Concrete is the most frequently used building material in Switzerland – but it is very energy-intensive. This is because the production of cement – an important component of concrete – is an energy-intensive process that releases enormous quantities of CO2. Cement is produced by heating the raw materials of limestone, clay and marl to around 1,500 degrees Celsius and converting them into a binder. This is referred to as clinker. The clinker is ground and mixed – together with other ingredients such as gypsum – in order to form cement. During burning, each tonne of cement produces half a tonne of CO2.
As part of the joint project “Low energy concrete”, methods and materials were developed that make concrete more environmentally friendly. Researchers from the EPF Lausanne have now investigated a special material during this sub-project: ultra-high performance fibre reinforced concrete (UHPFRC). This currently contains a large quantity of steel fibres and a high share of cement. In order to make it more environmentally friendly, the EPF Lausanne scientist Emmanuel Denarié and his colleague Amir Hajiesmaeili have developed a new ultra-high performance fibre reinforced concrete that reduces its environmental costs by 75 % relative to existing solutions. And the solution they have created has comparable properties with respect to strength, malleability and protection against liquids and gases.