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Aim of research

The aim is to determine interactions between concrete admixtures that accelerate strength development and cements with several main constituents. By systematically varying cement-technical parameters in conjunction with the targeted use of different accelerating agents, it is investigated how the reaction of the various main constituents in cement can be stimulated earlier and thus the early strength development can be increased without significantly affecting the late strength and durability of concrete. It is also  determined to what extent the latent hydraulic or pozzolanic reaction of the further main constituents besides clinker can partially compensate for this. The influence of reduced w/c ratios and partially retarding superplasticizers, which are necessary to process such water-reduced systems, on the strength development of accelerated systems is determined. The influence of more intensive, two-stage mixing processes on the early strength will also be comparatively investigated in tactile tests.

Methods and benefits for small and medium-sized companies

In addition to strength tests, hydration reactions and microstructure formation are determined by heat flow calorimetry and differential scanning calorimetry, X-ray analysis, electron microscopy, ultrasonic transmision measurements and porosity measurements. The results are verified by strength and durability tests on concrete. The results will primarily support SMEs in the development and marketing of innovative, clinker-efficient cements and the resulting sustainable concretes with improved strength development. This maintains and strengthens the competitiveness of SMEs in the decarbonisation of concrete construction.

Sponsors

The IGF project 21385 N of the Research Association VDZ Technology gemeinnützige GmbH - VDZ Technology gGmbH, Toulouser Allee 71, 40476 Düsseldorf, Germany, is funded by the Federal Ministry for Economic Affairs and Energy via the German Federation of Industrial Research Associations (AiF) within the framework of the programme to promote Joint Industrial Research (IGF) on the basis of a resolution of the German Bundestag.

Person to contact

Do you have any questions on this subject?

Dr Jörg Rickert
Chemistry and mineralogy

+49-211-45 78-283
zch@vdz-online.de

Other items of possible interest

01.08.2020

Research projects

Influences of two-stage mixing on the hydration behaviour of Portland-composite cements and composite cements as well as on the concrete performance

The acceptance of resource-efficient cements with significantly reduced specific CO₂ emissions is still too low in construction practice. The main reason is that the early strength is not high enough for economical production processes and competitive construction with concrete. The research project is investigating the extent to which more intensive mixing and further cement constituents besides clinker increase the mixing energy input and can increase the early cement hydration and thus the strength development.

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