The Grasscrete™ permeable paving system has been recently used for a residential driveway on Waiheke Island.
The driveway has a grade of approx. 1:5 and covers an area of approx. 60m2. The existing driveway had to be graded to a level substrate and a 50mm sand blinding layer placed and compacted before the 600mm x 600mm x 150mm deep Grasscrete™ modules were placed together. A gap of 250 – 300mm was left at either edge of the modules and a timber board was placed to retain the concrete edging. 200mm x 200mm x R8mm SE82 mesh sheets from Fletcher Reinforcing were placed into the Grasscrete™ grid locating onto the spacers on the formers suspending it off the ground.
Due to the gradient and access to the driveway, a concrete pump was used to pump the concrete into the modules. Local concretec contractors mixed black oxide into the concrete mix before pouring to create a dark grey aesthetic. Concrete was pumped and screeded off level to the top of the formers and due to the gradient finished by trowel and broom.
Concrete was allowed two days to harden prior to melting out the former tops to expose the voids for soil filling. Formers were then punctured in the centre and an industrial LPG-powered heat torch (used for torch on roofing membrane) was then used to melt out the top of the formers.
Once all voids were exposed the pumice/topsoil growing media was placed into the voids and watered into mallow settlement. Voids were then filled back to ground level and hard-wearing fescue, ryegrass and browntop blend grass seed were applied to the surface.
