Green chemistry for sustainable cement production and use

Concrete is in desperate need of revitalisation in the 21st century due to growing durability, maintenance and environmental concerns. Improving the cement within concrete is an essential part of addressing these concerns. While Portland cement manufacture and use can still undergo slight environmental improvements, great opportunities lie in the utilisation of cements based on alternative compositions, binding-phases and green chemistry. This allows cement to be synthesised from a variety of materials including recycled resources and mineral wastes, which reduces the energy demands during production. The present work introduces industrial ecology and the principles of green chemistry as a means of driving the research, development and commercial attractiveness of alternative and sustainable cements. Three promising alternative cements are reviewed (alkali-activated cements, magnesia cements and sulfoaluminate cements) and compared to blended ordinary Portland cements in terms of their chemistry and properties. Emphasis is given to the material properties, durability, performance and applications of the “greener” alternative cements. It is clear that alternative cements have considerable potential in terms of environmental, engineering and economic properties.