Scientists based at the Swinburne University of Technology and Hebei University of Technology have managed to turn construction waste into a sustainable new 3D printing material. Using recycled concrete aggregate, ceramsite particles and desert sand, the team have been able to formulate a low-cost extrudable building material, in three different particle gradings. During initial testing, the novel concrete substitute demonstrated a self-supporting ‘skeletal’ effect, potentially lending it the strength and durability needed for deployment within heavy-duty construction applications.
Although 3D printing has been used to build everything from 97 foot-long pedestrian bridgesto stylish concrete furniturein recent weeks, conventional materials continue to limit the technology’s construction potential. Once printed, existing cements feature weak bonding and yield structures with inadequate reinforcement, meaning that 3D printing is often deployed within one-off low-risk architectural projects.
However, the flexibility of additive manufacturing also has its advantages, and presents the opportunity to develop new eco-friendly substitutes for concrete, a material which produces over 70kg of CO2 per tonne. Within conventional building materials, aggregate forms more than half the mixture, thus many have experimented with switching to virgin aggregates, but this is now becoming a burden on natural resources.
As an alternative, the scientists have now combined desert sand with the ceramsite used to manage lake sediment as well as demolition waste, to formulate a novel lightweight concrete replacement. Given that less than 5% of concrete is recycled, and it’s often used within floor tile and pavement production, the team’s material could eventually help reduce the building industry’s wider environmental impact.