Using the mechanically activated fraction smaller 2 mm of crushed concrete as an altenative composite material in cement

• Applicant: Professor Dr.-Ing. Horst-Michael Ludwig
• Subject Area: Construction Material Sciences, Chemistry, Building Physics
• Term: from 2014 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 249375936

Because of scarce resources and the demand for recycling of waste materials, the recycling of concrete waste, not least due to the large mass flow, is an important area of ​​research to achieve necessary climate goals. In the first part of the project, it was explicitly shown that the usage of high-energy mills, in particular that of the agitator ball mill, has significant advantages in the treatment of old concrete crushed sand. In addition to the nucleating effect, an activation independent of the granulometric component could be detected. In addition, it has been shown that the separation of aggregate and cement stone plays a crucial role in the activability of recycled material. Accordingly, the new project should deal with the following questions:- What possibilities exist for the most effective separation of coarse and fine aggregate and cement stone?- Is it possible to combine separation, attrition and grinding?- Which properties does the recycled aggregate have?- What is the effect of the processed cement stone in the composite cement?- What cement performance can be achieved?- How does a "recycling cement" behave in concrete?As a key element of the proposed project period, the fundamental relationships between the mechanical impact and structural changes of the cement hydration products as well as the ecological benefits will be examined by means of practical applications in concretes.

• DFG Programme: Research Grants