There is a need to promote high performance and sustainable construction materials such as Self-Compacting Concrete (SCC) made from various wastes. In concrete manufacturing, there is a general tendency to worsen the workability and mechanical behavior when working with wastes instead of natural raw materials. It is therefore necessary to use multi-criteria algorithms to analyze the impact of using sustainable materials, and to balance the increase in sustainability with the deterioration of certain performances, such as flowability and strength. In addition, it is also necessary to include a cost analysis in the study, which allows us to find the most suitable products for varied real-life applications.
In this research, 19 SCC mixes have been manufactured, where conventional materials (CEM I, natural aggregates, and limestone filler) are progressively substituted by more sustainable ones (Ground Granulated Blast Furnace Slag -GGBFS- replacing cement, and Recycled Concrete Aggregate -RCA- in coarse, fine and filler sizes of the aggregate). The designed mixes are analyzed based on different criteria: mechanical criteria (flowability, compressive strength and modulus of elasticity), sustainability (carbon footprint) and cost. Five different scenarios are proposed for different priorities or situations, which are evaluated using three multi-criteria algorithms.
Some of the conclusions of the study show that coarse RCA and limestone fines perform adequately in most scenarios. Fine RCA rates above 50% were not recommended in any of the scenarios. A versatile design would be an SCC with RCA coarse aggregate, limestone fines, GGBFS and 0% fine RCA.
