Pavement Preservation Journal - Fall 2017 - 41

IMAGE CREDIT: TEXAS TRANSPORTATION INSTITUTE

One inch of stone matrix asphalt (SMA) Thinlay
is placed in Bryan, Tex.; paver used Pave-IR
system to detect uniformity of mat temperature,
control of which critical for thin asphalt lifts

THINLAYS FOR PRESERVATION
A different type of thin overlay that utilizes asphalt emulsions is the Thinlay.
Thinlays-as branded by the National
Asphalt Pavement Association-constitute a
suite of thin asphalt overlay mixes designed
to be placed at thickness as thin as 5/8 of
an inch, to 1.50 in.
This plant-mixed combination of asphalt
cement and aggregate is placed via conventional paver over aging asphalt or concrete
pavements as a pavement preservation
treatment. The liquid asphalt binds the
aggregates together in a strong but flexible
pavement structure.
"When used appropriately, thin asphalt
overlays are safe, reduce costs, and are
sustainable through the incorporation of recycled materials," NAPA says.
"Construction is fast, with less impact on
drivers, and there are additional environmental benefits, such as noise reduction.
In addition, thin asphalt overlays provide
a smooth driving surface, improving ride
quality and reducing fuel consumption
compared to rough pavements."
Because there are hot mix plants and
experienced HMA contractors almost
everywhere, thin HMA overlays have
become one of the most common pavement preservation treatments. Polymer
modified asphalt may be used for improved
performance, and reclaimed asphalt pavement (RAP) may be incorporated into the
hot mix to lower cost and as a more environmentally friendly option.
For the Thinlay to succeed, quality bond
coats are essential. "The tack coat is crucial
to bonding the new overlay to the old pavement, especially on unmilled surfaces,"

according to information published by
NAPA and available online. "Because the
overlay is thin, the interface between the
old and new pavement is in close proximity to the shear forces created by vehicles
during braking and turning movements."
Most specifications require a heavierthan-normal application of [bond] coat,
and in the instance of California, the tack
applicator is specified as being a part of
the paver, said David Newcomb, then vice
president-research and technology, NAPA,
and now with TTI.

Some locations such as California require
the use of polymer modified emulsions,
while others such as Minnesota use nonmodified emulsions. The application rate
range varies according to individual states
from as low as 0.04 to 0.08 gal. per sq. yd.
for North Carolina, to as high as an average of 0.20 gal. per sq. yd. for California.
Most states have a range closer to 0.10 to
0.15 gal. per sq. yd. he writes.
Article provided by the Asphalt Emulsion
Manufacturers Association

Preservation for the

H A U L
LOWER
LIFE-CYCLE
COSTS

LONGER
LASTING

SMOOTHER
RIDE

ENHANCED
STRUCTURAL
CAPACITY

Starting at ⅝ of an inch, Thinlays are the pavement preservation
treatment designed to extend service life while improving performance,
friction, and drivability. These thin asphalt overlays provide longlasting smoothness and can be used to increase structural capacity,
providing greater value for your pavement preservation dollar.

875770_National.indd 1

www.ThinlayAsphalt.com

Fall 2017 | PAVEMENT PRESERVATION JOURNAL

41

08/07/17 4:51 AM


http://www.asphaltpavement.org/thinlay http://www.asphaltpavement.org/thinlay

Table of Contents for the Digital Edition of Pavement Preservation Journal - Fall 2017

President's Message
FP2 Marks Silver Anniversary
ARRA, FP2 Preservation Proponents Assault Capitol Hill
Neglected Rural Roads Drag on Economy
Early NCAT Results Favor Preservation
Perservation Partnerships: Southeast PPP Ponders Early Treatment Failures; Midwest PPP Meets in Michigan
Texas Contractor Upgrades Performance
Asphalt Emulsion Bond Coats Optimize UTBO, Thinlay Performance
Student Studies Sustainable Chip Seals
Pavement Preservation Journal - Fall 2017 - Intro
Pavement Preservation Journal - Fall 2017 - cover1
Pavement Preservation Journal - Fall 2017 - cover2
Pavement Preservation Journal - Fall 2017 - 3
Pavement Preservation Journal - Fall 2017 - 4
Pavement Preservation Journal - Fall 2017 - 5
Pavement Preservation Journal - Fall 2017 - 6
Pavement Preservation Journal - Fall 2017 - 7
Pavement Preservation Journal - Fall 2017 - 8
Pavement Preservation Journal - Fall 2017 - President's Message
Pavement Preservation Journal - Fall 2017 - FP2 Marks Silver Anniversary
Pavement Preservation Journal - Fall 2017 - 11
Pavement Preservation Journal - Fall 2017 - 12
Pavement Preservation Journal - Fall 2017 - 13
Pavement Preservation Journal - Fall 2017 - 14
Pavement Preservation Journal - Fall 2017 - 15
Pavement Preservation Journal - Fall 2017 - 16
Pavement Preservation Journal - Fall 2017 - ARRA, FP2 Preservation Proponents Assault Capitol Hill
Pavement Preservation Journal - Fall 2017 - 18
Pavement Preservation Journal - Fall 2017 - 19
Pavement Preservation Journal - Fall 2017 - 20
Pavement Preservation Journal - Fall 2017 - 21
Pavement Preservation Journal - Fall 2017 - 22
Pavement Preservation Journal - Fall 2017 - Neglected Rural Roads Drag on Economy
Pavement Preservation Journal - Fall 2017 - 24
Pavement Preservation Journal - Fall 2017 - 25
Pavement Preservation Journal - Fall 2017 - 26
Pavement Preservation Journal - Fall 2017 - Early NCAT Results Favor Preservation
Pavement Preservation Journal - Fall 2017 - 28
Pavement Preservation Journal - Fall 2017 - Perservation Partnerships: Southeast PPP Ponders Early Treatment Failures; Midwest PPP Meets in Michigan
Pavement Preservation Journal - Fall 2017 - 30
Pavement Preservation Journal - Fall 2017 - 31
Pavement Preservation Journal - Fall 2017 - 32
Pavement Preservation Journal - Fall 2017 - Texas Contractor Upgrades Performance
Pavement Preservation Journal - Fall 2017 - Asphalt Emulsion Bond Coats Optimize UTBO, Thinlay Performance
Pavement Preservation Journal - Fall 2017 - 35
Pavement Preservation Journal - Fall 2017 - 36
Pavement Preservation Journal - Fall 2017 - 37
Pavement Preservation Journal - Fall 2017 - 38
Pavement Preservation Journal - Fall 2017 - 39
Pavement Preservation Journal - Fall 2017 - 40
Pavement Preservation Journal - Fall 2017 - 41
Pavement Preservation Journal - Fall 2017 - 42
Pavement Preservation Journal - Fall 2017 - Student Studies Sustainable Chip Seals
Pavement Preservation Journal - Fall 2017 - 44
Pavement Preservation Journal - Fall 2017 - 45
Pavement Preservation Journal - Fall 2017 - 46
Pavement Preservation Journal - Fall 2017 - cover3
Pavement Preservation Journal - Fall 2017 - cover4
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