Low-energy CO2-activated self-pulverising cement for sustainable concrete construction

Abstract

In order to achieve an efficient and sustainable concrete industry, there is an urgent need to reduce CO2 emissions from cement manufacture. The innovative scheme described here for the linked production of cement and concrete with low carbon footprint follows a three-stage process. Firstly, a Portland-like cement composition is calcined at reduced temperature and cooled under controlled conditions so that it self-pulverises spontaneously to a powder of normal fineness without grinding. Secondly, CO2-rich gas is extracted direct from the cement kiln flue and used to activate this poorly hydraulic cement in the third stage for making precast concrete products. Considerable energy savings 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-energy concrete or controlled setting are required.