Ireland’s journey toward a sustainable built environment just took a massive, clinker-free step forward. After attending a landmark demonstration at Sisk’s Cherry Orchard site, ROBBIE COUSINS writes about how a collaboration between Trinity College Dublin and industry leaders is moving geopolymer technology from lab to site – with the potential to slash carbon emissions by 70% and, with a circular economy approach, transform the nation’s biomass waste into the high-performance foundation of a greener future.
In a landmark moment for the Irish construction industry, March 2026 marked a significant leap toward decarbonising the built environment. At a demonstration event hosted by Sisk at their Land Development Agency (LDA) site in Cherry Orchard, Dublin, for the first time in Ireland, clinker-free geopolymer concrete—a material capable of reducing carbon emissions by up to 70% compared to CEM I—transitioned from the controlled environment of the laboratory to be presented on a construction site.
The event, attended by a number of key industry stakeholders, including representatives from Enterprise Ireland (EI), the National Standards Authority of Ireland (NSAI), Transport Infrastructure Ireland (TII), and Irish Concrete Federation (ICF), Construct Innovate and the LDA, Hines, IPUT, OPW and ARUP as well, showcased the results of a 20-month seed programme funded by Construct Innovate.
The project represents a powerhouse collaboration between Trinity College Dublin (TCD), Sisk, FLI Precast, Roadstone and Bord na Mona, all working toward a singular goal: turning biomass ash waste into high-performance infrastructure.
The science of circularity: beyond Portland cement
At the heart of this breakthrough is the work of Dr Zehao Lei and Prof Sara Pavia from the Department of Civil Engineering at Trinity College Dublin. For many years, Prof Pavia has investigated the latent potential of waste materials. However, this project marks a strategic shift from using waste as a mere “filler” to using it as a primary binder.
Traditional concrete relies on Portland cement, a material whose production is notoriously carbon-intensive. The process involves burning limestone and shales at extremely high temperatures, releasing CO2 both from the fuels used and the chemical “decarbonation” of the rocks themselves.
During a technical presentation, Dr Lei explained, “With geopolymers, we don’t use any rocks. We don’t burn any rocks. We use waste. We activate that waste with a safe, composite activator to create a chemical reaction. This creates a binder that is not only sustainable but mechanically stronger and more durable than traditional options.”
The specific waste stream in focus is biomass ash, produced in vast quantities across Ireland as power plants shift away from peat and coal. Currently, Ireland produces over 20,000 tonnes of biomass ash annually, much of which is destined for In this instance, the ash involved was exhaust material from Bord na Mona’s Edenderry power station in the midlands. By repurposing this ash as a concrete ingredient, the industry could avoid at least 20,000 tonnes of CO2 emissions every year—an impact equivalent to removing thousands of cars from Irish roads.
Breaking the industrial barrier: The two patents
While the chemistry of geopolymers has been understood for years, industrial adoption has been stalled by practical hurdles—primarily workability and setting times. To bridge the “lab-to-site” gap, the TCD team developed and patented two critical technologies.
The first is a bespoke biomass ash-based geopolymer formulation. By characterising the chemical composition, mineralogy, and particle size of the ash—sourced largely from the Edenderry power plant in the midlands for this research —the researchers optimised a mix that rivals the strength of CEM II or CEM III cements.
The second, and perhaps more crucial for site managers, is a specialised retarding system. Historically, geopolymers have been difficult to control once mixed, often setting too quickly for transport or placement. The new patented retarding system ensures the concrete remains workable and transportable in real-world conditions.
“This is about making low-carbon concrete usable at scale,” explained Prof Pavia. “Unlike many alternative materials that require entirely new processes, this system is designed to integrate within existing concrete production, transport, and placement infrastructure.”
Industry leadership: Sisk as a facilitator
For Sisk, hosting the demonstration was a natural extension of its Low Carbon Concrete Working Group’s agenda. Ross Cullen, Technical Director, at Sisk, emphasised that the company sees itself as a facilitator for innovation.
“We are neither a concrete specifier nor a supplier, but we are hearing the signals from our clients,” Cullen said. “They are asking for low-carbon options, and at present, our options are limited. We’ve been optimising mixes with ground granulated blast-furnace slag (GGBS), but that isn’t a long-term solution for total decarbonisation.”
The demonstration at the Cherry Orchard site showed that geopolymer concrete could be handled by site crews without specialised training.
Roadstone demonstrated that the biomass ash-Portland cement blends could be mixed and poured like normal concrete, while FLI Precast displayed “Kelly blocks” and structural beams made with 100% cement-free geopolymer binders.
The role of Construct Innovate
The project’s success was underpinned by Construct Innovate, Ireland’s national research centre for construction technology. Construct Innovate supported the project with funds from its seed funding programme.
Colm McHugh, Centre Manager, Construct Innovate, highlighted that the drive for these materials is being accelerated by looming European legislation.
“Between 2028 and 2030, we expect to see mandated carbon budgets on all types of construction projects,” McHugh explained. “This will focus the attention of everyone, from clients to subcontractors. Concrete, being such a carbon-intensive material, is front and centre of that focus.”
The 20-month seed programme served as a Pathfinder project. While the initial results are promising, the next phase will involve more rigorous testing on durability and long-term mechanical properties to provide the data required by the NSAI for official standardisation.
A site-ready solution
The demonstration event was a physical proof of concept. Attendees walked through the site to view a biomass ash concrete column poured by Roadstone and precast elements produced by FLI Precast. To the naked eye, the material looks and behaves like the concrete the industry has used for a century. However, its chemical footprint tells a different story.
Prof Pavia noted that 80% of the biomass ash used is indigenous to Ireland, with the remaining 20% coming from sustainable overseas sources.
A high level of “localism” further reduces the carbon footprint associated with transport and supports the circular economy within the Irish midlands.
The road ahead: Standards and procurement
As the event concluded, the discussion turned to the “valley of death” between research and widespread adoption. Ross Cullen acknowledged that getting new materials specified into national standards is a complex process involving risk management.
“We need the experts, the NSAI and the data to ensure we can use these materials with confidence and reliability,” Cullen remarked. “Dialogue and debate are key. By bringing the research onto a construction site, we generate the momentum needed to deliver these pathways.”
While the biomass ash product was not used in the permanent structure of the LDA development at Cherry Orchard, the LDA’s willingness to facilitate the on-site demonstration signals a growing appetite among semi-state bodies to champion sustainable procurement.
In conclusion
The “Biomass Ash to Concrete” project is more than just a successful laboratory experiment; it could be a blueprint for how Irish academia and industry can collaborate to solve global problems with local solutions.
By turning a waste product from the energy sector into a high-value asset for the construction sector, Trinity College and its partners have demonstrated that net-zero construction is not a distant dream but a tangible, pourable reality.
As Ireland looks toward its 2030 climate targets, the 20,000 tonnes of biomass ash currently sitting in landfills represent 20,000 tonnes of opportunity. With the patents in place and the industry leaders aligned, the Pathfinder has found its way.
And with that, in time, future concrete trucks that roll onto Irish building site may be hauling a binder inside that started life in a midlands power plant, marking a full circle in Ireland’s journey toward a sustainable future.
PROJECT KEY FACTS:
– Carbon Reduction: 60-70% compared to CEM I.
– Annual Potential: 20,000 tonnes of CO2 savings in Ireland.
– Lead Research: Trinity College Dublin (Prof Sara Pavia and Dr Zehao Lei).
– Industry Partners: Sisk, Roadstone, FLI Precast.
– Funding: Construct Innovate (Seed Programme)
– Technologies: Patented geopolymer formulation and retarding system.