Lower clinker cements have been developed over several years and this is where a cementitious material is used to partially substitute the clinker. In the past, fly ash from coal-fired power stations and slag from blast furnaces have been used. These material sources will diminish in the future and alternative materials such as calcined clay and carbonated concrete fines are being researched.
The use of other constituents in cement and the reduction of the clinker-to-cement ratio means lower emissions and lower energy use. Innovative clinker and cement products are being developed which will reduce the CO2 emissions during their manufacture due to their different formulations. Examples of these include Sulpho-Aluminate Clinker (SAC), Ferro-Aluminate Clinker (FAC), Belite-Ye’elimite-Ferrite Clinker, Calcium Aluminate Clinker and Amorphous Clinker (X-Clinker).