Section 4120. Granular Surfacing and Granular Shoulder Aggregate.

4120.01 DESCRIPTION.
Uniform mixture of fine and coarse particles of rushed stone, gravel, or a combination of these materials with sand. Crushed recycled materials shall total no more than 30% of the shoulder aggregate for new construction and no more than 50% of the total for existing granular shoulders.

4120.02 GRANULAR MATERIAL.

A. Granular Surfacing.
Furnish material meeting the requirements of Article 4120.04, or when specified in the contract documents, meet the requirements of Article 4120.03, 4120.05, or 4120.06.

B. Granular Shoulders.
Furnish material meeting the requirements of Article 4120.04 or recycled materials, or when specified in the contract documents, meet the requirements of Article 4120.05 or 4120.06.

For recycled materials, meet the following requirements:

The contract documents may allow a Class C gravel and crushed aggregate mixture for granular shoulders meeting the following:

4120.03 CLASS C GRAVEL.
Meet the requirements for gradation No. 10 of the Aggregate Gradation Table, Article 4109.02 and the following:

TABLE 4120.03
Coarse Aggregate Quality Maximum Percent Allowed Test Method
C Freeze 15 Iowa DOT Materials Test Laboratory Test Method 211, Method C
Shale (+ No. 4 (4.75 mm) sieve) 10 Materials I.M. 372
Total Clay Lumps and Friable Particles, plus % passing. No. 200 (75 μm) sieve 15 Materials I.M.s 368 and 306
Total of Shale, Clay lumps and friable particles, plus % passing. No. 200 (75 μm) sieve. 20 Materials I.M.s 372, 368, and 306

4120.04 CLASS A CRUSHED STONE.
Meet the requirements for Gradation No. 11 of the Aggregate Gradation Table, Article 4109.02 and the following:

TABLE 4120.04
Coarse Aggregate Quality Maximum Percent Allowed Test Method
Abrasion 45 AASHTO T 96
C Freeze 15 Iowa DOT Materials Test Laboratory Test Method 211, Method C
Clay Lumps and Friable Particles 4 Materials I.M. 368
Note: For shoulders only, abrasion limits may be raised to 55 if Alumina does not exceed 0.7 or A Freeze does not exceed 10.

4120.05 CLASS B CRUSHED STONE.
Meet the requirements for Gradation No. 11 of the Aggregate Gradation Table, Article 4109.02 and the following:

TABLE 4120.05
Coarse Aggregate Quality Maximum Percent Allowed Test Method
Abrasion 55 AASHTO T 96
C Freeze 20 Iowa DOT Materials Test Laboratory Test Method 211, Method C
Total of Abrasion & C Freeze 65 Materials I.M. 368
Clay Lumps and Friable Particles 4 Materials I.M. 368

4120.06 CLASS D CRUSHED STONE.
Refer to the contract documents for gradation and quality requirements.

4120.07 AGGREGATE FOR PAVED SHOULDER FILLETS.
Crushed stone or recycled materials meeting the requirements for Gradation No. 11 of the Aggregate Gradation Table, Article 4109.02, and meeting the quality requirement of Article 4120.04. For recycled materials, meet the requirements of Article 4120.02, B.