thomas zement GmbH receives approval for CEM II/C-M (S-LL) at Karsdorf site

thomas zement GmbH in Karsdorf is part of the thomas group and in April of this year received general building approval from the German Institute for Building Technology in Berlin (DIBt) for the CEM II/C-M (S-LL) 42.5 N Portland composite cement produced at the Karsdorf plant.

The CEM II/C-M (S-LL) as a composite cement

In CEM II/C-M (S-LL), a substantial part of the energy-intensively produced Portland cement clinker is replaced by other constituents. According to the European standard (EN) 197-5, the clinker content is between 50 mass% and 64 mass%. As this is a composite cement with several main constituents, granulated blastfurnace slag and selected limestone are ground in a qualified manner during the manufacturing process.

As blastfurnace slag will only be available in limited quantities in the future, care was taken in the development of the composite cement to ensure that, compared with a blastfurnace cement CEM III/A 42.5 N with comparable technical performance and clinker factor, significant quantities of the valuable secondary raw material blastfurnace slag are saved. The objective was not only to conserve this important resource but also to achieve a significantly more favorable ecological balance with very low CO2 emissions.

The CEM II/C-M (S-LL) at the Karsdorf site

The CEM II/C-M (S-LL) “Karsdorf” is approved in strength class 42.5 N. It may be used for the production of concrete, reinforced concrete and prestressed concrete in the following exposure classes: X0, XC1 to XC4, XD1 to XD3, XS1 to XS3, XF1, XA1 to XA3, XM1 to XM3. The cement may also be used for the production of bored piles according to DIN EN 1536 and for liquid-tight concrete (FD concrete) according to DAfStb guidelines. If alkali-sensitive aggregates are to be used in concrete according to the alkali guideline, the CEM II/C-M (S-LL) 42.5 N (na) may be used as cement with low effective alkali content (NA cement) according to the approval.

CEM II/C-M (S-LL) can be used in interior and exterior components of standard building construction and thus in at least 65% of in-situ concrete in Germany. This Portland-composite cement thus offers a clinker-efficient alternative to conventional cements in concrete construction. A major area of application for this cement is ready-mix concrete up to concrete compressive strength class C30/37.

Portland cement clinker will remain an important raw material for cement production in Germany in the foreseeable future. Therefore, increasing clinker efficiency while at the same time taking into account the resource availability of other cement constituents is a sensible approach to reducing CO2 emissions from concrete construction in the long term.

The cement division as a growth driver of the thomas group

For years, thomas gruppe has been pursuing a steady and long-term growth course in the cement, concrete components and ready-mix concrete segments. In the cement business, the acquisition of the Erwitte plant in 2017 and the Karsdorf plant in 2022 significantly improved the competitive position and the Group has since benefited from synergy effects. Furthermore, Karsdorf is of sufficient size to introduce a technology in the long term together with the clinker supplier Dorndorf that will capture the CO2 produced in cement production in an ecologically and economically viable size. “We are convinced that cement will become a ‘clean’ building material and believe in its future,” says Eckhardt Thomas, Managing Partner.


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