Section 301
Aggregate Subbase, Base Courses, and Base Course Material
PRECONSTRUCTION
Establish line, stationing, and blue top for finish grade. Verify that planned depths are in
agreement with the final surfacing section. (This work may also be done by the contractor
in certain circumstances.)
EQUIPMENT
The following equipment will be required for inspection purposes:
1. Measuring Tape (12' or 25').
2. String line.
INSPECTION
Determine the gradation required in the plans or if a change has been made to a different
gradation.
In accordance with specified procedures, observe and conduct as required QC/QA
testing. (Reference the Standard Specifications and the Materials Testing manual.)
Verify the correct gradation is being produced.
Gradation is established by contractor quality assurance testing.
Observe the condition of the stockpiling location, has the topsoil been stripped, and have
any other specified preparations been completed. Document in the project records and
comment as needed.
Observe stockpiling procedures, being especially alert to segregation of material. This
may be caused by the shape of the pile or the height of the conveyor or loader bucket as
the material is being deposited onto the stockpile. Do not exceed a drop from conveyance
to the stockpile of more than 6 feet. When this occurs, make a note in the project diary and
bring the situation to the attention of the contractor.
Be aware of the potential for:
1. Contamination caused by mud on equipment or conveyances.
2. Other stockpiles in close proximity to the stockpile being placed.
3. Degradation caused by operating equipment on a stockpile.
Prior to placing aggregate base material, the inspector will inspect the grade on which the
material is to be placed. Observe that conformity with line and grade has been met.
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Check for soft, pumping, or yielding areas. Observe equipment on the grade and, as
needed, request a full water truck or heavy roller to go over the grade to help determine
the uniformity of the subgrade (proof-rolling). Yielding, pumping, or soft spots should be
repaired before placing the aggregate base material; when repair is not feasible, replace
the affected area.
Periodically string-line the surface of the dirt grade, transversely, to verify that the
required dirt profile has been met.
Preparations for placing the planned thickness of material will be made by determining
the number of passes needed to place the prescribed thickness.
Verify that moisture content is within the specifications. Be aware that climatologic
changes will affect the material, in particular moisture content. Moisture checks should
be performed, periodically, to ensure conformance with specifications.
Color and texture of the material should be checked for irregularities that may indicate
changes in gradation and/or moisture content.
QC/QA is an ongoing process and regular communications with the field lab are
necessary to verify that materials are meeting gradation and moisture specifications.
Prepare form E-70 for the haul vehicles that the contractor will be using on public roads.
Verify by checking blue tops or other grade stakes that finish grade is being met.
Visually inspect for yielding or pumping of the aggregate base material that would indicate
the presence of soft spots.
Verify that density tests have met the values set forth in the specifications.
When problems with meeting density specifications occur examine or verify some of the
following:
1. Is moisture within specified parameters?
2. If the contractor is using a vibratory roller, is the roller in static mode?
3. If the roller is not in static mode, does amplitude and frequency of the roller need
to be changed?
Visually inspect by string line and measuring tape that the prescribed depth of material is
in place and the planned profile of the base material is in place.
DOCUMENTATION
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Aggregate base materials may be measured by the ton, cubic yard or square yard.
Computerized scales provided by the contractor will be used for weighing materials,
except when the material is designated to come from a commercial source.
Verify the accuracy of the scales by observing that a stamp of approval of accuracy by the
Wyoming State Department of Agriculture is in place, or by using the weights as set forth
in the specifications. (See form E-71)
Notes should be made in the project records pertaining to the beginning and ending of
ribbons, stationing, any breaks for structures, etc. and note actual beginning and ending
stations for each day material is placed, regardless of the number of hours worked each
day. Information concerning the actual quantities placed throughout the day can be
obtained from the tickets that each truck is required to have for each load.
The contractor shall submit daily tickets indicating quantities brought onto the project
along with a recap sheet (summarizing the information required in the specification book).
Verify the quantities claimed by the contractor.
Prior to hauling, vehicle weight limits for each individual hauling unit will be checked using
form E-75.
Square yard and cubic yard pay units will be documented by station with information as to
where the calibration process and verification of volumes being placed takes place.
For quantities that will be paid by the ton, verify the weights recorded on the contractor’s
tickets, check summary as contained in the contractor’s version of the E-78 recap sheet
and combine daily totals for the estimate period being paid.
For quantities paid on a volume basis of square yard or cubic yard, measure on a surface
plane the width and length (as measured along center line) of material placed in
accordance with the planned dimensions.
The daily quantities should be entered daily into the electronic documentation records for
the project. Reference the recap sheet number or location of other documentation in the
remarks of the electronic records.
Make periodic depth checks to assure the planned depth is being obtained. The inspector
will be familiar with the actual unit weight and density of the material so that periodic
spread checks can be made.
SAFETY
Use the following safety equipment:
1. Hard hat and vest.
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2. Eye protection and hearing protection.
3. Appropriate footwear.
Crushers producing materials have equipment (Loaders, Dump Trucks, and Service
Trucks) in motion in the immediate area. In addition, there is significant noise that may
warrant hearing protection. Be careful to not park vehicles where they may interfere with
the contractor’s operations.
Roadway work involves dump trucks, motor graders, rollers and other types of equipment
in the area where the material is being placed. Excessive noise and potential dust blowing
may be present. Wear hard hat, safety vest, and have protective hearing available.
Goggles in windy conditions are recommended.
The contractor is responsible to sample material being produced. Sampling of the
material requires the stopping of the final belt in the conveyor process. The contractor will
have lock-out procedures in place to preclude accidentally starting the belt while
personnel are sampling the material. Be sure that as an inspector you know the
procedure and can recognize deviation from established procedure which will be noted in
the project diary and reported to the contractor. A lack of cooperation from the contractor
concerning lock-out procedures will be brought to the attention of the engineer and the
contractor.
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