atch 1 2235 Crusher Agg Base roads.pdf

Crushed Aggregate Base Course for Roads FA5000-12-R-0001 Attachment 1

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1. SCOPE:

1.1 This section covers crushed aggregates and their placement as base course material under new asphalt pavement for roads.

2. REFERENCED SPECIFICATIONS:

2.1 Alaska Department of Highways "Standard Specification for Highway Construction," newest version, is included as part of these specifications to the extent noted hereinafter. Where the referenced specifications conflict with requirements noted in these specifications, these specifications will take precedence. All testing required by the referenced specifications will be done by the Contractor.

3. AGGREGATE:

3.1 Aggregates for the new base course and base course (recycled asphalt) shall conform to Section 703-2.03 of the Alaska Department of Highways Specification and the aggregate grading shall be D-as shown in Table I. All base course material shall be non-frost susceptible (no more than 3.0 percent finer than .02 mm).

TABLE I

Aggregate Gradation

BASE COURSE D-1

3.1 Crushed gravel retained on the #4 sieve and each coarser sieve shall contain at least 80 percent by weight of crushed pieces having one or more freshly fractured faces.

4. BASE COURSE PLACEMENT:

Sieve Sieve Percent Size Size Passing 1" 25 mm 100

3/4" 19 mm 70-100 3/8” 9.5 mm 50-80 #4 4.75 mm 35-65 #8 2.36 mm 20-50

#40 or #50 0.425 mm 8-30 #200 0.075 mm 0-6

Pavements - IDIQ

FXSB 11-2102

Section 2235

Crushed Aggregate Base Course for Roads

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4.1 Shall conform to Section 301-3.01 of the Alaska Department of Highways Specification. The actual depth of compacted base course shall be not less than 6 inches, unless indicated otherwise on the delivery order. The typical depth required for the base course is 6”. The base leveling course can vary from 2” to 4”. The base course sweetener can vary from 1” to 2”.

5. MIXING:

5.1 Shall conform to Section 301-3.02 of the Alaska Department of Highways specification.

6. SHAPING:

6.1 Shall conform to Section 301-3.03 of the Alaska Department of Highways specification shall be shaped so as to parallel the finished slope of the new asphalt.

7. JMF (JOB MIX FORMULA) FOR BASE COURSE:

7.1 The Contractor shall submit a job mix formula for the base course to be approved by the Contracting Officer. The JMF will indicate the percentage of aggregate passing each sieve, the optimum dry density (PCF) with required moisture content, and the required dry density (PCF) in the field to attain 98 percent compaction.

7.2 The JMF shall provide the dry density value (PCF) which shall become the standard dry density to measure the field density test results against. All field density test areas shall meet or exceed the standard dry density and those field density tests that fail to meet the designated standard dry density shall be removed and replaced at the Contractor's expense.

7.2.1 The minimum acceptable value for the standard dry density for the base course is 125 PCF.

8. COMPACTION:

8.1 Compaction of the base course shall be 98 percent

minimum of the maximum density determined in accordance with ASTM D 1557 (Modified Proctor). The field density shall be determined using ASTM D 2922 (Nuclear Method) or ASTM D 1556 (Sand Cone Method).

8.2 Testing shall be the responsibility of the contractor and field density and gradation tests shall be performed on the base course placed. Tests shall be performed by: the independent quality controller on existing base course; the independent quality controller on new base course; or an independent test lab. Tests shall be taken at locations selected by the government’s project engineer / project inspector.

8.3 When an area fails the field density test, the contractor shall further compact the area and retest, at the contractor's expense, until the area has attained the required field density.

9. THICKNESS CONTROL:

9.1 The completed thickness of the base shall be within 1/2-inch of the required thickness. Where the measured thickness of the base course is more than 1/2-inch deficient, such areas shall be corrected by adding more new base course to fill the deficiency or provide additional excavation of the sub-base, unless approved otherwise by the project engineer.

10. PULVERIZED ASPHALT:

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10.1 The pulverized asphalt shall meet the AK DOT 2’ minus gradation for base courses and the requirements listed above for the Job Mix Formula, compaction, shaping, and thickness control.

11. SUBMITTALS:

11.1 For off-JBER gravel, a statement from the base course aggregate supplier stating compliance with these specifications shall be submitted by the contractor for approval by the Contracting Officer. Include aggregate gradation test results.

12. INDEPENDENT QUALITY CONTROL (IQC):

12.1 The IQC shall establish and maintain quality control of the work covered under this section for each delivery order with new base course and existing base course line items to ensure compliance with the contract requirements, including but not limited to the items listed below:

12.1.1 Gradations of aggregates meet the specifications, work areas are properly compacted, and thickness measurements are performed.

12.2 The services of the IQC are in the line item “IQC for Base Course/Sub-base Testing”. The required lots or sub-lots for quality control or inspection on each work area for the new base course and the existing base course will be delineated on the issued delivery orders. See 1020-14 for additional IQC requirements.

13. TESTING REQUIREMENTS:

New Base Course

13.1 The aggregate gradation tests and the density tests shall be performed on the new base course per lift in a lot size as indicated below:

13.1.1 The aggregate gradation tests shall be performed in the field on the new in-place base course at the rate of 1 field gradation test per 1,000 tons

13.1.2 The aggregate density tests shall be performed in the field on the new in-place base course at the rate of 2 field density tests per 500 tons

13.1.3 The aggregate gradation tests and density tests on the new base course are included in the line item “Base Course/Sub-base Testing”.

Existing Base Course

13.2 The aggregate gradation tests and density tests shall be performed on the existing base course per top 6” lift in a lot size as indicated below:

13.2.1 The aggregate gradation tests shall be performed in the field on the existing base course at the rate of 1 field gradation test per 5,000 SY

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13.2.2 The aggregate density tests shall be performed in the field on the existing base course at the rate of 2 field density tests per 2,500 SY.

13.2.3 The aggregate gradation tests and density tests on the existing base course are in the line item “Base Course/Sub-base Testing”.

13.3 Perform gradation tests and fracture count tests on the new base course aggregate off the cold feed belts during the base course aggregate production at the rate of 1 test per 500 tons

(minimum) of aggregate processed. Provide this data to the government’s project engineer / project inspector for evaluation.

14. PAYMENT OF AGGREGATE GRADATION:

14.1 The mean absolute difference (the absolute difference between the average of the field aggregate gradation and the base course JMF) of 5 consecutive lots of the field aggregate gradation from the base course JMF for each sieve size will be evaluated and compared with Table II. The percent payment based on aggregate gradation shall be the lowest value determined for any sieve size in Table II.

TABLE II

Percent Payment

AGGREGATE GRADATIONS

BASE COURSE D-1

NOTE (A): Contractor shall remove and replace the newly placed base course at no additional cost to the Government. At the option of the government’s project engineer / project inspector, the percent payment of 75 percent may be used in lieu of remove and replace when determined to be in the best interest of the government.

15. UNIT OF MEASUREMENT AND PAYMENT: Per the Bid Schedule and Section 1020.

End of Section

0.0% 2.1% 4.1% 6.1% 7.1% Above Sieve Size 2.0% 4.0% 6.0% 7.0% 8.0% 8.0%

#4 & Larger 100 100 100 98 95 90 #8 thru #80 100 100 98 95 90 (A) #100 to #200 100 95 90 (A) (A) (A)