Supplementary Cementitious Materials - or SCMs for short - are substitute products with cement-like characteristics that can replace part of the cement in concrete. These are typically industrial waste products such as slag from the steel industry and fly ash from coal-fired power plants.
The company is already promoting the substitution of clinker in concrete with its concrete and cement admixtures. Here the challenge lies in the development of concrete strength and durability.
"With today's SCMs, the proportion of cement in concrete could theoretically be reduced by 30%-60%. In practice, however, these substitute products are only available to a limited extent, which is why demand is now significantly outstripping supply and the SCM substitution rate has remained stuck at around the 25% level over the last ten years." Philippe Jost, Head Construction and Member of Group Management
Global research efforts
In order to be able to further lower the proportion of clinker in cement, scientists all around the world are working on new substitute products. One thrust of this research is to make even more quality categories of steel slag and fly ash usable. Philippe Jost stresses the importance of these initiatives: "If these materials could be more broadly used, this would have a huge impact immediately." As things stand, a proportion of industrial waste products end up in landfill for a variety of reasons. For example, fly ash is not suitable for use as a substitute material in cement production if it contains too many coal particles, as this negatively impacts the quality of the final concrete. "At the moment, a residual coal proportion of 1%-2% is manageable. But if this figure could be increased to 5%-6%, less fly ash would end up in landfill," explains Philippe Jost. Other research approaches focus on the use of slag that is not yet utilized as an SCM in cement production. This development is all the more significant given that many countries will no longer be able to rely on coal-fired power stations in the future for climate and environmental protection reasons.
Reducing clinker content by 50% with LC3
The LC3 research project of the Swiss Federal Institute of Technology in Lausanne (EPFL), in which Sika is participating, is highly promising. With the use of a new additive, the volume of clinker used in the production of cement should be reduced by up to 50% in the future. This is a huge leap forward. In contrast to today's substitute products, LC3 is not a waste product but is produced from limestone and clay. "A crucial advantage of LC3 is its availability: Whereas the supply of current substitute agents is limited, the world is home to almost inexhaustible volumes of limestone and clay," says Philippe Jost. "Another positive aspect is that LC3 is a precisely formulated product."
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Sika AG published this content on 24 February 2022 and is solely responsible for the information contained therein. Distributed by Public, unedited and unaltered, on 24 February 2022 11:01:02 UTC.
Sika AG is the world leader in manufacturing and marketing construction chemicals. Net sales break down by family of products as follows:
- construction chemicals (84.1%): admixtures for concretes and mortars, repair mortars, reinforcement and sealing products, sealants, etc.;
- industrial manufacturing chemicals (15.9%): adhesives and sealants (mainly polyurethanes, glues, and butyls) primarily for the automotive, railway and shipbuilding sectors.
Net sales are distributed geographically as follows: Switzerland (3.5%), France (6%), Europe/Middle East/Africa (30.6%), the United States (21.4%), Americas (9%), China (11.6%), Asia/Pacific (10.4%) and other (7.5%).
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