Use this SimpleSpecs™ master specification to specify asphalt paving – hot-mix asphaltic paving. Base course may be crushed stone or gravel or hot-mix asphaltic concrete.
Asphalt paving is a mixture of asphalt, crushed aggregates, and bitumen. The asphalt mixture is deposited over a base layer of crushed rock or a coarser layer of asphaltic concrete and then rolled out to form a relatively smooth surface.
Hot-mix asphalt (HMA) concrete is produced by heating the asphalt binder to decrease its viscosity, and drying the aggregate to remove moisture from it prior to mixing. Mixing is generally performed with the aggregate at about 300 °F (or roughly 150 °C) for virgin asphalt and 330 °F (166 °C) for polymer modified asphalt, and the asphalt cement at 200 °F (95 °C).
In many countries paving is restricted to the summer months because in winter the compacted base will lower the temperature of the asphalt and prevent the proper packing of the asphalt to the required density. So keep in mind that the paving and compaction must be performed while the asphalt is sufficiently hot.
HMA is the form of asphalt concrete most commonly used on high traffic pavements such as those on major highways, racetracks, and airfields. It is also used as an environmental liner for landfills, reservoirs, and fish hatchery ponds.
Asphalt deterioration can include crocodile cracking, potholes, upheaval, raveling, bleeding, rutting, shoving, stripping, and grade depressions. In cold climates, frost heaves can crack asphalt even in one winter. Filling the cracks with bitumen is a temporary fix, but only proper compaction and drainage can slow this process.
Factors that cause asphalt concrete to deteriorate over time mostly fall into one of three categories: construction quality, environmental considerations, and traffic loads. Often, damage results from combinations of factors in all three categories.
To learn more about Asphalt, visit Wikipedia.
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