The cement industry is currently faced by the great challenge of reducing its vast carbon footprint, due to being the second highest industrial greenhouse gases (GHG) emitter. This value is expected to further increase, since cement production is foreseen to rise by about 20% until 2050. Therefore, more eco-efficient alternatives to ordinary Portland cement have been developed towards a sustainable concrete industry. This chapter presents some of the latest advances in low-carbon thermoactivated recycled cements (RC) obtained from old waste concrete, leading to a significant reduction of the GHG emissions, while also encouraging the valorization reuse of waste materials and the reduction of natural resource depletion. The manufacture and general performance of RC, including the main production issues, rehydration behavior and phase and microstructure development, as well as its incorporation in cement-based materials are discussed. Some of the most recent research, main challenges and future perspective of RC are addressed.
Part of the book: Sustainability of Concrete With Synthetic and Recycled Aggregates