342CENTRAL PLANT MIX COLD RECYCLED ASPHALT BASE COURSE

COURSE

342.1DESCRIPTION—This work is the construction of a central plant mixed cold recycled asphalt base

course (CPMCRABC), using a combination of RAP, RAM, virgin aggregates, or cement, mixed with an emulsified or foamed asphalt stabilizing agent in a continuous or batch type mixer.

342.2MATERIAL—Section 341.2 and as follows:

different types of RAP to prevent contamination. Build stockpiles in horizontal layers to minimize segregation. Keep stockpile height to a maximum of 10 feet.

342.3CONSTRUCTION—

emulsified asphalt, or foamed asphalt additive, metered cement additive, and water additive systems, with pumps and spray bars. Other equipment may include additive storage tanks, belt scales, a stacker belt conveyor, and a storage bin. Provide a screening/crushing unit if the maximum size of RAP cannot be controlled otherwise. Provide equipment capable of mixing reclaimed material and asphalt material into a homogeneous mixture without stripping the asphalt material. Provide a continuous -flow or batch-type mixer accepted by the Representative and equipped with batching or metering devices to measure the specified quantities of the materials. Equip the foamed asphalt system with a test nozzle to allow field samples of foamed asphalt. Equip hot asphalt supply tankers for foamed asphalt stabilized applications, with gauges that continuously display the temperature of the asphalt. Equip the foamed asphalt system to accurately and uniformly inject water into hot asphalt binder, and uniformly mix foamed asphalt, RAP material, and water, to meet mix design requirements. For emulsified asphalt additive, use a positive displacement pump capable of accurately metering the flow rate of additives into the reclaimed material down to 4 gallons per minute. Provide a positive interlock system that automatically shuts off the pump when material is not in the mixing chamber. Provide a meter capable of registering the flow rate and quantity of additive introduced into the reclaimed material.

by weight of liquids.

material and aggregates with the asphalt material. Add water to the RAP by a calibrated meter, as necessary, to aid in mixing and compaction.

may require vehicle protective covers. Use mechanical spreaders to place the loose mixture on the prepared surface to a uniform depth. Unless allowed, do not use motor graders. Do not place CPMCRABC from September 1 to April 30 in Districts 1-0, 2-0, 3-0, 4-0, 9-0, and 10-0; and from October 1 to April 30 in all other Districts. With written approval of the Representative, the Contractor may place CPMCRABC when no freezing temperatures occur for 24 hours before paving and when the project ambient air temperature is 45F and rising.

depth indicated and within the specified tolerances. The Representative will designate one test location in each 3,000 square yards of completed CPMCRABC and at locations the Representative suspects the depth is deficient. At each test location, record one depth measurement. If the depth is deficient 1/2 inch or more from the indicated depth, the pavement is defective. Immediately start removal of the defective pavement, beginning at the core location and continuing longitudinally and transversely until the depth is within 1/2 inch of the indicated depth.

342.4MEASUREMENT AND PAYMENT—