Name: Pamela Zuschlag

Title of project: Hydration mechanisms in novel blended cements

Description of project:

The replacement of clinker with supplementary cementitious materials (SCMs) is common practice in today’s cement production. Commonly used and standardized SCMs are for example fly ash, an industrial by-product from coal fired power plants or slag, an industrial by-product from pig iron production. The European standard EN 197-1 defines two Portland composite cements, which differ in the level of additional constituents. The so-called CEM II/A has a clinker replacement level from 6 % to 20 %. Portland composite cements with clinker replacement levels up to 35 % are classified as CEM II/B. The application of Portland composite cements in concrete has benefits in the short and long term of concrete structures. They can provide similar or improved concrete properties such as decreased permeability in aggressive environments, increased strength, and enhanced durability of concrete structures. Another benefit of blending in SCMs is the reduction of CO2 emission and energy consumption of the end-product, since there is no clinkering process involved in obtaining those by-products. However, the availability of today’s SCMs is decreasing. Consequently, there is an urgent need to identify new potential SCMs, but the finding of locally available materials in sufficiently quantities and for affordable prices, which can serve as a sustainable SCM is a challenge.

The most commonly used cement at Norcem AS cement plant in Brevik is a Portland composite cement containing 18 % fly ash, CEM II/A-V. But, the availability of fly ash in Europe will decrease within the next years. Therefore, Norcem needs to apply other SCMs in their cement production. Those new SCMs need to be available in sufficiently quantities and exhibit similar or better properties as the currently used fly ash. Therefore, the research project “NEWSCEM” was initiated. This project aims to provide the technical and scientific basis for Norcem’s cements, which they will produce in the future and offer on the Norwegian market. This PhD project contributes to WP4, where the hydration mechanisms will be analyzed. The new SCMs have various chemical compositions and physical properties. Consequently, the replacement of clinker with novel SCMs results in the formation of a different hydrate assemblage and microstructure. The focus in this study is the impact of the hydration temperature on the hydration phases and pore structure formed and its impact on the mechanical properties.

Funding: Norwegian research council (Link)

Date of start of PhD: 07.01.2019