Section 4120.  Granular Surfacing and Granular Shoulder Aggregate

 

4120.01     DESCRIPTION.

Uniform mixture of fine and coarse particles of crushed stone, gravel, or a combination of these materials with sand. Crushed recycled materials are to total no more than:

·         30% of the shoulder aggregate for new construction.

·         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.

 

1.     Furnish material meeting the requirements of Article 4120.04 or recycled materials. 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 sieve.

 

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

·         30% to 50% crushed stone meeting soundness and abrasion requirements of Article 4120.05. Meet the requirements for Gradation No. 10 of the Aggregate Gradation Table, Article 4109.02 with the exception of 8% to 16% passing the No. 200 sieve.

·         30% to 50% recycled crushed PCC or composite materials meeting the above requirements for Granular Shoulders. Meet the requirements for Gradation No. 10 of the Aggregate Gradation Table, Article 4109.02 with the exception of 8% to 16% passing the No. 200 sieve.

·         30% to 50% RAP processed to pass the 1.5 inch sieve.

 

4120.03     CLASS C GRAVEL.

Meet the requirements for gradation No. 10 of the Aggregate Gradation Table, Article 4109.02 and Table 4120.03-1:

 

 

Table 4120.03-1: Coarse Aggregate Quality (Class C Gravel)

Coarse Aggregate Quality

Maximum Percent Allowed

Test Method

C Freeze

15

Iowa DOT Materials Laboratory Test Method No. 211, Method C

Shale (+ No. 4 sieve)

10

Materials I.M. 372

Total of Clay Lumps and Friable Particles, plus % passing No. 200 sieve

15

Materials I.M.s 368 and 306

Total of Shale, Clay lumps and friable particles, plus % passing. No. 200 sieve

20

Materials I.M.s 372, 368, and 306v

 

4120.04     CLASS A CRUSHED STONE.

Meet the requirements for Gradation No. 11 of the Aggregate Gradation Table, Article 4109.02 and Table 4120.04-1:

       

        Table 4120.04-1: Coarse Aggregate Quality (Class A Crushed Stone)

Coarse Aggregate Quality

Maximum Percent Allowed

Test Method

Abrasion

45

AASHTO T 96

C Freeze

15

Iowa DOT Materials Laboratory Test Method No. 211, Method C

Clay Lumps and Friable Particles

4.0

Materials I.M. 368

Note:  For Granular Shoulder Aggregate only, the abrasion limit is 50.

 

4120.05     CLASS B CRUSHED STONE.

Meet the requirements for Gradation No. 11 of the Aggregate Gradation Table, Article 4109.02 and Table 4120.05-1:

 

Table 4120.05-1: Coarse Aggregate Quality (Class B Crushed Stone)

Coarse Aggregate Quality

Maximum Percent Allowed

Test Method

Abrasion

55

AASHTO T 96

C Freeze

20

Iowa DOT Materials Laboratory Test Method No. 211, Method C

Total of Abrasion & C Freeze

65

 

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.