3D printing for construction based on a complex wall of polymer-foam and concrete

The objective of this paper is to present a new advanced Additive Manufacturing (AM) process for the construction of concrete structures: Batiprint3dTM. The proposed advanced technology consists of creating a complex wall of 3D-printed materials using a mobile and polyarticulated robot: two polymer-foam printed walls are used to encase a subsequent third wall made of concrete. Once the walls were in place, the foam is maintained to provide both an internal and external insulation to the house without requiring thermal bridges. This technique of the complex wall with 3D-printed composite foam/concrete material is similar to the use of expansive-foam formwork (FW) filled by concrete or Insulated Concrete Forms (ICF) but in that case printed directly on site. By using 3D printing for the foam and extrusion of the concrete with the same robotic system, the technique creates jointly both the structure and thermal elements of the building. In the first part of this paper the composite foam/concrete 3D printing method and optimized process parameters are présented. Polyurethane (PU) foam has weak mechanical properties and the filling of the internal void with concrete can yield in high deformations and even failure of the FW, it is therefore necessary to control this phenomenon. For that, an experimental study has been conducted to determine a filling procedure capable of minimizing the deformations. The results show that spacers between the two foam walls can allow for wall heights of poured concrete up to 50 cm. The problems solved, it was decided to experiment in full scale this new walls 3D printing method with the construction of YhnovaTM, a real 95m² social housing. This technology Batiprint3dTMhave been used, it is possible now to propose a synthesis of the impacts of this new advanced technology for construction.