Heidelberg to test cement alternative
By Chris Sleight02 April 2013
Heidelberg Cement has developed a new binder called Ternacem, which it says can be produced with -30% fewer CO2 emissions. The company is planning a large-scale trail of the material later this year in Germany.
The new material uses calcium sulfoaluminate (CSA), a material already widely used in screeds and tile glues. However, Heidelberg says that despite the materials’ property of developing high strength early on in the curing process, previous experiments have shown it not to be durable enough for construction applications.
The company’s new approach is to combine CSA with belite (dicalcium silicate), which is the mineral in traditional Portland cement that provides its late strength. Dr Wolfgang Dienemann, director of global research & development at Heidelberg Cement’s Technology Center (HTC) said, “This combination seemed promising enough to us that we continued working on it.”
HTC has registered a total of six patents related to this material, following lab tests that began in 2010. It now plans to move ahead with trials of new binders containing ternesite (Belite Calciumsulfoaluminate Ternesite - BCT), which it says can be produced with -30% fewer CO2 emissions than traditional Portland cement clinker. Energy costs for producing the material are said to be -15% lower due to reduced fuel consumption, thanks to a lower burning temperature, and a less energy-hungry grinding process.
Heidelberg Cement added that the cement industry is the source of about 5% of global CO2 emissions attributable to human activity. For every tonne of cement produced, about 800 kg of CO2 is released into the atmosphere – 40% as a result of energy use and 60% as a result of the chemical reaction that takes place in the production of cement from raw materials. The company added that it had reduced its CO2 emissions to 621 kg per tonne of cement through the use of alternative fuels.