Ultra-Thin Overlay Mix (UT mix) - Texas A&M University · Pilot Program – Test Section Cost Analysis – SHOW ME THE MONEY!!! Estimate for UT Mix Test Section Total Tonnage = 120.00

THIN IS IN!!!

Ultra-Thin Overlay Mix (UT mix)

Background Thin Overlay (TOM) – 1” HMA Started 2009 Saved over $8 million to date Original test section has no distress Default overlay for the Austin District

What is UT Mix? ½” HMA Overlay Aggregate: SAC A Grade 2 Microsurface (Sandstone) Asphalt Binder: 7.0-7.3% PG 76-22

Potential Applications – Preventative Maintenance

Frictional Wearing Course Overlays Reset surface

serviceability properties For old, highly oxidized

pavements with low skid resistance and/or superficial cracking

For structurally adequate pavements only

Potential Applications – Preventative Maintenance

Alternate to 1 or 2 Course Surface Treatment For pavement needing a

highly flexible surface, but could also benefit from good ride quality associated with HMA

For pavement with a number of seal coats, shallow rutting, patching, and other distresses, such as flushing or raveling

Pilot Program Lab Design Target Density = 97.5% (TGC) Target Asphalt Content = 7.3%

Field Test Section Location: Ramming Paving – Buda Plant Haul Road Original Thin Overlay Mix (TOM) Test Section

constructed in 2009

Pilot Program – Test Section Two bonding courses Calumet “Trackless Tack” @ 0.1 gal/SY Ergon E-Tac @ 0.1 gal/SY Control Section with no tack

Two rolling patterns 2 high frequency vibratory passes & 2 static passes 4 static passes

700’

39’

24’

500’

TOTAL = 4370 SY UTOM HMA = [55 lbs/SY * 4370 SY]/2000 = ~120 TONS

ERGON E-TAC

CALUMET – TRACKLESS TACK

Control

Ramming Buda Plant - Test Section Lay Out

HMA PLANT

Vibe/Static

Static Only

Pilot Program – Test Section October 10, 2012: Construction Day Overcast to Partly Cloudy Ambient Temperature = 85 F Pavement Temperatures = 90-105 F Wind = 5-10 mph Humidity = 86%

Pilot Program – Test Section Preparation

Pilot Program – Test Section Bonding Course – Trackless Tack Coat TTI will be performing bond strength testing

Pilot Program – Test Section Placement – Lay Down Operation

Pilot Program – Test Section Placement – Lay Down Operation

Pilot Program – Test Section Placement – Cool Down Rate = ~8○F per minute

Thermal Images

Pilot Program – Test Section Compaction Experiment: Vibratory vs. Static Mix did not consolidate nor move with either

compaction.

Pilot Program – Test Section Compaction Experiment: Vibratory vs. Static Better Texture with Static Only

STATIC VIBRATORY

Pilot Program – Test Section Compaction

Experiment: Vibratory vs. Static

Vibratory compaction migrated tack to the surface – fat spots

Both compaction methods produced good permeability properties Drain Down Time

(Vibratory) = 16 minutes Drain Down Time

(Static) = 9 minutes

Pilot Program – Test Section

0.5” Tiny TOM

1” TOM

Pilot Program – Test Section Cost Analysis – SHOW ME THE MONEY!!!

Estimate for UT Mix Test Section

Total Tonnage = 120.00 TonsTotal Per Ton

Gr 2 Delta Material Material 13.00$ per ton 1,560.00$ Haul 14.25$ per ton 1,710.00$ 3,270.00$ 27.25$

Valero 76-22 Material 725.00$ per ton 6,351.00$ 7.3 % JMF Haul 35.00$ per ton 306.60$ 6,657.60$ 55.48$

Labor - Equip - Haul to Place 4,600.00$ 38.33$

Asphalt Plant Operating 1,080.00$ 9.00$

Track-Less Tack 2.70$ per gallon 215.00 est. gal 580.50$ 4.84$

Total Cost = 16,188.10$ 134.90$ per ton3.54$ per SY

UT Mix - Future Issue with obtaining target AC with fine mixes Target AC = 7.2%; Actual AC = 7.8-8.0%

Develop Special Specification Vary AC to match required performance Strict temperature requirements for placement Static Compaction Water Flow Rate ≥ 2 minutes

Proposed Project – Hamilton Pool Road Old, oxidized HMA with marginal skid resistance

Thank you! Questions?