R-ZiEMENT

R-ZiEMENT - Brick recycling in cement - Innovative research on the circular economy

Resource-efficient circular economy - construction and mineral material cycles (ReMin)

R-ZiEMENT is conducting interdisciplinary and cross-industry research into the extent to which resource-efficient cements can be produced with recycled building materials containing bricks and a reduced proportion of clinker. This would reduce process-related CO2 emissions, conserve resources and establish new process routes.

The project is being funded as part of the "Resource-efficient circular economy - construction and mineral material cycles (ReMin)" funding measure. "ReMin" is part of the BMBF research concept "Resource-efficient circular economy" and is aimed at resource-efficient construction and the expanded use of mineral secondary raw materials from construction waste, slag, ash and mining residues.

Recycled building materials as the main component in cement

To what extent can recycled building materials containing bricks be used as the main component in cement? The R-ZiEMENT project is investigating this question. If successful, this would contribute to the resource-saving use of raw materials and the establishment of new types of processes along the value chain of mineral building materials.

According to the German Brick and Tile Industry Association, around 11 million tons of broken bricks from deconstruction and demolition are available every year. RC roof tiles are used, for example, to produce turf and vegetation substrate. This can reduce the consumption of natural products such as lava or pumice.

The tried-and-tested process of producing cement and using it in concrete is to be expanded in the project to include the processing and recycling of bricks as a building material and researched in the laboratory. Whereas previously construction waste from old concrete was processed and turned into recycled aggregates for new concretes, in future brick-rich construction waste from demolition or residual brick masses from production and new construction, for example broken bricks, construction site returns and brick grinding dust, will be ground and used as the main component of new cements.

Closing material cycles by using recycled building materials containing bricks

By using recycled building materials containing bricks as the main components that react pozzolanically, the aim is to produce high-performance cements and durable concretes that meet the relevant assessment criteria in approval tests and thus prove their technical suitability for use in the construction industry. The project's outstanding ecological and economic relevance is due to the development of an innovative, cross-sector concept for the provision of technically and ecologically optimized construction products. This is to be achieved by closing material cycles.

Main topics and work steps

The project is divided into four main topics. VDZ and IZF are mainly responsible for the analytical work in the areas of environmental compatibility, mechanical process engineering, chemistry and mineralogy as well as extensive laboratory tests on raw materials, cements, mortars and concretes. The partners Leipfinger-Bader and Scherer & Kohl examine the material flows containing bricks, possible preparation and sorting processes in practice, take specific samples and support the logistics and analysis on site. Spenner provides the cement clinker and limestone components, which - in addition to the recycled building materials containing bricks - are to be used as the main components of the new cements. In addition, after extensive material and granulometric optimization, operational tests are planned for production in the cement plant and for use in concrete.