Graphene oxide creates stronger 3D printed concrete, but less seems to be more

Australian researchers have investigated adding graphene oxide to cement, resulting in concrete that works better as a 3D printing material, according to a statement from RMIT University.

Engineers from RMIT and University of Melbourne found that addition of the nanomaterial increased the strength of concrete by as much as 10 per cent and made it electrically conductive.

This could present an alternative to ultrasonic or acoustic sensors used in the construction industry to detect damage, according to RMIT Associate Professor Jonathan Tran. 

Such methods could be bulky and difficult to regularly use on monitoring very large structures.

“But the addition of graphene oxide creates the possibility of an electrical circuit in concrete structures, which could help detect structural issues, changes in temperature and other environmental factors,” said Tran.

Graphene oxide helped make the bonds between layers in additively manufactured concrete stronger, and the material easier to extrude through a nozzle.

Tran added that the research was preliminary, though graphene oxide could potentially make 3D printed concrete a more viable choice in construction.

“With 3D printed concrete, not only does it help save time, money and labour, but you can also create more complex structures and reuse some construction waste in cement-based materials,” he explained.

The researchers compared dosages of graphene oxide at 0.015 per cent of the weight of cement versus 0.03 per cent, with the lower dosage having better strength.

RMIT PhD candidate and lead author Junli Liu said that too much could impact the flow of concrete and how well it extrudes, leading to more gaps between layers of concrete.

“Graphene oxide can also clump together instead of spreading out evenly, which can create weak spots in the concrete and reduce its overall strength,” said Liu.

The group’s work, titled “Exploration of using graphene oxide for strength enhancement of 3D-printed cementitious mortar” and published in Additive Manufacturing Letters, can be accessed here.

Picture: (Left to right) RMIT Engineering students Hoang Khieu, Wen Si, Thanh Ha Nguyen, Junli Liu and Shuai Li. (Credit Jonathan Tran)