1. Achieving Better Quality Roads
through Better Specifications
APWA Florida Chapter Annual
Tradeshow
Presented by
Matthew J. LaChance
Vanasse Hangen Brustlin, Inc.

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Achieving Better Quality Roads through Better Specifications
Do I really need my own paving specifications?
 Specifications are a tool to help insure you get the
product that is right for your job.
 But you also have to test for conformance to make
sure you’re getting what you asked for!

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Achieving Better Quality Roads through Better Specifications
Issues with Use of Typical Specifications
 Insufficient material properties specified
 Don’t handle multiple roads in one day well
 Difficult to enforce
 May be outdated
 “Method Based” Specifications
 Little or no testing to determine conformance

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Achieving Better Quality Roads through Better Specifications
Issues with Use of Typical Specifications
 Insufficient material properties specified
• FDOT Standard Specification 331 – Marshall Mix Design
o Limited aggregate testing
o Allows excessive use of RAP
o Cannot adapt to today’s traffic levels
o Viscosity graded asphalt cements
o Potential for unstable mixes

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Achieving Better Quality Roads through Better Specifications
Unstable mix examples

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Achieving Better Quality Roads through Better Specifications
Issues with Use of Typical Specifications
 Don’t handle multiple roads in one lot well
• State specs based on long runs on state highways
• One “sample lot” = up to 4000 tons of production
• When applied across several roads, a single road may fail,
even though lot average passes

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Achieving Better Quality Roads through Better Specifications
Issues with Use of Typical Specifications
 Difficult to enforce
• When material is just slightly off spec – what do you do?
Accept? Reject and remove?
 May be outdated
• Existing municipal specifications may refer to older State
specs that refer to liquid asphalt grades that aren’t
produced today

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Achieving Better Quality Roads through Better Specifications
Issues with Use of Typical Specifications
 “Method Based” Specifications
• Specify how work must be done – what tools to use, etc.
• When desired end results are not met – who is
responsible?

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Achieving Better Quality Roads through Better Specifications
Issues with Use of Typical Specifications
 Difficult to Read or Interpret
• Many municipalities “piggy back” or reference state or
county specifications
• Often amendments to state or county specifications are
made in separate documents
• Requires Inspectors to have multiple specifications in order
to reference
• More difficult to interpret and enforce than the Federal Tax
Code

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Achieving Better Quality Roads through Better Specifications
Issues with Use of Typical Specifications
 Little or no testing to determine conformance
• “No need to test – they do QC testing at the plant”
• Many municipalities don’t do density testing for
conformance
• The mat looked good…

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Achieving Better Quality Roads through Better Specifications
Which pavement met the density spec?
This one?

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Achieving Better Quality Roads through Better Specifications
or this one?

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Achieving Better Quality Roads through Better Specifications
So what can I do differently?
 Standalone, All-inclusive Document
 Quality Based Specifications
 Joint Density
 Superpave
 Test for Conformance

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Achieving Better Quality Roads through Better Specifications
Standalone, All-inclusive Document
 Based on State specifications
 Includes standard specifications and alterations for
the “special needs” of the municipality
 Easier for contractors to provide a quality product
when all information in one place
 Easier to enforce with all requirements in one
place

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Achieving Better Quality Roads through Better Specifications
Quality Based Specifications
 Contractor assumes primary responsibility for
quality of material and construction
 Owner responsible for sampling to verify accuracy
of contractor’s tests
 Sampling based on estimated volume of material
to be placed
 Control strips to establish achievable process
control (dress rehearsal)

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Achieving Better Quality Roads through Better Specifications
Quality Based Specifications
 Normally Includes pay factors
• Provides penalties to handle material or work that is slightly
out of spec (to offset lower than average quality)
• Provides understood procedure for when material is “out of
control”
• Provides incentive for tighter control of material and work
(to reward better than average quality)
• Reduces disputes after job is done

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Achieving Better Quality Roads through Better Specifications
Joint Density
 Recognized fact that density at joint is more
difficult to achieve
 Rather than simply ignore density at joint, require
slightly lower density – verify with control strip

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Achieving Better Quality Roads through Better Specifications
Joint Density
 Joint construction methods
• Conventional (confined edge)
• Cutting Wheel (FAA)
• Notch wedge joint
• Hot poured rubber “tack”
• No “casting” of material

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Achieving Better Quality Roads through Better Specifications
Confined Edge Joint
Confines the outside edge of the mat as much as possible to create a
“nearly vertical” edge with end gates or other attachments

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Achieving Better Quality Roads through Better Specifications
Cutting Wheel
 Cutting a 1 to 2 in. (25-50
mm) of the unconfined edge
after compaction of the initial
pull
 10 in. (250 mm) cutting
wheel
 Vertical face tacked
 Rolled from hot side with 6
in. (150 mm) overlap on cold
side

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Achieving Better Quality Roads through Better Specifications
Notched Wedge Joint
Variation of wedge joint
NOTCH ±
12.5mm(1/2 in)

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Achieving Better Quality Roads through Better Specifications
 Hot rubberized joint
compound may improve
the bond between lanes,
but figure on an extra
dollar a foot cost

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Achieving Better Quality Roads through Better Specifications
No “Casting”

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Achieving Better Quality Roads through Better Specifications
Superpave
There is nothing super about it…
 No new aggregate or liquid asphalt
 Not just for highways & heavy vehicles
 It is a new way of specifying the materials and
quality of construction that is required
 Better ability to match materials and construction
to expected use of the pavement

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Achieving Better Quality Roads through Better Specifications
What is Superpave?
Superpave is an acronym for
Superior Performing Asphalt Pavements

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Achieving Better Quality Roads through Better Specifications
What is Superpave?
Improved System for Specifying:
• Asphalt Binders
• Mineral Aggregates
• Mixture Designs
• Performance Prediction

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Achieving Better Quality Roads through Better Specifications
What makes Superpave so great?
 Aggregate Property Tests
• Coarse aggregate angularity
• Fine aggregate angularity
• Flat or elongated particles
• Clay content
• Toughness
• Soundness
• Deleterious materials

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Achieving Better Quality Roads through Better Specifications
What makes Superpave
so great?
 Improved Mix Design
•Gyratory Compaction
is more realistic and
provides flexibility Photo goes here
•Moisture susceptibility
tests have been added
Gyratory Compactor

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Achieving Better Quality Roads through Better Specifications
Performance Graded Asphalt Binder (PGAB)
Represents hot temperature design criteria in ˚C
Represents cold temperature design criteria in ˚C

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Achieving Better Quality Roads through Better Specifications
Performance Grades
 Average 7-day Maximum Pavement Temperatures, C
46 52 58 64 70 76 82 ?
 Average 1-day Minimum Pavement Temperature, C
+2 -4 -10 -16 -22 -28 -34 ?

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Achieving Better Quality Roads through Better Specifications
Typical Cross Section
Bituminous Surface Course
Bituminous Binder Course
Base Course

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Achieving Better Quality Roads through Better Specifications
New Cross Section
HMA Superpave 9.5mm Level ?
HMA Superpave 12.5mm Level ?
Base Course

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Achieving Better Quality Roads through Better Specifications
Comparison of Mix Names
MassDOT Superpave Course
Type S III 9.5mm Surface
Type S I 12.5mm Intermediate or
Surface
ABC 25mm or Base
37.5mm

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Achieving Better Quality Roads through Better Specifications
Where do Superpave Levels come from?
ESAL = Equivalent Single Axle Load
Level Design ESALs
(million)
A < 0.3
B 0.3 - < 3.0
C 3.0 - < 30.0
D > 30.0

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Achieving Better Quality Roads through Better Specifications
Will Superpave cost more?
Most of the time, no. In fact, because they are
already approved for state use and the
inconvenience of producing several types of
mixes, many producers are charging less for
Superpave mixes.

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Achieving Better Quality Roads through Better Specifications
Do I have to use Superpave mixes?
 No, Type S mixes are still available
 Using state mixes makes design and approval
process easier and faster
 Superpave gives designers more flexibility with
lift thickness and loading characteristics

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Achieving Better Quality Roads through Better Specifications
Summary
 Ability to pay per mix type per street
 Control Strip (Dress Rehearsal)
 Joint Density Requirement
 Incentive/Disincentive
 Test material at the plant
 Density testing in field

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Achieving Better Quality Roads through Better Specifications
Test for Conformance

39. Questions & Answers
Achieving Better Quality Roads
through Better Specifications
APWA Florida Chapter Annual
Tradeshow
mlachance@vhb.com Presented by
Matthew J. LaChance
Vanasse Hangen Brustlin, Inc.