02725_agg_base_surface.rtf

02725-1

SECTION 02725

AGGREGATE BASE OR SURFACE COURSE

PART 1 - GENERAL

1.1 - Description

This work shall consist of furnishing, hauling, and placing aggregate base GRADING D as defined in Table 02725-2; underneath the concrete slab and on top of the imported fill.

The Contractor shall conduct tests required in Subsection 2.2. and 3.3.

Testing frequency, for tests listed below, shall be as indicated. Repeat tests shall be conducted in any areas where test results indicate noncompliance with specification requirements. All tests shall be conducted under the direction of a certified testing laboratory.

Section 02336 – Imported Structural Fill Section 03300 – Concrete

PART 2 – PRODUCTS Materials shall be obtained from Contractor Furnished Sources.

2.1 - Materials shall be obtained from Contractor Furnished Sources.

The Contractor shall be responsible for quality testing in conformance with applicable requirements and acceptable to the COR to establish the equivalency of the end product. Test results shall be furnished to the COR.

The Contractor shall submit test results and a Certificate of Compliance that states that the aggregate meets the contract requirements. The COR may at any time sample the delivered materials and make compliance tests.

Any variances from the crushed aggregate quality and gradation requirements must be approved in writing by the COR prior to use of the material on the project.

Sampling and testing of the material before incorporation into the work shall be in accordance with AASHTO requirements and shall occur for commercially produced aggregates, at the producer's plant or stockpile.

These test results shall not preclude later sampling and testing for final acceptance after final processing of the material. Crushing, screening, and mixing plants shall be equipped with sampling devices. The Contractor shall take additional samples as required to validate the certification.

The Contractor, with the written approval of the COR, may use on site suitable stone, gravel, sand, or other material found in the excavation. The Contractor shall replace, without additional compensation, sufficient suitable materials to complete the portion of the work that was originally contemplated to be constructed with such material.

2.2 - Gradation & Quality

All aggregate shall meet the quality requirements shown in Table 02725-1.

Material for crushed aggregate base or surface courses shall be crushed stone, slag, or gravel meeting the grading requirements shown in Table 02725-2. The crushed aggregate gradation shall meet the requirements of Table 02725-2 for the grading AS SHOWN ON THE DRAWINGS. Aggregate shall be well graded from coarse to fine within the gradation band. Grading type will be as SHOWN ON THE SCHEDULE OF ITEMS. When crushed gravel is used, at least 50 percent by weight of the particles retained on No. 4 sieve shall have at least one fractured face. Naturally fractured faces may be included in the 50 percent requirement, provided the roughness and angularity produce strength characteristics equivalent to mechanically fractured faces.

Table 02725-1--Crushed Aggregate Quality Requirements for Base or Surface Courses

Table 02725-2--Crushed Aggregate Grading Requirements for Base or Surface Courses Percent Passing (AASHTO T 11 and T 27)

(a) For untreated base used under bituminous materials, the maximum percent passing the No. 200 sieve shall be eight. For surfacing, the minimum percent passing the No. 200 sieve shall be six.

2.3 - Water

Water shall be potable and shall be free of oil, acid, salt or other substances harmful to plants or animals.

PART 3 - EXECUTION

3.1 - Preparation of Subgrade

The subgrade shall be completed in accordance with Section 02336 and approved by the COR before placing base or surface course.

3.2 – Compaction Method Each layer of aggregate shall be compacted to a density of at least 95 percent of the maximum density, as determined by AASHTO T99, Method C or D.

The surface of each layer shall be bladed during the compaction operations to remove irregularities and produce a smooth, even surface. The density of each layer will be determined in accordance with AASHTO T 191, T 205 or T 238; T 217, T 239 or T 255; and T 224.

Compaction equipment shall be capable of obtaining compaction requirements without detrimentally affecting the compacted material. The compacting units may be of any type, provided they are capable of compacting each lift of material as specified herein.

3.3 - Watering

Mobile watering equipment shall have watertight tanks. Equipment used for finishing operations of subgrade and surfaces shall provide uniform and controlled application of water without ponding or washing. Positive control of water from the driver's position is required at all times.

3.4 - Thickness Requirements

The thickness of the compacted aggregate shall not vary more than 1/2 inch from the thickness SHOWN ON THE DRAWINGS. The compacted thickness shall not be consistently above or below the specified thickness.

3.5 - Stockpiling

If SHOWN ON THE DRAWINGS or if the Contractor elects to produce and stockpile aggregates prior to placement, the aggregates shall be handled and stockpiled in accordance with the requirements shown below. Stockpile sites shall be at locations as approved by the COR.

All materials shall be transported and handled to preserve their quality and fitness for the work. Aggregates shall be stockpiled, loaded, and transported in a manner that will preserve specified gradation and avoid contamination. Stockpiles of aggregate having different gradations shall not be stockpiles where mixing of gradations may occur.

PART 4 - MEASUREMENT AND PAYMENT

MEASUREMENT

The work specified herein shall be measured as cubic yards of aggregate base furnished, installed and compacted.

PAYMENT

This work shall be paid under the following pay item:

Pay Item Description Pay Unit

02725(01) Aggregate Base or Surface Course for Shelter Slab CY 02725(02) Aggregate Base or Surface Course for Parking Slab CY

END OF SECTION