Be advised SS851 dated 4/18/2008 is included in
its entirety at the end of this document for reference only; the official
version is available online.
This work consists of
constructing asphalt treated free draining base (ATFDB)
course, mixed in a central plant, and spread and compacted on a prepared
surface. The (ATFDB)
drainage layer is immediately beneath the pavement and is made of graded
aggregate, asphalt-treated, permeable material. Construction of this drainage
layer will serve satisfactorily as drains and structural support for the
surfacing materials.
The requirements of Item 401
apply, except as modified by Supplemental Specification 851.
The aggregate gradation
should conform to Table 703.01-1
and 703.04
with the exceptions detailed in 851.02, and the binder
should be PG 64-22 and conform to the requirements of 702.01. The Contractor is not allowed to use
reclaimed asphalt concrete pavement in the mix.
The binder amount should be
1.5 to 3.5 percent by weight of the mix with the aggregate. Ensure that the aggregate does not show
excess drainage at 250 °F (120 °C) and is coated with a shiny, black coating of asphalt binder.
Brown or dull mix appearance
is not acceptable and is a sign of excess aggregate absorption of the asphalt
binder or low asphalt binder content.
Minor bare aggregate exposure is acceptable.
A minimum of 3 weeks before
the production of the ATFDB, the Contractor should
submit a computed blend of aggregate and asphalt binder using standard JMF submittal forms and production temperature range to the
Laboratory for initial design verification.
The Contractor should notify the Laboratory before the delivery of any
material.
Final design verification is
subject to field verification and actual performance. Field verification may include additional
testing by the Laboratory.
The Contractor should use
only tandem steel wheel rollers weighing 6 to 10 tons (5.5 to 9 metric tons)
for compaction.
The Contractor should spread
the ATFDB mix only when the atmospheric temperature
is above 45 °F (7 °C).
Cease all operations if rain
occurs during placement of the ATFDB or when rain is
imminent. Do not spread on frozen
material.
The Contractor should spread
the ATFDB material in a method that produces a
smooth, uniform layer before compacting.
Cease all operations when signs of degradation, segregation, or
contamination are evident. Communicate
with the Contractor and the material monitor to resolve the problem before
resuming placement.
The Contractor should
sufficiently compact the ATFDB by compacting the
layer at least two roller passes over any given point, unless otherwise
directed by the Engineer for more passes.
Do not over compact the ATFDB to the extent
where the aggregate particles are crushed or broken. Complete rolling before the mix temperature
has dropped to less than 100 °F (38 °C).
Do not cool ATFDB with water.
Form transverse construction
joints by cutting back into the completed work to form a vertical face.
If significant breakup of the
ATFDB occurs at or near the outer portion of a lift
during the compaction operation, provide lateral support using forms or other
methods approved by the Engineer at no additional cost to the Department. Do not contaminate the ATFDB
with this lateral support.
When the ATFDB
is placed in areas inaccessible to rollers, compact the pavement using a method
approved by the Engineer.
After compaction is complete,
do not place the next layer of pavement on the ATFDB
until the next day.
The compacted thickness of
the ATFDB layer should be 4 inches (100 mm). Ensure the placed ATFDB
conforms to the specified thickness by randomly checking the thickness during
construction. The district could run a
dry-rodded unit weight to establish a conversion
factor that could be used to establish the required placement rate as per
401. Also, since the loose layer does
not compact much, a prod is frequently used to check the layer thickness.
Remove all sections found to be ± 1/2 inch (± 13 mm) from the specified thickness and replace them
with ATFDB at no additional expense to the
Department.
Ensure that the finished
surface is uniform and varies no more than 1/2 inch (13 mm) from a 10-foot
(3 m) straightedge applied to the surface, parallel to the centerline of the
pavement. Remove any section found to be
out of tolerance and replace it with ATFDB within the
specified tolerance at no additional expense to the Department.
The quality control and
acceptance requirements of Item 403
apply, except as detailed in 851.11. Project administrators should check with the
district lab to ensure material conformance to the specifications.
The ATFDB
should be coated with shiny, black coating of asphalt binder and not be brown
or dull in appearance. Minor
inconsistent bare aggregate exposure is acceptable. If the delivered mix is brown or dull in
appearance, immediately inform the district lab and the Contractor to adjust
the asphalt binder content.
Ensure that the underdrain
system is functional before placing the ATFDB. Do not allow construction equipment to crush
the underdrain pipe or system as a result of the placement or compaction of the
ATFDB. Ensure
a positive connection between the underdrain system and the ATFDB,
regardless of the sequence of operations in the contract documents.
The ATFDB
is not designed to carry construction traffic.
The Engineer will allow hauling units and other construction vehicles to
operate on the ATFDB, provided no significant
displacement, breakup, or contamination occurs.
If the Engineer determines significant displacement, breakup, or
contamination of the ATFDB is occurring, the
Contractor shall stop operating hauling units and construction vehicles on the ATFDB. The
Contractor should repair or replace all damage to the ATFDB,
subbase, subgrade, or underdrains
caused by the hauling units or construction vehicles at no additional expense
to the Department.
The ATFDB
layer should be protected from fine material contamination. Adequate surface and subsurface drainage for
the ATFDB, subbase, and
subgrade should be provided at all times.
The Contractor may use a rubber
tire paver if it does not damage the ATFDB, subbase, subgrade, or underdrains. If damage occurs, cease paving and switch the
rubber tire paver with a track mounted paver before restarting the paving.
When constructing asphalt
concrete pavement on the ATFDB, allow the first
course to cure overnight before placing the succeeding pavement courses.
The ATFDB
layer should be covered by constructing the pavement within 40 days and before
the atmospheric temperature falls below 35 °F (2 °C) for any period of time
The Contractor should remove
and replace all damage caused to the ATFDB, subbase, subgrade, or underdrains
by the exposure to temperatures below 35 °F (2 °C) at no additional expense to the Department.
The Department will measure
the accepted quantities of asphalt treated free draining base by the number of
square yards (square meters). The Department will measure the width as the
width of the ATFDB shown on the typical sections of
the plans and additional widening where called for, or otherwise directed in
writing, by the Engineer. The Department
will measure the length horizontally along the centerline of each roadway or
ramp. Payment will be made at the
Contract bid price for work that is accepted in place.
1. State condition of base (e.g., primed 304,
clean and dry concrete, etc.)
2. Write location on tickets where material is placed.
3. Mark on ticket the time unloaded.
4. Obtain temperature of the mix at project site and
place this information on ticket of load checked. This should be done a minimum
of four times daily or any time temperature is in question.
5. State kind of rolling equipment.
6. Calculate and document the required placement rate
(tons/station).
7. Document on form CA-FP-4
project documents compliance with Item 851, on Form CA-D-3A,
and measurements on CA-D-1
and 2.
8. Document lift thickness.
9. Tickets should be totaled with initialed and dated
tape attached.
SUPPLEMENTAL SPECIFICATION 851
Asphalt Treated Free Draining Base
April 18, 2008
851.01 Description
851.02 Materials
851.03 Composition
851.04 Design Verification
851.05 Preparation of Materials
851.06 Rollers
851.07 Weather Limitations
851.08 Spreading and Compacting
851.09 Thickness Tolerances
851.10 Surface Tolerance
851.11 Quality Control and Acceptance
851.12 Underdrains
851.13 Protection of the ATFDB
851.14 Exposure to the Elements
851.15 Method of Measurements
851.16 Basis of Payment
851.01 Description. This work
consists of constructing an asphalt treated free
draining base (ATFDB) course, mixed in a central
plant and spread and compacted on a prepared surface.
The requirements of
Item 401
apply, except as modified by this specification.
851.02 Materials. Furnish
aggregate conforming to the gradation requirements of
No. 67 or 57 aggregate as defined in Table 703.01-1
and consisting of a crushed carbonate stone, crushed gravel, or air cooled
blast furnace slag conforming to the requirements of 703.04
for 301
asphalt concrete base, except provide aggregate with a maximum percentage
of wear for the Los Angeles test of 40.
If using crushed gravel, ensure that 90 percent by count has at least
two mechanically fractured faces conforming to ASTM D5821.
Use PG 64-22 asphalt binder conforming to the
requirements of 702.01.
Do not use
reclaimed asphalt concrete pavement.
851.03 Composition. Combine
asphalt binder with the aggregate in an amount equal to 1.5 to 3.5 percent by
weight of the mix. After mixing with
asphalt binder, ensure that the aggregate:
A. Does not show excess drainage
at 250 °F (120 °C).
B. Is coated with shiny black
coating of asphalt binder. Minor bare
aggregate exposure is acceptable.
C. Is not brown or dull in appearance, a sign
of excess aggregate absorption of the asphalt binder or low asphalt binder
content.
851.04 Design Verification. A
minimum of 3 weeks before the production of the ATFDB,
submit a computed blend of aggregate and asphalt binder, using standard JMF submittal forms, and production temperature range to
the Laboratory for initial design verification.
Deliver to the Laboratory 1 gallon (4 L) of asphalt binder and one bag
of aggregate. Notify the Laboratory
before the delivery of any material.
Final design
verification is subject to field verification and actual performance. Field verification may include additional
testing by the Laboratory.
851.05 Preparation of Materials. Mix the
ATFDB material within the established temperature
range and immediately load it into the trucks.
851.06 Rollers. Use only
tandem steel wheel rollers weighing 6 to 10 tons (5.5 to 9 metric tons) for
compaction.
851.07 Weather Limitations. Spread the ATFDB only when
the atmospheric temperature is above 45 °F (7 °C).
Do not place the ATFDB when rain is imminent. If rain occurs during placement of the ATFDB, cease all operations. Do not place the ATFDB
during any weather conditions that would cause its degradation, segregation, or
contamination.
851.08 Spreading and Compacting. Spread
the ATFDB material in a method that produces a
smooth, uniform layer before compacting.
Do not spread on frozen material.
Unless otherwise
directed, when compacting the ATFDB
material, make at least two roller passes over any given point on the
surface. Compact the ATFDB
sufficiently to support the weight of the equipment that will place the next
layer of pavement. Do not overcompact the ATFDB to the extent the aggregate particles are crushed or
broken. Complete rolling before the mix
temperature has dropped to less than 100 °F (38 °C).
Do not cool ATFDB with water.
Form transverse
construction joints by cutting back into the completed work to form a vertical
face.
If significant
breakup of the ATFDB occurs at or near the outer
portion of a lift during the compaction operation, provide lateral support
using forms or other methods approved by the Engineer at no
additional cost to the Department. Do
not contaminate the ATFDB with this lateral support.
When the ATFDB is placed in areas inaccessible to rollers; compact
it using a method approved by the Engineer.
After compaction
has been completed, do not place the next layer of pavement on the ATFDB until the next day.
851.09 Thickness Tolerances. Make
the compacted thickness of the ATFDB 4 inches (100
mm). Ensure the placed ATFDB conforms to the specified thickness by randomly
checking the thickness during construction.
Remove all sections found to be ±1/2 inch (±12 mm) from the specified thickness and replace them
with ATFDB at no additional expense to the
Department.
851.10 Surface Tolerance. Ensure
that the finished surface is uniform and varies no more than 1/2 inch
(12 mm) from a 10-foot (3 m) straightedge applied to the surface parallel
to the centerline of the pavement.
Remove any section found to be out of tolerance and replace it with ATFDB within the specified tolerance at no additional
expense to the Department.
851.11 Quality Control and Acceptance. The quality control and acceptance requirements of
Item 403
apply, except as follows.
Each day before the
start of production, obtain two separate samples of the aggregate stockpile and
test the samples for gradation. If both
samples pass the gradation test, the Contractor may produce ATFDB all day. If
one or both of the samples fail the gradation test, do not begin production
until the Department is satisfied that the stockpile conforms to
requirements. Record results on a TE-199. If any material is added to the stockpile,
immediately take another sample and test it.
The Department will
base acceptance of the Contractor’s daily aggregate gradation test results on one
Department stockpile verification sample from the asphalt plant aggregate
stockpile taken and tested for each five days of production. If the Department test shows the stockpile
conforms to the appropriate requirements, the Department can accept material
per the Contractor’s daily results. If
the Department test does not verify the stockpile condition, test aggregate
according to Item 403
for the remainder of the project.
If testing
according to Item 403,
split each sample and retain half of it for Department verification. The Department will randomly verify a
Contractor gradation test
once in every 5 production days. If the
Department verification test compares by ±3.0 percent on the No. 4 (4.75 mm) sieve and is not
outside the gradation band, the Department will base acceptance on the
Contractor’s test results. The
Department may verify using additional tests if desired. If the Department test does not verify the
Contractor’s results, the Department will base acceptance on the test results
of one split sample for each day represented by the original verification
sample. Replace failed material in place
unless otherwise directed by the District.
The Department will
base acceptance of the asphalt binder content on the field inspection of the
coating on the aggregate. To be
accepted, the ATFDB should be coated with shiny black
coating of asphalt binder and not be brown or dull in appearance. Minor inconsistent bare aggregate exposure is
acceptable. If the delivered mix is
brown or dull in appearance, adjust the asphalt binder content to the
satisfaction of the Engineer.
851.12 Underdrains. Ensure that the underdrain system is functional before
placing the ATFDB.
Do not allow
construction equipment to crush the underdrain pipe or system as a result of
the placement or compaction of the ATFDB.
Ensure a positive
connection between the underdrain system and the ATFDB
regardless of the sequence of operations in the Contract Documents.
851.13 Protection of the ATFDB. The Department has not designed the ATFDB to be a haul road.
The Engineer will allow
hauling units and other construction vehicles to operate on the ATFDB provided no significant displacement, breakup, or
contamination occurs. If the Engineer
determines significant displacement, breakup, or contamination of the ATFDB is occurring, the Contractor shall stop
operating hauling units and construction vehicles on the ATFDB. Repair or replace all damage to the ATFDB, subbase, subgrade, or underdrains caused by the hauling units or construction
vehicles at no additional expense to the Department.
Protect the ATFDB from fine
material contamination at all times.
Provide adequate surface and subsurface drainage for
the ATFDB, subbase, and
subgrade at all times.
The Contractor may use a
rubber tire paver if it does not damage the ATFDB, subbase, subgrade, or underdrains. If damage occurs, cease paving and switch the
rubber tire paver with a track mounted paver before restarting the paving.
When constructing
asphalt concrete pavement on the ATFDB, allow the
first course to cure overnight before placing the succeeding pavement courses.
851.14 Exposure to the Elements. Place
the next layer of pavement on the ATFDB within 40
days.
The Contractor may construct
the ATFDB at any time if the temperature requirements
of this specification are met. Following
construction of the ATFDB, completely cover the ATFDB with the next layer of pavement before the
atmospheric temperature falls below 35 °F (2 °C) for any period of time.
Remove and replace all damage caused to the ATFDB,
subbase, subgrade, or underdrains
by the exposure to temperatures below 35 °F (2 °C) at no additional expense to the Department.
851.15 Method of Measurement. The
Department will measure the accepted quantities of Asphalt Treated Free
Draining Base by the number
of square yards (square meters). The
Department will measure the width as the width of the asphalt treated free
draining base shown on the typical sections of the plans and additional
widening where called for, or otherwise directed in writing by the Engineer. The
Department will measure the length horizontally along the centerline of each
roadway or ramp.
851.16 Basis of Payment. The
Department will pay for accepted quantities, complete in place, at the contract
price as follows:
Item Unit Description
851 Square Yard Asphalt Treated Free Draining Base
(Square Meter)