GeoSpray Storwmwater Sewer
GeoSpray Storwmwater Sewer
GeoSpray Storwmwater Sewer

Auckland, New Zealand
GeoSpray® Geopolymer: Stormwater Sewer Rehabilitation

Background
The city of Auckland, as with many other parts of New Zealand and
around the world, have utilised galvanised corrugated iron culverts as
part of the drainage network. Typical installations are to enable roads
and rail to cost effectively traverse creeks, streams and small rivers. The
original purpose for the installation of the Kashmir Road culvert is not
entirely clear but could have been to improve residential development
opportunities or to address streambank erosion that may have threatened
an existing residential dwelling. Whatever the previous reasoning for its
installation, nearby residential dwellings were under threat due to the
looming collapse of the 1.8 metre (70”) diameter culvert as a result of
eroded ground support and missing culvert invert for the majority of its
30 metre (98’) length. The local council was concerned that failure of the
pipe could destabilise adjacent land and cause flooding of neighbouring
properties.


Options
1) Open Cut Replacement – 14 days
Removal of old pipe and replace with new pipe. This option would require
sheet piling to support the nearby residential dwellings and whilst
technically feasible was discounted due to environmental concerns, cost
and disruption to local residents.
2) CIPP – 7 days
Installation of resin impregnated liner inside old pipe. Minimised risk
to local residential dwellings. Ability to perform works with minimal
disruption to local residents. Some concerns of impact on stream fauna.
3) GeoSpray – 7 days
Reinstatement of lost culvert invert using premix concrete to reduce
some culvert collapse risk. Installation of centrifugally cast geopolymer
mortar inside old pipe to provide fully structural rehabilitation. Minimised
risk to local residential dwellings. Ability to perform works with minimal
disruption to local residents. Environmentally friendly due to product
being inert once cured.

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