c.Spec820.pdf

Section 820 – Crush and Stockpile Aggregate

Services Required

Contractor shall prepare the materials source for production, and produce and stockpile the ordered quantity.

Performance Standards

Develop the materials source as shown on the Pit Plan. All work shall be performed in accordance with MSHA 30 CFR, part 56.

Furnish hard, durable particles or fragments of crushed stone, normally used locally in the construction and maintenance of highways by Federal or State agencies, conforming to the size and quality requirements shown in the Gradation Table.

Furnish crushed aggregate with a maximum size of 1 inch, as determined by AASHTO T 27 and T 11, is uniformly graded from coarse to fine, and free of organic matter, lumps or balls of clay, and other deleterious matter.

Target Value Ranges for Subbase and Base Gradation

Sieve Size Percent by Mass Passing Designated Sieve (AASHTO T 27 and T 11)

Grading Designation D (Base)

2½ inch (63 mm) 2 inch (50 mm)

1½ inch (37.5 mm) 1 inch (25 mm) 100(1) ¾ inch (19 mm) 86 – 100 (6)

½ inch (12.5 mm) ⅜ inch (9.5 mm) 51 – 82 (6) No. 4 (4.75 mm) 36 – 64 (6) No. 40 (425 µm) 12 – 26 (4) No. 200 (75 µm) 4.0 – 7.0 (3)

(1) Statistical procedures do not apply.

( ) The value in the parentheses is the allowable deviation (±) from the target values.

When multiple gradations are required, each shall be stockpiled separately, at least 10 feet apart at the nearest point. The stockpiles shall be neat and regular in shape, not conical or pushed into a pile, and the side slopes no flatter than 1:1.5.

Use AASHTO methods T 27 and T 11 to ensure each gradation for the entire quantity is within target ranges.

Once target values are reached, the performance standard requires split samples to be taken from the belt at least once per 1,000 tons produced. Reject aggregate may be used to stabilize the pit access road or work area, or shall be stockpiled separately. It shall not be mixed with acceptable aggregate.

Acceptable Quality Levels

References to AASHTO standard test methods refer to the methods in effect on the date of this solicitation.

Contract specification values are the values to be strived for and complied with as the design values from which any deviations are allowed. Perform work and provide material that is uniform in character and within the specified tolerance range. The purpose of a tolerance range is to accommodate occasional minor variations from the median zone that are unavoidable for practical reasons.

Measurement

The volume shall be monitored during production, and measurement of the stockpile shall be the final determination of the volume of the quantity produced.

Use an approved format for the volume records. Furnish the original record(s) and a written certification as to the accuracy of the volumes at the end of each shift.

Measurement will be made of the total stockpiled quantity, as shown in the Schedule of Items, completed and accepted in accordance with the contract provisions, specifications, and drawings.

Payment

The accepted quantities, measured as provided above, will be paid at the contract price per unit of measurement for the Section 820 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this section.

Section 820 – Crush and Stockpile Aggregate