### **ITEM P-209 CRUSHED AGGREGATE BASE COURSE**

DESCRIPTION

**209-1.1**  This item consists of a base course composed of crushed
aggregates constructed on a prepared course in accordance with these
specifications and in conformity to the dimensions and typical cross
sections shown on the plans.

MATERIALS

**209-2.1 AGGREGATE**.  Aggregates shall consist of clean, sound,
durable particles of crushed stone, crushed gravel, or crushed slag and
shall be free from coatings of clay, silt, vegetable matter, and other
objectionable materials and shall contain no clay balls.  Fine aggregate
passing the No. 4 (4.75 mm) sieve shall consist of fines from the
operation of crushing the coarse aggregate.  If necessary, fine
aggregate may be added to produce the correct gradation.  The fine
aggregate shall be produced by crushing stone, gravel, or slag that meet
the requirements for wear and soundness specified for coarse aggregate.

The crushed slag shall be an air-cooled, blast furnace slag and shall
have a unit weight of not less than 70 pounds per cubic foot (1.12
Mg/cubic meter) when tested in accordance with ASTM C 29.

The coarse aggregate portion, defined as the material retained on the
No. 4 (4.75 mm) sieve and larger, shall contain not more than 15
percent, by weight, of flat or elongated pieces as defined in ASTM D 693
and shall have at least 90 percent by weight of particles with at least
two fractured faces and 100 percent with at least one fractured face. 
The area of each face shall be equal to at least 75 percent of the
smallest midsectional area of the piece.  When two fractured faces are
contiguous, the angle between the planes of fractures shall be at least
30 to count as two fractured faces.

The percentage of wear shall not be greater than 45 percent when tested
in accordance with ASTM C 131.  The sodium sulfate soundness loss shall
not exceed 12 percent, after 5 cycles, when tested in accordance with
ASTM C 88.

The fraction passing the No. 40 (0.42 mm) sieve shall have a liquid
limit no greater than 25 and a plasticity index of not more than 4 when
tested in accordance with ASTM D 4318.  The fine aggregate shall have a
minimum sand equivalent value of 35 when tested in accordance with ASTM
D 2419.

**a. Sampling and Testing**.  Aggregates for preliminary testing shall
be furnished by the Contractor prior to the start of production.  All
tests for initial aggregate submittals necessary to determine compliance
with the specification requirements will be made by the Engineer at no
expense to the Contractor.

Samples of aggregates shall be furnished by the Contractor at the start
of production and at intervals during production.  The sampling points
and intervals will be designated by the Engineer.  The samples will be
the basis of approval of specific lots of aggregates from the standpoint
of the quality requirements of this section.

In lieu of testing, the Engineer may accept certified state test results
indicating that the aggregate meets specification requirements.
Certified test results shall be less than 6 months old.

Samples of aggregates to check gradation shall be taken by the Engineer
at least two per lot.  The lot will be consistent with acceptable
sampling for density. The samples shall be taken from the in-place,
compacted material. Sampling shall be in accordance with ASTM D 75, and
testing shall be in accordance with ASTM C 136 and ASTM C 117.

**b. Gradation Requirements**.  The gradation (job mix) of the final
mixture shall fall within the design range indicated in Table 1, when
tested in accordance with ASTM C 117 and ASTM C 136.  The final
gradation shall be continuously well graded from coarse to fine and
shall not vary from the low limit on one sieve to the high limit on an
adjacent sieve or vice versa.

**TABLE 1. REQUIREMENTS FOR GRADATION OF AGGREGATE \\1\\**

+---------------------+------------------------+----------------------+
| **Sieve Size**      | **Design Range**       | **Job Mix            |
|                     |                        | Tolerances**         |
|                     | **Percentage by        |                      |
|                     | Weight**               | **Percent**          |
|                     |                        |                      |
|                     | **Percentage by        |                      |
|                     | Weight**               |                      |
+---------------------+------------------------+----------------------+
| 2 in (50.0 mm)      | 100                    | 0                    |
+---------------------+------------------------+----------------------+
| 1-1/2 (37.0 mm)     | 95-100                 | +/- 5                |
+---------------------+------------------------+----------------------+
| 1 in (25.0 mm)      | 70-95                  | +/- 8                |
+---------------------+------------------------+----------------------+
| 3/4 in (19.0 mm)    | 55-85                  | +/‑ 8                |
+---------------------+------------------------+----------------------+
| No. 4 (4.75 mm)     | 30-60                  | +/‑ 8                |
+---------------------+------------------------+----------------------+
| No. 30 (0.60 mm)    | 12-30                  | +/‑ 5                |
+---------------------+------------------------+----------------------+
| No. 200 (0.075 mm)  | 0-8                    | +/‑ 3                |
+---------------------+------------------------+----------------------+

\\1\\ Where environmental conditions (temperature and availability of
free moisture) indicate potential damage due to frost action, the
maximum percent of material, by weight, of particles smaller than 0.02
mm shall be 3 percent when tested in accordance with ASTM D 422.  It
also may be necessary to have a lower percentage of material passing the
No. 200 sieve to help control the percentage of particles smaller than
0.02 mm maximum limit of 5 percent is recommended).

The job mix tolerances in Table 1 shall be applied to the job mix
gradation to establish a job control grading band.  The full tolerance
still will apply if application of the tolerances results in a job
control grading band outside the design range.

The fraction of the final mixture that passes the No. 200 (0.075 mm)
sieve shall not exceed 60 percent of the fraction passing the No. 30
(0.60 mm) sieve.

CONSTRUCTION METHODS

**209-3.1 PREPARING UNDERLYING COURSE**.  The underlying course shall be
checked and accepted by the Engineer before placing and spreading
operations are started.  Any ruts or soft yielding places caused by
improper drainage conditions, hauling, or any other cause shall be
corrected at the Contractor\'s expense before the base course is placed
thereon.  Material shall not be placed on frozen subgrade.

**209-3.2 MIXING**. The aggregate shall be uniformly blended during
crushing operations or mixed in a plant.  The plant shall blend and mix
the materials to meet the specifications and to secure the proper
moisture content for compaction.

**209-3.3 PLACING**.  The crushed aggregate base material shall be
placed on the moistened subgrade in layers of uniform thickness with a
mechanical spreader.

The maximum depth of a compacted layer shall be 6 inches (150 mm).  If
the total depth of the compacted material is more than 6 inches (150
mm), it shall be constructed in two or more layers.  In multi-layer
construction, the base course shall be placed in approximately
equal-depth layers.

The previously constructed layer should be cleaned of loose and foreign
material prior to placing the next layer.  The surface of the compacted
material shall be kept moist until covered with the next layer.

**209-3.4 COMPACTION**.  Immediately upon completion of the spreading
operations, the crushed aggregate shall be thoroughly compacted.  The
number, type, and weight of rollers shall be sufficient to compact the
material to the required density.

The moisture content of the material during placing operations shall not
be below, nor more than 2 percentage points above, the optimum moisture
content as determined by ASTM **\[ \]**.

**209-3.5 ACCEPTANCE SAMPLING AND TESTING FOR DENSITY**.  Aggregate base
course shall be accepted for density on a lot basis.  A lot will consist
of one day\'s production where it is not expected to exceed 2400 square
yards (2000 square meters).  A lot will consist of one-half day\'s
production where a day\'s production is expected to consist of between
2400 and 4800 square yards (2000 and 4000 square meters).

Each lot shall be divided into two equal sublots.  One test shall be
made for each sublot.  Sampling locations will be determined by the
Engineer on a random basis in accordance with statistical procedures
contained in ASTM D 3665.

Each lot will be accepted for density when the field density is at least
100 percent of the maximum density of laboratory specimens prepared from
samples of the base course material delivered to the job site.  The
specimens shall be compacted and tested in accordance with ASTM **\[
\]**.  The in-place field density shall be determined in accordance with
ASTM D 1556 or D 2167.  If the specified density is not attained, the
entire lot shall be reworked and/or recompacted and two additional
random tests made.  This procedure shall be followed until the specified
density is reached.

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> **The Engineer shall specify ASTM D 698 for areas designated for
> aircraft with gross weights of 60,000 pounds (27 200 kg) or less and
> ASTM D 1557 for areas designated for aircraft with gross weights
> greater than 60,000 pounds (27 200 kg).**

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In lieu of the core method of field density determination, acceptance
testing may be accomplished using a nuclear gage in accordance with ASTM
D 2922 and ASTM D 3017.  The gage should be field calibrated in
accordance with paragraph 4 of ASTM D 2922.  Calibration tests shall be
conducted on the first lot of material placed that meets the density
requirements.

Use of ASTM D 2922 results in a wet unit weight, and when using this
method, ASTM D 3017 shall be used to determine the moisture content of
the material.  Calibration and Standardization shall be conducted in
accordance with ASTM standards.

If a nuclear gage is used for density determination, two random readings
shall be made for each sublot.

**209-3.6 FINISHING**.  The surface of the aggregate base course shall
be finished by blading or with automated equipment especially designed
for this purpose.

In no case will the addition of thin layers of material be added to the
top layer of base course to meet grade.  If the elevation of the top
layer is 1/2 inch (12 mm) or more below grade, the top layer of base
shall be scarified to a depth of at least 3 inches (75 mm), new material
added, and the layer shall be blended and recompacted to bring it to
grade.  If the finished surface is above plan grade, it shall be cut
back to grade and rerolled.

**209-3.7 SURFACE TOLERANCES**.  The finished surface shall not vary
more than 3/8 inch (9 mm) when tested with a 16-foot (4.8 m)
straightedge applied parallel with or at right angles to the
centerline.  Any deviation in excess of this amount shall be corrected
by the Contractor at the Contractor\'s expense.

**209-3.8 THICKNESS CONTROL**.  The completed thickness of the base
course shall be within 1/2 inch (12 mm) of the design thickness.  Four
determinations of thickness shall be made for each lot of material
placed.  The lot size shall be consistent with that specified in
paragraph 3.5.  Each lot shall be divided into four equal sublots.  One
test shall be made for each sublot.  Sampling locations will be
determined by the Engineer on a random basis in accordance with
procedures contained in ASTM D 3665.  Where the thickness is deficient
by more than 1/2 inch (12 mm), the Contractor shall correct such areas
at no additional cost by excavating to the required depth and replacing
with new material.  Additional test holes may be required to identify
the limits of deficient areas.

**209-3.9 MAINTENANCE**.  The base course shall be maintained in a
condition that will meet all specification requirements until the work
is accepted.  Equipment used in the construction of an adjoining section
may be routed over completed portions of the base course, provided no
damage results and provided that the equipment is routed over the full
width of the base course to avoid rutting or uneven compaction.

The Contractor shall remove all survey and grade hubs from the base
courses prior to placing any bituminous surface course.

METHOD OF MEASUREMENT

**209-4.1**  The quantity of crushed aggregate base course to be paid
for will be determined by measurement of the number of **\[square yards
(square meters)\]\[cubic yards (cubic meters)\]** of material actually
constructed and accepted by the Engineer as complying with the plans and
specifications.  **\[On individual depth measurements, thicknesses more
than 1/2 inch (12 mm) in excess of the design thickness shall be
considered as the specified thickness, plus 1/2 inch (12 mm) in
computing the number of cubic yards (cubic meters) for payment.\]**

BASIS OF PAYMENT

**209-5.1**  Payment shall be made at the contract unit price per
**\[square yard (square meter)\]\[cubic yard (cubic meter)\]** for
crushed aggregate base course.  This price shall be full compensation
for furnishing all materials, for preparing and placing these materials,
and for all labor, equipment tools, and incidentals necessary to
complete the item.

Payment will be made under:

Item P-209-5.1 Crushed Aggregate Base Course---per **\[square yard
(square meter\]\[cubic yard (cubic meter)\]**

TESTING REQUIREMENTS

ASTM C 29 Unit Weight of Aggregate

ASTM C 88 Soundness of Aggregates by Use of Sodium Sulfate

or Magnesium Sulfate

ASTM C 117 Materials Finer than 75μm (No. 200) Sieve in Mineral
Aggregates by Washing

ASTM C 131 Resistance to Degradation of Small-Size Coarse Aggregate by
abrasion and impact in the Los Angeles Machine

ASTM C 136 Sieve Analysis of Fine and Coarse Aggregates

ASTM D 75 Sampling Aggregate

ASTM D 422 Particle Size Analysis of Soils

ASTM D 693 Crushed Aggregate for Macadam Pavements

ASTM D 698 Moisture-Density Relations of Soils and Soil-Aggregate
Mixtures Using 5.5-lb (2.49-kg) Rammer and 12-in (305mm) Drop

ASTM D 1556 Density of Soil in Place by the Sand-Cone Method

ASTM D 1557 Test for Laboratory Compaction Characteristics of Soil Using
Modified Effort

ASTM D 2167 Density and Unit Weight of Soil in Place by the Rubber
Ballon Method

ASTM D 2419 Sand Equivalent Value of Soils and Fine Aggregate

ASTM D 2922 Density of Soil and Soil-Aggregate in Place by Nuclear
Methods

ASTM D 3017 Water Content of Soil and Rock in Place by Nuclear Methods

ASTM D 3665 Random Sampling of Construction Materials

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

**END OF P-209**

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