With the proliferation of repair and construction 3D printing, we’ve seen ones that can make bridges and even houses. Now, the same principle is proving beneficial to infrastructure and road renovations. Leeds University have developed a prototype asphalt 3D printing drone that can fill in cracks in roadways by remote control. The concept has already attracted the attention of several road development contractors.
The project brings in researchers from Leeds University and also UCL, who developed the bitumen deposition technology. “Our 2050 vision is to have zero-disruption road works,” says Richard Jackson, the research associate at UCL who developed the printing mechanism. “It will be quieter, so we can do it at night and the goal is to have no human input at all.”
The use of drones and 3D printing significantly decreases costs, especially in comparison to full repair crews. After finding the cracks using a sensor, the drones navigate with GPS and repair cracks using the exact amount necessary. Richard Jackson gave the 3D printer a three-axis system with individual stepper motors that move the printed nozzle around.
The nozzle consists of an auger screw, a stepper motor for driving the screw and a pellet hopper which feeds in bitumen pellets. Then, heating resistors heat the pellets to liquid, which pass through the auger and come out through a 2mm aperture. Over the course of the project, they went through several versions and different levels of heat. The final prototype uses 125°C and 135°C at 1mm/second print speed and 4.4 rpm.
Self-repairing Cities Project
Both the printer and the drone are part of the wider project ‘Self-repairing Cities’. It has drawn the interest of various contractors, however according to Jackson, their interest is in a shorter-term solution using a semi-automated process, rather than a full-blown drone-delivered repair.
The asphalt 3D printing drone conforms to the principles of preventative maintenance. The self-repairing cities project also goes far deeper than just the drones. The ultimate vision is one where roads undergo constant scanning through sensors. These sensors could, for example, be placed on the underside of municipal vehicles such as refuse wagons or garbage trucks, where they could detect small cracks treated as soon as they are identified.
The researchers already tested the process on the Leeds University car park, where Jackson created bars of bitumen for testing. The printed bars showed up to nine times the ductility of the cast one, with similar fracture strengths. The printed sample was found to contain a stretchy brown substance dotted throughout its cross-section which wasn’t in the cast one.
Overall, the asphalt 3D printing drone prototype represents a great means of employing 3D printing for practical road repair. It has the potential to make better structures while also cutting costs and making pre-emptive renovations. We wouldn’t be surprised if this concept takes off in a big way.
Featured images courtesy of UCL and Leeds, retrieved via World Highways website.