Low-Carbon ${\mathrm{CO}}_2$-Activated Self-Pulverizing Cement for Sustainable Concrete Construction

In order for the concrete industry to become more efficient and sustainable, there is an urgent need to reduce emissions of carbon dioxide (${\mathrm{CO}}_2$) from cement manufacture. The innovative scheme described here for the linked production of cement and concrete with a low-carbon footprint follows a three-stage process. First, a Portland-like cement composition is calcined at reduced temperature and cooled under controlled conditions so that it self-pulverizes spontaneously to a powder of normal fineness without grinding. Second, ${\mathrm{CO}}_2$-rich gas is extracted directly from the cement kiln flue and used to activate this poorly hydraulic cement by carbonation in the third stage for making precast concrete products. The feasibility study described here aims to provide proof of the principle of this scheme. Considerable energy savings and sustainability gains are anticipated, and the challenges of process enhancements and scale-up are currently being addressed. In addition to its use in precast concrete items such as blocks, roof tiles, and pipes, other potential on-site applications are foreseen for this cement where low-carbon concrete or controlled setting are required.