Use of circular construction materials for concrete 3D printing of recyclable concrete elements

Purpose and goal:

Concrete is one of the most common building materials in Sweden, and increased construction of housing and infrastructure makes it important to develop a more climate-neutral and circular construction industry. The goal is to produce a 3D printer material made from recycled concrete for 3D printing of lost forms for casting with green concrete and its further recycling.

The project aims to develop a concrete recycling process, early connected to 3D concrete printing for an improved, more circular material flow. Expected results and effects:

There are three key elements for the development within the project. The first is the development of material for 3D printing with a high content of recycled concrete. The second is the development of a green concrete for casting in 3D written lost forms. And finally, the recycling of all test writings and castings to gain knowledge about multiple recycling passages. At present, there is no knowledge of changes in the material parameters in recycled concrete for several cycles.

Approach and implementation:

Divided into 6 work packages, Svensk Processteknik, ConcetePrint, Betongindustri and RISE, together with their expertise, carry out the basic development to achieve the main goals. Material development and 3D printing tests lead directly to the first milestone at the halfway. Improving printer materials and developing a castable green concrete to reach the next milestone.

The last milestone is to recycle the materials used to investigate the impact of several recycling cycles on material properties. Life cycle analysis to examine the environmental impact of the process.