Eco-mechanical index for structural concrete

Design and production of industrial components and materials are nowadays a compromise between the required performances and the environmental impact. In the case of structural concrete, the existing ecological approaches are mainly focused on sustainability, regardless of mechanical performances. Tailoring a new generation of concretes, capable of maintaining acceptable mechanical properties with a reduced ecological impact, is therefore the big challenge that construction industry has to face. Accordingly, new instruments, based on both mechanical and environmental performances, need to be introduced in place of the classical life cycle assessment procedure. This is the case of the so-called eco-mechanical index (EMI), described in the present paper and applied to different series of plain and fiber-reinforced self-compacting concretes. The basic mechanical properties, such as compression and flexural strengths, and the related post-peak curves, are taken into account by the proposed EMI. Conversely, water, embodied energy consumption and the amount of carbon dioxide, necessary for the production of concrete, are here assumed to represent the environmental performance. As a result, in presence of fiber-reinforced concrete, despite the higher ecological impact than plain concrete, the best eco-mechanical performances are generally measured at each stage of concrete life.