BioZEment: Developing a Zero Emission concrete based on bio-catalytic calcium carbonate cementation

Cement is an important ingredient in concrete, which is one of our most common construction materials. Today's cement production works on the principle of activating stable raw materials by exposing them to very high temperatures. When exposed to water, they will cure to form a strong, solid material. This process is highly energy demanding, and the extensive use of fossil fuels leads to large emissions of CO2. In addition, about half a tonne of CO2 is released to the atmosphere during the calcination process, where limestone (CaCO3) is decomposed to form lime (CaO) at high temperatures. In total, cement production is responsible for more than 5% of global CO2 emissions from human activities. The goal of the BioZEment project is to develop a cement that complies with today's standards of strength and durability, but without using the calcination process. Instead of decomposing the limestone to make the reactive lime, we seek to find a method for activating the mineral surfaces to make the limestone part icles bind to each other, using modern biotechnology to find microorganisms that can perform this grain boundary activation in a controlled manner. The project includes detailed studies of how cementation takes place on the micro- and nano-scale, in combination with microbiology and biotechnology. In order to ensure that we are working toward a product that truly is a better alternative to today's cement, we actively use models for life cycle assessment of products and studies of ethical, legal and societal aspects of the process. We have managed to find suitable bacterial strains and make prototypes of the bio-concrete, exploring a range of production parameters in order to optimize material performance. We have also investigated several fundamental aspects of the process. The knowledge gained in this project will be used as a basis for a follow-up project which will last for the next 3.5 years, where we aim to obtain better control of the microbiological processes and how they relate to material performance. In this project, we will also continue to explore issues related to the environmental footprint of the material, societal acceptance and market penetration.

With the world's population having passed 7 billion, a sustainable use of Earth's limited resources is today more important than ever, demanding for, among others, a sustainable use of energy and a reduction of emissions of carbon dioxide (CO2). On a glob al scale, the cement industry accounts for about 5% of all man-made emissions of CO2. In the light of the majority of today's cement production still building on the same energy demanding and CO2 emitting general production principles as have been applied for several thousand years, there is a pressing need to develop new, more sustainable methods for the production of cement, or materials which can replace cement in some of its many applications, including in concrete for construction. The BioZEment proj ect addresses this challenge by proposing an entirely new interdisciplinary approach to achieve cementation in concrete with the potential to drastically reduce energy demands and CO2 emissions in the construction industry compared to established methods. By combining studies of phenomena relevant for cementation and consolidation at the micro- and nano-scale with advanced microbiology and molecular biotechnology methods, application driven material development and characterization with life-cycle analysi s and ELSA studies concerning its new approach, BioZEment will develop and demonstrate a new and more sustainable way towards concrete materials. The vision of BioZEment is a new type of construction material with dramatically reduced energy demands and C O2 emissions, while exhibiting competitive material properties suitable for diverse applications, including at the large-scale. With its radical innovative approach, BioZEment aims at making an important contribution on the way towards a Zero Emission Soc iety.