ASPHALT PAVING BASIC INFORMATION AND TUTORIALS


The asphalt paving required on the project is generally subcontracted to someone specializing in paving. The general contractor’s estimator will make an estimate to check the subcontractor’s price.

Asphalt paving will most commonly be hot-mix and is generally classified by traffic (heavy, medium, or light) and use (walks, courts, streets, driveways, etc.).

The estimator will be concerned with subgrade preparation, subdrains, soil sterilization, insulation course, subbase course, base courses, prime and tack coats, and the asphalt paving required.Not all items are required on any given project, so the estimator should determine which items will be required, the material and equipment necessary for each portion of the work, and the requisite thickness and amount of compaction.

Specifications.
Check the requirements for compaction, thickness of layers, total thicknesses, and materials required for each portion of the work. The drawings will also have to be checked for some of these items.

The drawings will show the location of most of the work to be completed, but the specifications should also be checked. The specifications and drawings will list different requirements for the various uses. (These are called traffic requirements.)

Estimate.
The number of square feet (or square yards) of surface area to be covered is determined, and the thickness (compacted) of each course and the type of materials required are noted. Base courses and the asphalt paving are often taken off by the ton, as this is the unit in which these materials must be bought.

The type of asphalt and aggregate size required must also be noted. Two layers of asphalt paving are required on some projects: A coarse base mix may be used with a fine topping mix. Equipment required may include a steel-wheel roller, trailers to transport equipment, dump trucks, paving machines, and various small tools.

To estimate the tons of material required per 1,000 sf of surface area, refer to Figure 9.44. Different requirements will be listed for the various uses (walk, driveway, etc.), and the different spaces must be kept separately.

In many climates, the asphalt paving has a cutoff date in cold weather, and the paving that is not placed when the mixing plants shut down will not be laid until the start-up time in the spring. The plants may be shut down for as long as four months or more, depending on the locale.

FIGURE 9.44. Approximate Asphalt Paving Materials Tonnage.

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