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 concrete may be used as aggregate for Granular Shoulders
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:
- Recycle PCC, Rap, or Composite pavements to meet the requirements of Materials I.M. 210.
- Crush PCC or composite pavement to meet the requirements for Gradation No. 11 of the Aggregate Gradation Table, Article 4109.02.
- Process RAP to pass the 1.5 inch (37.5 mm) sieve.
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: 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. 4120.06 CLASS D CRUSHED STONE. 4120.07 AGGREGATE FOR PAVED SHOULDER FILLETS.
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
Refer to the contract documents for gradation and quality requirements.
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 4120.03. For
recycled materials, meet the requirements of Article 4120.02, B.