Atch_08_Spec_Section_32_11_16_Subbase.doc

MAINTAIN/REPAIR PAVEMENTS IDIQ

IFB No.: F26600-99-R-C118

RKMF 98-0105

Contract No.:

PAVING IDIQ

Solicitation: FA4861-16-R-A300

SECTION 32 11 16

SUBBASE COURSE

1. PART 1 GENERAL

1.1. REFERENCES: The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by basic designation only.

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

ASTM C 29

(1987) Unit Weight and Voids in Aggregate

ASTM C 117

(1987) Materials Finer Than 75-um (No. 200) Sieve in

Mineral Aggregates by Washing

ASTM C 131

(1981; R 1987) Resistance to Degradation of Small-size

Coarse Aggregate by Abrasion and Impact in the Los

Angeles Machine

ASTM C 136

(1984a) Sieve Analysis of fine and Coarse Aggregates

ASTM D 75

(1987) Sampling Aggregates

ASTM D 1556

(1982) Density of Soil In-Place by the Sand-Cone Method

ASTM D 1557

(1987) Moisture-Density Relations of Soils Soil-Aggregate Mixtures Using 10lb. (4.54-kg) Rammer and 18-In. (457- m) Drop

ASTM D 2167

(1984) Density and Unit Weight of Soil In-Place by the Rubber Balloon Method

ASTM D 2487

(1985) Classification of Soils for Engineering Purposes

ASTM D 2922

(1981) Density of Soil and Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth)

ASTM D 3017

(1978) Moisture Content of Soil and Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth)

ASTM D 4318

(1984) Liquid Limit, Plastic Limit, and Plasticity Index of Soils

ASTM E 11

(1987) Wire-Cloth Sieves for Testing Purposes

1.2. MEASUREMENT: The quantity of subbase completed and accepted as determined by the Contracting Officer will be measured in square yards. The thickness of the subbase will be 6".

1.3. PAYMENT: Quantities of subbase course, determined as specified in paragraph "MEASUREMENT," will be paid for at the respective contract unit prices, which will constitute full compensation for the construction and completion of the subbase course.

1.4. DEGREE OF COMPACTION: Degree of compaction is a percentage of the maximum density obtained by the test procedure presented in ASTM D 1557, Method D abbreviated herein as percent laboratory maximum density.

1.5. SAMPLING AND TESTING: Sampling and testing shall be the responsibility of the Contractor. Sampling and testing shall be performed by an approved commercial testing laboratory. The materials shall be tested to establish compliance with the specified requirements.

1.5.1. Samples: Samples for laboratory testing shall be taken in conformance with ASTM D 75. When deemed necessary, the sampling will be observed by the Contracting Officer.

1.5.2. Tests

1.5.2.1. Sieve Analysis: Sieve analysis shall be made in performance with ASTM C 117 and ASTM C 136. Sieves shall conform to ASTM E 11. After the initial test, a minimum of one analysis shall be performed for each 5000 square yards of material placed.

1.5.2.2. Liquid Limit and Plasticity Index: Liquid limit and plasticity index shall be determined in accordance with ASTM D 4318.

1.5.2.3. Optimum Moisture and Maximum Density: Tests shall be made for each type material or source of material to determine the optimum moisture and laboratory maximum density values. Before starting construction, at least one test shall be performed. During construction, one representative test per 5000 square yards, or when any change in material occurs which may affect the optimum moisture content.

1.5.2.4. Density Tests: Density shall be measured in the field in accordance with ASTM D 1556 or ASTM D 2922. For the method presented in ASTM D 2922 the calibration curves shall be checked, and adjusted if necessary, using only the sand cone method as described in paragraph "Calibration" of the ASTM publication. Tests performed in accordance with ASTM D 2922 result in a wet unit weight of soil and when using this method, ASTM D 4017 shall be used to determine the moisture content of the soil. The calibration curves furnished with the moisture gauges shall also be checked along with density calibration checks as described in ASTM D 3017 AASHTO T 239. The calibration checks of both the density and moisture gauges shall be made by the prepared containers of material method, as described in paragraph "Calibration" in ASTM D 2922, on each different type of material to be tested at the beginning of a job and at intervals as directed. The following number of tests, if performed at the appropriate time, will be the minimum acceptable for each type operation: Five tests per 2000 square yards shall be performed at locations selected at random. The locations may be selected by a Government representative. The five tests shall be considered a statistical random sample of a representative area. No more than two of the five tests can be less than the 100 percent (98% for PCC) laboratory maximum density, and none can show a density less than 97% (95% for PCC). If these results are not achieved, the entire area represented by the random sample shall be recompacted and tested.

1.5.2.5. Wear Test: Wear tests shall be made in conformance with ASTM C 131.

1.5.2.6. Weight Per Cubic Foot of Slag: Weight per cubic foot of slag shall be determined in accordance with ASTM C 29.

1.5.3. Approval of Material: The source of, and tests on the material to be used on the job shall be submitted to the Contracting Officer for approval prior to use on the jobsite. Tentative approval of the source will be based on tests of samples for the specific job. Final approval of both the source and the material will be based on tests performed on samples taken from the completed subbase course.

1.6. WEATHER LIMITATIONS: Subbase courses shall be constructed when the atmospheric temperature is above 35 degrees F. When the temperature falls below 35 degrees F, the Contractor shall protect all areas of completed subbase course by approved methods against detrimental effects of freezing. Areas of completed subbase course damaged by freezing, rainfall, or other weather conditions shall be corrected to meet specified requirements.

1.7. EQUIPMENT: All plant, equipment, and tools used in the performance of the work may be subject to inspection before the work is started and shall be maintained in satisfactory working condition at all times. The equipment shall be adequate and shall have the capability of producing the required compaction, meeting grade controls, thickness control, and smoothness requirements as set forth herein.

2. PART 2 PRODUCTS

2.1. MATERIALS: Aggregates shall consist of crushed stone or slag, gravel, shell, sand, or other sound, durable, approved materials processed and blended or naturally combined. Aggregates shall be durable and sound, free from lumps and balls of clay, organic matter, objectionable coatings, and other foreign material. Material retained on the No. 4 sieve shall have a percentage of wear not to exceed 50 percent after 500 revolutions when tested as specified in ASTM C 131. Aggregate shall be reasonably uniform in density and quality. Slag shall be an air-cooled, blast-furnace product having a dry weight of not less than 65 pcf. Aggregates shall have a maximum size of 2 inches and shall be within the limits specified as follows:

Maximum Allowable Percentage by Weight

Passing Square-Mesh Sieve

Sieve Designation

No. 10 50

No. 200 15

The portion of any blended component and of the completed course passing the No. 40 sieve shall be either nonplastic or shall have a liquid limit not greater than 25 and a plasticity index not greater than 5.

3. PART 3 EXECUTION

3.1. OPERATION OF AGGREGATE SOURCES: All clearing, stripping and excavating work involved in the opening or operation for aggregate sources shall be performed by the Contractor. Aggregate sources shall be opened to working depth in a manner that produces excavation faces that are as nearly vertical as practicable for the materials being excavated. Materials excavated from aggregate sources shall be obtained in successive cuts extending through all exposed strata. All pockets or strata of unsuitable materials overlying or occuring in the deposit shall be wasted as directed. The methods of operating aggregate sources and the processing and blending of the material may be changed or modified by the Contracting Officer when necessary in order to obtain material conforming to specified requirements. Upon completion of work, aggregate sources on Government reservations shall be conditioned to drain readily, and shall be left in satisfactory condition. Aggregated sources on private lands shall be conditioned in agreement with local laws and authorities.

3.2. PREPARATION OF UNDERLYING MATERIAL: Prior to constructing the subbasecourse, the underlying course shall be cleaned of all foreign substances. Subgrade shall conform to the requirements of Section 02225. Ruts or soft, yielding spots in the underlying course, areas having inadequate compaction, and deviations of the surface from requirements set forth herein shall be corrected by loosening and removing soft or unsatisfactory materials and by adding approved material, reshaping to line and grade, and recompacting to specified density requirements. For cohesionless underlying courses containing sands or gravels, as defined in ASTM D 2487, the surface shall be stabilized prior to placement of the subbase course. Stabilization shall be accomplished by mixing subbase-course material into the underlying course, and compacting by approved methods. The stabilized material will be considered as part of the underlying course and shall meet all requirements for the underlying course. The finished underlying course shall be maintained by the Contractor in a satisfactory condition until the subbase course is placed.

3.3. GRADE CONTROL: The finished and completed subbase course shall conform to the lines, grades, and cross sections shown. The lines, grades,and course sections shown shall be maintained by means of line and grade stakes placed by the Contractor at the site of the work.

3.4. MIXING AND PLACING MATERIALS: The materials shall be mixed and placed in such a manner as to obtain uniformity of the subbase material and at the water content specified. The Contractor shall make such adjustments in mixing or placing procedures or in equipment as may be directed to obtain the true grades, to minimize segregation and degradation, to reduce, to accelerate, or increase water content, and to insure a satisfactory subbase course.

3.5. LAYER THICKNESS: The compacted thickness of the subbase course shall be as indicated. When a compacted layer of 6 inches is specified, the material may be placed in a single layer; when a compacted thickness of more than 6 inches is required, no layer shall exceed 6 inches nor be less than 3 inches when compacted.

3.6. COMPACTION: Each layer of the subbase course shall be compacted as specified with approved compaction equipment. Water content shall be maintained during the compaction procedure such that the water content is within plus or minus (2) percent of optimum water content as determined from laboratory tests as specified in paragraph "SAMPLING AND TESTING". In all places not accessible to the rollers, the mixture shall be compacted with hand-operated power tampers. Compaction shall continue until each layer is compacted through the full depth. The Contractor shall make such adjustments in compacting or finishing procedures as may be directed to obtain true grades, to minimize segregation and degradation, to reduce or increase water content, and to insure a satisfactory subbase course. Any materials that are found to be unsatisfactory shall be removed and replaced with satisfactory material or reworked, as directed, to meet the requirements of this specification.

3.7. EDGES OF SUBBASE COURSE: Approved material shall be placed along the edges of the subbase course in such quantity as will compact to the thickness of the course being constructed. When the course is being constructed in two or more layers, at least a 1-foot width of the shoulder shall be rolled and compacted simultaneously with the rolling and compacting of each layer of the subbase course, as directed.

3.8. SMOOTHNESS TEST: The surface of each layer shall not show deviations in excess of 3/8 inch when tested with a 10-foot straightedge applied parallel with and at right angles to the centerline of the area to be paved. Deviations exceeding this amount shall be corrected by removing material, replacing with new material, or reworking existing material and compacting, as directed.

3.9. THICKNESS CONTROL: The completed thickness of the subbase course shall bear in accordance with the thickness and grade indicated on the drawings. If requested, the thickness measurement shall be made by test holes, at least 3 inches in diameter through the course. The completed subbase course shall not be more than 1/2 inch deficient in thickness nor more than 1/2 inch above or below the established grade. Where any of these tolerances are exceeded, the Contractor shall correct such areas by scarifying, adding new material of proper gradation or removing material, and compacting, as directed. Where the measured thickness of the subbase course is 1/2 inch or more thicker than shown, the course will be considered as conforming with the specified thickness requirements plus 1/2 inch. The average job thickness shall be the average of the job measurements as specified above but within 1/4 inch of the thickness shown.

3.10. MAINTENANCE: The subbase course shall be maintained in a satisfactory condition until accepted.

END OF SECTION

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Subbase

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