2014 APC/ Dist. 9-0 BITUMINOUS PAVING

2014 APC/ Dist. 9-0
BITUMINOUS
PAVING
To Be CoveredBLUE KNOB MC PILOT SPECIAL
PROVISIONS
• TACK COAT
• LONGITUDINAL JOINT
• PERCENT WITHING TOLERANCE
(PWT) SPEC
• LOCAL ACCEPTANCE- RETESTS
• SAFETY EDGE
PennDOT 9-0 Construction
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Importance of Tack
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So why use tack coat?
Without tack coat the asphalt layers in a roadway may
separate which reduces the structural integrity of the road
and may also allow water to penetrate the structure.
Proper tack application rates and material creates a
composite pavement section, transferring stresses
throughout the entire paving section.
A good bond is important for all mixes, &
has a large affect on mix performance.
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4
So what’s changing?
Pilot project using CSS-1h (E-8) emulsion
 Looking at improving bond strength using harder based
asphalt.
 Considerably less break time (about ½ the water Vs. AET)
 Less pick-up by paving train equipment due to harder base
asphalt
 More uniform coverage, with application rates specified
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District Special Provision for
all Paving Projects
Tack Coat Special Provision
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So what’s the cost?
• CSS-1h (E-8) has about twice the asphalt Vs. AET
• Costs about 69% more per Gal. of emulsion
• Example: 1 mile road @ 32’ wide (18,775 SY)
• Using AET @ 0.03 Gal/Sy Residual
• Would use 1706 Gal of AET @ $1.38/Gal= $2,355
• Using E-8 @ 0.03 Gal/Sy Residual
• Would use 908 Gal of E-8 @ $1.99/Gal= $1,807
• Savings:
• Approx. $550 per 2-lane mile
• Uses approx. 800 gal. less emulsion
PennDOT 9-0 Construction
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Tack SummarySpec. Changes Material will be CSS-1h (E-8).
 Specified residual application rates for surface type
 100 LF min. test section to verify application rate, bar height,
nozzle function & proper overlap and orientation.
Surface Type
Uniform Asphalt Residue
Application Rate
(gallons per square yard)
New HMA pavement course
0.02 to 0.03
Existing HMA pavement course
0.03 to 0.05
Milled Surface (HMA & PCC)
0.05 to 0.07
Portland Cement Concrete (PCC)
0.04 to 0.06
PennDOT 9-0 Construction
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Tack SummaryBenefits- Seen from switching to CSS-1h (E-8)
 Increased bond & shear strength - Composite section
 Much quicker break time, less waiting
 Less “puddling” and run-off
 Less tracking by equipment
 Uses less “Liquid” material (about 53%), less hauling
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Longitudinal Joint Pilot
Special provision to assist in achieving
better joint density (non-incentive)
 Requires nuke readings at min. 500’
 Correlation cores if mat is not using
cores for density acceptance
 Information cores required 6” from joint
if mat is accepted using density cores
 Cores run at producer’s lab
 Stop paving operations if lot avg. < 91%
 Provide corrective action prior to
proceeding with paving operations
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Longitudinal Joint Pilot
Currently in Clearance Transmittal review
to become a State Std. Special Prov.
 Longitudinal Joint Spec.
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Percent Within Tolerance
(PWT)
Pilot project using a pure PWT spec
 Payment factors for four criteria
 AC Content
 #200 Sieve
 Primary Control Screen (PCS)
 Density
 Each pay factor evaluated statistically for spec limits
 Up to 4% bonus available to contractor
 Less “Harsh” penalty structure – Eases R&R’s
 Samples tested at LTS
 Directive from FHWA to move in this direction
PennDOT 9-0 Construction
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Percent Within Tolerance
(PWT)
So, how it went…
 Lot #1, 25 mm Base (Info only)
 Incentive = 2% Bonus
 Lot #2, 9 mm Wearing
 Incentive = 1% Bonus
 Lot #3, 9 mm Wearing
 Incentive = 4% Bonus
High Precision
but low Accuracy
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High Accuracy
but low precision
Percent Within Tolerance
(PWT)
Contractor’s View…
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Local Acceptance
What’s Changing…
 Retest requests will be permitted and reviewed as follows:
“Retests may be requested for material failures (Asphalt &
No. 200), resulting in remove and replace only. Retests for
density are not permitted. If the retest request is approved,
testing will be performed by the Department utilizing the
Local Acceptance Testing location identified in the approved
QC Plan.”
 Applies to Superpave and SMA utilizing Local Acceptance
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FHWA Everyday Counts
Safety Edge Issues:
 Adjusting paver- Driveways, Structures, etc…
 Stopping paver to switch between Wedge and Safety
Edge
 Rural areas – Lack of available shoulder, guiderail, etc…
 Prep work/ lack of
 Others?
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