Concrete Change: Analyzing strategies to reduce climate impact of cement

Abstract

To be able to reach the Paris agreement significant efforts to reduce greenhouse gas emission will be required in all areas of society. The emissions from the construction sector is a large contributor to the global emissions. Within the construction sector a large contribution to emission comes from the concrete production. It is an important area to reduce the emissions in since it is essential in many areas of society for e.g. buildings and infrastructure. The largest contributor to emissions in the concrete industry is the production of cement, which accounts for 8% of global CO2-emissions. Nearly 60% of these emissions comes from the calcination reaction during the production of cement clinker. Therefore, the cement industry faces a different challenge than other industries, since shifting towards alternative fuels will not be enough. Carbon capture and storage will most likely be necessary for this industry, but since this is far from available in a commercial scale in the near future other measures must be taken before that is implemented. The main goal of this thesis is to construct an overview of the cement material flow in the Swedish society and mapping the end uses of cement. Due to a lack of actual industrial data, an approximation model based on standard cement products was created. In extension to this model, a set of 5 scenarios was created where various methods to reduce the CO2 emissions from cement were illustrated. The results from the scenarios was also compared to representative data from other EU countries. The comparison showed that Sweden have a long way to go in this area of CO2 emission reduction regarding both cement clinker levels and cement and binder intensity in concrete. This thesis shows the importance of having a thorough statistical base describing different end-uses of cement containing products to be able to see the emission reduction potential on all levels of the usage of the materials. There is a need for accurate data from the mortar, screed and render businesses to allow for a more detailed material flow, as well as more advanced statistics from the concrete industry, related to both end-uses, binder intensity and cement types used in various applications. This type of data would be very useful to be able to analyze the usage (and potential over-usage) of cement and cement clinker in constructions and how to reduce both the cement use, the cement clinker use and the associated CO2 emissions.