CHIP SEAL COAT
PART 1 GENERAL
1.1SECTION INCLUDES
A.Materials and procedures for applying emulsified asphalt, followed with an
application of, either a standard chip seal cover material or lightweight chip seal cover material and bituminous flush coat.
1.2RELATED SECTIONS
A.Section 02742S: Project Specific Surfacing Requirements
B.Section 02745: Asphalt Material
C.Section 02748: Prime Coat/Tack Coat
1.3REFERENCES
A.AASHTO T 11: Materials Finer Than 75 µm (No. 200) Sieve in Mineral
Aggregates by Washing
B.AASHTO T 19: Bulk Density (Unit Weight) and Voids in Aggregate
C.AASHTO T 27: Sieve Analysis of Fine and Coarse Aggregates
D.AASHTO T 96: Resistance to Degradation of Small Size Coarse
Aggregate by Abrasion and Impact in the Los Angeles Machine
E.AASHTO T 104: Soundness of Aggregates by Use of Sodium Sulfate or
Magnesium Sulfate
F.AASHTO T 278: Surface Frictional Properties Using the British Pendulum
Tester
G.AASHTO T 279: Accelerated Polishing of Aggregates Using the British
Wheel
H.AASHTO T 335: Determining the Percentage of Fracture in Coarse
Aggregate
Chip Seal Coat
I.UDOT Materials Manual of Instruction (MMOI)
1.4DEFINITIONS Not Used
1.5SUBMITTALS
A.Test reports for information that the cover material and emulsion meets
requirements of this Section, Part 2.
B.Equipment Calibration information including verifying asphalt application
rates and chip application for information.
C.Documentation verifying daily asphalt application rates and chip
application for information.
D.Vendor’s bill of lading upon delivery for each emulsion used on the project
for information.
1.This bill of lading should certify if the emulsion was diluted or not
according to this Section, Part 2.
PART 2 PRODUCTS
2.1CATIONIC EMULSIONS
A.CRS-2A according to Section 02745.
B.CRS-2P according to Section 02745.
C.LMCRS-2 according to Section 02745.
2.2HIGH FLOAT EMULSIONS
A.HFRS-2P according to Section 02745.
B.HFMS-2 according to Section 02745.
C.HFMS-2P according to Section 02745.
2.3FLUSH COAT
A.Use the emulsion as specified in Special Provision 02742S, diluted two
parts concentrate to one part water by the manufacturer.
Chip Seal Coat
2.4COVER MATERIAL
A.Meet the requirements of Table 1.
1.Use crusher processed virgin aggregate consisting of
natural stone, gravel, or slag for standard chips.
2.Use crusher-processed rotary-kiln lightweight expanded
shale chips for lightweight chips.
Table 1 Chip Seal Cover Material Properties Test Test Method Standard Chip Lightweight Chip Seal Seal Type I & II Type I &II 3 3 *Unit Weight AASHTO T 19 100 lb/ft , max 60 lb/ft , max One Fractured AASHTO T 335 95% minimum N/A Face Two Fractured AASHTO T 335 90% minimum N/A Faces *LA wear AASHTO T 96 30% maximum 30% maximum *Soundness AASHTO T 104 10% maximum 10% maximum Flakiness Index Materials MOI 933 17 maximum 25 maximum *Stripping Materials MOI 945 10% maximum 10% maximum *Polishing AASHTO T 278, T 279 31 minimum 31 minimum * This requirement may be waived if the aggregates have proven acceptable through successful past performance as determined by the Engineer.
B.Meet gradation limits in Table 2. Refer to AASHTO T 27 and T 11.
Table 2 Gradation Limits Percent Passing Sieve Standard Aggregate Lightweight Aggregate Size Type I Type II Type I Type II ½ in 100 - 98 100 100 - 90 ⅜ in 100 69 - 91 80 - 100 55 - 80 No. 4 0 - 15 0 - 11 5 - 40 0 - 10 No. 8 0-6 0 - 20 0-3 No. 16 0 - 10 No. 200 0-1 0 - 1.5 0-2
2.5BLOTTER MATERIAL
A.Refer to Section 02748.
Chip Seal Coat
2.6EQUIPMENT
A.Use distributor trucks with the following:
1.Tachometer, pressure gauges, accurate volume measuring devices
or a calibrated tank, and a thermometer for measuring temperatures of the tank contents.
2.Insulated tanks capable of storing the binder at temperatures that
allow the binder to remain consistent with the appropriate viscosity for proper application rates.
a.Use tanks equipped with baffles to prevent pressure surges
resulting from the asphalt sloshing in the tank when starting and stopping.
b.Use trucks equipped with devices to provide for accurate
control of the amount of bituminous material being applied.
3.Constant volume circulation pumps and heaters to maintain a
pressurized system so binder will be uniformly heated.
a.Circulation pump must spray a constant volume for the entire
length of the spray bar for each application.
4.Spray bar and nozzles designed to provide an appropriate fan width
to provide uniform transverse distribution without corrugation or streaking.
a.Adjust the spray bar height to provide uniform distribution of
binder across the application width and triple lapping of the binder on the pavement surface.
b.Use a fully circulating spray bar with a positive shutoff valve.
5.Computerized rate control system allowing the operator to control
all distributor operations from the cab to include:
a.Pressure regulation of the material application and
automatic rate control adjustment to the unit ground speed. 1) Hydrostatic system capable of maintaining a tolerance of ± 0.03 gal/yd2.
b.Spray bar height and width adjustment and shut off of
individual spray bar sections.
B.Use a self-propelled aggregate (chip) spreader specifically designed and
manufactured for chip seal operations, equipped with the following:
1.Computerized controls that will apply a uniform, even layer of
aggregate across the full width of the binder and adjust output to the unit ground speed.
a.Use gates adjustable to drop the correct amount of
aggregate plus or minus 1 lb/yd2.
2.Variable width spreader with hydraulic control extension and
adjustable discharge gates.
3.Spreading hopper with a minimum capacity to cover a full lane of
travel plus 1 ft/pass.
4.Spinner broadcast type of aggregate spreader not allowed.
Chip Seal Coat
C.Use at least three articulating type pneumatic rollers for rolling operations.
1.Use rollers weighing between 8 tons minimum and 12 tons
maximum with a minimum width of 6 ft.
2.Use rollers with pneumatic tires of equal size diameter and having
treads satisfactory to the Engineer.
3.Inflate tires so that the entire roller width area is compacted by the
rear-axle tires and the front-axle tires.
a.Inflate tires to 90 lb/in2, or lower with permission from the
Engineer. 1) Maintain tire pressure within 5 lb/in2.
D.Sweeping Equipment
1.Use rotary brooms with nylon or steel bristles or pickup or vacuum
brooms for pavement cleaning or brooming operations.
E.Blotter Material Equipment
1.Apply blotter material using a truck mounted spinner broadcast
spreader.
PART 3 EXECUTION
3.1PREPARATION
A.Clean the road surface of all dirt, sand, dust, and other objectionable
material to the satisfaction of the Engineer.
B.Protect structures including but not limited to guardrail, guideposts,
concrete barriers, drains, and parapets.
C.Protect manholes, valve boxes, drop inlets, and other service utility
entrances before placing any chip seal coat.
D.Stockpile blotter material with a quantity of at least 0.25 lb/yd2 for the
production day.
1.Blotter material must be ready to be spread within 20 minutes of a
road section being chip sealed.
2.Use blotter material, as needed to cover up oil if it bleeds through
the new chip seal.
3.2LIMITATIONS
A.Complete all work between May 15, and August 31.
B.Do not place chip seal coat if surface moisture is present.
Chip Seal Coat
C.Chip seal coat application:
1.Place when the pavement temperature is between 70 and 136
degrees F.
2.Place when the air temperature is between 50 and 110 degrees F.
3.Do not apply after 6:00 pm if the temperature is expected to be
below 50 F during the night.
4.Place when the forecasted temperature is not expected to be below
40 degrees F within 3 days after placement.
D.Do not open to traffic the same day chip seal coat is placed on Interstate
routes.
1.Sweep chip seal to remove unbound aggregates prior to opening to
traffic.
E.Allow at least 48 hours after completing application of cover material
before applying bituminous flush coat material.
1.Apply bituminous flush coat material when the air temperature in
the shade is at least 50 degrees F and the pavement temperature is at least 70 degrees F.
2.Do not apply bituminous flush coat material during fog, rain, or
other adverse conditions.
3.3COVER MATERIAL STOCKPILE
A.Construct individual 500 ton stockpiles for aggregates.
1.Construct on a clean base to minimize contamination.
2.Construct to facilitate uniform dampening.
3.Avoid excess moisture.
4.Combining, altering, or moving accepted stockpiles may require
retesting by the Engineer before use.
B.Notify the Engineer at least seven calendar days before placement in
order for the initial stockpiles to be sampled and tested for acceptance.
C.Obtain the Engineer’s acceptance of a stockpile before use.
D.Rework or remove material not meeting specifications from the stockpile
area. Identify stockpiles that will be reworked.
Chip Seal Coat
3.4ASPHALT MATERIAL/COVER MATERIAL APPLICATION
A.Apply asphalt material at a rate sufficient to obtain 50 percent chip
embedment before the rolling operation and 70 percent chip embedment after rolling operation.
1.Adjust application rates throughout the project depending on
existing conditions.
B.Apply the asphalt emulsion at a minimum temperature of 145 degrees F.
C.Do not apply asphalt material if material does not spray through the
distributor in a uniform way and remain in place on the roadway.
D.Place building paper adjacent to the transverse construction joint before
starting each spraying operation.
1.Maintain the control valve to act instantaneously both at start-up
and cut- off.
E.Locate longitudinal joints within 6 inches of the traffic lane line location.
1.Construct meet lines with no skip or voids between adjacent
passes.
2.Do not place a double thickness of cover material.
F.Calibrate the spreader at the beginning of each day and as often
as necessary to comply with Table 3.
1.Maintain a distance of less than 150 ft between the
distributor and the chip spreader.
2.Maintain the chip spreader speed so that chips do not bounce
or roll during application.
Chip Seal Coat
Table 3 Approximate Spread Rates Unit Application Weight Rate lbs/ft3 lbs/yd2 Lightweight Type I Chip Seal 45 - 50 9.6 50 - 55 10.6 55 - 60 11.6 Lightweight Type II Chip Seal 45 - 50 11.8 50 - 55 13.1 55 - 60 14.3 Standard Chip Seal 60 - 65 17.0 65 - 70 18.4 70 - 75 19.8 75 - 80 20.7 80 - 85 22.1 85 - 90 23.5 90 - 95 24.9 95 - 100 25.8
3.5SURFACE ROLLING
A.Use at least three pneumatic-tire rollers in a longitudinal direction to roll
surface after the cover material has been spread.
B.Roll at least three passes to seat the cover material.
1.A pass is defined as traveling in one direction only.
C.Control bleeding with blotter material and as determined by the Engineer.
D.Set the roller speed to prevent bouncing or skidding.
1.Do not exceed 5 mph.
2.Reduce roller speeds during directional changes to prevent surface
tearing.
E.Synchronize the speed of the distributor and chip spreader with that of the
rolling operation.
1.Begin initial rolling, consisting of one complete coverage,
immediately behind the chip spreader.
2.Begin secondary rolling, consisting of second and third coverage,
immediately after completing initial rolling.
3.Synchronize all operations to keep rolling operations within 2,500
feet of the ongoing chip seal application.
Chip Seal Coat
F.Sweep excess cover material off the roadway after the emulsion has set.
1.Remove excess cover material to the satisfaction of the Engineer
before opening the roadway to traffic.
2.Keep downward pressure of broom to a minimum.
3.Use water as requested by the Engineer if excessive dust is
generated during sweeping operations.
4.Use pickup or vacuum sweepers in urban areas where aggregate
accumulates in gutters or where removal is required from the edge of the shoulder.
5.Do not dislodge embedded aggregate when brooming chip sealed
roadway.
G.Repair all damage to the seal coat before opening the roadway to traffic.
3.6BITUMINOUS FLUSH COAT APPLICATION
A.Clean the surface of all dirt, sand, dust, loose chips, and other
objectionable material to the satisfaction of the Engineer before applying bituminous flush coat.
B.Apply the bituminous flush coat at a rate of 0.11, ± 0.01 gal/yd2.
1.Keep traffic off the flushed surface until the bituminous material has
set sufficiently to prevent tracking or pick-up.
3.7PAVEMENT MARKING PAINT
A.Allow at least 24 hours after completing flush coat before applying
permanent pavement markings.
END OF SECTION
Chip Seal Coat
Utah revises spec sections through supplementals and new editions. We check this one every week and email you the day it changes. Free, no account.
Source: Utah Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 598–606 of 1,331.
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