Located on the Queensland Central Coast, the City of Mackay has experienced major population growth over the past 10 years. This growth has been driven predominately by the booming mining, engineering and sugar cane industries.

This population rise has led to significant infrastructure projects being commissioned, including the federally sponsored “Mackay Sports Area.” The work required the installation of a new slip lane, turning lane and culvert crossing over a tidal flood drain.

MCC commissioned C&C Civil and Mining contractors to install shotcrete ground support to the banks of the culvert crossing. To meet the design life requirements, eliminate the risk of salt water corrosion and improve the structural integrity of the substrate, MCC specified BarChip structural synthetic fiber reinforced shotcrete (SFRS) for the ground support.

Implementing the wet delivery method BarChip fibers were added at the batch plant at a dose rate of 5 kg/m3 and transported to the site to be applied by robotic spray equipment.

Using state of the art Jacon Pronto remote spraying equipment, C&C applied 65 cubic meters of BarChip SFRS at an approximate thickness of 100mm to all four banks. All SFRS for the project was supplied by Hanson Construction Materials.

To ensure all work could be carried out within the low tide time frame, alkali free accelerator was injected at the nozzle allowing for quicker set of the final shotcrete layer. This method allowed all 4 banks to be completed in one day over the course of a single tidal shift. This method significantly outperformed expected time frames of more traditional construction methods that would require securing form work, placing steel mesh and trowel finishing, which would have taken an estimated 4 to 5 days.