Foam Concrete 3D-Printed for Load-Bearing Walls

Many modern structures are built with insulation, for example insulated concrete forms (ICFs), foam concrete walls, and core-insulated double walls. foam concrete walls are a cost-efficient and energy-efficient alternative to traditional construction methods. They provide a high thermal insulation value, and they have good dampening properties against exterior noise. foam concrete walls also contribute to a more sturdier building structure, which can resist stronger wind loads.

ICFs consist of styrofoam blocks, like Legos, that are joined together and filled with concrete. They are a great alternative to wood framing, and can save up to 40% in material costs compared to traditional frame wall systems. They also help regulate indoor temperatures, significantly reduce energy costs, and dampen outside sounds.

The concrete on-site 3D-printing concept developed by Technische Universitat Dresden (CONPrint3D) allows the direct production of formwork-free load-bearing foam concrete walls. These walls can be printed with foam concrete and with an additional insulation layer. Moreover, the CONPrint3D method provides a high degree of automation and can be used in large quantities.

The aim of this study is to determine whether foam concrete, which is produced using the CONPrint3D method, possesses the strength needed for use in load-bearing walls. For this purpose, foam concrete samples with different mixture compositions were extruded and tested for compressive and flexural strength. A scanning electron microscope (ESEM) was used to investigate the pore structure of the foam concretes. It was found that the foam concretes possessed shape stability, and the compressive and flexural strengths were comparable to those of conventionally cast foam concrete. The pore structure of the foam concretes consists of gel pores and capillary pores, as well as entrained and entrapped air voids.