+LAB is the 3D printing laboratory of Politecnico di Milano, based at Department of Chemistry, Materials and Chemical Engineering "Giulio Natta". Its activity began in November 2013, and since then Marinella Levi and its team welcome engineers, designers, researchers and makers every day, proposing a multidisciplinary approach to 3D printing where research, design and teaching come together to create innovation in materials and technology itself.
In the context of the European project SaltGae, which aims at the use of microalgal biomass for the purification of industrial wastewater and its exploitation at the end of its life, the +LAB has studied the possibility to print in 3D geopolymers with additive microalgae at the end of its life. The research has shown that the addition of microalgae reduces the viscosity of the fluid, thus improving the printing process, without reducing the mechanical properties.
When mixed correctly with other materials, such as clay or bentonite, geopolymers form a viscous fluid that can be printed in 3D. The geopolymer reacts at room temperature without requiring heat treatment, which is necessary for clays. The final material is a solid with properties similar to those of concrete, but with greater heat and flame resistance. In addition, geopolymers have a less severe environmental impact than cement paste and it is possible to replace some starting reagents with materials from industrial waste or renewable resources.