Indicative regional ground conditions
Dandenong sits on the Greater Dandenong plain, where the profile is mixed — from A-S sand margins to soft alluvial and swamp clay in pockets. Uncontrolled fill and high water table are common local considerations. The actual AS 2870 site classification for any individual property can only be established through a site-specific geotechnical investigation, taking into account soil profile, fill, moisture conditions and vegetation.
Regional ground movement (indicative, AS 2870)
Ground of this type may exhibit variable — soft-clay pockets can move significantly and may include Class P conditions. This is a regional indicator only — actual movement at a given address depends on soil profile, moisture history and tree influence.
| Application | Slab thickness | Sub-base | Reinforcement |
|---|---|---|---|
| Path / foot traffic | 100 mm | 100 mm compacted crushed rock | SL72 (SL82 on soft pockets) |
| Driveway (cars up to 3 t) | 125 mm | 100–125 mm compacted crushed rock | SL72–SL82 |
| Occasional truck (3–10 t) | 150 mm | 125–150 mm compacted crushed rock (consider geotextile separation on soft ground) | Rebar |
Nupave standard specification for typical conditions of this soil group — subject to site-specific assessment. Not a design substitute for a project engineer's report where one is required.
| Saw-cut / control joint spacing (100 mm slab) | |
|---|---|
| Spacing between cuts | 2.0 m – 2.4 m (tighter — soft/fill-prone ground) |
| Cut depth & timing | At least 25 mm on a 100 mm slab (¼ slab thickness). Saw-cut as soon as the concrete can be cut without excessive ravelling — timing will vary with the mix, weather and saw type. A quick trial cut on a low-visibility edge or offcut is best practice before committing to the full grid. |
| What joints do | Closer joint spacing and properly proportioned panels encourage drying-shrinkage and thermal movement to occur at planned locations. Control joints reduce the risk of random cracking; they do not prevent cracking caused by inadequate support or differential ground movement. |
| Panel shape | Keep panels close to square (length ≤ 1.5× width). Long, narrow panels are more prone to random cracking regardless of joint spacing. |
Concrete grade
All Nupave exposed aggregate is poured at N32 as standard, regardless of soil group. The aggregate-exposure process removes the top cement paste layer, so the slab benefits from the higher compressive strength, improved durability and better abrasion resistance of N32. For non-exposed external concrete work, Nupave specifies N25 or N32 depending on application, anticipated loading, exposure conditions, selected finish and any site-specific engineering requirements. Concrete strength alone does not compensate for inadequate subgrade preparation, drainage or ground movement — it is one element within a properly detailed slab system.
Slip layer (poly membrane)
A polyethylene separation or slip membrane may be considered where required by the slab design or site conditions. It can reduce friction between the slab and compacted base during concrete shrinkage, but does not prevent settlement, heave or other vertical ground movement. Where a project engineer or geotechnical report specifies membrane use, that specification takes precedence.
Sub-base — why it's a key part of the quote
Correct excavation, drainage, and a uniformly compacted crushed-rock base significantly reduce settlement and provide consistent support under the slab. It adds cost — both in laying and compacting the base, and in the extra excavation and spoil-removal that comes with the deeper dig — but that preparation is what a slab needs to perform over the long term. The preparation actually required may vary where uncontrolled fill, soft areas or unsuitable material are encountered on the specific site.
Curing coat
Concrete requires curing to develop its full design strength and durability. A liquid curing coat is applied after finishing, once bleed water has disappeared and in accordance with the manufacturer's requirements. It seals moisture into the concrete so hydration continues over the first 7 days — when the concrete's real strength develops. In summer, hot dry weather removes surface moisture quickly, so curing coat is essential to prevent surface crazing and reduced final strength. In winter, lower temperatures slow hydration, so curing is still required to reach design strength — the curing coat is still applied, and duration may need to be extended. Nupave applies curing coat as standard on all pours year-round.
Microfibres in concrete mix Optional add-on
What fibres actually do. Microfibres (polypropylene) get mixed through the whole pour and mainly control plastic shrinkage cracking in the first 24 hours, plus improve abrasion / impact resistance — they don't add real structural tensile capacity. Macrofibres (heavier synthetic or steel) go further, adding post-crack toughness and some flexural strength.
Genuine benefit as an add-on: reduces fine / hairline shrinkage cracking and improves durability on any slab, sand or clay.
Should NOT replace mesh on soft or highly plastic clay soils: fibres provide no real resistance to the larger, ground-movement-driven cracks that mesh or rebar controls.
Important: This is Nupave's enhanced standard specification for typical conditions in this suburb group, and is presented as a general reference. It is not a site-specific engineering design. Actual specifications for any individual property may vary based on site conditions, uncontrolled fill, tree influence, drainage, or requirements identified in a site-specific geotechnical or engineer's report. Where an engineered design has been prepared for the site, that design takes precedence.

