Summary of Rubber Modified Asphalt Product Specifications around ...

discharge chute of the drier in order to record automatically the temperature of the asphaltic
concrete or mineral aggregate. A copy of the recording shall be given to the Engineer at the
end of each shift.
The moisture content of the asphaltic concrete shall not exceed 0.5 percent. The moisture
content will be determined in accordance with Arizona Test Method 406. Drying and
heating shall be accomplished in such a manner as to preclude the mineral aggregate from
becoming coated with fuel oil or carbon.
413-7.05 Mixing:
The production of the plant shall be governed by the rate required to obtain a thorough and
uniform mixture of the materials.
A positive signal system shall be provided to indicate the low level of mineral aggregate in
the bins. The plant will not be permitted to operate unless this signal system is in good
working condition. Each bin shall have an overflow chute or a divider to prevent material
from spilling into adjacent bins.
The temperature of asphaltic concrete upon discharge from the mixer shall not exceed
350 degrees F. If the asphaltic concrete is discharged from the mixer into a hopper, the
hopper shall be constructed so that segregation of the asphaltic concrete will be minimized.
413-7.06 Placing and Finishing:
(A) General Requirements:
The handling of asphaltic concrete shall at all times be such as to minimize segregation.
Any asphaltic concrete which displays segregation shall be removed and replaced.
Before asphaltic concrete is placed, the surface to be paved shall be cleaned of all
objectionable material and tacked with asphalt cement in accordance with the requirements
of Section 404 of the specifications. The cleaning of the surface, the tacking of the surface,
and the amount and grade of asphalt cement used shall be as directed by and acceptable to
the Engineer.
A light coat of asphalt cement shall be applied as directed to edges or vertical surfaces
against which asphaltic concrete is to be placed.
The base or subgrade upon which the asphaltic concrete is to be placed shall be prepared
in accordance with the applicable requirement for the material involved and maintained in a
smooth and firm condition until placement. Asphaltic concrete shall not be placed on a
frozen or excessively wet base or subgrade.
Asphaltic concrete shall be placed only when the temperature of the surface on which the
asphaltic concrete is to be placed is at least 65 degrees F and the ambient temperature is at
least 65 degrees F and rising. The placement shall be stopped when the ambient
temperature is at or below 70 degrees F and falling.
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