The fundamental challenge that is being faced by the cement industry is the climate change. It is anticipated that emissions of greenhouse gases such as CO2 will be tightly regulated. Moreover, is the high cost of cement production which is due to energy consumption and electricity. This drives researchers to look for improved ways to reduce the cost and the net CO2 emissions from the production and use of cement. Efforts to reduce the energy-related emissions involves reducing dependence on fossil fuels whereas limestone-related emissions involve substituting some of the clinker with supplementary cementitious material. The current approach of using slag and fly ash is reaching its limits due to lack of sufficient and sustainable sources of these materials. Alternative low-CO2 and low-cost approaches are being investigated. The most promising strategy entails the partial substitution of Portland cement clinker by the combined addition of calcined kaolinite clay and limestone.