Future Cast has recently been awarded a grant by the Department of the Environment, Climate and Communications under the Circular Economy Innovation Grant Scheme (CEIGS), to undertake research into the feasibility of using crushed construction and demolition (C&D) waste as a replacement for first-use aggregate stone in concrete, to be extruded by our 3D construction printer.
This process will implement the Circular Economy in three ways:
1) by the reuse of a material that would otherwise go into landfill
2) by avoiding the need for first-use aggregate
3) using a waste-free 3D construction printer.
The project team intend to 3d print outdoor street furniture as part of public realm projects around Ireland.
Our first project will be to design and 3D print benches for the use of local communities and picnic tables to be sited in outdoor amenity areas.
In 2020, the latest reference year reported, Ireland produced 8,200,000 tons of construction and demolition (C&D) waste, but only 8% of this (656,000 tons) was recycled 1.
Figure: Quantity of construction waste managed in Ireland, compared with CSO construction index (Source: EPA, NWCPO and CSO). Taken from the EPA website1.
The predominant type of waste produced was soil and stone waste (84%); this was almost all disposed of by backfilling, reclaiming excavated areas or for landscaping, practices that have negligible negative impacts on the environment in the case of soil.
Of all the concrete, brick, tile and gypsum waste, approximately 60% was backfilled or disposed of by other means, and only 40% recycled. This means that 295,200 tons of potentially useful material was sent to landfill.
Although Ireland has surpassed its target of 70% for the reuse of C&D waste (78% for 2020) 2, there is still room for improvement. As natural (first use) aggregate is a finite resource with an appreciable carbon footprint, the use of C&D waste as aggregate in concrete can be seen as a more environmentally friendly alternative 3,4.
Both the National Standards Authority of Ireland (NSAI) and the Environmental Protection Agency (EPA) are currently deciding on the criteria for accepting crushed C&D waste as a replacement for first-use aggregate in concrete 5,6,7.
Through research into the most favourable C&D waste to use as aggregate and rigorous testing to ensure it is fit for purpose, followed by the actual design and printing of structures to be used as public amenities (similar to those seen in Figure 2), our project hopes to advance the research into the reuses of C&D waste while providing a service to the local community.
- Environmental Protection Agency. Construction & Demolition Waste Statistics for Ireland. Environment and You Key Trends https://www.epa.ie/our-services/monitoring–assessment/waste/national-waste-statistics/construction–demolition/ (2022).
- Environmental, P. A. Best practice guidelines. BEST PRACTICE GUIDELINES for the preparation of resource & waste management plans for construction & demolition projects https://www.epa.ie/publications/circular-economy/resources/CDWasteGuidelines.pdf (2021) doi:10.2307/j.ctv19cwb64.9.
- Bravo, M., De Brito, J., Pontes, J. & Evangelista, L. Mechanical performance of concrete made with aggregates from construction and demolition waste recycling plants. J. Clean. Prod. 99, 59–74 (2015).
- Federation, C. I. Public Consultation on the : Waste Action Plan for a Circular Economy. (2020).
- National, S. A. I. En 13139:2002 s. 1–10 (2002).
- EPA. Decision on End of Waste Criteria relating to Recycled Aggregates from Construction and Demolition Wastes for use by Integrated Materials Solutions, 8-9 Hanover Street East Dublin 2. (2019).
- Environmental, P. A. BEST PRACTICE GUIDELINES for the preparation of resource & waste management plans for construction & demolition projects. Department of Environment, Climate and Communications. https://www.epa.ie/publications/circular-economy/resources/CDWasteGuidelines.pdf (2021).
Author: Dr Julia Montelin Powers, Geo-Technical Laboratory Technician and Quality Manager at Future Cast
Julia is currently currently researching ways to implement Circular Economic principles in the construction and quarry industries. Recent topics under review are the use of locally sourced construction and demolition waste as replacement aggregate in concrete, thus reducing embodied carbon in two ways, and the use of aerated recycled glass spheres as a lightweight aggregate replacement to improve the thermal properties of concrete while at the same time preventing a reusable resource from going into landfill.
Julia completed a first class honours BSc degree in Forensic Investigation and Analysis at IT Sligo in 2011. In 2012 she accepted a funding offer from the Irish Research Council to begin research into the effects of ultraviolet light exposure on mitochondrial DNA, with a view to developing a suite of prognostic biomarkers for skin cancer risk, culminating in the award of a PhD. She has worked as a water analyst for an environmental remediation project, as a lab technician investigating a novel form of cancer therapy and as an assistant lecturer in inorganic chemistry and molecular biology.