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The water shall be potable and shall be free of harmful soluble salts.
Modifier

Special quick-setting emulsifier agents shall be milled into the asphalt emulsion. The emulsified
asphalt shall be so formulated that when the paving mixture is applied at a thickness of one inch
with the relative humidity at not more than 50% and an ambient air temperature of at least 75
degrees F, the material will cure sufficiently so that rolling traffic can be allowed in one hour
with no damage to the surface, as verified by the Engineer.

Additives

A mineral additive shall be introduced to the aggregate and may be any recognized brand of non-
air entrained Portland cement or hydrated lime that is free of lumps, or other approved mineral
additive. It may be accepted upon visual inspection. The amount of mineral additive needed
shall be determined by the laboratory mix design and will be considered as part of the material
gradation requirement.

A liquid field control additive may be introduced and blended with water to provide effective
control of the required quick-set properties. This additive shall be made available by the
chemical supplier or emulsion manufacturer, and certified to be compatible with the mixture.

C. ENGINEERING
General

Before work commences, the contractor shall submit a signed and certified mix design covering
the specific material(s) to be used on the project. This design shall be performed by a qualified,
independent laboratory. Once the materials are approved, no substitution will be permitted
unless first tested and approved by the laboratory preparing the mix design.

Mix Design

The independent laboratory shall develop the job mix design and present certified test results for
the contractor’s and Engineer’s approval. Compatibility of the aggregate and emulsion shall be
verified by the mix design. The job mix formula shall meet standard ISSA A143 micro-
surfacing mix design requirements. All component material used in the mix design shall be
representative of the material proposed by the contractor for use on the project.

Fiber-Reinforced Mix Design

Fiber-reinforced mix designs shall be tested for flexibility utilizing the TxDOT Overlay Test
(Tex-248-F) traditionally used for hot mix asphalts (HMA), and adapted for micro-surfacing as
follows:

1.) Section 2.1 -- constant maximum displacement should be increased from 0.025 in. to
0.050 in., 10 seconds (one cycle) to 60 seconds (one cycle).

2.) Sections 4.1 and 4.1.1 -- to be disregarded as they are solely intended for HMA.

3.) Section 4.2 — replaced in its entirety to read “Test Specimens — specimen length and
width must match Figure | (cutting template), and specimen height must be 0.50 in.
Make and cure the micro-surfacing overlay test specimens using similar methods and
resulting in similar mixture composition and mix consistency as done for the TB 100
(Wet Track Abrasion) and TB 147 (Loaded Wheel Test) specimens.

4.) Sections 5.1 and 5.2.3 — to be disregarded as they are solely intended for HMA.

5.) Section 5.3.1 — only the first sentence shall apply (“Mount and secure the base plates to
the mounting jig.”)

6.) Sections 5.4 and 5.7.1 — change 77 degrees F to 41 degrees F.

7.) Section 5.7.2 — change 93% to 90% and add “specimens are required to meet 100 cycles
minimum before reaching the 90% reduction.”

In the event that new performance testing standards are developed to supersede the modified

TxDOT Overlay Test standards outlined above, such new standards shall be submitted and
approved by the Engineer.

Specifications

The Engineer shall approve the design mix and all micro-surfacing materials and methods prior
to use. The component materials shall be within the following limits.

Residual Asphalt 5% to 9% by dry weight of aggregate

Mineral Additive 0.5% to 3% by dry weight of aggregate

Polymer Modifier As required to provide specified properties

and Field Control

Additives

Water As required to produce consistency

Fibers 0.05% to 0.25% by dry weight of aggregate as required to meet the

performance requirements of the TxDOT Overlay Test (Tex-248-
F) as described above

Aggregate - Recommended Gradations:

Type II Production

Screen Size % Passing Tolerance

3/8” 100 +7.0/+7.0
#4 90-100 + 7.0
#8 65-90 +40
#16 45-70 +40
#30 30-50 +40
#50 18-30 +40
#100 10-21 +40
#200 5-15 +2.0

Suggested Application Rates:

Type II - Urban and Residential Streets and Airport Runways:
single course = 18-20 lbs//s.y.
double course = 28-32 Ibs./s.y.

Note: all application rates above are dry aggregate weights exclusive of emulsion and all other
additives.

D. EQUIPMENT
General

All equipment, tools, and machines used in the performance of this work shall be maintained in
satisfactory working condition at all times to ensure a high quality product.

Mixing Equipment

The material shall be mixed by a self-propelled micro-surfacing mixing machine which shall be a
continuous flow, continuous run mixing unit able to accurately deliver and proportion the
aggregate, emulsified asphalt, mineral and field control additives, and water to a revolving multi-
blade twin shafted mixer, and discharge the mixed product on a continuous flow basis. The
contractor shall own and have available two (2) continuous flow, continuous run mixing
machines to ensure highest quality, and to mitigate the effect of equipment breakdowns. The
machines shall have sufficient storage capacity for aggregate, emulsified asphalt, mineral and
field control additives, and water to maintain an adequate supply to the proportioning controls.
The machines shall be equipped with self-loading devices which provide for the loading of
materials while continuing to lay micro-surfacing, thereby minimizing construction joints.

Proportioning Devices

Individual volume or weight controls for proportioning each material to be added to the mix, 1.e.,
aggregate, emulsified asphalt, mineral and field control additives, and water shall be provided
and properly marked. These proportioning devices are usually revolution counters or similar
devices, and are used in material calibration and determining the materials output at any time.

Emulsion Pump

The emulsion pump shall be a heated, positive displacement type pump.

Spreading Equipment

The surfacing mixture shall be spread uniformly by means of a mechanical type spreader box
attached to the mixer, equipped with paddles to agitate and spread the materials throughout the
box. The spreader box width shall be capable of adjustment while paving in order to
accommodate the changing width of some roadways without excessive overlaps. A front seal
shall be provided to insure no loss of the mixture at the road contact point. The rear seal and
secondary strike-off shall act as the final strike-off, and both shall be adjustable. The mixture
shall be spread to fill cracks and minor surface irregularities, and leave a uniform skid resistant
application of material on the surface. The spreader box and rear strike-off shall be so designed
and operated that a uniform consistency is achieved to produce a free flow of material to the rear
strike-off. The longitudinal joint where two passes join shall be neat in appearance, uniform and
lapped. All excess material shall be removed from the jobsite prior to opening the road. The
spreader box shall have suitable means provided to side-shift the box to compensate for
variations in pavement width and longitudinal alignment.

A rut box shall be available to pre-fill wheel ruts when necessary prior to overlay to eliminate
puddles or runoff interruption. The rut box shall be no less than 4’ wide and no more than 6’
wide.

Auxiliary Equipment

Suitable surface cleaning equipment, traffic control equipment, hand tools and any support
equipment shall be provided as necessary to perform the work.

Screening Plant

All aggregate shall be rescreened immediately prior to being loaded onto micro-surfacing
equipment. The screening plant shall be equipped with a 3/8” screen to remove all oversized
aggregate, and shall be capable of discharging screened aggregate directly onto the support
equipment. Any material discharged onto the ground must be rescreened prior to use.

Machine Calibration

Each mixing unit to be used in the performance of the work shall be calibrated in the presence of
the Engineer prior to construction, or previous calibration documentation covering the exact
materials to be used may be acceptable provided they were made during the same calendar year.
The documentation shall include the individual calibration of each material at various settings,
which can be related to the machine metering devices.

E. WEATHER LIMITATIONS

The material shall be spread only when the road surface and atmospheric temperatures are at
least 45 degrees F and rising, the weather is not rainy, and there is no forecast of temperatures
below 32 degrees F within 48 hours from the time of placement of the mixture.

F. SURFACE PREPARATION
General

The area to be resurfaced shall be thoroughly cleaned of vegetation, loose aggregate and soil,
particularly soil that is bound to the surface. Manholes, valve boxes and other service entrances
will be protected from the surfacing material with polyethylene sheeting. All services will be
uncovered upon completion of work.

Cracks in Surface

If required by the Engineer, pre-treat the cracks in the surface with a fiberized crack sealer prior
to the application of the micro-surfacing. Crack sealer shall be a polymer and crumb rubber
modified asphalt cement including not less than 3% polymers, 7% recycled tire crumb rubber (80
mesh), and 8% polyester fibers (PCRM + fibers). The modified asphalt cement incorporated in
the PCRM + fibers material must meet PG 64-28E MSCR testing requirements.

Tack Coat

The contractor shall be required to apply a tack coat on any heavily oxidized pavements, and on
high traffic roadways as directed by the Engineer. The tack coat shall consist of one part
emulsified asphalt (CSS-1H) and three parts water, and be applied with a distributor at a rate of
0.05-0.10 gallons per square yard.

G. CONSTRUCTION

Stockpile

Precautions shall be taken to insure that aggregate stockpiles do not become contaminated. The
mineral aggregate shall be re-screened prior to being directly loaded onto micro-surfacing
equipment.

General

The surface should be pre-wetted by fogging ahead of the spreader box when required by surface
and ambient conditions. The rate of application of the fog spray shall be adjusted during the day
to suit temperatures, surface texture, humidity, and dryness of the pavement surface.

The micro-surfacing mixture shall be of the desired consistency upon leaving the mixer and no
additional materials should be added. A sufficient amount of material shall be carried in all parts
of the spreader at all times so that a complete coverage is obtained. Overloading of the spreader
shall be avoided. No lumping, balling, or unmixed aggregate shall be permitted.

No streaks, such as those caused by oversized aggregate, will be left in the finished surface. If

excessive amounts of oversized aggregates appear in the mix, the job will be stopped until the
contractor proves to the Engineer that the situation has been corrected.

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Joints

No excessive buildup, uncovered areas or unsightly appearances shall be permitted on
longitudinal or transverse joints. The contractor shall provide suitable width spreading
equipment to produce a minimum number of longitudinal joints throughout the project. When
possible, longitudinal joints shall be placed on lane lines. Half passes and odd width passes will
be used only in minimum amounts. If half passes are used, they shall not be the last pass of any
paved areas.

Mix Stability

The micro-surfacing mixture shall possess sufficient stability so that premature breaking of the
material in the spreader box does not occur. The mixture shall be homogeneous during and
following mixing and spreading. It shall be free of excess water or emulsion, and free of
segregation of the emulsion and aggregate fines from the coarser aggregate.

Hand Work

Areas which cannot be reached with the mixing machine shall be surfaced using hand squeegees
to provide complete and uniform coverage. The area to be hand-worked shall be lightly
dampened prior to mix placement. Care shall be exercised to leave no unsightly appearance
from handwork.

The same type finish as applied by the spreader box shall be required. Handwork shall be
completed immediately after the micro-surfacing mixture is discharged from the spreader box.

Lines

Care shall be taken to insure straight lines along curbs and shoulders. No runoff on these areas
will be permitted. Lines at intersections will be kept straight to provide a neat workmanship
appearance.

Rolling

If required by the Engineer, specified areas shall be rolled by a self-propelled, 5 tol0 ton
pneumatic roller with a tire pressure of 50 PSI and equipped with a water spray system.

H. QUALITY CONTROL
Materials

The contractor will permit the Engineer to take samples of the aggregate and asphalt emulsion to
be used in the project at the Engineer’s discretion. Gradation and sand equivalency tests may be
run on the aggregate, and residual asphalt content test run on the emulsion. Test results will be
compared to specifications. Tests will be run by a qualified laboratory at the expense of the
Owner. The Owner must notify the contractor immediately if any test fails to meet the
specifications.

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Micro-Surfacing Mixture

Samples of the mixture should be taken daily and may be taken directly from the mixing unit(s).
Consistency and residual asphalt content tests may be made on the samples and compared to the
specifications. Tests will be run by a qualified laboratory at the expense of the Owner. The
Owner must notify the contractor immediately if any test fails to meet specifications.

The Engineer may use the recorder and measuring facilities of the unit to determine application
rates, asphalt emulsion content, mineral and field control additives, and water.

Non-Compliance

If any two successive tests fail on the stockpile material, the job shall be stopped. It is the
responsibility of the contractor, at his own expense, to prove to the Engineer that the conditions
have been corrected. If any two successive tests on the mix from the same machine fail, the use
of the machine shall be suspended. It will be the responsibility of the contractor, at his own
expense, to prove to the Engineer that the problems have been corrected and that the machine 1s
working properly.

I. MEASUREMENT AND PAYMENT

Micro-surfacing will be paid by the square yard (SY) complete in place as measured in the field
to the nearest 0.1 SY. Payment for micro-surfacing includes full compensation for material,
labor, transportation, and equipment necessary to complete this portion of the Bid Schedule. A
price adjustment for liquid asphalt is provided in this contract as outlined in Item 900 Liquid
Asphalt Adjustment. No payment will be made for materials delivered but not placed.

All materials, labor, equipment, and transportation for the following is considered subsidiary to

this item: mobilization and demobilization, street sweeping, installing and removing plastic on
manhole and service entrances, and tack coat.

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ITEM 405.11 - CRACK SEALING

A. SCOPE

The work covered by this section of the specification consists of furnishing all materials, labor,
transportation, and equipment necessary to perform all operations in connection with the
cleaning and sealing of construction and random cracks in bituminous concrete pavements,
including vegetation removal and sterilization of cracks, where necessary.

B. MATERIAL

Crack sealant shall be a modified asphalt-fiber compound designed specifically for improving
the strength and performance of the parent asphalt sealant.

Asphalt Binder
The asphalt binder shall consist of a blend of neat asphalt binder, chemically modified crumb
rubber (CMCR), and a polymer package, all of which meet the following specifications:

- The binder will meet PG 64-28E requirements after modification including:
- PG grade requirements of AASHTO M320
- Requirements of AASHTO TP70/MP19
- Modification, at a minimum, shall consist of 7% crumb rubber, and the maximum particle
size for the recycled tire rubber shall be 80 mesh (#80 sieve)

The asphalt supplier shall provide testing for both the neat and modified asphalt binders
See below for typical modified test results for 64-28E with crumb rubber:

DSR ORIGINAL: — kPa >1.00 @ 64° C. Fail temp = 76+° C

DSR RTFO: kPa >2.20 @ 64° C. Fail temp = 76+° C

MSCR: JNR (MSCR unit of measure): 3.2 E <0.5% @ 64° C
R3200 (Average % Recovery): >70%

DSR PAV: kPa <6000 @ 64° C

BBR: Stiffness <300 @ -18° C. M-Value >0.300 @ -18° C

Fiber reinforcing materials shall be short-length polyester fibers having the following properties:

Length* 0.25 in. + 0.02 in.

Elongation at Break (ASTM D2256-90) 35% + 3%

Melting Point (ASTM D3418-82) >475 degrees F (246 degrees C)
Crimps/Inch (ASTM D3937-90) None

Cross Section Round

Denier (ASTM D1577-90) 4.5 Nominal dpf

Tensile Strength (ASTM D2256-90) >70,000 psi

Diameter 0.0008 in. **

Specific Gravity (ASTM D792-91) 1.32 to 1.40

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* At temperatures ranging from ambient to maximum finished product mix
temperature
** Subject to Normal Variations

The modified asphalt-fiber compound shall be mixed at a rate of 8% fiber weight to weight of
asphalt cement. This compound having the same chemical base provides compatibility and
exhibits excellent bond strengths. The fiber functions to re-distribute high stress and strain
concentrations that are imposed on the sealant by thermal sources, traffic loading, etc.

C. EQUIPMENT

Equipment used in the performance of the work required by this section of the specification shall
be subject to approval by the Owner, and maintained in a satisfactory working condition at all
times.

Air Compressor: Air compressors shall be capable of furnishing not less than 100 cubic feet of
air per minute at not less than 90 Ibs. per square inch pressure at the nozzle. The compressor
shall be equipped with traps that will maintain the compressed air free of oil and water.

Manually operated, gas powered air-broom or self-propelled sweeper: It shall be designed
especially for use in cleaning highway and airfield pavements shall be used to remove debris, dirt
and dust from the cracks.

Melter: The unit used to melt or maintain the crack sealant compound at the recommended
application temperature shall be the indirect fired type. It shall be equipped with a remote heat
exchanger and hot oil circulation pump capable of maintaining a consistent temperature of the
heat transfer oil. The heat transfer oil shall be circulated to all sides and the bottom of the vat
containing the crack sealant compound making a continuous loop back to the heat exchanger and
having a flash point of not less than 600 degrees F. The melter shall be equipped with a
satisfactory means of agitating the crack sealant at all times. This may be accomplished by
continuous stirring with mechanically operated paddles and/or by a circulating gear pump
attached to the melter. The melter must be equipped with a thermostatic control calibrated
between 200 degrees F and 550 degrees F, and must be capable of pumping an 8% fiber content
blend.

D. CONSTRUCTION

Preparation of Cracks
All cracks shall be blown clean and sterilized by use of a propane air torch generating 2,000

degrees F and 3,000 feet/second velocity to eliminate all vegetation, dirt, moisture and seeds. All
debris removed from the cracks shall be removed from the pavement surface immediately by
means of a power sweeper, hand or air broom.

No crack sealant material shall be applied in wet cracks or where frost, snow or ice is present,
nor when the ambient temperature is below 25 degrees F.

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Preparation and Placement of Sealant

No crack sealant material shall be applied in wet cracks or where frost, snow or ice is present,
nor when the ambient temperature is below 25 degrees F.

The asphalt-fiber compound shall be thoroughly mixed for a minimum of one hour before
application can begin. To ensure a uniform fiber distribution in the sealant, and also to limit
fluctuations in the application temperature of the blended material, the contractor must have a
full melter kettle of sealant mixed, heated to the proper application temperature, and ready for
testing at the start of each work day. Once that batch of sealant is emptied from the melter kettle,
crack sealing operations will cease for the remainder of the day. No new materials will be
allowed to be added to the melter kettle during the work day under any circumstances. Minimum
application temperature shall be 320 degrees F.

Sealant shall be delivered to the pavement cracks through a high pressure hose line and
applicator shoe. Diameter of the applicator shoe is not to exceed 3.5 inches. Once the pavement
cracks are sealed, the width of the sealant on the pavement (overbanding) shall be no greater than
3 inches. When traffic requires immediate use of the roadway, a boiler slag aggregate shall be
broadcast over the cracks to prevent the sealant from being picked up.

All workmanship shall be of the highest quality, and any excess of spilled sealant shall be
removed from the pavement by approved methods and discarded. Any workmanship determined
to be below the high standards of the particular craft involved will not be accepted, and will be
corrected and/or replaced as required by the Owner.

E. PERFORMANCE

Properly formulated and mixed asphalt fiber compound overbanding shall not be greater than
three inches (3”) in width. Penalties will be imposed upon the contractor for overbanding

beyond three inches (3”’).

The contractor must submit the following with his bid proposal:
=" The trade name of the crack sealant the bidder intends to use.
=" The manufacturer of the crack sealant the bidder intends to use.

The Engineer will require the contractor to successfully perform a 200 foot test strip in the field
prior to commencing work under the contract.

Manufacturer’s certificate of material compliance will be furnished to the Engineer certifying
conformance to the above material specifications, including the following:

" Performance Grade of Modified Asphalt: PG 64-28E (able to withstand
“extremely heavy” traffic loads)
" 7% chemically-modified crumb rubber (CMCR) composed of 100% 80-mesh
recycled tire rubber
= 3-4% specially formulated polymer package
» AASHTO M-320, Table 1
o “E” Jnr 3.2 kPa @ 64°C: <0.5%
o R3200 (Average % Recovery) @ 3.200 kPa: >70%

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