Section 4115. Coarse Aggregate for PC Concrete.

4115.01 DESCRIPTION.
Gravel or crushed stone particles meeting one of the following aggregate Durability Classes:

A. Class 2 Durability.
No deterioration of pavements of non-Interstate segments of the road system after 15 years and only minimal deterioration in pavements after 20 years of age.

B. Class 3 Durability.
No deterioration of pavements of non-Interstate segments of the road system after 20 years of age and less than 5% deterioration of the joints after 25 years.

C. Class 3i Durability.
No deterioration of pavements of the Interstate Road System after 30 years of service and less than 5% deterioration of the joints after 35 years.

Acquire aggregates from an approved source meeting the requirements of Materials I.M. 409.

4115.02 QUALITY.

TABLE 4115.02 - 1
Aggregate Quality Maximum Percent Allowed Test Method
Abrasion (Cr. Stone) 50 AASHTO T 96
Abrasion (Gravel) 35
(may be increased by 0.1% for each 1% of particles with at least one fractured face)		 AASHTO T 96
Alumina (a) <0.5 Iowa DOT Materials Laboratory Test Method 222
A Freeze 6 Iowa DOT Materials Laboratory Test Method 211, Method A
Clay Lumps and Friable Particles 0.5 Materials I.M. 368
(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.

TABLE 4115.02 - 2
Maximum Permissible Amounts of Objectionable Materials Maximum Percent Allowed Test Method
Coal and carbonaceous shale 0.5 Materials I.M. 372
Total of all shale, similar objectionable materials, and coal combined. 1.0 Materials I.M. 372
Organic Materials, except coal 0.01 Iowa DOT Materials Laboratory Test Method 215
Unsound chert particles retained on 3/8 inch (9.5 mm) sieve (Nonstructural concrete) 3.0 Materials I.M. 372
Unsound chert particles retained on 3/8 inch (9.5 mm) sieve (Structural concrete) 2.0 Materials I.M. 372

Note: Chert particles which break into three or more pieces when subjected to the freezing and thawing test will be considered unsound.

Chert in aggregate produced from limestone sources is defined as unsound when any of the fractions of the crushed or uncrushed chert do not meet the soundness requirements.

4115.03 GRADATION.
Meet the requirements of Article 4109.02.

TABLE 4115.03
MIX CLASS MIX NUMBER GRADATION NUMBERS
D 57, 57-6 3 or 5
A, B, C 2 to 8, V47B 3, 4, or 5
M 4 3, 4, or 5
A, B, C, M V 7

4115.04 AGGREGATE USE DURABILITY REQUIREMENTS.

TABLE 4115.04
Specification Number Minimum Durability Class Required Use
3i 3 2
2122, 2201 2212, 2213 2301, 2302, 2310, 2529, 2530
Interstate System,
Primary System,
Other
X*		  


X*

  

 

X

 PCC Paved Shoulders, Base, Base Repair, Base Widening PCC Overlay, Finish Patches, and Bridge Approaches
2403     X Structural Concrete, Concrete Structures
2406 (See 2403)     X Concrete Structures
2407     X Precast Units
2407, 2501  

X

   Prestressed Units, Concrete Piles
2412 (See 2403)     X Concrete Bridge Floors
2413 (See 2413.02A)     X Surfacing, Repair & Overlay of Bridge Floors
2414 (See 2403)     X Concrete Railings
2415 (See 2403)     X Concrete Box, Arch & Circular Culverts
2416 See 4145)     X Rigid Pipe Culverts
2424     X Shotcrete
2503 (See 2403)     X Storm Sewers (Intakes & Utility Access)
2504 (See 2403)     X Sanitary Sewers (Utility Access)
2505 (See 2403)     X Guardrails (Concrete End Anchorage)
2511, 2515 (See 2403)     X PCC Sidewalks, Paved Driveways
2512 (See 2403)     X PCC Curb & Gutter
2513 (See 2403)     X Concrete Barrier
2516 (See 2403)     X Concrete Walls and Steps
2517
Primary
Other 		  X  

X

 Railroad Approach Sections
2522 (See 2403)     X Tower Lighting (Concrete Footings & Foundations)
2523 (See 2403)     X Highway Lighting (Concrete Footings & Foundations)
2524 (See 2403)     X Highway Signing (Concrete Footings & Foundations)
2525 (See 2403)      X Traffic Signals (Concrete Footings & Foundations
Note: 
* For patches and PCC base repair, Class 2 durability or better aggregate will be required if the existing pavement was constructed of Class 2 or lower durability aggregate. If the existing pavement was constructed of Class 3 or Class 3i durability aggregate, the aggregate used in the repair shall be Class 3 or better and Class 3i, respectively.

4115.05 COARSE AGGREGATE FOR BRIDGE DECK SURFACING AND REPAIR AND OVERLAY.
Acquire from a Class 2 durability or better source meeting the following requirements:

A. Quality.

TABLE 4115.05 - 1
Aggregate Quality Maximum Percent Allowed Test Method
Abrasion 40 AASHTO T 96
Alumina (a) 0.4 Iowa DOT Materials Laboratory Test Method 222
A Freeze 4 Iowa DOT Materials Laboratory Test Method 211, Method A
Absorption 2.5 Iowa DOT Materials Laboratory Test Method 201
(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.

TABLE 4115.05 - 2
Objectionable Materials Maximum Percent Allowed Test Method
Unsound chert particles retained on No. 4 4.75 mm) sieve 0.5 Materials I.M. 372
Total of all unsound chert, shale, coal, and iron combined 1.0 Materials I.M. 372
Organic materials, except coal 0.01 Iowa DOT Materials Laboratory Test Method 215
Note:  Unsound chert particles are defined in Article 4115.032.

B. Gradation.
Meet the gradation requirements for Gradation No. 6 of the Aggregate Gradation Table, Article 4109.02.