Trackless Tack/ Spray Pavers - Texas A&M University · 2017-01-04 · Specifying Trackless Tack...

2013 Transportation Short Course

Jerry Peterson - CST

TRACKLESS TACK/ SPRAY PAVERS


Table of Contents

7-12

13-15

16-18

19-23

24-26

1-6 Trackless Tack - Overview

Research – Pulloff Test

Research – Tracking test

Trackless Tack Tips

Spray Paver - Overview

Best Practices

1

2

3

4

5

6

2


What is Trackless Tack

Tack coat applied ahead of laydown operation How does it work?

– Cures or hardens to a non-sticky surface – Reduces pickup on equipment – Mix melts the hardened tack to create a bond

Superior Bonding?

3


Specifying Trackless Tack

Lots of different products out there – Emulsion/hot applied – Time to become track free – Amount of residue – Dilution – Rates

Writing a spec is difficult – Can’t encompass all properties and still be meaningful – Would like to have performance spec – May use MPL strategy in short term

4


Property Trackless Tack Ultrafuse MOS-50 FastSet NanoTac E-Tac

Saybolt Viscosity 15 min n/a 21-250 15-100

Storage stability, 1-day settlement

1% n/a 1%

Settlement, 5-day 2%-5% n/a Sieve test 0.3% n/a 0.1% Track free time 30 2 30 30 15 30 Residue 50 100 50-60 65 61.5 58 Dilute? No No ?? 40% 50% No Test on residue: Residue Pen 20 max 25 max 12 max 40-90

Min Solubility 97.5 97.5 Min Soft point 150 170

Min DSR, 82°C 1.0 1.0

Min 275°F Viscosity

3000

APPLICATION RATE 0.08 0.12 0.20 0.1 0.11 0.065

Varieties

5


Performance Based Spec?

What behaviors are important to trackless tack materials? – Track-free – Good bond

Try to devise tests to identify these behaviors – Pull-off test – Paint pickup test

6


Direct Tensile Bond Test: ASTM C-1583

7


2 inch diameter cores to just below interface

8


Ready to Pull Off

9


Clean break at lower interface

After Pulloff

10


High 0.1

Low 0.04

Res 63.3%

High 0.1

Low 0.04

Res 64.3%

High 0.1

Low 0.06

Res 62.0%

High 0.12

Low 0.08

Res 65% 40%

diluted

High 0.12

Low 0.10

Res 61.5% 50%

diluted

High 0.08

Low 0.05

Res 58.0%

High 0.20

Low 0.12

Res 64.3%

High 0.18

Low 0.08

Res 100.0%

None

Mono

1 2 3 4 5 6 7 8 C

Pulloff Experiment – Summer 2013

11


600.0

700.0

800.0

900.0

1000.0

1100.0

1200.0

A B C D E F G H No Tack Monolithic

Peak

Loa

d (lb

f)

Pulloff Experiment – Summer 2013

Average pulloff loads at 4°C

12


Tracking Test - ASTM D711

13


Summer Tracking Test Results

14

0

50

100

150

200

250

SS-1H CSS-1H CRS-2P A B C D E

Trac

k Fr

ee T

ime

(min

)

ASTM D 711 No Pickup Time


Research Bottom Line

Needs more work – Results were not very conclusive – Tracking test may not be severe enough

Performance based spec won’t be ready right away Need to use vetted products!

– MPL – Required successful demos

15


Trackless Tack Coat: Tips for Use

Know which product you have Communicate with the vendor

– Handling/dilution – Application rates are critical!

Shoot a test strip – Even application – Check for tracking

16


Austin District Practice

Do not apply trackless tack like a seal coat asphalt – More like a fog seal operation

Do not shot asphalt perpendicular to roadway – Will streak – Non-uniform – Too heavy in area – will pick up – Too light in areas – will not bond

17

2013 Transportation Short Course 18

Austin District Standard

Use fogger nozzles Every 3 feet Shot parallel to the

roadway surface – Use a 90 degree elbow to fix

nozzle parallel Creates a misting of the

surface Should look like the

surface is spray painted black


Spray Paver

19


What is a Spray Paver?

20


The Paver

21


The Paver

22


How Does it Work?

Mix Spray-bar

23


Things to Watch For

Look for an even distribution of emulsion and a consistent texture and color behind the spray bar Make sure emulsion breaks properly Be careful of fat spots

– Paver sitting without tray recirculating – Problem with nozzle – High spot in the pavement surface

24


Watching the Spray Pattern

25


Best Practices

Avoid start and stop paving – Can give inconsistent membrane application – Paver can refill on the fly

Keep a clean lane out ahead – Don’t want mix on the pavement before membrane – Mix falling off of trucks

26


Thanks!

Spray paver info/materials – Robert Lee Austin District tack info – Mike Arellano

27

Trackless Tack/ Spray Pavers - Texas A&M University · 2017-01-04 · Specifying Trackless Tack...

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Transcript of Trackless Tack/ Spray Pavers - Texas A&M University · 2017-01-04 · Specifying Trackless Tack...