Geopolymer 3D Printing | the new frontier of sustainable construction

3D Printing is opening the doors to new Sustainable Construction Materials: Geopolymers

What are Geopolymers?

Geopolymers are innovative materials that offer a sustainable alternative to traditional cement, with a production process that generates up to 80% fewer CO₂ emissions. Used in construction, they ensure high chemical and mechanical performance, withstanding extreme conditions. Their use dates back to ancient times, with the Romans utilizing pozzolana for durable structures like the Pantheon.

For years, WASP has been researching the possibility of 3D printing geopolymers with its LDM technology, opening doors to new applications for sustainable architecture through computational design and additive manufacturing.

Using Geopolymers instead of Clay

Behaving similarly to concrete, geopolymer pieces do not require firing to gain strength and become water-resistant.

This makes geopolymers a great alternative to clay, as they eliminate the need for the firing process, which can be highly energy-consuming in some cases, and drastically reduce shrinkage during printing.

Additionally, geopolymers often exhibit superior mechanical performance compared to clay. They typically offer greater compressive strength, enhanced durability, and improved resistance to thermal and environmental stresses, making them a more reliable material choice for a wider range of applications.

What are the challenges of 3D printing Geopolymers?

Due to their abrasive nature and high viscosity, most standard extrusion systems are unsuitable for printing geopolymers, as the material can damage or clog the machine during the process.

One solution developed by WASP to address this issue is the Manual Feeding Extruder. The system includes a hopper with a stainless steel mixer connected directly to a technopolymer screw and a stainless steel nozzle, enabling the printing of highly abrasive materials such as concrete and geopolymers.

Another aspect that has to be considered is curing and setting times, as geopolymers typically require controlled curing conditions (temperature, humidity) to develop their full mechanical properties.

It should be noted that printing with geopolymers requires significant expertise and caution, as the materials can be potentially dangerous if handled incorrectly. Since it is still primarily used for research, it is also not as accessible as more common materials like concrete and cement.

The combination of technical challenges, economic considerations, and the slow pace of standardization in new material technologies has limited the broader adoption of geopolymer 3D printing for now. However, its potential for sustainability, lower CO₂ emissions, and durability make it a focus of ongoing research and development, which could address these barriers over time.

Geopolymer 3D Printing and Moon Exploration

One of the most intriguing applications of geopolymers being explored in the aerospace field is the potential use of 3D printers to construct structures on the Moon using local soil, eliminating the need to transport tons of materials from Earth.

Funded by ASI – the Italian Space Agency, the two-year GLAMS Project aims to create structural elements for the construction of lunar bases through a 3D printing approach that uses geopolymer materials and binders extracted from lunar soils (regolith).

The research team, including the University of Padova, ICMATE, and WASP, optimized this geopolymer-based material and successfully printed the first prototype of what will be a larger 3D-printed architectural structure.

Uses of Geopolymers in Architecture, Design, and Research – WASP & Eindhoven University of Technology

There are many ways in which geopolymers can already be used through Additive Manufacturing here on Earth as well. For instance, the Eindhoven University of Technology and WASP have collaborated in the creation of a Computational Column in Geopolymer instead of traditional clay.

For this project, geopolymers were chosen over ceramics to reduce energy consumption by eliminating the firing process and to avoid the high levels of shrinkage and warping typical of ceramics, while simultaneously advancing research on this material.

Using the same base material developed as part of the GLAMS Project, WASP 3D printed a series of modules that were later assembled in the final product and presented at Formnext 2024 at BE-AM Stand.

The structure functions as a cladding system for structural steel columns, meant to accommodate plant growth in exterior spaces, as well as insects and small birds.

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3D Printers for Research

Discover WASP LDM (Liquid Deposition Modeling) technologies that enable the 3D printing of experimental materials for academic research, ranging from earth-based materials to concrete and more.