New Supplementary Materials in Cement Production

Production of Portland clinker leads to considerable CO2 emissions. Replacing parts of the Portland clinker by supplementary cementitious materials (SCMs) in production of Portland cements is an effective way of reducing CO2 emission from manufacturing of Portland cement, and is widely used today. Norcem apply more than 200.000 tons of fly ash annually. Fly ash is a by-product from the combustion of coal in coal-fired powerplants. The supply of traditional SCMs, such as fly ash, will decrease substantially in the future. It is essential to find new SCMs that can replace the traditional SCMs in production of Portland cements. These new SCMs can be natural minerals or waste-based materials from various industries. The aim of the project has been to identify potential new SCMs, and document the suitability of the various new SCMs, for use in cement production. Reactivity (strength development), water demand and durability properties of new SCMs have been investigated and thoroughly documented. The results obtained obtained show that three of the investigated new SCMs have properties that makes them qualified to replace fly ash. One of these materials, a natural vulcanic rock with pozzolanic properties from Iceland, is considered to be the most attractive material to replace fly ash. Norcem have started a project to prapare for the implementation of the Icelandic material at our cement plants and in our products. A HeidelbergCement project has been established to plan the necessary production- and logistic facilities of the new SCMs, and prepare an AFE. This is a substantial industrial project which will require considerable investments. According to the current plan, Norcem will be able to use the new SCMs as substitute for fly ash by the end of 2025. This will ensure that Norcem will be able to produce cementproducts low in CO2 emission, also after the supply of fly ash diminishes or comes to a stop.

Replacing Portland clinker by SCMs are an effective way of reducing CO2 emission from manufacturing of cement. Norcem has used fly ash from incineration of hard coal in power plants as SCM for more than 30 years. However, as this type of power plants are being phased out the supply of coal fly ash will diminish. The anticipated and actual outcome of the project is primarily the identification and the technical- and scientific documentation of new SCMs that can replace coal fly ash in the future. This has led to internal projects in the company with the aim to industrialize the exploitation of one of the identified SCMs. An effect of the actual outcome is a considerable reduction in CO2 emission from the cement and concrete industry in Norway, compared to the situation where alternative SCMs to replace fly ash would not have been established. The impacts of the project for the society is primarily the securing of cement and concrete products low in CO2 emission for the future.

Reducing the CO2 emissions from Norcem's cement production has high priority for Norcem. Replacing Portland clinker by supplementary cementitious materials (SCMs) is one of the effective technologies to reduce CO2 emissions. Norcem has up to now applied fly ash as an SCM for this purpose. However, the supply of fly ash from coal fired power plants will diminish in the future, as coal based electricity increasingly will be replaced by renewable energy sources. In order for Norcem to continue their efforts to reduce CO2 emissions, and continue to be among the most environmentally friendly cement manufacturers in Europe, Norcem needs to apply other SCMs than fly ash in their cement production. The main objective of the project is to develop the technical and scientific basis for Norcems future cement products based on the use of new SCMs. Some of the new SCMs may possess less beneficial properties than fly ash, for example they may provide less workable concrete and they may provide lower reactivity. However, by combining various SCMs in a clever way synergy effects may be obtained, and the less beneficial properties may be suppressed. Finding these synergy effects and optimize these is the major R&D challenge.