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State of California, Department of Transportation - page 15 / 52





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cardboard boxes should be available, in case a sample of the completed AC mixture is required for future testing. A calibrated thermometer or infrared gun for verifying the temperature of the aggregate or the completed mix. When taking aggregate samples, metal pails, sample bags, a sample bag funnel, wire ties, a wire twister, permenant marking pens for labeling sample bags, TL-101 booklets, heavy duty gloves, safety glasses, hard hat and appropiate clothing are required. Be sure to do a few stretching exercises to warm up your muscles and always use the proper lifting procedures. If its to heavy to lift by yourself, get help!

Crushers This portion of asphalt concrete production is of the utmost importance. If the aggregate is crushed incorrectly, the chance of producing a product that meets specification is almost impossible. It is difficult for an inspector to become familiar with all aspects of a crushing operation in a short period of time, but armed with some basic information, problems with AC aggregates can be corrected before a mountain of material is stockpiled.

Aggregate crushing operations vary in size and type, but the basics are very similar.

The AC plant inspector should make a habit of visually inspecting the pit or quarry area on a regular basis. Be aware of changes in the material, such as pockets of clayey material, color changes, deleterious rock or excessive vegetation. Document any areas of concern and discuss potential problems with the person in charge of the crushing operation and the Resident Engineer.

This stockpile has problems with segregation, note coarse aggregate at outside bottom edge.

Some areas to keep an eye on at the crusher should include the primary and secondary crushers. Are the crushers and screen decks overloaded with material or are they running efficiently? If the crusher (cone or impact) is not being run properly, the particle size percentage will change.

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