1.5 Uses cementitious materials from a responsible industry

Between 1990 and 2018 CO2 emissions from cement manufacturing were reduced by 19,2%, directly improving the carbon footprint of concrete.

The precast industry works hard to improve the efficiency of cement use by maximising hydration and by optimising cement content to reduce embodied CO2. Other binders with much lower embodied CO2 than portland cement can be used; today the use of other cementitious materials such as ground granulated blast furnace slag and pulverised fuel ash is a common practice.

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1.6 ...which is reducing its carbon emissions

Although making cement in a kiln requires a great deal of heat energy, the amount of non-renewable fossil fuels used to produce this heat is being reduced and replaced with alternative waste derived fuels. Over 40% of thermal energy used to supply the clinker making process comes from waste and biomass. Energy efficiency in cement kilns varies between 70% to 80% depending on the raw materials moisture content.

The great majority of precast concrete mixes are made up of low carbon footprint sand, gravel or crushed rock, meaning that the carbon content of cement is diluted many times over. The embodied carbon of 1 tonne of concrete is around one tenth than that of a tonne of cement. The confusion between cement and concrete carbon footprints is the major source of misinformation about the beneficial sustainability characteristics of concrete. Using less cement in concrete even by using existing technology is improving its environmental impact.