Asphalt Mix Basics - Florida Department of Transportation

Report

6503 Bridges
 95% in excellent to good condition.
FDOT: 12,088 centerline miles, 42,633 lane
miles.
 Statewide: 121,446 centerline miles, 267,793
lane miles.
 FDOT: 10% centerline miles, 16% lane miles.
 FDOT carries 54% of all traffic in state.

1
Deficient Pavements (%)
Criteria
2005
2006
2007
2008
2009
2010
2011
Ride
5.6
3.8
3.5
3.2
2.6
2.6
2.6
Crack
17.0
15.8
14.6
14.9
13.0
10.9
9.7
Rut
1.2
0.9
0.9
1.0
0.6
0.6
0.6
Section 334.046 of Florida Statutes: “Ensuring that 80% of
the pavement on the SHS meets Department Standards”
24%
22%
20%
Crack
Ride
Rut
% of SHS Deficient
18%
16%
14%
12%
10%
8%
6%
4%
2%
0%
4
5
334 Superpave Asphalt Concrete

Variable Thickness Overbuild
 SP 9.5 minimum thickness = 3/8 inch
 SP 12.5 minimum thickness = 3/4 inch

Roadway Sampling and Testing
 Allows engineer to move core location for safety reasons

Individual Test Tolerance for QC Testing
 ONE average sublot density MPR failure terminates the
LOT – course or fine.

Defective Material
 Removal of mandatory requirement to remove material
if delineation occurs.
6

300 Prime and Tack Coats
 Minimum tack rate for newly constructed asphalt
layers = 0.03 gal/sy

330 Construction Requirements
 Straightedge Exceptions – clarification of intersection
 Friction Course - Address all deficiencies in either
wheel path that exceed 3/16 inch.

338 Value Added pavements
 Bleeding area description clarified to an “area  10 sf.”
7


Replacement of RA binders with PG binders.
300 Prime and Tack Coats
 NTSS-1hm now allowed for use as prime coat.
 Tack all asphalt layers prior to constructing next
course.

330 General Construction
 Clarification to Table 330-1 – Ambient Air
Temperature Requirements
 Deleted requirement for RSE QC testing on friction course
on jobs w/ laser acceptance
 Clarified straightedge deficiency corrections
8



Changed minimum overbuild thickness for
SP-12.5 to ½”
Deleted RA Grades and references to
viscosity
Replaced Pavement Composition Reports
with Pavement Coring Reports
 No more gradation and binder content

Do not perform density testing in areas less
than 50 tons within a sublot
9

Change in density tonnage for pay factor
calculation
Deleted Ninitial mix design requirement

New RAP Binder Table

Percent RAP
Binder Grade
0 - 15
PG 67-22
16 - 30
PG 58-22
> 30
PG 52-28
10


Concept: Focus on performance rather than
prescriptive construction requirements
Eliminate all specification requirements for
tacking (materials, application rates,
methods of control, etc.) for all dense graded
mixtures



Eliminate all FDOT pre-testing of tack coat
materials
Require Contractor to identify in QC Plan the
methods to be used for bonding pavements
Provision for bond strength testing if
determined necessary by the Engineer
 Based on visual inspection

Informational bond strength testing available
upon request
 Contact Sungho Kim
352-955-6314 / [email protected]

Will be used on trial project:
 SR-26 Alachua County

Multiple test sections:
 SR-2 Baker County
 US-90 Gadsden County
 HVS
ARMI = Poorest performance for rutting and
cracking on test sections
 UF Study = Bad
 Will be removed as a standard design alternative
 Current research being done to find appropriate
replacement for ARMI







Maintain use of current quantity of GTR.
Minimum of 7% GTR
Optional addition of SBS polymer.
Replace ARB-5 and ARB-12 with PG 76-22R.
Meet the criteria of a performance graded
binder.
Separation and Workability
July 2013 Specification Changes
16

Planned test section on US-98 in Gulf County (2012) to
evaluate:
 Micro-surfacing.
 1/2” and 3/4” HMA overlays with FC-4.75 mix.
 1” HMA overlay with FC-9.5 mm mix.
 Hot-in-place recycling.
 Bonded friction course.
 Mill and resurface 1” FC-9.5.
 Mill and resurface 1.5” FC-12.5.
 Control sections.
17

Located in Auburn, AL.
FDOT’s sections
(2 ea x 200’)
 Bonded Friction
Course
 RAP versus RAS
 PG 76-22 (SBS)
versus PG 76-22R
1.7 mile total length of track
18


Thick polymer modified tack coats.
Two types (emulsified - spray paver) or non-emulsified.
Asphalt Mix
Emulsified
Polymer
Membrane
Surface of Mix
Direction of Paving
1/2
1/3
Existing Pavement
19




Loads at 8 mph.
Temperature controlled.
Can change wheel type (single or dual).
Purchased in S. Africa.

Current Round of
Testing
 PG 76-22R Sections
 4.75 mm mix
 Prime vs. no prime vs.
tack
20
Effects of increased
RAP in dense graded
friction courses (UF)
 FC-5 durability study
(Rutgers)

Sampling at the Paver
(NCAT)
 Data Analysis (NCAT)
 CPF Analysis (FDOT)

 End of Project CPF
 QC Adjusted Lot CPF
 F & t Statistical

New LIMS system
(FDOT)
284,996
300,000
250,000
223,093
191,030
Tonnage
200,000
150,000
100,000
50,000
39,869
7,856
730
15,165
0
2006
2007
2008
2009
Year
2010
2011
2012
Questions/ Comments?
23

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