Brunel University London scientists have shown how waste glass could find use in 3D printed buildings, reports The Engineer.
According to the scientists, ground-up glass offers better insulating properties than more traditional concrete mixes and can be introduced to the cementitious composites as a lightweight filler.
Shedding light on their research, Dr Seyed Ghaffar – who is the lead of the Additive Manufacturing Technology in Construction Research Group at Brunel – says that “although much of our waste glass can be recycled to produce new glass products, a big quantity is still being sent to landfill.”
“So to reduce the waste glass that is being sent to landfill, different recycling strategies need to be investigated.”
According to Ghaffar, the construction industry could be one potential destination for the unrecycled glass, a partial substitute for the vast quantities of natural sand that is currently being used to meet global demand for concrete.
He and his team estimate that around 2000 recycled beer bottles could be used per square meter, if used in the 3D printing of a building.
In the course of their study, the scientists found that glass waste when used as a substitute for basalt aggregate – a substance that already provides good insulation – had a thermal conductivity almost a fifth lower.
“To be specific, the samples with 50% and 100% waste glass volume substitution had lower thermal conductivity by 11% and 17% respectively,” says Brunel’s Dr Mehdi Chougan.
“But it’s also worth noting that the thermal conductivity of soda-lime glass – the most common type of glass that you’d find in windows and bottles – is more than three times lower than that of quartz aggregate.”
The Engineer reports that the team also discovered that the addition of ‘expanded thermoplastic microspheres’ – spheres of polymer filled with gas – provided an additional boost to its thermal properties while increasing the viscosity of the poured concrete simultaneously.
Ghaffar and his team are currently scaling-up the project and 3D printing demonstration walls to get a better understanding of their thermal and mechanical performance.
Image and content: Cottonbro-Pexels/The Engineer