial recycling process. This last point will also provide some findings which depend on economic conditions (such as the cost of a ton of CO2) concerning the optimum between CO2 capture, the cost of the treatment and the improvement in the properties of the aggregate.
WG2 also consists of 3 sub-groups:
- WG2.1 has as its goal the application of the accelerated carbonation process on an industrial scale. In coordination with the experiments conducted in the framework of WG1.1, manufacture will be performed under industrial conditions in order to test the feasibility of the methods. Such manufacturing could combine the use of the available materials (for example air which contains a certain percentage of CO2 that has been recovered from the exhaust gases of a cement factory kiln) and possible techniques (total or partial pressure). After this treatment, the aggregate in question will be characterised and the results compared to those obtained in the laboratory, primarily in order to verify the applicability of the models developed by WG1.2. Last, conclusions will be drawn from these experiments for aggregate standardisation.
- WG2.2 deals with a transfer to concrete and applications to precast elements and structures that are cast in situ. Concretes will be manufactured with aggregates that have been made in the framework of the project, and this will include the pouring of precast elements or parts of structures in situ. This will allow us to measure the impact of the treatment on the density of the aggregate grains and their mechanical performance in the concrete in which they are recycled in order to identify any impact on the optimisation of mix design. The aim is also to characterise not only the mechanical performance of concretes that include RCA but also their durability. With regard to the latter, in particular it will be verified that the treatment of the aggregate does not increase the risk of reinforcement corrosion in reinforced concrete.
- The role of WG2.3 is to perform economic and environmental evaluations of the process. It will carry out an economic evaluation which will include any possible conflicts of use. This will be a forward-looking study that will take account of possible changes in the cost of a tonne of CO2. An environmental evaluation of the process (Life Cycle Analysis – LCA) will be conducted based on this economic analysis.