Motivation and project objectives

Around 30 million tonnes of concrete are produced in Germany every year. In addition to cement, concrete contains 70-80% aggregates by volume. Due to a rapid increase in construction activities and regulatory restrictions, there are now regional shortages of sand. Bottlenecks could be overcome by recovering and reusing aggregates from concrete rubble. Compared to other industries, the recycling of building materials is still very limited. In the case of concrete, the cement-based binder matrix has not yet been sufficiently separated from the aggregates. Crushed concrete sands therefore do not yet have the same strength properties as pure sands and may not be used in the fraction (< 2 mm) in concretes. This project aims to develop a new technology based on wet grinding technology in combination with attrition to improve the separation of aggregate and binder matrix. This will make it possible to obtain high-quality recycled sand for concrete production and a fine fraction rich in cement paste.

Tasks of the IART

Development of a wet grinding process for separating cement paste from the fine aggregate in mortar and concrete to produce high-quality recycled crushed sand (< 2 mm) for use as recycled aggregate, and cement paste for reuse in cement production.

Optional funding information

***Funded by the Central Innovation Programme for SMEs under the auspices of VDI/VDE Innovation + Technik GmbH***