Item 422 CHIP SEAL
422.01
Description
422.02
Materials
422.03
Equipment
422.04 Weather
Limitations
422.05 Test
Strip
422.06 Surface
Preparation
422.07 Binder
Application
422.08 Cover
Aggregate Application
422.09
Construction Operation
422.10 Quality
Control
422.11
Acceptance
422.12 Method
of Measurement
422.13 Basis of
Payment
422.01 Description. This work consists of
preparing and applying a single or double chip seal.
422.02 Materials. Use an RS-2 emulsified binder
conforming to 702.04 for projects with an
ADT less than 500. Use polymer emulsified binder conforming to 702.16 Type A for projects with an ADT
greater than 500. When a project has multiple pavements with ADTs above and below 500 use the polymer emulsified binder,
702.16.A.
Provide
cover aggregate for the chip seal Job Mix Formula (JMF)
of washed limestone or dolomite conforming to 703.05.
Do not use an aggregate source designated with “SR” on the Aggregate Source
Group list in accordance with 703.01.F.
Additionally the following requirements apply:
Stockpile
the material to be used for the chip seal at the aggregate source.
Obtain
five (5) samples from the stockpile and perform gradation testing on each
sample and determine the percent passing for each sieve size listed in Table 422.02-1
A.
Calculate the total range for the No. 8 (2.36 mm) sieve for all five
samples. The range will not exceed 6%.
B.
Calculate the percent passing the No. 200 (75 µm) sieve for each sample.
No single sample value will exceed 2.0 percent.
C
Calculate the average of each sieve for all five samples. Assure the
average value for each sieve is within the requirements of Table 422.02-1.
Submit
a letter to the Engineer and DET containing the Job
Mix Formula (JMF) gradations and the calculations to
show the cover aggregate meets requirements.
If
a staging location will be used for the chip seal aggregate first move the
initially tested aggregates from the aggregate source stockpile to the staging
location and construct a staging stockpile. Then obtain five (5)
aggregate samples from the staging location stockpile and perform gradation
testing on each sample to determine the percent passing for each sieve size
listed in Table 422.02-1.
Evaluate
the staging location aggregate samples the same as the aggregate source samples
except allow an average for the No. 200 (75 µm) sieve not greater than 1.7
percent.
Submit
the Job Mix Formula (JMF) gradations from the staged
stockpile and the calculations to show the cover aggregate meets requirements
in letter form to the Engineer and DET.
If
the chip seal aggregates fail to meet requirements, either at the aggregate
source or the staging location, re-wash and/or rework the aggregate materials
and retest the new stockpiles.
|
Sieve Size |
Total Percent Passing |
|
|
1/2 inch |
(12.5 mm) |
100 |
|
3/8 inch |
(9.5 mm) |
85 to 100 |
|
No. 4 |
(4.75 mm) |
5 to 25 |
|
No. 8 |
(2.36 mm) |
0 to 10 |
|
No. 16 |
(1.18 mm) |
0 to 5 |
|
No. 200 |
(75 µm) |
0 to 1.5 [1] |
|
[1] Washed gradation value |
||
The
District may obtain and test validation samples of the JMF
aggregates at any time. If a single validation sample is either outside the values
in Table 422.02-1 with the exception
that the No. 200 (75 µm) value is not greater than 2.0 percent, the
district will obtain five (5) samples and retest to determine if the aggregate JMF falls within the limits of Table 422.02-1. If the JMF
verification test doesn’t meet the source or staging location limits the
stockpile is not acceptable.
422.03 Equipment. Provide equipment conforming to
the requirements of this section. Obtain approval of equipment before
starting the job.
Use equipment
for binder distribution conforming to 407.03,
except ensure that it has a computerized rate control that automatically
adjusts the binder pump to the unit ground speed and has a gauge or meter in
plain view for reading gallons (liters). Use appropriate spray nozzles
for the material and rate specified.
Use Type II
pneumatic tire rollers conforming to 401.13,
except the maximum capacity shall not apply.
Use
self-propelled aggregate spreaders with a variable width aggregate hopper
capable of placing from 8 to 16 feet (2.4 to 4.8 m) in any increment and a
computerized rate control that automatically adjusts the aggregate output to
the unit ground speed. Equip spreaders with pneumatic tires, a screen to
remove oversized material, revolving cylinders, and adjustments necessary to
produce a uniform distribution of particles at the specified rate.
Use
power sweepers or rotary brooms in initial surface preparation and for removing
loose particles. Use pickup type sweepers in areas where the aggregate
shoulder does not exist. Do not sweep loose aggregate onto lawns, curbed
areas, or intersections.
Furnish
accurate thermometers for determining any of the applicable temperature
requirements of this specification.
422.04 Weather Limitations. Place the
chip seal when the pavement and atmospheric temperature is 60 °F (16 °C) or
above and the atmospheric temperature is 70 °F (24 °C) or above. Do not
schedule the performance of this work for the time period before May 1 or after
September 1. Do not place chip seal if any of the following conditions
exist:
A.
Impending weather conditions do not allow for proper curing or if temperatures
are forecasted below 50 °F (10 °C) within 24 hours from the time of work.
B.
The existing pavement temperature is 140 °F (60 °C) or above.
422.05 Test Strip. Construct a continuous 1000-foot
(300 m) long by lane width test strip. Do not waive test strips regardless if
the same materials have been used on another project.
Determine
the initial binder application rates and aggregate application rates for the
test strip.
For
a single chip seal, an initial target rate of 0.37 ±0.03 gallon per square yard
(1.68 L/m²) is recommended for the test strip. For double chip seal, a
target rate of 0.36 ±0.03 gallon per square yard (1.54 L/m²) for the first
course and 0.33 ±0.05 gallon per square yard (1.68 L/m²) for the second course
is recommended for the test strip. Notify the Engineer of the initial
target rates.
Calibrate
the aggregate spreader and verify the application rates with a one square yard
(one square meter) piece of cardboard or other material to collect and weigh
the aggregate. Do not over apply cover aggregate relying on vacuum and broom
sweeping to pick up all excess. Amounts of loose aggregate that create a
nuisance to the public will result in work stoppage. If work is stopped by the
Engineer recalibrate the aggregate spreader determining a new application rate
and apply cover aggregate at the new rate. Verify the aggregate gradation
during the test strip and give results to the Engineer.
The
Engineer and Contractor will review the test strip the next workday for
streaking, ridging, bleeding, aggregate loss or other problems. If the review
shows the test strip meets the requirements of 422.11
and the application rate and quality control tests show all is in control
compared to the JMF, then progress with the work.
Should problems be noted, the Engineer may require another test strip.
422.06 Surface Preparation. Clean the
pavement according to 407.05. If
necessary, clean areas of the pavement with a hand broom.
Remove
all existing pavement markings 740.03
(polyester), 740.04 (thermoplastic) and 740.07 (epoxy) using an abrasion method
conforming to 641.10.
For
a single chip seal either remove and replace any existing raised pavement
markers or protect the existing raised pavement markers from the single chip
application process.
For
a double chip seal application remove the raised pavement markers according to 621.08.
Do
not place material until the Engineer approves the surface.
422.07 Binder Application. Before
applying binder, ensure that sufficient cover aggregate is available for
immediate application. Apply the binder at the target rate(s) established
during the test strip.
Maintain
the binder temperature from 150 to 185 °F (65 to 85 °C) during construction,
including the start of each day. Reheat the binder at a rate of no more
than 25 °F (14 °C) per hour, when the binder is allowed to cool below 150 °F
(65 °C).
If
the target application rates are not the optimum application rates to achieve
proper stone embedment during the actual application, immediately notify the
Engineer. Proper stone embedment is typically 1/2 to 2/3 of the stone chip
height and can be checked by pulling out several chips by hand. Adjust and
document the new application rate by stationing. Recheck stone
embedment after adjustment and obtain the Engineer’s approval of the new rate.
Do
not allow the binder to streak on the road surface. If the Engineer
determines that streaking is occurring, cease operations until the Engineer is
satisfied that streaking has been eliminated.
At
the beginning and at the end of a contract section, start and stop the
application on a removable protective cover (paper, metal sheets, or other
suitable material) sufficiently wide enough to allow full application on the
surface being treated. Make transverse and longitudinal laps in such
manner to ensure that the texture of the finished surface is uniform and continuous.
To prevent lapping at transverse junctions, promptly shut off the binder spray
at the end of the application. Before continuing the application, place a
removable protective cover a sufficient distance back from the joint on the
cover aggregate so the sprayers are operating at full force when the
distributor has attained the predetermined speed upon reaching the uncovered
surface. Upon completion, remove all removable protective covers.
422.08 Cover Aggregate Application. Verify
the application rate with a one square yard (one square meter) piece of
cardboard or other material to collect and weigh the aggregate before placing
binder. Adjust if necessary and re-verify. Record final results and
inform the Engineer. Immediately after applying the binder, apply cover
aggregate uniformly without ridges or laps at the specified rate adjusted as
directed by the Engineer to produce a minimum of excess loose particles.
Spread the material in such manner that the tires of the truck or aggregate spreader
at no time contact the uncovered and newly applied binder. Before
rolling, correct deficiencies in the application of cover aggregate in a manner
satisfactory to the Engineer.
After
rolling, protect the surface from traffic damage during the period required for
the binder to cure sufficiently and prevent dislodging of the aggregate
particles by normal traffic. During this period and as directed by the
Engineer, correct deficiencies in cover aggregate by spreading additional
aggregate or by light brooming.
Apply
cover aggregate at a rate necessary to provide full coverage of the binder and
to avoid tracking. Do not over apply cover aggregate relying on vacuum and
broom sweeping to pick up all excess. Nuisance to the public amounts of
aggregate will result in work stoppage. If work is stopped by the
Engineer recalibrate the aggregate spreader determining a new application rate
and apply cover aggregate at the new rate. If the target rate needs adjustment
due to the gradation of the aggregate or due to existing surface conditions of
the pavement, immediately notify the Engineer and document the new rate by
stationing.
422.09 Construction Operation. Establish
stations at 1000-foot (300 m) intervals on the entire project before placing
materials. Clearly identify and maintain the stations until project
completion.
Keep
the binder distributor, aggregate spreader, and rollers as close to each other
as possible. Do not allow the binder distributor to be more than 150 feet
(45 m) ahead of the aggregate spreader.
Perform
rolling immediately after placing the aggregate, but before the binder sets
up. Do not leave aggregate unrolled for more than 5 minutes.
Perform a minimum of two complete roller passes over the aggregate. A
single complete pass is forward and backward over the same path. For each
new pass, overlap the previous pass by about one-half the width of the
roller. Use a minimum of three rollers, and roll in a longitudinal
direction at a speed not greater than 5 miles per hour (8 km/h). Do not
operate rollers at speeds that cause pick-up or dislodging of aggregate
particles.
After
the binder sets, and before placing a second course for double chip seals, and
within 4 hours, sweep the pavement using a power broom or pickup sweeper as
needed to remove all loose aggregate. If the pavement cannot be swept within
the 4-hour period due to problems associated with the stone moisture, binder,
breaking, humidity, or other unknown, the Engineer may suspend the operation
until the problem is resolved or more suitable conditions are obtained to
maintain the 4-hour time frame for sweeping. Extend sweeping 1 foot (0.3 m)
beyond the edge of the pavement to help prevent migration of loose aggregate
back onto the pavement. Do not re-use aggregate from a chip seal that is
swept from the pavement or that is already loose off the pavement edge.
The
Contractor is responsible for claims of damage to vehicles until the pavement
and shoulders receive a final sweeping immediately before application of permanent
pavement markings or a fog seal, if a fog seal is required.
Wait
at least 24 hours before placing the second course of a double chip seal.
Ensure that the first course meets requirements of this specification and is
cured, swept and capable of withstanding construction traffic without
damage.
Correct
damage to the underlying chip seal before placing the final chip seal.
Place
the longitudinal construction joint on a lane line or as directed by the
Engineer. For double chip seal, place the longitudinal construction joint
for the first course 6 inches (150 mm) off the centerline and place the second
course so the longitudinal joint is at the centerline.
Before
opening to traffic, post the roadway with “Loose Stone” signs and a “35 mph”
speed plaque mounted below the sign. Ensure that signs conform to Item 614. Place these signs at a maximum of 0.5-mile
(0.8 km) intervals. Remove the signs as directed by the Engineer.
On
two-lane roads or pavements where traffic is maintained on a chip seal
constructed that workday, provide a traffic control pilot vehicle operated at
no more than 25 miles per hour (40 km/h) in the immediate work area.
Protect
all utility castings, monument boxes, and other similar items using tarpaper or
other approved material. Remove protection before sweeping and opening to
traffic.
A. General. Use the methods described in this section to
measure compliance. If test results exceed any of the identified quality
control tolerances, stop placement and immediately notify the Engineer and
DET. Identify the cause of exceeding any of the identified quality
control tolerances and document in detail the corrective action necessary to
bring the deficiency into compliance. Obtain the Engineer’s approval
before resuming work. Upon resuming work, take another sample and
immediately provide the test results to the Engineer. If the tolerances
are exceeded, stop the work. Do not resume work until approved by the
Engineer and DET. The Department can obtain samples of materials at any
time. Aggregate samples can be taken from sources, on-hand stockpiles or the
aggregate spreader box. Work can be stopped and materials can be rejected
on the basis of poor Department test results.
B. Binder. Within one hour of start of production obtain
and label a binder sample from the distributor truck and give the sample to the
Engineer the same day. Provide and sample the binder in one quart plastic
containers with plastic screw tops. Take more samples when requested by
the Engineer.
For the binder
application rate, as determined by a yield check, do not exceed a tolerance of
±0.02 gallon per square yard (0.09 L/m²) from the established application rate.
C. Coarse Aggregate. At a minimum test one sample
taken from the aggregate spreader box at production start and sample and test
one sample from the aggregate spreader box randomly during the day.
An aggregate spreader box sample may be taken by laying a piece of suitable
material under the spreader as it moves forward. Include additional
testing when directed to sample and test by the Engineer. Sample and test
aggregate according to AASHTO T 2, AASHTO T 248, and Supplement
1004 (AASHTO T 11 where
required). Use washed gradations for
determining the No. 200 (75 µm) sieve.
The Contractor may use additional tests.
These may include dry gradations for control purposes but acceptance of
on-hand aggregate will be based on washed gradations only. Reject and do not use aggregate creating
dusting nuisance to the public on the project.
Reject truckloads of aggregate if water is seen
coming from the truck bed.
Reject aggregate that does not meet the following
requirements:
|
No. 4 (4.75 mm) sieve from JMF |
±5.0% |
|
No. 8 (2.36
mm) sieve from JMF |
±3.0% |
|
No. 200 (75 µm) sieve from JMF |
±1.0%, 2.05% upper limit |
|
Aggregate moisture content (by dry weight) |
4.0% max. for aggregates with an
Absorption > 2.0%, 3.0% max.
for aggregates with an Absorption ≤ 2.0% |
D. Documentation. Provide the
Engineer a daily report with the following:
1. Control
section, project number, county, route, and Engineer.
2. Date,
air temperature, pavement temperature, and humidity.
3. Binder
temperature.
4.
Beginning and ending stations.
5. Yield
checks on binder (three per day, minimum).
6. Yield
checks on aggregate (three per day, minimum).
7.
Gradation, moisture content, and station (One sample from spreader box
at production start, one random sample during the day and any other samples
when directed by the Engineer).
8. Length,
width, and total area.
9.
Condition of “Loose Stone” signs with “35 mph” speed plaques.
10.
Contractor representative’s signature.
Provide a bill of lading for binder and aggregate as
requested or at project completion.
422.11 Acceptance. During the application of the chip seal,
inspect the chip seal for deficiencies resulting from poor workmanship, flushing,
tracking from equipment, surface patterns, loss of stone, and sweeping. Inspect workmanship for untreated areas,
minimum overlap on longitudinal joints, and minimum overlap on construction
joints.
Verify the following for daily acceptance:
A. Finished
surface has no more than four tears or untreated areas greater than 1 inch (25
mm) wide and 4 inches (100 mm) long in any 120-square yard (100 m2) area.
B. Joints
appear neat and uniform without buildup, uncovered areas, or unsightly
appearance.
C.
Longitudinal joints have less than a 2-inch (50 mm) overlap on the
adjacent passes.
D.
Transverse joints have no more than 1/4-inch (6 mm) difference in
elevation across the joint as measured with a 6-foot (2 m) straightedge.
E. Chip
seal edge is neat and uniform along the roadway lane, shoulder, and curb lines.
F. Chip
seal edge has no more than 2-inch (50 mm) variance in any 100 feet (30 m),
along the roadway edge or shoulder.
G. Typical
stone chip embedment is 1/2 to 2/3 of typical stone chip height.
For project acceptance, the Contractor and Engineer
will review the completed work 25 to 35 days after placement. The finished work must meet the following
requirements:
|
Defect [1] |
Severity |
|
Surface patterns |
Alternate lean and heavy lines (Ridges or streaking over the surface) |
|
Bleeding/flushing |
Distinctive appearance (Excess binder on surface) |
|
Loss of cover aggregate |
Patches or lines of aggregate lost from surface |
[1]
No more than 20% of any 120 square yard area can contain any
defect. The measurement of the 120
square yard area begins at the start of the defect.
Perform all corrective work to the satisfaction the
Engineer.
422.12 Method of Measurement. The Department will measure
Single Chip Seal Course or Double Chip Seal Course by the number of square
yards (square meters), completed and accepted in place. The Department will determine the width by
measuring the actual width of the chip seal.
The Department will determine the length along the centerline of each
roadway or ramp.
The Department will measure the number of raised
pavement markers removed if a Double Chip Seal is specified.
422.13 Basis of Payment. The Department will not pay for
materials, equipment, or labor to make corrections.
The cost of removal of all existing pavement markings
according to 422.06 is incidental to this item.
The cost of any removal or protection of existing
raised pavement markers on a single chip seal according to 422.06 is incidental to this item.
The Department will pay for removal of existing
raised pavement markers on a Double Chip Seal application according to Item 621 Raised Pavement Markers Removed
The Department will pay for accepted quantities at
the contract prices as follows:
Item Unit Description
422
Square Yard Single
Chip Seal
(Square Meter)
422
Square Yard Double
Chip Seal
(Square Meter)