A project by Manchester Metropolitan University in the UK, along with partners across Europe, uses crushed waste concrete from demolished buildings to create 3D printed concrete designs such as public furniture.

Currently, about 65 million tonnes of demolition waste goes to landfills in Northwest Europe each year, whilst demand on natural resources for the production of new building materials remains high. Concrete production requires the extraction 54 million tonnes of marine sand annually in Northern Europe alone, with the dredging of this sand being unsustainable and causing damage to fragile marine beds and life.

The new project by Manchester Metropolitan University uses Recycled Fine Aggregates (RFA), which are produced when concrete from demolished buildings is crushed, to 3D print concrete designs.

The reuse of waste RFA could help save threatened natural resources and divert tonnes of waste from the landfills. However, concrete cannot currently be easily recycled for use in construction as the materials that make up RFA are so varied, meaning that the material does not meet strict building regulations. In addition, the RFA can be contaminated in the demolition process.

The researchers aim to perfect a 3D printing cement mortar using the recycled aggregates, to be used with five new, purpose-built concrete printers, which will be capable of manufacturing customisable urban, memorial or garden furniture and much more, since 3D printed products are not subject to the building restrictions.

3D printing can be used cheaply and effectively for one-off projects that would otherwise cost substantially more than using traditional concrete mould methods.

Photos: Manchester Metropolitan University