Section 4127.� Aggregate for Hot Mix Asphalt
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A.��� Crushed stone, gravel, slag, sand, and filler from an approved source. Crushed gravel may be used to satisfy crushed particle and friction requirements for HMA mixtures. Produce crushed gravel as a separate operation by crushing the portion of a gravel aggregate retained on a screen at least 1/4 inch (6 mm) larger than the sieve size that 100% of the gravel will pass after crushing.
B.��� If a gravel aggregate has less than 5% retained on the No. 4 sieve (6 mm), the Engineer may replace the requirements of Table 4127.02-1 with the requirements of Article 4127.03.
Meet the requirements of Table 4127.02-1:
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Table 4127.02-1: Coarse Aggregate Quality (Hot Mix Asphalt) |
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Coarse Aggregate Quality |
Type A Maximum % |
Type B Maximum % |
Test Method |
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Primary |
Other |
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Abrasion |
45 |
45 |
45 |
AASHTO T 96 |
|
Absorption |
6.0 |
6.0 |
6.0 |
Office of Materials Test Method No. Iowa 201 |
|
Alumina(a) |
0.7 |
1.5 |
2.5 |
Office of Materials Test Method No. Iowa 222 |
|
A Freeze |
10 |
25 |
45 |
Office of Materials Test Method No. Iowa 211, Method A |
|
C Freeze |
N/A |
10 |
10 |
Office of Materials Test Method No. Iowa 211, Method C |
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Clay Lumps/Friable Particles |
0.5 |
N/A |
N/A |
Materials I.M. 368 |
|
Organic Material |
0.01 |
0.01 |
0.01 |
Office of Materials Test Method No. Iowa 215 |
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(a)�� If the Alumina value fails, determine the A Freeze value for specification compliance.� Office of Materials Test Method No. Iowa 222 does not apply to gravel. |
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A.��� Natural sand containing no more than 0.01% organic matter when tested using Iowa Test Method 215. A gradation for wearing course mixture of no more than 50% retained between two consecutive standard sieves below the No. 4 (4.75 mm).
B.��� Crushed gravel or stone processed from coarse aggregate meeting the requirements of Article 4127.02.
4127.04���� COMBINED AGGREGATES.
A.��� Use aggregate, which does not contain adherent films of clay or other matter that will prevent coating of particles with asphalt binder. Meet gradations of Materials I.M. 510.
B.��� Maximum shale allowed in the fine portion of the combined materials:
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Table 4127.04: Maximum Shale Allowed |
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Aggregate Type |
Maximum Percent Allowed |
Test Method |
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Type A |
2.0 |
|
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Type B |
5.0 |
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For fine material added to the mixture, separate from cold feed, meet the requirements for mineral filler in AASHTO M 17, except determine the gradation according to AASHTO T 11.