Waterproofing FAQ

Mix design (types)

A mix design is the asphalt pavement mixture design of rock, asphalt binder, and air.

The choice of which mix design to use will largely be dependent on the type of traffic and use it will receive.

Larger aggregate mixes will often do better with higher loads and thicker compacted mixes. Smaller aggregate mixes provide a smooth visually pleasing surface and are suited to thinner compacted thickness.

Light loads such as pedestrians and cars will be considered light and a smaller aggregate mixture is often preferrable. Sometimes this is called a driveway mix. This is the most common mix for pedestrian use, overlays, and skin patches.

Medium loads of light truck and higher volume light vehicles a typical 12mm to 19mm mix design is used. This is the most common mix design for patching.

Heavy loads as in commercial truck traffic and industry would require greater load dispersion and a larger aggregate use or combination of layers. 19mm plus aggregate sizes are common.

Most mix designs are done via the Marshall method in the lab which is tried and true. The Superpave method which is more sophisticated in design from the lab is customized to the site conditions and can have superior performance.

How thick?

The compacted thickness of the asphalt is important to know and it will depend on the loading.

Asphalt is flexible by design and will move with the base preparation. Making asphalt thicker doesn't necessarily make it stronger. Thicker asphalt helps disperse loading over a larger area. A larger area of loading reduces deflection and shear failures. This larger load must be supported by the base gravels and sub-base or it will fail.

• 35mm is a minimum we suggest for any asphalt placed ontop of old asphalt.

• 50mm is a standard thickness to support pedestrians, lightweight cars.

• 65mm is a minimum for 1 ton pickups and RV's

• 75mm is a typical minimum thickness for commercial industrial yard, medium duty trucks, moderate traffic. Do not go thicker than 75mm without adding another layer.

• 80mm is placed in two lifts and is closer to a road design.

• 100mm is a two lift (layer) system used for high volume commercial, industrial, heavy duty vehicles, and roadways.

Are there weather restrictions

Asphalt paving should be done when the temperature of the ground is at 10 degrees and higher.

The ground should NOT be frozen.

Moisture should not be present on overlays. There can be some moisture when paving on a gravel base but runoff (flowing) water and anything more than light rain is going to degrade the product performance.

Hot weather will extend curing times and therefore associated closure times.

When is the best time to pave

Best times are Monday to Friday during noise bylaw permitting hours.

Best seasons are April to October.

How long does it last?

The lifespan of asphalt pavement is highly dependent on the traffic loading, volume, exposure, and water content int he soil.

Generally speaking, with proper maintenance, asphalt pavement can last up to 30 years. High traffic volumes and loads can cut this in half to 15 years.

Patching repairs and overlays also have a shortened lifespan due to thermal movements and flexural properties of dissimilar asphalt pavements.

How long until it can be used?

Asphalt pavement can be used almost immediately, but it depends on the conditions.

If pedestrians are using, it should cool enough to people and pets don't burn their feet.

Driving can be done immediately after compaction, but only if turning isn't happening. Turning will cause marking. Large trucks can create heavy marking until the product has cooled.

As a safe rule, we like to see the asphalt cool overnight until opening the next morning.