Researchers Use Recycled Glass To Develop 3D Printable Concrete
Researchers from RMIT University have developed a new eco-friendly 3D printable concrete material that uses recycled glass as an aggregate. By opting for recycled glass particles instead, the RMIT team believes its work could propagate circular economy principles in the construction sector, bridging the benefits of 3D printing and sustainable concrete production. Interestingly, the team also investigated the effects of the glass particles on the flexural strength and crack propagation characteristics of the concrete. They determined that the novel formulation could actually provide benefits in the way of mechanical properties too, depending on the direction it is 3D printed. To make concrete, you need a mixture of portland cement, water, and several aggregates such as sand and gravel. The aggregates are crucial as they act as a binder for the concrete mix. Without them, water-based cement mixtures don’t hold very well and aren’t suitable for construction applications. Aggregates also act as a filler for the mix, reducing the porosity of the concrete for a stronger product. The RMIT team believes that a more sustainable approach to concrete 3D printing lies in the use of recycled glass instead, since glass has a chemical composition and physical properties not too dissimilar to raw sand. The flexural strength of the structures was characterized via a three-point bending test, while X-ray micro-computed tomography and scanning electron microscopy (SEM) were used to evaluate the specimens’ microstructures. This allowed the team to analyze the pore size distribution and crack propagation pathways in the post-test specimens. The results showed that, firstly, the integration of recycled glass particles increased the porosity of the 3D printed samples. This was more evident with the use of coarse glass particles than fine glass particles. Using X-ray imaging, the researchers were able to show that the primary component of crack propagation was the presence of glass particles in voids. Despite this, the flexural strength of the 3D printed samples actually increased by 25% to 33% with the addition of glass particles, but only when the beam span was perpendicular to the direction of printing. When the beam span and printing direction were parallel, the glass particles were found to decrease flexural strength by 8% to 20%. As such, the RMIT team determined that recycled glass could be used as a suitable alternative to river sand for sustainable concrete 3D printing, provided the printing direction was carefully controlled.
Tags : INTERNATIONAL construction recycled glass eco-friendly Sustainable 3D Printing RMIT University Concrete Mix River Sand