The project BioZEment (University of Oslo 2014) was carried out 2014-2017, with the aim of developing a concrete product that complies with today’s standards of strength and durability, but without using the calcination process. Instead of thermally decomposing the limestone to make reactive lime, the project strived towards finding a low-temperature method for partial dissolution and re-precipitation of the mineral surfaces to make the limestone particles bind to each other, and thereby creating an alternative to conventional concrete with significantly lower climate impact. Modern biotechnology was applied to find microorganisms that could perform the dissolution and precipitation in a controlled manner. The project also included detailed studies of how cementation takes place on the micro- and nano-scale, in combination with microbiology and biotechnology.

In order to ensure that the project was striving toward a product that truly could be seen as a sustainable alternative to today’s concrete, both the method life cycle assessment (LCA) and studies of ethical, legal and societal aspects of the process were applied. This report presents the results of the LCA.

The LCA was carried out by SP Technical Research Institute of Sweden. The project was led by the University of Oslo. Other project partners, all based in Norway, were the Norwegian University of Science and Technology (NTNU), the research institute SINTEF, the consultancy company Dr. tech. Olav Olsen, and the research institute SIFO.

Results indicate that the BioZEment has the potential to reduce climate impact considerably, in a range of 70-85%. For other environmental impact categories (ozone depletion potential, eutrophication potential, and land use, and for the higher acidification estimate), the BioZEment has a higher environmental impact than conventional concrete. The impact levels are, however, not severe. Nevertheless, ammonia emissions (causing eutrophication and acidification) should be monitored. In the further development of the BioZEment, specific attention should be paid to:

• Reducing water consumption

• Establishing systems for waste water treatment

• Minimizing urea demand

• Minimizing ammonia emissions and/or capture ammonia emissions

Key words: life cycle assessment, concrete, cement, bacteria, climate