4127.01 DESCRIPTION.
Crushed stone, gravel, slag, sand, and filler from an approved source. Crushed gravel may be used to satisfy crushed particle and Ffriction Type 3 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.

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 with the requirements of Article 4127.03.

4127.02 COARSE AGGREGATE.
Meet the following requirements:

TABLE 4127.02
Coarse Aggregate Quality	Type A Maximum %	Type B Maximum %		Test Method
		Primary	Other
Abrasion	45	45	45	AASHTO T 96
Absorption	6.0	6.0	6.0	Iowa DOT Materials Laboratory Test Method 201
Alumina (a)	0.7	1.5	2.5	Iowa DOT Materials Laboratory Test Method 222
A Freeze	10	25	45	Iowa DOT Materials Laboratory Test Method 211, Method A
C Freeze	N/A	10	10	Iowa DOT Materials Laboratory Test Method 211, Method C
Clay Lumps/Friable Particles	0.5	N/A	N/A	Materials I.M. 368
Organic Material	0.01	0.01	0.01	Iowa DOT Materials Laboratory Test Method 215
(a) If the Alumina value fails, the A Freeze value shall be determined for specification compliance.  Iowa DOT Materials Laboratory Test Method 222 does not apply to gravel.

4127.03 FINE AGGREGATE.
Use:

A. Natural sand. A gradation for wearing course mixture shall not have 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.

Fine aggregate shall contain no more than 0.01% organic matter when tested using Iowa Test Method 215.

4127.04 COMBINED AGGREGATES.
Use aggregate, which does not contain adherent films of clay or other matter, which will prevent coating of particles with asphalt binder. Meet gradations of Materials I.M. 510.

Maximum shale allowed in the fine portion of the combined materials:

TABLE 4127.04
Aggregate Type	Maximum Percent Allowed	Test Method
Type A	2.0	Materials I.M. 344
Type B	5.0	Materials I.M. 344

4127.05 MINERAL FILLER.
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.