Improving the CO2 performance of cement, part I: utilizing life-cycle assessment and key performance indicators to assess development within the cement industry.

Cement is a vital and commonly used construction material that requires large amounts of resources and the manufacture of which causes significant environmental impact. However, there are many different types of cement products, roughly ranging from traditional products with rather linear resource flows to more synergistic alternatives where industrial byproducts are utilized to a large extent. Life Cycle Assessment (LCA) studies indicate the synergistic products are favorable from an environmental perspective. In co-operation with the global cement producing company CEMEX a research project has been carried out to contribute to a better understanding of the CO 2 performance of different ways of producing cement, and different cement products. The focus has been on Cluster West, which is a cement production cluster consisting of three plants in Germany. This paper is the first in a series of three, all of which are included in this special issue. It has two main aims. The first is to carry out an attributional LCA and compare three different cement products produced in both linear and synergistic production setups. This has been done for cradle to gate, focusing on CO 2 -eq emissions for Cluster West. The second aim of this part is to develop and test a simplified LCA model for this production cluster, with the intention to be able to compare different versions of the production system based on the information of a few parameters. The attributional LCA showed that cement products that contain a large proportion of byproducts, in this case, ground granulated blast furnace slag from the iron and steel industry, had the lowest unit emissions of CO 2 -eq. The difference between the lowest emission product (CEM III/B) and the highest (CEM I) was about 66% per tonne. A simplified LCA model based on six key performance indicators, instead of approximately 50 parameters for the attributional LCA, was established. It showed that Cluster West currently emits about 45% less CO 2 -eq per tonne of average product compared to 1997. The simplified LCA model can be used effectively to model future changes of both plants and products (which is further discussed in part II and part III). [ABSTRACT FROM AUTHOR]