Introduction (and aim) – Because of high environmental goals set by the government regarding carbon dioxide emission, changes are required in the construction sector, which in year 2020 accounted for 21 % of Sweden’s total emissions. In the construction sector, concrete is used frequently since it has good qualities. An ingredient in concrete is cement, which, with its carbon dioxide-demanding production, annually accounts for 4 % of Sweden’s total emissions.

This study investigates the possibility of replacing parts of the cement in concrete with husk ashes from cereals, which is a biproduct from cereal production, and how it affects carbon dioxide emission. It also investigates what is required to implement the material on the Swedish construction market.

Method – The study has been conducted as a survey using the collection techniques literature study and surveys. The surveys were distributed to people working at companies and organizations that work with or research concrete. Through these, primary data has been generated, and secondary data has been collected through the literature study.

Results – If all the cement is replaced with husk ashes the carbon dioxide emission is reduced by 99,8 %. Studies show that the concrete will preserve its properties when up to 25 % of the cement is replaced with cereal husk ashes. When 25 % of the cement is replaced with cereal husk ashes, the carbon dioxide emission from the binder will decrease by 25 %. The survey results proved that the method of using cereal husk ashes in concrete is rather unknown, with only 53,8 % of the respondents being familiar with the method. The survey generated the result that research and new working methods are needed to be able to implement cereal husk ashes to the Swedish construction market.

Analysis – The carbon dioxide emission from cereal husk ashes is close to zero, since the energy used for combustion of the husks can be used in the district heating network. The emissions from the cereal husk ashes comes from the energy used to grind the ashes. The problems with implementation in the construction market are the lack of marketing and the volume of husks available in Sweden, which provides a low volume of useful ash. The process to calcinate the husks to obtain the right reactivity demands precision. The way it is incinerated today in district heating plants does not yield a good enough result to be used right away in concrete manufacturing.

Discussion – The results show that carbon dioxide emissions are significantly reduced by substituting cement with cereal husk ashes. One of the problems is the low volume of material, as the oats husk ashes that are currently put in landfills can only replace 0,9 % of the cement produced every year. From the survey one can infer that changes in laws and rules are required to implement the method, and that the material needs to be promoted since it is unknown. It is positive because of its low carbon dioxide emission, its use of residual products, and because it increases the strength of the concrete.