Most concretes used at present are based on Portland cement. It is a well-known very good cementitious binder but unfortunately, its production technology requires application of high calcination temperatures reaching over 1400 ℃. That results in a very high CO2 emission reaching 900 kg for each ton of the produced cement. The worldwide production of Portland cement topped over 2 billion tons in 2012. Consequently, the global emission of CO2 reached about 1.8 billion tons annually only due to the Portland cement. Common ways to reduce the CO2 related to Portland cement are:
- More efficient utilization of fuels in the cement kiln
- Usage of alternative types of fuels (often wastes)
- Reducing the amount of Portland cement by its partial replacement with secondary binders like limestone, blast furnace slag or fly ash.
- The most dramatic but also the most efficient way is to replace it fully with other binder having significantly lower CO2 footprint.
The main focus of this project is to search for more environmental friendly binder which could fully replace Portland cement at least in certain applications. The source of raw materials should be commonly available and sustainable. Certainly, natural clay minerals fulfill those objectives as they are a major component of soil all over the world. Clay is characterized by a variety of properties according to the precise conditions occurring during its formation. The most common clay minerals are kaolinite, illite (hydrated mica), smectite (montmorillonite, saponite etc.) and chlorite. Clay composed mainly of illite dominates in Sweden. Properties of clay minerals can be altered by the application of various types of activation processes.
The present project will focus on the development of a novel more ecological activation technology for producing cementitious binders from natural clay minerals.