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Material information

What is asphalt?

Asphalt is a surfacing material used for road, car park, and driveway construction. It consists of a mixture of aggregate (gravel and sand) and bitumen binder.

What is hot mix asphalt?

Aggregate (granite or laterite/gravel) is dried and and bitumen binder is added, mixed and heated to a temperature (around 150-170 degrees Celsius), to create hot-mix asphalt. NK Asphalt uses hot-mix asphalt for all our projects to meet exacting relevant standards and specifications.

What is bitumen?

Bitumen is a by-product of the refining process of crude oil and is a heavier end product, lighter ones being petrol, diesel and kerosene among others. This material is liquid at higher temperatures, stiffening as it cools to ambient temperature. It’s the binding agent in producing asphalt.

What’s better – asphalt or concrete? (For surfacing)

Both asphalt and concrete provide a good solution for large driveways, car parks, and commercial areas. However, asphalt is preferred for its durability, reduced glare, simple repairs, and fast, affordable resurfacing without the need for initial demolition and removal in most cases along with reduced time between laying and being open to traffic.

Why is hot mix asphalt better than other surfacing options?

Hot mix asphalt has a number of advantages when compared to concrete, brick paving and even recycled asphalt.

What type of areas can be surfaced with asphalt?

The most common asphalt surfaces are roads, car parks, larger driveways, strata residential areas, commercial properties, industrial warehouses, hardstands, racetracks, loading docks, and airport runways/helipads.

Sometimes asphalt is also used for outdoor basketball courts, tennis courts, and playgrounds.

What is a hardstand?

An asphalt hardstand area is thicker than a traditional asphalt surface so it can support heavy loads such as industrial-grade machinery, shipping containers, and large quantities of vehicles or construction equipment.

Why is asphalt quieter than other surfacing materials?

Asphalt has no need for joints to be installed in the way that concrete requires and is laid to give a virtually one-piece result unlike brick paving, so no added tyre noise from traffic.

Additionally, hot mix asphalt has a smoother dense bound surface, unlike recycled asphalt or bitumen seals which have coarser, loose aggregate surfaces.

How hot does it need to be for asphalt to melt?

Asphalt will not ‘melt’. Asphalt is extremely durable, even in the extreme Australian climate. By comparison, in some cases a bitumen sealed surface is mistakenly assumed to be asphalt. The bitumen seals can sometimes ‘bleed’ as the bitumen rises to cover its aggregate surface, resulting in a shiny, sticky black surface and is caused by a combination of over applied bitumen when constructed, traffic volumes, vehicle loadings and heat. This does not occur with asphalt.

A new asphalt surface can scuff if laid in hotter weather when a car does a stationary power-steering turn. Further traffic will often close up the scuff or can be repaired with a gentle reheat and tamping down, with no long-term detrimental effect.

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Asphalt colours

What asphalt colours are available in Victoria?

The primary colours of asphalt are black, dark brown gravel/laterite (no oxide), and 1% red oxide gravel/laterite. Each will gradually lighten over time as the oxidation process occurs.

Are all asphalt colours the same price?

Colours other than the standard black asphalt are going to cost more per square metre because the asphalt mixture requires oxides to be added and different aggregate type. The basecourse and other preparation steps beneath the surface use the same process no matter the colour of the asphalt above.

Why does asphalt change colour?

Asphalt will lighten in colour over time due to the oxidation process which occurs because of its exposure to traffic, air, weathering, sunlight, dirt, and varying levels of use. With time and use, the film of bitumen on the aggregate wears off, exposing the natural colour of the aggregate. Once the aggregate colour is visible, the resulting colour is relatively permanent and won’t continue to fade like concrete can.

Can asphalt be painted?

Coloured asphalt surfaces aren’t painted, rather, the asphalt mixture is combined with oxide pigments and aggregate changes.

Asphalt can be surfaced with several layers of acrylic-based material as in a sports court, with a standard granite asphalt under the acrylic, but is not suited to vehicle use.

Asphalt can be painted with lines, arrows, signage, and more.

Can asphalt be painted?

Coloured asphalt surfaces aren’t painted, rather, the asphalt mixture is combined with oxide pigments and aggregate changes.

Asphalt can be surfaced with several layers of acrylic-based material as in a sports court, with a standard granite asphalt under the acrylic, but is not suited to vehicle use.

Asphalt can be painted with lines, arrows, signage, and more.

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Asphalt maintenance

How do I care for an asphalt driveway?

An asphalt surface is a low-maintenance material, but to maximise longevity, it’s important to routinely sweep, remove stains, patch cracks and any damage to the surface.

Why has my asphalt cracked?

In time, asphalt can eventually show signs of damage such as cracks. The main causes for cracking are water ingress damage, tree roots, fuel/oil spills, sub-grade movement (e.g., clay, rock, or unstable sand) and use by heavier vehicles/ traffic than the design intended.

When do I need asphalt repairs?

As soon as possible after you notice signs of damage such as cracking or potholes. If damaged areas aren’t patched, they can deteriorate as water soaks in, and the base and underlying subgrade move underneath the surface.

What is the process for repairing asphalt?

The process for repairing asphalt varies depending on the extent and type of damage. Sometimes a simple patch is sufficient, but if you notice the damage persists, you may have a deep-rooted problem that requires resurfacing.

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Asphalt timeline

How long does an asphalt driveway last?

A well-maintained asphalt surface constructed by a professional contractor like NK Asphalt should last at least 15 to as many as 30 years – depending on its use.

How long does asphalt take to lay?

Depending on the scope of the asphalt job and other services required, total laying time may take anywhere from half a day to several days. For example, a 2,000m2 standard layout in a car park would be completed in a day on site or possibly two smaller car parks or driveways of several hundred square metres also in a day.

How long does asphalt take to ‘harden’ (cure)?

Hot mix asphalt is suitable for light use the day after being laid, otherwise can be used as normal a couple of days after. However, the full oxidation/hardening process can take several months.

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Asphalt Resurfacing

What is asphalt laid on top of?

For the best results, we recommend a sturdy base made of either limestone, roadbase, gravel, or first-grade recycled concrete base. Recycled asphalt that has become loose and uneven can often be resurfaced with new hot asphalt to achieve a better long-term surface. The asphalt material depends on the existing foundation and the availability of materials in the region.

Does a new asphalt driveway get laid on top of an existing driveway?

If the existing bitumen or asphalt driveway is in reasonable to good condition and the finished level isn’t too high, then yes, a new asphalt driveway may be laid directly on top. In some cases, the existing surface may need the surface removed by profiling (milling) process due to poor surface condition or levels being too high relative to adjacent floors, concrete pads, doorways, steps etc.

How thick should asphalt be?

The thickness of an asphalt surface depends on its intended use. For a standard driveway or car park, the asphalt is usually 30-40mm thick. If the surface is used for heavy loads, the thickness may be closer to 60mm. For hardstands, the asphalt thickness will be over 40mm and may go as thick as 100mm laid in two layers.

How thick is the foundation (basecourse) for an asphalt driveway?

If no existing foundations are in place, we will lay 100-250mm of compacted base material as the basecourse, depending on local ground conditions and intended use of the area.

What tools and machines do I need to lay asphalt?

Professionally laid asphalt requires heavy-duty machines including asphalt delivery trucks, asphalt paving machine, rollers/compactors, and the float to move all to/from site plus a sweeper to clean before and afterwards. NK Asphalt owns and maintains all our own machines and equipment.

Can I install asphalt in the rain?

Not ideally. Some jobs have timetables or other requirements that require a job deadline to be met but isn’t a preferred option

How wide should an asphalt driveway be?

To suit common vehicles, an asphalt driveway should be at least 3 metres wide, though we recommend a wider area if vehicles are larger or if space is required to turn around or at bends/corners. You should consult the local council regarding the requirements for a new crossover before siteworks begin, as each council has varying requirements.

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Additional components of an asphalt project

What drainage options are available?

All asphalt surfaces should be constructed to ensure water run-off is directed to a suitable drainage point. Asphalt is best laid with at least a 1 in 100 (1%) fall or more to ensure run-off and minimise the possibility of puddles.

Water can be drained to the perimeter/sides, to soakwell(s) or spoon drains or other collection points.

What kerbing options are available?

Kerbs provided by NK Asphalt are made with 32Mpa ready mixed concrete (not hand-mixed garden kerb), laid with an extruded kerb machine and come in four styles: flush/flat, mountable, semi-mountable, and barrier kerbs.

Colour can be added if preferred.

What carparking options are available?

Asphalt car parks are usually finished with lines to outline parking bays and may use arrows or text to direct drivers. Also commonplace are concrete, plastic or rubber bumpstops in front of the bays and speedbumps on main routes.

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Asphalt Sustainability

Is asphalt recyclable?

Yes, asphalt is recyclable, though we recommend new hot-mix asphalt for our surfacing projects, as the recycled material can vary in quality, appearance, and lifespan before needing ongoing maintenance. Asphalt is apparently one of the most recycled products in the world.

Is asphalt sustainable?

With uses for reclaimed asphalt and other asphalt mixtures that include recycled plastics, glass, and crumb rubber, asphalt is relatively sustainable.

Is hot-mix asphalt better than recycled asphalt?

New hot-mix asphalt is manufactured to meet Australian Standards or other specifications such as Main Roads WA and local government IPWEA/AAPA specifications, among others. As the recycled material is made from old bitumen and/or asphalt from old roads and car parks the material can vary greatly, resulting in a variable finished product that may need ongoing maintenance. The best way to be sure is to ask for some examples near you that have been laid several months or a number of years before to allow a comparison and see what may be ahead.

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Asphalt facts Australia

Asphalt is the most used surfacing material in Australia.
Australia has over 800,000 kilometres of roads.
Annual asphalt production is approximately 10 million metric tonnes.
Australia has around 120 asphalt production plants ranging from small 30 to 40 tph capacity to large 300 to 400 tph plants.
Bitumen use annually in Australia is over 800,000 metric tonnes.
The viscosity of bitumen in Australia is specific to AS 2008 specifications.
The asphalt/bitumen industry in Australia employs around 4,000 people.

Source: Asphalt Magazine

FAQ’s

Have any Questions?

Material information

Asphalt colours

Asphalt maintenance

Asphalt timeline

Asphalt Resurfacing

Additional components of an asphalt project

Asphalt Sustainability

Asphalt facts Australia

Useful Links

Contact Us

REQUEST A FREE QUOTE AND
GET A 10% DISCOUNT NOW!

FAQ’s

Have any Questions?

Material information

Asphalt colours

Asphalt maintenance

Asphalt timeline

Asphalt Resurfacing

Additional components of an asphalt project

Asphalt Sustainability

Asphalt facts Australia

Useful Links

Contact Us

REQUEST A FREE QUOTE AND GET A 10% DISCOUNT NOW!

REQUEST A FREE QUOTE AND
GET A 10% DISCOUNT NOW!