Wa-Karroong
Wathaurong Aboriginal Co-operative in Geelong has a new home. Wa-Karroong began as a conversation and got built by many hands, APC's among them.
For engineers and specifiers
Permcon technical data
One surface, three functions: pavement, stormwater quantity and stormwater quality. The figures on this page are the ones APC puts its name to.
A structural permeable pavement
Permcon is a 25+ MPa permeable concrete: a continuous poured surface with no joints, placed by APC's own crews in association with Boral Concrete ready-mix operations. A proprietary admixture and mix designs tailored to local conditions give it a void content of 20 to 25 per cent, so rain passes through the wearing surface at 8,000 to 10,000 mm/hr into a designed drainage, treatment or infiltration profile beneath.
The strength does not change between a footpath, a driveway and a car park. The thickness does. The standard slab is 125 mm and covers almost every application; larger car parks and heavier vehicles go thicker, and the loading chart below shows what that buys.
Aggregate is 7 mm in Victoria and 10 mm in other states. Ultracon, the smooth-finish version, uses 2 to 5 mm stone with a permeable resin for driveways, paths, pool surrounds and car parks. Finishes: plain grey, charcoal, soapstone and sandstone.
Estimated maximum axle load by slab thickness
Permcon is a rigid pavement, so its capacity rises steeply with thickness. At the standard 125 mm it carries cars, utes and vans every day. At 200 mm it is rated for a 14.8 t axle, and by 300 mm the estimate passes 30 t.
| Slab thickness (mm) | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 | 300 |
|---|---|---|---|---|---|---|---|---|---|
| Max axle load (t) | 3.7 | 5.8 | 8.3 | 11.3 | 14.8 | 18.7 | 23.1 | 28 | 33.3 |
Estimates from a rigid-slab extrapolation with flexural capacity proportional to the square of thickness, calibrated to 14.8 t at 200 mm from a Benkelman beam back-analysis for crane loading. For early sizing only: every pavement is designed for its own subgrade, base and traffic.
Typical design profiles
Every job is designed for its site, but three build-ups cover most of what we pour. Each sits on clean screenings, with geotextile where the subgrade needs it and a sub-surface drain with an elbow detail where the base is being used for retention.
Footpath and shared path
100 mm Permcon over a 100 mm base course. Detention in the base of about 28 litres per square metre at 85 per cent design capacity.
Driveway
125 mm to 150 mm Permcon over a 125 mm to 150 mm base course. Detention of about 37 to 42 litres per square metre at 85 per cent design capacity.
Car park and right of way
150 mm to 200 mm Permcon over a 150 mm base course and a sub base. Detention of about 42 to 56 litres per square metre at 85 per cent design capacity.
The rule behind those numbers: each 100 mm of clean screenings holds about 28 litres per square metre at 85 per cent design capacity. Where the ground will not take water quickly, the base holds it and an under-drain releases it at a controlled rate, which is what the council's stormwater engineer is usually asking for.
Stormwater quality
Permcon is MUSIC certified. If your council wants the treatment modelled in MUSIC, ask us for the parameters and we will send them with the quote. That matters most in Queensland, where a MUSIC model is part of the approval.
The pavement removes up to 70 per cent of heavy metals, hydrocarbons, detritus and suspended solids from the water passing through it. Independent assessment puts total suspended solids removal at 80 per cent, in line with the South East Queensland objective, with up to 60 per cent phosphate and 40 per cent nitrogen removal supporting the treatment train. Runoff temperature drops too, which the receiving creek notices.
Carbon
The mix carries 62 per cent less embodied carbon in its cementitious materials than a conventional concrete alternative, assessed to ISO 14067:2018 by Bureau Veritas and Toitū Envirocare.
Surface, durability and warranty
- Slip: P4 slip rating (45 to 54 BPN), so it is a wet-area surface as well as a pavement.
- Design life in excess of 30 years with the maintenance below.
- 10-year structural warranty. If the pavement fails structurally we assess it, remove it and replace it. Terms and conditions apply.
- Colours: plain grey, charcoal, soapstone and sandstone.
Maintenance
Monthly: look at it. Clear of leaves and debris, draining after rain, no sediment building up on the surface.
As required: keep adjacent garden beds and landscaping from washing soil onto the pavement, plant out bare ground upstream of it, sweep, blow or wash the surface, and check that overland flow paths have not changed (a landscaping change is the usual cause) so the pavement is not taking water it was never designed for.
Annually: sweep if the monthly checks did not call for it, and inspect the voids for moss or organic build-up and remove it.
Where it is used
Car parks, shared paths and council footpaths, shared driveways, sports courts, tree protection zones, bus stops on VicRoads roads and internal roads in caravan parks. APC has installed more than 100,000 m² of permeable surface since 2018, with teams in each state and crews placing 500 m² and more in a day.
Each build-up is repeatable: the shared-driveway detail below is delivered through seven of the eleven Victorian Government housing panel builders.
Case studies
Early Learning Centre, Warwick
A council job in Warwick: light-coloured Ultracon poured around an Early Learning Centre's existing cubby houses, sandstone blocks and garden beds to make a permeable play area.
Permcon Garage Driveway
A grey Permcon driveway runs up to a brown garage door, with a mulched garden bed and timber posts along the side.
Driveway for Residential Units
Ferns and red-leaved planting mark the bend where this dark grey Ultracon driveway curves past shared garages, its edges softened by garden beds.
Questions engineers ask
Can it take trucks?+
Yes, with the right thickness. The mix is the same 25+ MPa; the slab gets thicker. At 200 mm the estimate is a 14.8 t axle and at 300 mm it is over 30 t. Give us the design axle load and we will size it.
What happens on clay?+
The base does the work. Each 100 mm of clean screenings holds about 28 litres per square metre at 85 per cent design capacity, and a sub-surface drain releases it at a controlled rate. Vertical infiltration cores can reach a better layer below, as they did at HOTA on the Gold Coast.
Is there a MUSIC node?+
Permcon is MUSIC certified. Ask us for the parameters for your model and we will send them with the quote.
Does it need joints or expansion cuts?+
No. It is one continuous poured surface with no joints, which is also why there is nothing to sink, spread or grow weeds.
Who designs the base?+
We do, with your engineer. We use clean screenings, add an under-drain and filter cloth where the site needs them, and match the profile to the subgrade and the stormwater target.
Certified
MUSICcertified
MUSICcertifiedSend us the drawings
An estimator will come back with a profile, a thickness and a real figure. If Permcon is not the right pavement for the job we will tell you.