Aim of research
The aim is to determine the influence of more intensive, two-stage mixing processes on the early hydration and microstructure formation of differently composed, ressource-efficient Portland-composite cements and composite cements and also on the strength development and durability of concrete. Systematically, it is determined to what extent the cement performance can be improved by more intensive, two-stage mixing and the combination of limestone and blast furnace slag or fly ash or calcined clay, and the proportion of raw material-intensive and also energy-intensive clinker can be used more efficiently or further reduced.
Methods
The hydration and microstructure formation of suspensions and mortars produced in intensive mixers or suspension mixers at different energy inputs are determined by heat flow calorimetry, X-ray diffraction analysis, differential scanning calorimetry and electron microscopy as well as ultrasonic transmission measurements, compressive strength testing and porosity measurements. The results are verified on fresh concretes and hardened concretes, produced in industry-oriented, two-stage mixing processes on a pilot plant scale, by means of consistency, compressive strength and durability investigations.
Benefits for small and medium-sized companies (SME)
The results can be used in particular by SMEs in the cement and concrete industry to expand the portfolio of clinker-efficient cements with reduced specific CO₂ emissions and high-performance concretes and to evaluate corresponding mixing systems. The results will provide insights into ressource-efficient standard cements, which are currently used in a rather subordinate way, and help the concrete industry to better assess their performance using intensive mixing systems. This maintains and strengthens the competitiveness of SMEs in the decarbonisation of concrete construction.
