Due to its good properties such as high strength, formability and durability concrete is one of the world's most widely used materials. At the same time, concrete, or rather the production of the concrete's main raw material, cement, has a negative climate impact. This is because a lot of carbon dioxide is emitted during the manufacturing process. To reduce this climate impact, a possibility is to replace a proportion of the cement with ground granulated blast-furnace slag (GGBS) and/or fly ash (FA) and use so-called environmentally improved concrete. But as the components or proportions of these are changed in the environmentally improved concrete, the properties of the material can also change, and thus it may be required that the current working method in production should change. The purpose of the work is to produce practical key figures and recommendations for how a casting, especially a winter casting, with green concrete can be done compared to a casting with gray concrete. This by focusing on temperature and strength development, compaction, and pumpability of three different construction concrete products during production. To investigate this, the projects Slussen, Veddestabron, and Hamnbanan have been visited. Questions about concrete casting have been asked to those in the projects, and data have been inquired and obtained. The products that have been examined and compared with each other are conventional gray concrete, concrete containing cement FA and green concrete where the cement has been replaced with 10% respectively 50% GGBS. The results obtained showed that no major differences are needed to be made in production, especially when small amounts of cement were replaced. When the cement is replaced with green concrete with 50% GGBS, it is required that the concrete is warmer and that extra observation should be made during the vibration, as the green concrete must not be vibrated as long as the gray concrete.