— David Wagner 2007/06/29 15:40

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Asphalt emulsions can be applied to wet aggregates and are not flammable or toxic.

The concrete develops sufficient strength to support itself before it leaves the paver.

1. 240ºF to Laydown Temperature: Upper Temperature Zone
2. 190-240ºF: Intermediate Temperature Zone
3. 160-190ºF: Lower Temperature Zone

200

Breakdown rolling starts immediately after placement of HMA, followed by intermediate rolling and final or finish rolling. The outside edge of the pavement should be rolled before the remainder. The temperature of the asphalt during rolling is critical.

Nuclear density devices, nonnuclear density gauges, and equipment-mounted measuring systems are available to determine the density of a compacted HMA pavement.

Asphalt Recycling

1. Remove by milling, cold planing, or profiling.
2. Load into haul units.
3. Process in a recycling plant.

Old asphalt may also be removed, rejuvenated, and reused.

Recycling saves energy and aggregate while reducing landfilled waste. However, the properties of recycled asphalt will be more variable than those of virgin asphalt.

The main purpose of a prime coat is to seal a porous surface while a tack coat is provided to bond to a previously paved surface.