Section 4127.  Aggregate for Flexible Paving Mixtures

4127.01     DESCRIPTION.

Crushed stone, gravel, slag, sand, and filler from an approved source. Crushed gravel may be used to satisfy crushed particle and friction requirements for flexible paving 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 larger than the sieve size that 100% of the gravel will pass after crushing.

4127.02     COARSE AGGREGATE.

Meet the requirements of Table 4127.02-1:

Table 4127.02-1: Coarse Aggregate Quality (Flexible Paving Mixtues)
Coarse Aggregate Quality	Type A Maximum %	Type B Maximum %		Test Method
		Primary	Other
Abrasion	45	45	45	AASHTO T 96
Absorption^(a)	6.0	6.0	6.0	Iowa DOT Materials Laboratory Test Method No. 201
Alumina^(b, c)	1.0	1.5	1.8	Iowa DOT Materials Laboratory Test Method No. 222
A Freeze	15	25	28	Iowa DOT Materials Laboratory Test Method No. 211, Method A
Clay Lumps/Friable Particles	2.0	3.0	3.0	Materials I.M. 368
Organic Material	0.01	0.01	0.01	Iowa DOT Materials Laboratory Test Method No. 215
(a)    When a coarse aggregate for use in asphalt fails absorption using Iowa DOT Materials Laboratory Test Method No. 201; absorption determined by Materials I.M. 380 (Vacuum-saturated specific gravity & absorption) will be used. The 6.0% maximum absorption applies. (b)   If the Alumina value passes, the A-Freeze is not needed for specification compliance. If the Alumina value fails, determine the A Freeze value for specification compliance. (c)    Alumina does not apply to gravel.

4127.03     FINE AGGREGATE.

A.    Natural sand meeting the requirements of Table 4127.03-1. A gradation for wearing course mixture of no more than 50% retained between two consecutive standard sieves below the No. 4 sieve or gravel aggregate with 100% passing the 3/8 inch sieve meeting these requirements.

Table 4127.03-1: Fine Aggregate Quality (Flexible Paving Mixtures)
Fine Aggregate Quality	Type A Maximum %	Type B Maximum %	Test Method
Organic Matter	0.01	0.01	Iowa DOT Materials Laboratory Test Method No. 215
Clay Lumps/Friable Particles	1.5	3.0	Materials I.M. 368^(a)
Shale	2.0	5.0	Materials I.M. 344
(a) Use Method A for initial test. If Method A fails, Method B may be used.

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. Coarse and fine aggregate shall meet quality requirements of Articles 4127.02 and 4127.03 before combining aggregates.

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.