Trinity researchers 3D print Ireland’s first cement-free geopolymer
The trial, run with Harcourt Technologies Ltd., produced a Portland cement-free material made largely from bauxite refining residue
Researchers at Trinity College Dublin’s School of Engineering have demonstrated Ireland’s first cement-free, 3D printed geopolymer, working with construction technology firm Harcourt Technologies Ltd. The trial was held at HTL.Tech’s facility and confirmed that the red-brown material, made with bauxite refining residue, could be mixed, pumped, extruded and printed.
The geopolymer contained no Portland cement, and more than 30% of its cement-like content came from local industrial waste that would otherwise require treatment, long-term storage or landfill disposal.
“Broadly speaking, this successful trial demonstrates how local industrial residues can be transformed into functional, adaptable and visually distinctive construction materials,” said Sara Pavia, Professor at Trinity College Dublin’s School of Engineering.
“And because the material and method of production and printing essentially delivers two environmental benefits: it reduces dependence on carbon-intensive clinker cements, and creates a high-value use for industrial residues.
“Our preliminary assessment suggests the material could reduce embodied carbon emissions by approximately 70% compared to conventional Portland cement (PC) concretes, which would be a big improvement.
“The significance of the material itself extends beyond cement replacement. It is a flexible binder platform whose composition, rheology, setting behaviour and early-age performance can be tailored to different manufacturing processes and construction applications.”
A waste stream turned into a building material
3D printed construction offers several advantages over traditional methods, including shorter project timelines, the elimination of molds and formwork, and reduced material waste.
Printers build structures layer by layer from digital models with minimal manual labor and can produce complex curves and geometries that are difficult or costly to achieve with conventional construction.
Consortium eyes industrial-scale production
The geopolymer trial forms part of a wider research effort funded by Research Ireland alongside industry partners SISK, FLI Precast Solutions, McGrath Quarries, Techcrete and Roadstone, who contribute expertise spanning material development, concrete production, precast manufacturing, construction delivery and digital fabrication.
SISK leads the industry consortium, which aims to move the low-carbon material from laboratory research toward industrial use.
The next stage involves scaling the geopolymer from laboratory batches to the volumes and consistency required for industrial equipment, a step that introduces additional variables and which will focus on mechanical performance, durability, reinforcement, long-term stability, process control and regulatory compliance.
