Transcript PROTECTION & PRESERVATION OF ASPHALT SURFACES AN

SEALCOATING PRINCIPLES for
CONTRACTORS
PROTECTION & PRESERVATION
OF ASPHALT SURFACES
part i-general
PRESENTED BY
Girish C. Dubey
President, STAR, INC.
1
OBJECTIVES
1. To understand Asphalt Pavements , their;
a. Basic construction and make up,
b. Strengths and weaknesses,
c. Why they have to be protected ?
d. Which types of pavements can be protected?
e. How can they be protected ?
Concept of SEALCOATINGS
2. Overall Savings and value to the
property owner.
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OBJECTIVES
3. Sealcoating Materials:
a. Refined Tar Based sealcoatings (RTS)
b. Asphalt Emulsion Based sealcoatings (AE).
4. Sealcoating Application:
a. Equipment
b. Mix Design compositions
c. Application details and Cautions
5. Drying and cure of sealcoatings
6. Good Sealcoating Practices
7. Do and Don’ts.
8. Trouble-shooting
9. Commonly asked questions.
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ROAD CONSTRUCTION
A.
PRIOR HISTORY OF ROAD CONSTRUCTION:
Constructed with Clay, Limestone, RocksFunctional but severely damaged by rain:
The aggregates absorbed water, became soft and lost
their strength to support loads.
Roads were destroyed in no time.
B. ASPHALT AS A PAVING MATERIAL-
Used since 18th. century
A by-product of petroleum refining process was plentiful and had excellent;
 Adhesive (Gluing) properties,
 Water Proofing (repellency)
will not let water penetrate the pavement and damage it.
 Flexibility- Pavement surface will flex under traffic without
cracking.
ASPHALT KEPT WATER OUT OF THE PAVEMENTS,
KEEPING THE BASE DRY AND FUNCTIONAL
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WHAT
?
WHATISISASPHALT
ASPHALT
IT IS A BY-PRODUCT OF PETROLEUM REFINING PROCESS.
CRUDE PETROLEUM- ORIGINATED FROM THE DECAY OF MARINE
LIFE OVER MILLIONS OF YEARS.
CRUDE PETROLEUM
REFINIG PROCESS
REMOVE LIGHTER FRACTIONS:
SOLVENTS, GREASE, OIL….
RESIDUE: ASPHALT
ASPHALT IS A VERY COMPLEX MIXTURE OF OVER 5000 COMPOUNDS.
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ASPHALT PAVEMENTS
WHAT THEY ARE AND HOW ARE THEY CONSTRUCTED ?
Pavements are the solid floor of any construction that carries traffic;
 VEHICULAR :
High Traffic :Highways, Roads, Streets,
Low traffic : Airport runways, aprons, parking lots, driveways, service stations..
 PEDESTRIAN: Walkways, Play Grounds, Schools, etc.
CONSTRUCTION
The earth is removed and
- Filled with large aggregates (gravel, rocks, limestone- Base course
- Filled with smaller aggregates- Sub-base course
- Covered with hot molten asphalt (5-10% By weight) mixed with finer aggregates- top course.
THIS TOP LAYER, SO TO SPEAK , IS THE " ROOF OF THE PAVEMENT".
TOP COURSE, Asphalt Hot-Mix.
SUB-BASE COURSE
BASE COURSE
THE CONSTRUCTION VARIES WITH THE TRAFFIC LOAD REQUIREMENTS.
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ASPHALT AS A PAVING MATERIAL
SHORTCOMINGS
1. DETERIORATES UNDER SUN'S ULTRAVIOLET RAYS
Unstable (aliphatic) compound in asphalt breakdown.
2. Attacked or Dissolved by:
a. DISSOLVED BY PETRO-CHEMICALS:
GASOLINE, OILS, FATS, GREASE ETC.
 Same origin-crude petroleum.
 Natural Affinity-Co-exited in nature over mils. Of yrs.
Like dissolves like.
b. DEICING SALTS- Attack unstable compound in asphalt
c. WATER- Strips asphalt form aggregates.
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HOW ASPHALT BREAKS DOWN
The top layer degrades from the elements
soon after the asphalt installation.
Surface cracks develop, Asphalt becomes
brittle, water seeps in, and cracks widen,
damaging the base.
Trapped water weakens the foundation and
further damage occurs under traffic and
seasonal freeze / thaw cycles.
Further asphalt damage is done over time.
Chunks of asphalt begin to break away and
potholes quickly develop.
End of The Pavement
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HOW TO PROTECT ASPHALT PAVEMENTS :
-
APPLY A COATING ON THE ASPHALT SURFACE THAT WILL:
FORM A BARRIER COAT TO SHIELD THE ASPHALT PAVMENT FROM THE ELEMENTS THAT
DESTROY ASPHALT
SUN’S UV RAYS,
GAS, OIL,FAT AND PETROCHEMICALS,
WATER AND DE-ICING SALTS
ULTRAVOILT (UV) RADIATIONS
SOLVENTS
WATER & DE-ICING SALTS
FUEL, OIL & FATS
SEALCOATING
ASPHALT PROPERTIE
STAY "SEALED IN“.
SEALS IN THE EXCELLENT PROPERTIES OF ASPHALT
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REGULAR MAINTENANCE PROGRAMS:
1. SAVES MONEY FOR THE OWNER;
PAVEMENT LIFE CAN BE EXTENDED BY OVER 300%
2. PROTECTS AND PRESERVES THE ASPHALT PAVEMENT.
3. BEAUTIFIES THE PAVEMENT &
ENHANCES THE BUISNESS IMAGE.
4. CLEANING BECOMES EASIER;
RAIN WASHES OFF THE DIRT AND DEBRIS EASILY
TRAFFIC MARKINGS LAST LONGER.
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Pavement Preservation Program
Cost-Benefits Analysis
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REGULAR MAINTENACE RESTORES LOST PROPERTIES
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Economics of Sealcoating
Un-maintained Asphalt costs 3 times
more than a maintained lot
80.00
Cumulative Cost ($) per Sq. Yard
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
2006
2007
2008
2009
2010
2011
2012
Sealed
2013
2014
2015
Unsealed
2016
2017
2018
2019
2020
2021
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DO ALL PAVEMENTS NEED SEALCOATING ?
MAY NOT BE NEEDED
HIGH TRAFFIC BEARING PAVEMENTS
HIGHWAYS, ROADS, STREETS
THE ADVANTAGE- The kneading action of the traffic.
Brings up fresh asphalt to the surface.
The breakdown is not localized.
DESPERATELY NEEDED
LOW TRAFFIC, NON-TRAFFIC BEARING PAVEMENTS:
Lack of the kneading action of traffic.
Driveways
Fast food
Parking Lots
Shopping Malls
Gas Stations
Schools………….
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SEALCOATINGS ARE WATER-BASED COATINGS,
MADE BY DISPERSING: (Batch or Mill process)
1. Refined Tar (RTS) or Asphalt (AE)
2. Water
3. Clays and
4. Surfactants, Emulsifiers, Polymers.
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WHY WATER-BASED?
1. SAFE TO HANDLE AND STORE.
2. NON-FLAMMABLE
3. EASE OF WATER CLEAN UP OF TOOLS,
4. NO SOLVENT FUMES OR HAZARDS OF SOLVENT
5. EASY TO APPLY WITH BRUSH, SQUEEGEE
APPLICABLE SPECIFICATIONS
ASTM, 5727-00,
U.S. FEDERAL AVIATION ADMINISTRATION
(FAA SPECS.)
ASPHALT SEALCOATING MANUFACTURERS
ASSOCIATION (ASMA)
COMMERCIAL SPECIFICATIONS
Now you know
WHAT SEALCOATINGS DO?
1. Protect the Asphalt pavements from:
Sealcoats form a barrier coat to shield asphalt pavements from
The damaging elements;





Breakdown under sun’s UV radiation,
Oxidation,
De-icing salts and water
Gasoline, oil, fats, etc.,
Petrochemicals, anti-freeze, etc.
2.
Extends the life of the pavement by avg. 3 times.
3.
4.
5.
Reduces overall up maintenance cost of the pavement.
Improves the curb appeal.
Adds to the over-all value of the property.
Seals the asphaltic oils in the pavement and keeps
them functional (flexible) for a long time.
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DO NOT OVERSELL SEALCOATINGS!!
1. Sealcoatings are not designed to repair
the pavement defects
 Cracks, surface or structural.
 Alligatored cracks.
 Lose chunks of asphalt,
 Deteriorating shoulders.
2. Do not over-promise, sealcoating will make
the pavement look like new.
3. Do not sealcoat over
 Gravel or dirt roads
 Wood
 Gilsonite coated pavements
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





What are pavements,
How asphalt Pavements are constructed
What is asphalt- Its strengths and weaknesses
How asphalt can be protected- SEALCOATINGS !
Sealcoatings- Protects & Preserves asphalt
Extend the life of asphalt pavements by more than 3
times.
 Costs Less than 1/3 the cost. Of pavement
replacement.
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SEALCOATING PRINCIPLES for
CONTRACTORS
PROTECTION & PRESERVATION
OF ASPHALT SURFACES
part iI- APPLICATION
PRESENTED BY
Girish C. Dubey
President, STAR, INC.
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SEALCOATING APPLICATION
Sequence, Steps, Procedure & Precautions
SEQUENCE




MEASURE, CALCUALTE, COST MATERIAL,
O/H, % PROFITS .
BID COMPETITIVELY. RECALCUALTE
DEVELOP LOGISTICS-CREW, TOOLS, SUPPLIES.
MOBILIZE –PERSONNEL, MATERIALS, EQUIPMENT.





PAVEMENT PREPARATION- TRIMMING, CLEANING, REAIRS, ETC.
SEALCOATING APPLICATION
BLOCK OFF SEALED AREAS, OPEN AS AGREED
DEMOBILIZE-EQUIPMENT. LEAVE A SIGN. NO TRASH NO DEBRIS
COLLECT PAYMENT AS AGREED.
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Materials, Equipment, Procedures & Precautions
MATERIALS
SEALCOATINGS
:Good Quality, Must Meet
Applicable Specifications.
WATER: Clean, Potable.
SAND: Clean, Quarts, Angular, 50-70 Mesh
ADDITIVES: As Recommended.
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INSTRUCTIONS FROM SEALER SUPPLIER. DETAILS ON;
MIX DESIGN- Proportions of Sealer, Water,
Sand and Additives.
 PAVEMENT PREPARATION- Cleaning,
Spot Priming, Patching and Crack filling, Patching.
 APPLICATION RATES- Coverage Rates.
 PRECAUTIONS- Application, Handling and
Storage.
Must read MSDS
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SEALCOATING MIX DESIGN
SEALER IS GENERALLY SUPPLIED AS A CONCENTRATE.
Prior to application, It is mixed with:
Water
Sand/Aggregate
Additive
In specified proportions. That is called a Mix Design,
The quantities are denoted as % of Undiluted Sealer,
With sealer being 100%.
Manufacturers recommend a specific mix design for a
given job.
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1. Water
Achieves proper fluidity
Expressed as % of sealer
Clean, Potable and Free of salt
2. Sand/Aggregates
Adds traction & appearance,
Fills minor surface cracks
Expressed as lbs./Gallon of sealer
Must meet specs.
3. Additives
Fast/Uniform drying
Sand suspension and anchoring
Improves chemical and UV resistance
Expressed as % of sealer
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A TYPICAL MIX DESIGN
Sealer (RTS)
Water (25-30% dilution)
100 Gals.
25-30 gals.
Sand (2-3 lbs./gal)
Additive (2-5%)
200-300 lb.
2-5 gal.
Sealer is always used as the base @ 100
Quantities of other materials are
Calculated using sealer @ 100
Mixing has to be thorough.
Hand Mixing may not be enough.
Improper mixing –Poor Performance
.
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Hazards in Altering Mix Designs
FOLLOW THE MANUFACTURERS’S INSTRUCTIONS
Water
a. Too much- Will reduce the dry film thickness- Poor performance.
b. Too little- Poor flow of the mix, too much sealer may cause trackingwaste of money
Sand/Aggregates
a.
b.
Too much (over 5 lb./gal) – Reduced flexibility, may cause premature surface cracks. Excessive amount-may cause peeling.
Too little or none- Uneven appearance, may affect slipperiness
Additives
a.
b.
Too much (over recommended amount)- May destabilize the
sealer mix. Waste of money.
Too little- May be ineffective for the intended purpose.
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COVERAGE RATES
Definition ~ Expressed in 2 ways
1. Gallons of conc. Sealer needed cover One (1) sq. yard.
2. Square feet covered by One (1) gal of conc. Sealer.
Commonly Expressed as Gallon/sq. Yard.
Standard Coverage Rates
Commonly calculated for two (2) coats of sealer
1st Coat applied @ 0.10-0.12 gal. conc. Sealer/sq. yd.
2nd Coat, applied @0.08-0.10 gal. conc. sealer/sq. yd.
T Total of two (2) coats = 0.18-0.20 gal. Of conc. Sealer /sq. yd.
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JOB CALCULATIONS
1.
Calculate the area
Assume 10,000 sq. yd.
2. Calculate total undiluted sealer needed
@ 0.18 to 0.20 gals. Per sq. yd
Application/
Conc. Sealer
Coverage rate
Rate
Total Sq.
Total
Gal/Sq. Yd
yards Conc. Gals.
1st. Coat
0.12
10000
1200
2nd. Coat
0.08
10000
800
Total for 2 coat
0.20
10000
2000
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JOB CALCULATIONS
Mixture From Conc. Sealer
Application
Mix Design
Conc. Sealer Water @ 30%
Total Mixed Sealer
Sand, 3lb. Mixture
Factor
Gal
Gal
Lbs. (Gal)
Gals.
MSF
1st. Coat
1200
360
3600 (166)
1726
1.44
2nd. Coat
800
240
2300 (111)
1151
1.44
Total for 2 coat
2000
600
6000 (277)
2877
1.44
Mixed Sealer Factor (MSF)
Ratio between mixture and the conc. Sealer
Conc. Coverage Rates Shall be30multiplied with MSF
SEALCOATING APPLICATION
Sequence, Steps, Procedure & Precautions
STEPS IN APPLICATION
1. PAVEMENT PREPARATION
1.1. CLEAN
1.2 REPAIR
1.2 OIL SPOTS
REMOVE GRASS, WEEDS, AND DIRT
USING BRUSH, BROOM, BLOWER, POWER WASHING.
CRACK FILL WITH:
- COLD POUR FOR CRACKS UPTO ½ INCH WIDE
- HOT POUR CRACK FILLER FOR LARGER CRACKS.
PATCH & OVERLAY THE PROBLEM AREA- BADLY ALLIGATORED,
BASE PROBLEMS. ALLOW THE FRESH ASPAHLT TO CURE.
SCRAPE HEAVY BUILD UPS. WASH WITH DETERGENT, AND
SEAL WITH OIL SPOT PROMERS. SOFT AREAS-PATCH.
Sealcoating will not fix the pavement problems.
Pavement must be sound, free of defects prior to sealcoating.
SEALCOATINGS ARE SURFACE PROTECTIVE TREATMENTS, NOT REPAIR PRODUCTS.
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SEALCOATING APPLICATION
Sequence, Steps, Procedure & Precautions
STEPS IN APPLICATION
2. SEALCOATING APPLICATION
2.1. MATERIAL PREPARATION FOR THE JOB:





USE SUGEGSTED MATERAILS AND MIX
DESIGN FOR THE JOB.
HAVE THE RIGHT MIXING EQUIPMENT WITH
MECHANICAL AGITATION
KEEP MATERIAL AGIATETD DUING APPLICATION
MAKE SURE THAT SAND STAYS IN SUSPENSION.
MAKE SURE APPLICATION EQUIPMENT
(PUMPS, NOZZLES, TIPS, WAND, ETC. ARE
IN GOOD WORKING CONDITION.
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SEALCOATING APPLICATION
Sequence, Steps, Procedure & Precautions
STEPS IN APPLICATION
2. SEALCOATING APPLICATION
2.2. APPLICATION







TRIM THE EDGES WITH A SQUEEGEE OR A BRUSH
APPLY THE SEALER ON A SAMLL PRE-MEASURED
AREA TO SET CORRECT APPLICATION RATE.
APPLY THE SEALER IN LARGER AREAS USING A
SUITABLE METHOD- SPRAY, BURSH OR SQUEEGEE.
KEEP MATERIAL AGIATETD DUING APPLICATION
MAKE SURE THAT SAND STAYS IN SUSPENSION.
APPLY THE NO. OF REQUREID NUMBER OF COATS
IN MULTIPLE COAT APPLICATION-ALLOW EACH COAT
TO DRY SIFFICIENTLY BEFORE APPLYING THE
FOLLOWING COAT
ALLOW TO THE FINAL COAT TO DRY FOR A MIN.OF
24 HRS., BEFORE OPENIG THE LOT FOR TRAIIFC.
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SEALER APPLICATION MEHODS
BRUSH SQUEEGEE OR SPRAY???
Comparison aspects
SPRAY
SQUEEGEE
Investment
Considerable
Economical to considerable.
Cost Controls.
Material usage.
Controllable , Better Control
of Material Usage
Un-controllable, material
usage will depend upon the
surface roughness and age.
Skill Level
Highly Skilled work. Thorough Moderate skill. Not much
training required
training is needed.
Size of Projects
Medium to large
Small, medium, large
Appearance of the finished
job
Excellent, Uniform
Textured appearance.
Fair-to good, May appear
streaky
Safety in handling
Good, Material is under
pressure, may accidently
discharge due to equipment
malfunction.
V. Safe
Application under windy
Risky- Stay away from
No problem
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SEALER APPLICATION MEHODS
BRUSH SQUEEGEE OR SPRAY???
Comparison aspects
SPRAY
SQUEEGEE
Investment
Considerable
Economical
Uniformity of the coating
application
Uniform on the surface as
well as in the profile of the
pavement.
Thick in the profile and wipes
the top of the aggregates in
the pavement.
Conclusions
Mechanical application for
both types are well accepted
and have yielded years of
dependable performance. le
The main drawback is the cost
control of the material usage
Best compromise
Brush application of the first
coat and spray application of
the second coat.
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SEALCOATING PRINCIPLES for
CONTRACTORS
PROTECTION & PRESERVATION
OF ASPHALT SURFACES
part iII-special notes
(Do & DON’TS, TROUBLESHOOTING)
PRESENTED BY
Girish C. Dubey
President, STAR, INC.
36
SEALCOATINGS- DO & DON’Ts
General
Inspection &
Bidding
DO
DO NOT
1. Sell for intended purpose
Oversell. Sealcoating will not repair
deteriorated pavements.
2. Follow manufactures
recommendations for Application,
safety in handling, compliance to
regulations, and personal safety.
FLY BY THE SEAT OF YOUR PANTS.
-Ignore instructions and safety
instructions.
-Indulge in reckless practices.
Walk through, Measure,
Pavement Prep steps. Calculate,
Material, Labor, overheads (direct
and general), profits.
Depend on sketches, GPS maps,
Property owners estimates and cost
calculation for previous jobs.
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SEALCOATINGS- DO & DON’Ts
Technical
Details
DO
DO NOT
1. Sealer shall meet appl. Specs.
2. Mix design- Follow
recommendations
a. Water- clean and potable
b. Sand-Clean, Quartz 50-70 mesh.
c. Additives- As recommended.
1. Miscalculate the mix design. Sealer
is 100 base.
a. Sand- no used foundry or sand
blasting spent sand
b. Mix additives from diff. suppliers.
Always seek sealer suppliers
approval.
3. Mixing shall be thorough
2. Incomplete/improper mixing shall
result in poor performance.
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SEALCOATINGS- DO & DON’Ts
APPLICATION
DO
DO NOT
Follow manufacturers
recommendation for ;
a. Pavement preparation.
b. Selection of application tools,
brush, squeegee, spray , etc.
c. No. of coats and coverage rates.
d. Ambient application conditions
and drying times
a. Take Short cuts in pavement
preparation.
b. Over or under apply.
c. Open the lot too soon. Have a
disclaimer signed by the property
owner if they want the lot opened
sooner.
d. Let the wash water go into storm
sewer.
e. Do not apply if there is any chance
that rain will wash away the sealer into
the bodies of water.
Do a professional Job.
Be a professional
Leave dirt and debris, etc. on the job after
finishing.
DO NOT SHORTCHANGE YOUR CUSTOMER
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TROUBLE SHOOTING
Problems, Causes & Remedies
Problems
 Pre-mature
wear,
 Un-even
wear,
 Sand
knocked off
Causes
1. Thin coat application
2. Too much water in the mix.
3. Too much sand and large size, sand roll
out that will abrade the sealcoating.
4. Inadequate mixing of components in the
sealer
5. Improper cure conditions, too cold or
freezing overnight temps. Get weather
report for analysis.
6. Dirty, over-oxidized pavement.
7. Inadequate drying and cure, job was
rushed and lot opened too soon.
8. Inferior Product-Quality Issues.
Remedies
1. Right coverage rate
2.Right Mix design
3.Mix thoroughly.
4. Prepare the pavement
right.
5. Do not apply under
cold, high humid or foggy
conditions.
5. Select the right
products. Ask for
performance reports
from your manufacturer.
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TROUBLE SHOOTING
Problems, Causes & Remedies
Problems
Un-even color
& appearance
problems
Causes
Remedies
1. Cure under improper ambient conditions.
2. Curing under sun and shade.
3. Inadequate mixing of the components in the mix
design.
4. Changing mix designs for the same project.
5. No or very little sand in the mix. Also sand unevenly suspended in the mix.
6. Streaky appearance- sand falling in the
windrows. Poor sand suspension in the mix.
7. Uneven rate of application, machine malfunction or in-experienced applicator.
8. Inconsistent pavement condition (smooth,
rough, patchy, oxidized)
9. Changing direction of application, uneven brush
or squeegee patterns.
10. Landscape irrigation run off.
1.Must apply under the right
cure conditions.
2. Allow more cure time, the
color will blend in.
3. Use the same mix design for
the entire project.
4. Check the accuracy of the
appl. Rate on a test area.
5.Follow uniform windrows.
6.Make property owner aware
about inconsistent pavement.
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TROUBLE SHOOTING
Problems, Causes & Remedies
Problems
Adhesion
failure
Causes
1. Pavement not sufficiently cured
(surface oily).
2. Pavement too old and oxidized,
not properly cleaned and
primed
3. Oil Spots not properly primed.
4. Dirty pavement Excessive oil,
grease, etc.
5. Polished aggregates
6. Excessive sand loads (>8lb./gal)
Remedies
1. Test the
pavement to make
sure the pavement
is aged (cured
enough)
2. Clean and prime
with oil spot sealer
or specialty
coatings.
3. cure conditions
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SEALCOATING PRINCIPLES for
CONTRACTORS
PROTECTION & PRESERVATION
OF ASPHALT SURFACES
part Iv-
FREQUENTLY ASKED QUESTIONS
PRESENTED BY
Girish C. Dubey
President, STAR, INC.
43
FREQUENTLY ASKED QUESTIONS:
Sealer Performance
Q.1.
Why are two (2) thin coats better than one thick coat?
A.1.
Sealer applied in two coats dries and cures much better than one thick coat application.
Remember sealers are water-based coatings, which cure through the process of water release (evaporation). A
thin coat will release water much faster than a thick coat. If applied in one thick coat, sealer will have a
tendency to hold water and stay soft for a longer period of time, possibly causing tracking.
Q.2.
Why did the sealer fail or peel?
A.2.
Peeling is caused by sealer not bonding to oil spots or any other surface contaminants like dirt,
grease, etc. or oxidized pavements. All the areas shall be thoroughly cleaned; oil spots shall be primed with
specialty primers. Oxidized pavements shall be treated with a diluted coat of sealer or a specialty coating or a
diluted asphalt emulsion.
Q.3.
What causes white streaks in the sealer?
A.3.
Streaks in the cured sealer film are possibly caused by incomplete mixing of clays and fillers in the
manufacturing process of the sealer. The Sealcoating manufacturer should be able to rectify this problem.
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FREQUENTLY ASKED QUESTIONS:
Q.4.
Why does the sealer dry gray?
A.4.
Due to less than ideal conditions:
High Humidity, Cooler temperatures , Shade.
Mostly it is temporary, it will cure to a darker color.
Remedy- Use of fast drying additives- helps sealer dry faster and at a uniform rate.
Q.5.
Why does the sealer wear out faster in traffic lanes, entrances and exits?
A.5.
More traffic More Wear.
Excessive wear- Indication of adhesion problem to smooth/polished
aggregates. Such
Remedy- Use of specialty primers to penetrate the smooth polished aggregates and
allow the sealcoating to bond, effectively. Prime faster traffic lanes, exits
and entrances.
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FREQUENTLY ASKED QUESTIONS
APPLICATION
Q.6.
How soon I can sealcoat a freshly laid asphalt pavement?
A.6.
As soon as the surface rids of light oils through oxidation.
Allow 90 days or more, depending upon locations.
Perform a simple test called "water break test". - Spread some water on the
surface. If the water sheets out without beading, you are ready to sealcoat.
Remedy- For fresh patches, etc. prime with a specialty primer.
Q.7.
While spraying how do I know if I am applying at the recommended
coverage rate e.g. 0.12-gallon/sq. yard?
A.7.
1. Select 10’ x 10’ area of the pavement and place a
3"x 6" metal plate in the center.
2. Spray Sealcoating in this area.
3. Lift the metal plate before the Sealcoating dries.
4. Use the film thickness gauge to determine the wet film thickness. The
reading will be in mils (1/1000 of an inch). Compare this reading with the
desired film thickness for 0.12 gallon/ sq. yard coverage which is 21 mils.
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FREQUENTLY ASKED QUESTIONS
APPLICATION
Q. 8.
What type of striping paints should be used and
how soon can the lot be striped?
A. 8.
Water based Acrylic Traffic Paints are preferred.
Alkyd (oil) based paints are also used.
a. Allow the sealer to dry and cure at least 24 hr. after the
application of the final coat of the sealer, prior to striping.
b. If applied sooner, traffic markings may turn brown and blotchy.
Note:
-Most of the water borne traffic paints contain some fast evaporating
solvents.
-These solvents extract lighter fractions from the binder (coal tar or
asphalt) portion of the partially cured film of the sealer.
-The extract floats to the surface of the paint film, thus rendering it
47
brown and blotchy.
FREQUENTLY ASKED QUESTIONS
Mix Designs- Sand/Aggregate
Q. 9.
A. 9
Can you explain sieve size, % retained, % passing, etc.?
a. Sieve sizes- Sand/aggregates must fall within a range
of particle sizes, neither too coarse nor too fine.
The sand is sifted through a set of screens with varying
mesh sizes (openings in the screen).
b. Percent retained means how much of 100 grams of sand was
retained on the screen and,
c . Percent passing is how much passed through the screen.
Use your manufacturers recommended grades.
Q.10.
A.10.
Why should we use sand?
a. Traction/ skid resistance,
Note- Be aware of the liability issues before making claims
sealcoating will improve the skid resistance or make a surface slip
resistant.
b. Toughness of the cured coating film,
c. A uniform textured, non-glare surface.
D. It fills minor hairline cracks. Do not claim that it will fill larger cracks.
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FREQUENTLY ASKED QUESTIONS
Mix Designs-Additives
Q.11.
Why use latex additives?
A.11. The use of latex additives is very common. There are many latex
additives to impart all types of performance advantages. For example;
a. Rubberizing additives improve flexibility, durability, toughness, etc.
b. Faster drying additives help sealers dry fast.
c. Water repellent additives improve water resistance of the cured
sealer
d. Thickening additives build the viscosity of sealcoatings diluted
with large amounts of water. Suspend large amount of sand.
Follow the manufacturer’s recommendations.
49
FREQUENTLY ASKED QUESTIONS
Mix Designs-Additives
Q.12. What happens when you use different additives (different suppliers) in the
same tank? Why did the viscosity go haywire?
A. 12.
The viscosity went haywire because the additives were not compatible with
each other. Do not mix different additives and stick to manufacturer
recommendations. Also the manufacturers’ warranty may be void if you use other
additives. Additionally, use the additive recommended by your sealcoat manufacturer.
Additive made by someone else may not be compatible with the sealer made by
another manufacturer.
Q.13.
Why apply two coats, when one coat looks good enough?
A. 13.
Appearance is only part of the benefits. The sole purpose of sealcoating is to
protect and preserve the asphalt. One coat may not last even half as two coats. It will
provide only half (or less) of the protection and will wear out, prematurely. You will
have to sealcoat more frequently if you used only one coat.
50
FREQUENTLY ASKED QUESTIONS
Mix Designs
Q.14.
How much water can I use?
A.14.
Follow the manufacturers’ recommendations. Normally
25-30 gallons per 100 gallons of concentrated sealer are
recommended. Higher percentages are recommended for mix
designs
that use additives and larger amounts of sand.
Q.15.
What is the deal with specifications using excessive amounts of sand, e.g.
18 lb. of sand in one of the FAA Specifications?
A.15.
Those are special sand slurry specifications and not used commonly for
sealcoating specifications. The industry recommends a maximum of 8 lb. of sand per
gallon. Very high sand loading (18 lb. for example) will result in a coating that will be
poor in flexibility, adhesion and chemical resistance.
Q. 16.
A. 16.
Where can I get straight, objective answers?
From your supplier.
Editor of the “Pavement” magazine.
51
RIGHT??
Thanks for your time & attention and
participation.
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