LOUISIANA DOTD
STRIPING STANDARDS
TYPES OF PAVEMENT MARKINGS
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Paint
90 Mil Thermoplastic
40 Mil Thermoplastic
Preformed Thermoplastic
Tape
Plural Components (currently being tested).
All Of The Above Contain Glass Beads For
Retroreflectivity.
PAINT
Water-based paint is used for our district maintenance
operations.
• La DOTD currently uses the third generation high-build
paint with type 3 beads.
• This durable paint helps us get better life; in some cases
you can stripe roads ever other year.
• Using the type 3 beads give us better wet recovery; the
type 1 beads will not give any wet recovery.
• This paint is applied at a thickness of 22 to 25 mils.
• On a good application, you should get approx. readings of
250 mcd for white and 175 mcd for yellow.
90 MIL THERMOPLASTIC
• Thermoplastic is heated between 400° to 425° and
extruded onto the pavement surface. (No spray application
is allowed.)
• Thermoplastics have a long service life, good visibility, and
good retroreflectivity.
• We use type 4 glass beads for the first drop and type 1 glass
beads for the second drop. The type 4 glass beads give wet
recovery.
• Our spec’s call for initial readings of 375 for white and 250
for yellow; we have gotten readings of up to 700 for white
and 400 in yellow.
• Thermoplastic has short track time. (30 seconds)
• Its cost is mid-range.
40 mil thermoplastic
• Thermoplastic is heated to 400° and sprayed
onto the pavement surface.
• Our only use of 40 mil is in some chip seal
applications.
• Will talk about striping on chip seal roads later
in the presentation.
Preformed thermoplastic
• Easy to apply – requires only one person and a gas flame
torch.
• Precise and consistent line and symbol definition due to
off-site factory manufacture.
• Available in precut lines, rolls, numbers, letters, symbols
and multi-colored designs.
• Surface can be returned to use within minutes.
• Permanent – as good as conventional liquid-applied
thermoplastic.
• Long lasting.
• Preformed thermo includes glass beads for high visibility.
Tape
• Pre-formed tape has excellent visibility and
retroreflectivity. This is due to off-site factory
manufacture under highly-controlled
conditions.
• Retroreflectivity readings can exceed 1000
mcd.
• Lasts 7-8 years.
• But is higher in cost.
Plural Components
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Outstanding adhesion to asphalt and concrete.
Available in retroreflective white and yellow
Applied as a two to one mixture by volume
Ambient and surface temperature 40° f and rising for
application
• 100% solids formulation resulting in virtually no Voc’s
• Long dry time (45 minutes at 75° f).
• Currently testing a 3M product that dries in about 2
minutes with no track; applied at a range of 20 to 25
mils and at 30° f.
Glass Beads
LA DOTD Requirements
• Paint: Type 3 glass beads.
• Thermo: A double drop system, first drop is
type 4 glass beads and the second drop is
either type 1 or at the contractor’s discretion.
• Tape: Uses a type 1 glass bead, but it is usually
a high-index bead and could have some
cluster beads also.
Types of Reflection
Performance / Visibility
and
Daytime:
We depend on diffuse reflection
color contrast to see pavement
marking during the day.
Nighttime:
We depend on retroreflection to
see pavement markings at night.
30-meter geometry
30-meter viewing distance
Glass Bead Embedment
High Embedment, Poor
Low Embedment, Poor
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60% Embedment, Good
Effects of Water
Bead embedment
Perfect bead embedment in thermo
Under bead embedment in thermo
Beads lost due to under embedment
in thermo
Over bead embedment
Over bead embedment in paint
Not enough beads
Chip seal applications
• Chip seal striping is difficult, and methods are
still being evaluated.
• The main problem is the rough surface caused
by the large rock that is used.
• The striping material doesn’t have enough
surface to hold on to.
Paint Application on Chip Seal
90 Mil Thermo on Chip Seal
Traveling in direction striped
90 Mil Thermo on Chip Seal
Traveling opposite direction striped
40 Mil Spray on Chip Seal
Test Project Using 1.9 and 1.6 Beads on
Chip Seal in District 05
• Material was installed on 8-15-2012.
• Monitored every 3 months for the first year and then
every 6 months thereafter.
• Monitoring will show how the 1.9 and 1.6 beads hold
up.
• The 1.9 bead has a higher index but is said to be a
softer bead.
• The 1.6 bead has a lower index than the 1.9 but
higher than the 1.5 and is said to be harder.
• Both beads are the same size as the AASHTO type 1.
Thermo vs. Paint
40 Mile Thermo
Paint Application
Photo of 1.6 bead in paint after 6
months
Test Results
40 Mil Thermo Retro Readings
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1.9 Bead
Initial white
6 Months white
Initial Yellow
6 Months Yellow
687
370
328
207
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1.6 Bead
Initial white
6 Months white
Initial Yellow
6 Months Yellow
N/A
N/A
N/A
N/A
Test Results Paint
Retro Readings
1.9 Bead Paint
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Initial white
6 Months white
Initial Yellow
6 Months Yellow
1462
771
781
372
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1.6 Bead Paint
Initial white
6 Months white
Initial Yellow
6 Months Yellow
635
503
446
420
• The most commonly used bead is the ASSHTO
Type I bead. This Bead has a refractive index
of 1.5. The average readings at 6 months for
yellow have been around 96 mcd.
• LA DOTD districts use the ASSHTO type 3
beads. The average readings at 6 months for
yellow have been around 129 mcd.
Questions?