On-site ready-mix concrete 3D Printing with Karlos

Construction 3D Printing has been growing rapidly enabling construction sector to overcome long-standing challenges such as low productivity and slow construction speed. Most of the industrial 3D printing technologies print with fine mortar and follow assembly of prefabricated elements either off or on-site. Another approach often followed is printing lost formwork with mortar and then filling with conventional concrete. All these approaches have many limitations including proneness to shrinkages cracks, high CO2-footprint, high material usage and high production & transportation costs.In contrast to other technologies the Karlos (see Fig. 1) 3D Printing technology focuses on the on-site production of load-bearing walls with coarse aggregated concrete. The printed structures use standardized ready-mix concrete, and are massive with right-angled corners and flat surfaces, thus enabling application of existing norms for the structural design and material approvals (see Fig. 2). In 2023, first on-site printing projects with Karlos mobile on-site printer are completed in Germany and has demonstrated the potential of this innovative technology. The truck-mounted Karlos boom printer has integrated piston-pump and advanced control software which enable mobility, faster-setup, and in-situ production of large concrete structures such as multi-story houses and industrial buildings.