Challenge the practice is addressing: The production of cement, a key component of concrete, involves combustion processes that release CO2 into the atmosphere, contributing to global climate change. Each year, about three billion tons of CO2 can be traced back to cement production, representing 8% of global carbon emissions. With a rising concrete demand, the demolition waste is also rising and is by now one of the biggest waste streams worldwide.
Concrete practice to achieve the expected goal: zirkulit®, a low-carbon circular concrete, is a product in the circular industry and largely composed of secondary materials. To reduce carbon emissions, the new zirkulit® mix-design contains a minimum of cement. Additionally, zirkulit AG has developed a carbon storage technology: CO2 penetrates the pores of the grains/granulates, where it is converted into limestone by a chemical process and thus stored long term. The CO2 storage leads to a higher quality of the sand and gravel grains and to an increase in weight, which in turn increases the static properties of the concrete. For each cubic metre of zirkulit® concrete, more than 10kg of CO2 are stored. This type of CO2 storage technology is meanwhile integrated into the regular concrete production process, but the concrete production plant has to be modified according to the zirkulit® mix-design and CO2 storage technology. In the future, zirkulit® concrete can be recycled again.
Expected impact/goal of the practice: Maximum material circularity, minimal carbon emissions and same technical properties as conventional concrete.
Who is the target user group of the practice/intervention or implementing the practice/intervention? This practice is for companies in the extractive industry.