32 11 16 BASE COURSE FOR RIGID AND SUBBASES FOR FLEXIBLE PAV.doc

SECTION 32 11 16

BASE COURSE FOR RIGID AND SUBBASES FOR FLEXIBLE PAVING

PART 1 GENERAL

1.1 REFERENCES

1.1.1 The latest issue of the publications listed below and referenced to thereafter by basic designations only, forms a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

1.1.1.1 AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS (AASHTO)

a. AASHTO T 180 Moisture-Density Relations of Soils Using a 10-lb Rammer and an 18-in Drop

b. AASHTO T 224 Correction for Coarse Particles in the Soil Compaction Test

1.1.1.2 ASTM INTERNATIONAL (ASTM)

a. ASTM C 117 Standard Test Method for Materials Finer than 75-um (No. 200) Sieve in Mineral Aggregates by Washing

b. ASTM C 131 Standard Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine

c. ASTM C 136 Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates

d. ASTM C 29/C 29M Standard Test Method for Bulk Density ("Unit Weight") and Voids in Aggregate

e. ASTM D 1556 Density and Unit Weight of Soil in Place by the Sand-Cone Method

f. ASTM D 1557 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort 56,000 ft-lbf/ft3

g. ASTM D 2167 Density and Unit Weight of Soil in Place by the Rubber Balloon Method

h. ASTM D 2487 Soils for Engineering Purposes (Unified Soil Classification System)

i. ASTM D 422 Particle-Size Analysis of Soils

j. ASTM D 4318 Liquid Limit, Plastic Limit, and Plasticity Index of Soils

k. ASTM D 6938 Standard Test Method for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth)

l. ASTM D 75 Standard Practice for Sampling Aggregates

m. ASTM E 11 Wire Cloth and Sieves for Testing Purposes

1.2 SUBMITTALS

1.2.1 Government approval may be required on any of the following items. Items requiring submittals shall be listed on the AF Form 66. Copies of all submittals shall be provided per the requirements in Section 01 33 00, Submittal Procedures, or as listed on the AF Form 66.

1.2.1.1 SD-03 Product Data

a. Equipment

(1) List of proposed equipment to be used in performance of construction work, including descriptive data.

b. Waybills and Delivery Tickets

(1) Copies of waybills and delivery tickets during the progress of the work.

1.2.1.2 SD-06 Test Reports

a. Sampling and Testing

b. Field Density Tests

(1) Certified copies of test results for approval not less than 30 days before material shall be required for the work.

(2) Calibration curves and related test results prior to using the device or equipment being calibrated.

(3) Copies of field test results within 24 hours after the tests are performed.

1.3 UNIT PRICES

1.3.1 Measurement

1.3.1.1 Area

a. The quantity of subbase and select-material subbase or rigid pavement base course completed and accepted as determined by the Contracting Officer shall be measured in square yards.

1.3.1.2 Volume

a. The quantity of subbase and select-material subbase or rigid pavement base course completed and accepted as determined by the Contracting Officer shall be measured in cubic yards. The volume of material in-place and accepted shall be determined by the average job thickness obtained in accordance with paragraph THICKNESS CONTROL and the dimensions shown.

1.3.1.3 Weight

a. The tonnage of subbase and select-material subbase or rigid pavement base course material shall be the number of tons of aggregate, placed and accepted in the completed course in authorized stockpiles as determined by the Contracting Officer. Deductions shall be made for any material wasted, unused, rejected, or used for convenience of the Contractor, and for water exceeding specified amount at time of weighing.

1.3.2 Payment

1.3.2.1 Course Material

a. Quantities of subbase and select-material subbase or rigid pavement base course, determined as specified in paragraph Measurement, shall be paid for at the respective contract unit prices, which shall constitute full compensation for the construction and completion of the subbase and select-material subbase or rigid pavement base course.

1.3.2.2 Stabilization

a. Cohesionless subgrades or select subbase courses to be stabilized, as specified in paragraph PREPARATION OF UNDERLYING MATERIAL, shall be paid as a special item on the tonnage basis including extra manipulation as required.

1.3.3 Waybills and Delivery Tickets

1.3.3.1 Copies of waybills and delivery tickets shall be submitted during the progress of the work.

1.4 DEGREE OF COMPACTION

1.4.1 Degree of compaction required, except as noted in the second sentence, shall be expressed as a percentage of the maximum laboratory dry density obtained by the test procedure presented in ASTM D 1557 abbreviated as a percent of laboratory maximum dry density. Since ASTM D 1557 applies only to soils that have 30 percent or less by weight of their particles retained on the (3/4 inch) sieve, the degree of compaction for material having more than 30 percent by weight of their particles retained on the (3/4 inch) sieve shall be expressed as a percentage of the laboratory maximum dry density in accordance with AASHTO T 180 Method D and corrected with AASHTO T 224.

1.5 SAMPLING AND TESTING

1.5.1 Sampling and testing shall be the responsibility of the Contractor. Sampling and testing shall be performed by an approved testing laboratory in accordance with Section 01 45 04.00 10 CONTRACTOR QUALITY CONTROL. Tests shall be performed at the specified frequency. No work requiring testing shall be permitted until the testing laboratory has been inspected and approved. The materials shall be tested to establish compliance with the specified requirements.

1.5.2 Sampling

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

1.5.3 Tests

1.5.3.1 Sieve Analysis

a. Sieve analysis shall be made in conformance with ASTM C 117 and ASTM C 136. Particle-size analysis of the soils shall be completed in conformance with ASTM D 422. Sieves shall conform to ASTM E 11.

(1) Liquid Limit and Plasticity Index

(a) Liquid limit and plasticity index shall be determined in accordance with ASTM D 4318.

(2) Moisture-Density Determinations

(a) The laboratory maximum dry density and optimum moisture shall be determined in accordance with ASTM D 1557, AASHTO T 180, Method D and corrected with AASHTO T 224.

(3) Field Density Tests

(a) Density shall be field measured in accordance with ASTM D 1556, ASTM D 2167, or ASTM D 6938. For the method presented in ASTM D 1556, the base plate, as shown in the drawing, shall be used. For the method presented in ASTM D 6938, 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 6938 result in a wet unit weight of soil and ASTM D 6938 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 6938. 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 6938, on each different type of material to be tested at the beginning of a job and at intervals as directed.

(4) Wear Test

(a) Wear tests shall be made in conformance with ASTM C 131.

(5) Weight of Slag

(a) Weight per cubic foot of slag shall be determined in accordance with ASTM C 29/C 29M.

1.5.4 Testing Frequency

1.5.4.1 Initial Tests

a. One of each of the following tests shall be performed on the proposed material prior to commencing construction to demonstrate that the proposed material meets all specified requirements prior to installation.

(1) Sieve Analysis including 0.000787 inch size material

(2) Liquid limit and plasticity index

(3) Moisture-density relationship

(4) Wear

(5) Weight per cubic foot of Slag

1.5.4.2 In-Place Tests

a. One of each of the following tests shall be performed on samples taken from the placed and compacted subbase and select-material subbase or rigid pavement base course. Samples shall be taken and tested at the rates indicated.

(1) Density tests shall be performed on every lift of material placed and at a frequency of one set of tests for every 500 square yards, or portion thereof, of completed area.

(2) Sieve Analysis including 0.000787 inch size material shall be performed on every lift of material placed and at a frequency of one sieve analysis for every 1000 square yards, or portion thereof, of material placed.

(3) Liquid limit and plasticity index tests shall be performed at the same frequency as the sieve analysis.

(4) The thickness of each course shall be measured at intervals providing at least one measurement for each square yards or part thereof. The thickness measurement shall be made by test holes, at least 3 inches in diameter through the course.

1.5.5 Approval of Material

1.5.5.1 The source of the material shall be selected 30 days prior to the time the material shall be required in the work. Tentative approval shall be based on initial test results. Final approval of the materials shall be based on tests for gradation, liquid limit, and plasticity index performed on samples taken from the completed and compacted course.

1.6 WEATHER LIMITATIONS

1.6.1 Construction shall be done when the atmospheric temperature is above 35 degrees F. When the temperature falls below 35 degrees F, the Contractor shall protect all completed areas by approved methods against detrimental effects of freezing. Completed areas damaged by freezing, rainfall, or other weather conditions shall be corrected to meet specified requirements.

1.7 EQUIPMENT

1.7.1 All plant, equipment, and tools used in the performance of the work shall be subject to approval before the work has 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.

PART 2 PRODUCTS

2.1 MATERIALS

2.1.1 Subbase Course

2.1.1.1 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 3 inch and shall be within the limits specified as follows:

Maximum Allowable Percentage by Weight

Passing Square-Mesh Sieve

Sieve Designation No. 1

No.2

No. 3

No. 10

No. 200

2.1.1.2 Particles having diameters less than 0.0008 inches shall not be in excess of 3 percent by weight of the total sample tested as determined in accordance with ASTM D 422. 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.

2.1.2 Select-Material Subbase Course

2.1.2.1 Materials shall consist of selected soil or other materials from field excavation, stockpiles, or other sources. Material shall be free from lumps and balls of clay and from organic and other objectionable matter. Not more than 25 percent by weight shall pass the No. 200 sieve. The portion of material passing the No. 40 sieve shall have a liquid limit less than 35 and a plasticity index less than 12. The maximum particle size shall not exceed 3 inches. Particles having diameters less than 0.02 mm shall not be in excess of 3 percent by weight of the total sample tested as determined in accordance with ASTM D 422.

2.1.3 Rigid Pavement Base Course

2.1.3.1 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. At least 50 percent by weight retained on each sieve shall have one freshly fractured face with the area at least equal to 75 percent of the smallest midsectional area of the piece. 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

Rigid Pavement ____________________________________Base Course No. 10

No. 200

2.1.3.2 Particles having diameters less than 0.02 mm shall not be in excess of 3 percent by weight of the total sample tested as determined in accordance with ASTM D 422. 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 8. The Contractor shall be responsible for any additional stability required to provide a working platform for construction equipment. If the Contractor can demonstrate with a test section that a material has adequate stability to support construction equipment, the fractured face requirement can be deleted, subject to the approval of the Contracting Officer.

PART 3 EXECUTION

3.1 OPERATION OF AGGREGATE SOURCES

3.1.1 Clearing, stripping and excavating shall be the responsibility of the Contractor. The aggregate sources shall be operated to produce the quantity and quality of materials meeting these specifications requirements in the specified time limit. Upon completion of work, aggregate sources on Government property shall be conditioned to drain readily, and shall be left in a satisfactory condition. Aggregate sources on private lands shall be conditioned in agreement with local laws and authorities.

3.2 STOCKPILING MATERIAL

3.2.1 Prior to stockpiling of material, storage sites shall be cleared and leveled by the Contractor. All materials, including approved material available from excavation and grading, shall be stockpiled in the manner and at the locations designated. Aggregates shall be stockpiled on the cleared and leveled areas designated by the Contracting Officer to prevent segregation. Materials obtained from different sources shall be stockpiled separately.

3.3 PREPARATION OF UNDERLYING MATERIAL

3.3.1 Prior to constructing the subbase or select-material subbase or rigid pavement base course, the underlying course or subgrade shall be cleaned of all foreign substances. The surface of the underlying course or subgrade shall meet specified compaction and surface tolerances. Ruts, or soft yielding spots, in the underlying courses, subgrade areas having inadequate compaction, and deviations of the surface from the specified requirements, shall be corrected by loosening and removing soft or unsatisfactory material and by adding approved material, reshaping to line and grade, and recompacting to specified density requirements. For cohesionless underlying courses or subgrades containing sands or gravels, as defined in ASTM D 2487, the surface shall be stabilized prior to placement of the overlying course. Stabilization shall be accomplished by mixing the overlying course material into the underlying course, and compacting by approved methods. The stabilized material shall be considered as part of the underlying course and shall meet all requirements for the underlying course. The finished underlying course shall not be disturbed by traffic or other operations and shall be maintained by the Contractor in a satisfactory condition until the overlying course shall be placed.

3.4 GRADE CONTROL

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

3.5 MIXING AND PLACING MATERIALS

3.5.1 The materials shall be mixed and placed to obtain uniformity of the material 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 or accelerate loss or increase of water, and to insure a satisfactory subbase course.

3.6 LAYER THICKNESS

3.6.1 The compacted thickness of the completed 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 be thicker than 6 inches nor be thinner than 3 inches when compacted.

3.7 COMPACTION

3.7.1 Each layer of the material shall be compacted as specified with approved compaction equipment. Water content shall be maintained during the compaction procedure to 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 of the subbase or select-material subbase shall continue until each layer has been compacted through the full depth to at least 100 percent of laboratory maximum density. Compaction of the rigid base course shall continue until each layer has been compacted through the full depth to at least 95 percent of laboratory maximum density. 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 ensure 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.

3.8 PROOF ROLLING

3.8.1 Areas designated on the drawings to be proof rolled shall receive an application of coverages with a heavy pneumatic-tired roller having four or more tires abreast, each tire loaded to a minimum of 30,000 pounds and inflated to a minimum of 125 psi. A coverage shall be defined as the application of one tire print over the designated area. In the areas designated, proof rolling shall be applied to the top layer of the subbase course. Water content of the top layer of the subbase course shall be maintained such that the water content shall be within plus or minus 2 percent of optimum water content, as determined from laboratory tests, as specified in paragraph SAMPLING AND TESTING. Any material in the subbase courses or underlying materials indicated to be unsatisfactory by the proof rolling shall be removed, dried, and recompacted, or removed and replaced with satisfactory materials.

3.9 EDGES

3.9.1 Approved material shall be placed along the edges of the subbase and select-material subbase course in such quantity as will compact to the thickness of the course being constructed. When the course shall be 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.

3.10 SMOOTHNESS TEST

3.10.1 The surface of the top layer shall show no deviations in excess of 3/8 inch when tested with a 12 foot straightedge. Measurements shall be taken in successive positions parallel to the centerline of the area to be paved. Measurements shall also be taken perpendicular to the centerline at 50 foot intervals. Deviations exceeding this amount shall be corrected by removing material and replacing with new material, or by reworking existing material and compacting it to meet these specifications.

3.11 THICKNESS CONTROL

3.11.1 The completed thickness of the course(s) shall be in accordance with the thickness and grade indicated on the drawings. The completed 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 is 1/2 inch or more than shown, the course shall 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.

3.12 MAINTENANCE

3.12.1 The completed course shall be maintained in a satisfactory condition until accepted.

END OF SECTION 32 11 16

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32 11 16-1 03/16/10