Towards greener concrete: the challenges of SUS-CON project

Portland cement production is an energy-intensive process responsible for a significant share of the total CO2 production. Its replacement with low carbon binders from by-products of industrial processes is a sustainable alternative for innovative construction materials. In addition, the combination of low carbon binders with recycled aggregates results in a more sustainable concrete, also contributing to reduce waste amounts sent to landfills or incinerators. SUS-CON (SUStainable, innovative and energy-efficient CONcrete, based on the integration of all-waste materials) project (Funded by EC under FP7 (call EeB-NMP.2011-1/3, grant agreement no. 285463).), aimed at developing new concepts and technologies to integrate secondary raw materials in the concrete production cycle, resulting in cost-effective, lightweight and insulating concretes with reduced embodied energy and CO2 footprint. This paper presents a comprehensive overview of the technical work carried out during the Project. The work was structured in three major phases: 1. material research, leading to set-up and assess eco-sustainable concretes with recycled aggregates (e.g. waste polyurethane foams, mixed plastic scraps, end-of-life tyres and plastics from electrical and electronic equipment) and low carbon alkali activated binders (e.g. pulverized fly ash from power stations and blast furnace slags from steel plants); 2. industrial implementation, validating the developed technologies in industrially relevant environment through pre-cast components and ready-mixed concrete production and pilot buildings construction; 3. industrial uptake, creating the bases for transferring results and methodologies by environmental and economical assessments (LCA, LCC, HSE) and certification issues. Mechanical, insulation and fire resistance properties of SUS-CON components were tested; energy efficiency performances of SUS-CON pilot buildings were also monitored.