MATERIAL QUALITY CONTROL SPECIFICATIONS:
AGGREGATE BASE COURSE
PART 1 GENERAL
1.01 SECTION INCLUDES
A. The WORK to be performed includes the preparation of the aggregate base course
foundation; and the production, stockpiling, hauling, placing, and compacting of
aggregate base course.
1.02 RELATED SECTIONS
A. The following is a list of SPECIFICATIONS which may be related to this section:
1. Section 31 23 00, Excavation and Fill.
2. Section 31 23 19, Dewatering.
3. Section 32 23 33, Trenching and Backfilling.
4. Section 31 37 19, Grouted Boulders, Stcked Grouted Boulders and Grouted
Boulder Retaining Walls.
5. Section 31 62 16, Steel Sheet Piles.
6. Section 32 15 40, Crusher Fine Surfacing.
7. Section 32 16 00, Sidewalks, Curbs, and Gutters.
8. Section 33 05 13, Manholes.
9. Section 33 41 00, Reinforced Concrete Pipe.
10. Section 33 46 00, Subdrainage.
1.03 REFERENCES
A. The following is a list of standards which may be referenced in this section:
1. American Association of State Highway and Transportation Officials
(AASHTO):
a. M147, Standard Specification for Materials for Aggregate and SoilAggregate Subbase, Base, and Surface Courses. T11, Standard Method of Test for Materials Finer Than 75m (No. 200)
Sieve in Mineral Aggregates by Washing. T27, Standard Method of Test for Sieve Analysis of Fine and Coarse
Aggregates. Revised 03/2012
32 11 23 - 2
d. T89, Standard Specification for Determining the Liquid Limit of Soils. T90, Standard Specification for Determining the Plastic Limit and
Plasticity Index of Soils. T96, Standard Specification for Resistance to Degradation of Small-Size
Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine. T99, Standard Specification for the Moisture-Density Relations of Soils
Using a 2.5 kg (5.5 pound) Rammer and a 305 mm (12 in) Drop. T180, Standard Specification for Moisture-Density Relations of Soils Using
a 4.54 kg (10-lb) Rammer and a 457 mm (18-in) Drop. T190, Standard Specification for Resistance R-Value and Expansion
Pressure of Compacted Soils. T265, Standard Method of Test for Laboratory Determination of Moisture
Content of Soils. T310, Standard Specification for In-Place Density and Moisture Content of
Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth).
2. ASTM International (ASTM):
a. C88, Test Method for Soundness of Aggregates by Use of Sodium Sulfate
or Magnesium Sulfate. D698, Standard Test Methods for Laboratory Compaction Characteristics
of Soil Using Standard Effort (12 400 ft-lbf/ft
3
(600 kN-m/m
3
)). D1557, Standard Test Methods for Laboratory Compaction Characteristics
of Soil Using Modified Effort (56,000 ft-lbf/ft
3
(2,700 kN-m/m
3
)). D1883, Test Method for CBR (California Bearing Ratio) of Laboratory
Compacted Soils. D2419, Test Method for Sand Equivalent Value of Soils and Fine
Aggregate. D4791, Test Method for Flat Particles, Elongated Particles, or Flat and
Elongated Particles in Coarse Aggregate.
1.04 SUBMITTALS
A. CONTRACTOR shall cooperate with ENGINEER in obtaining and providing
samples of all specified materials. CONTRACTOR shall submit certified laboratory test certificates for all items
required in this section. C. CONTRACTOR shall submit tickets for each load of aggregate. Revised 03/2012
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PART 2 PRODUCTS
2.01 MATERIALS
A. Aggregates: Aggregates for bases shall be crushed stone, crushed slag, crushed gravel
or natural gravel that conforms to the quality requirements of AASHTO M147,
except that the requirements for the ratio for the minus No. 200 sieve fraction to the
minus No. 40 sieve fraction shall not apply. The requirements for the Los Angeles
wear test shall not apply to Class 1, 2, and 3. Aggregates for bases shall meet the
grading requirements as called out in the DRAWINGS. The liquid limit shall be as
shown in the table and the plasticity index shall be 6. Gradations:
Standard
US Sieve
Size
Percentage by Weight Passing Square-Mesh Sieves
LL < 35 LL < 30
Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
4 inches -- 100 -- -- -- -- --
3 inches -- 95 - 100 -- -- -- -- --
2½inches 100 -- -- -- -- -- --
2 inches 95 - 100 -- -- 100 -- -- --
1½inches -- -- -- 90 - 100 100 -- --
1 inch -- -- -- -- 95 - 100 -- 100
¾ inch -- -- -- 50 - 90 -- 100 --
No. 4 30 - 65 -- -- 30 - 50 30 - 70 30 - 65 --
No. 8 -- -- -- -- -- 25 - 55 20 - 85
No. 200 3 - 15 3 - 15 20 max. 3 - 12 3 - 15 3 - 12 5 - 15
Note: Class 3 materials shall consist of bank or pit run material. PART 3 EX*****ON
3.01 GENERAL
A. Equipment:
1. Equipment shall be capable of performing the WORK as described in this
SPECIFICATION. Equipment that is inadequate to obtain the results specified
shall be replaced or supplemented as required to meet the requirements of this
SPECIFICATION. Any equipment that is used in an improper manner may be
cause for rejection of the WORK if in the opinion of ENGINEER the WORK
fails to meet the requirements of this SPECIFICATION.
2. Equipment used for compaction shall be the rolling type, vibratory type, or
combination of both types, and shall be of sufficient capacity to meet the
compaction requirements herein. Revised 03/2012
32 11 23 - 4
3.02 PREPARATION OF FOUNDATION
A. General:
1. The foundation shall be considered to be the finished earth subgrade, subbase
course, or base course, as the case may be, upon which any subbase, base, or
surface course is to be constructed.
2. Preparation of foundation for construction of a subbase, base, or surface course
shall consist of the WORK necessary to restore, correct, strengthen, or prepare
the foundation to a condition suitable for applying and supporting the intended
course.
3. The foundation shall be prepared and constructed such that it will have a
uniform density throughout. It shall be brought to the required alignment and
cross section with equipment and methods adapted for the purpose. Upon
completion of the shaping and compacting operations, the foundation shall be
smooth, at the required density, and at the proper elevation and contour to
receive the aggregate base course.
4. Unless otherwise provided, all holes, ruts, and other depressions in the
foundation shall be filled with materials similar to those existing in the
foundation. High places shall be excavated and removed to the required lines,
grade and section.
5. Areas of yielding or unstable material shall be excavated and backfilled with
stabilization rock as determined by ENGINEER. Base course material shall not
be placed on a foundation that is soft, spongy, or one that is covered by ice or
snow. Base course shall not be placed on a dry or dusty foundation where the
existing condition would cause rapid dissipation of moisture from the base
course material and hinder or preclude its proper compaction. Dry foundations
shall have water applied, reworked, and compacted as necessary.
6. ENGINEER may direct CONTRACTOR to make minor adjustments in the
finish grade from that shown in the DRAWINGS as may be necessary or
desirable to maintain the characteristics of a stabilized foundation by minimizing
the amount of cutting into or filling. Roads and Parking Areas: For aggregate base course roads and parking areas, the top
six (6) inches of topsoil shall be stripped within the area to be aggregate surfaced. Following stripping of the topsoil, the upper twelve (12) inches of the subgrade shall
be scarified and compacted to a minimum of ninety-five percent (95%) of the
Maximum Standard Proctor Density (ASTM D698). Onsite material may be used as
accepted by ENGINEER, for compacted fill for the aggregate base course. Fill shall
be placed within two percent (2%) of optimum moisture content and compacted to a
minimum of ninety five percent (95%) of the Maximum Standard Proctor Density
(ASTM D698). Pavements: Aggregate base course used as a foundation for pavements shall be
placed on the subgrade within two percent (2%) of optimum moisture and compacted
to a minimum of one hundred percent (100%) of the Maximum Modified Proctor
Density (ASTM D1557). The top six (6) inches of topsoil shall be stripped within the
area to be aggregate surfaced. Following stripping of the topsoil, the upper twelve Revised 03/2012
32 11 23 - 5
(12) inches of the subgrade shall be scarified and compacted to a minimum of ninetyfive percent (95%) of the Maximum Standard Proctor Density (ASTM D698). Onsite
material may be used, as accepted by ENGINEER, for compacted fill for the
aggregate base course. Fill shall be placed within two percent (2%) of optimum
moisture content and compacted to a minimum of ninety five percent (95%) of the
Maximum Standard Proctor Density (ASTM D698). Deviations in aggregate base
course under pavements of more than one-quarter (1/4) inch in ten (10) feet,
measured with a ten-foot (10') straight edge, shall be corrected prior to pavement
construction. D. Earth Subgrade: When the foundation is an earth subgrade it shall be prepared by
removing all vegetation, excavating and removing materials, filling depressions,
scarifying, shaping, smoothing and compacting to meet the required grade, section
and density. Stones over six (6) inches in greatest dimension shall be removed.
3.03 PLACEMENT
A. The aggregate base course shall be constructed to the width and section shown in the
DRAWINGS. If the required compacted depth of base course exceeds six (6) inches,
the base shall be constructed in two (2) or more layers of approximate equal
thickness. The maximum compacted thickness of any one (1) layer shall not exceed
six (6) inches. Each layer shall be constructed as far in advance of the succeeding layer as
ENGINEER may direct. The WORK shall, in general, proceed from the point on the
PROJECT nearest the point of supply of the aggregate in order that the hauling
equipment may travel over the previously placed material, and the hauling equipment
shall be routed as uniformly as possible over all portions of the previously
constructed courses or layers of the base course. The material shall be deposited on the soil foundation, or previously placed layer, in
a manner to minimize segregation and to facilitate spreading to a uniform layer of the
required section. In the event that blending of materials is necessary to provide
required gradation and properties of the material, and is done in the roadway, the
same shall be accomplished by mixing the aggregate and blending material by means
of blade graders, discs, harrows, or other equipment to effect a uniform distribution
and gradation throughout the finished mixture. Excessive mixing and grading that
will cause segregation between the coarse and fine materials is prohibited.
3.04 COMPACTION
A. After a layer or course has been placed and spread to the required thickness, width
and contour, it shall be compacted. If the material is too dry to readily attain the
required density, it shall be uniformly moistened to the degree necessary during
compaction operations for proper compaction. Compaction of each layer shall continue until the required density specified in Article
Preparation of Foundation is reached. The surface of each layer shall be maintained
during compaction operations in such a manner that a uniform texture is produced
and aggregates firmly keyed. All areas where proper compaction is not obtainable due to segregation of materials,
excess fines, or other deficiencies in the aggregate shall be reworked as necessary or Revised 03/2012
32 11 23 - 6
the material removed and replaced with aggregates that will meet this
SPECIFICATION. The surface of each layer shall be kept true and smooth at all times.
3.05 MIXING
A. Unless otherwise specified, CONTRACTOR shall mix the aggregate by any one of
the three following methods:
1. Stationary Plant Method: Aggregate base course and water shall be mixed in an
approved mixer. After mixing, the aggregate shall be transported to the
PROJECT site while it contains the proper moisture content and shall be placed
on the roadbed by means of an approved spreader.
2. Travel Plant Method: After the material for each layer has been placed through
an aggregate spreader or windrow-sizing device, it shall be uniformly mixed by
a traveling mixing plant.
3. Road Mix Method: After material for each layer has been placed, the materials
shall be mixed while at optimum moisture content by motor graders or other
approved equipment until the mixture is uniform throughout.
3.06 SHOULDER CONSTRUCTION
A. Shoulders shall be constructed with base course material to conform to the elevation
and section shown in the DRAWINGS. No equipment shall be used which by its
design or through its manner of operation will damage the pavement or curbs. Insofar
as practicable, the base course material shall be placed directly on the shoulder area. Materials that are deposited outside the shoulder area, if not contaminated, shall be
recovered and placed within the required limits. CONTRACTOR shall not be
compensated for materials not recovered as determined by ENGINEER. Materials shall not be deposited on the pavement or surfacing during placing unless
specifically permitted by ENGINEER. The base course material as placed shall be spread and compacted to the required
density in layers not exceeding six (6) inches in compacted thickness. Any material
inadvertently placed on the pavement shall be broomed from the pavement. The
result shall not effect a change in the gradation of the shoulder material.
