State Materials Office
Pavements Research Update
Construction Conference
February 2013
1
Topics

Accelerated Pavement Testing (APT) Update

Crack Sealant Experiment

Hydroplaning Prediction Tool

Wide Spot Laser for Pavement Smoothness

Pavement Noise

Concrete Test Road
2
Research Goals

Develop safer & longer lasting roadways

Minimize impact to the public
 Safety
 Delays

Goals of presentation
 Get the word out
High Speed Inertial Profiler
3
Accelerated Pavement Testing

Initiated in 2000

Housed at the State Materials Office in Gainesville

Test site consists of eight 12 ft. linear tracks
 Originally 150 ft. long
 Seven tracks extended additional 300 ft. in 2011

Two additional tracks include water table control

Loading performed using a Heavy Vehicle Simulator
(HVS)
4
Original Test Tracks
C
7
B
6
5
A
4
3
2
1
5
Heavy Vehicle Simulator

Wheel speed up to 8 mph

Automated rut measurements

Loading: 7 to 45 kips

Semi-automated crack analysis

Wander from 0 to 30 inches

Pavement instrumentation

10,000 passes per day
6
APT Research Projects

Recently Completed Projects
 Effect of an Asphalt Rubber Membrane Interlayer
(ARMI) on Instability Rutting
 Rut Resistance of Heavy Polymer Asphalt Binders

Current Projects
 Ground tire rubber modified binder as an alternative to
polymer modified binder in structural courses
 4.75-mm mixture as a preservation treatment or
overbuild
 Composite bridge deck as an alternative to open grid
steel decks
7
Effect of ARMI on Instability Rutting

Asphalt Rubber Membrane Interlayer (ARMI)
 Florida’s primary reflection crack mitigation technique
 Districts suspect ARMI may contribute to rutting

Objective
 Evaluate ARMI in terms of rutting contribution
8
Pavement Structure
Experimental Sections
Control Sections
3-inch SP-12.5
4-inch SP-12.5
4-inch SP-12.5
2-inch SP-12.5
2-inch SP-12.5
1-inch existing SP-12.5
0.75-inch ARMI
1-inch existing SP-12.5
0.75-inch ARMI
1-inch existing SP-12.5
0.75-inch ARMI
1-inch existing SP-12.5
10.5-inch limerock
base
10.5-inch limerock
base
10.5-inch limerock
base
10.5-inch limerock
base
10.5-inch limerock
base
12-inch granular
subbase
12-inch granular
subbase
12-inch granular
subbase
12-inch granular
subbase
12-inch granular
subbase
9
Rut History
Lane slices indicated rutting
confined to layers above the
ARMI. Ignition tests on cores
showed that ARMI had not
migrated into structural layer.
1.2
2 inch overlay with
ARMI
Rut Depth, inch
1.0
4 inch overlay with
ARMI
0.8
3 inch overlay with
ARMI
0.6
0.5 inch rut depth
0.4
4 inch overlay w/o
ARMI
2 inch new
pavement
0.2
0.0
0
20,000
40,000
60,000
HVS Passes
80,000
100,000
Summary – ARMI Contribution to
Instability Rutting

An ARMI as deep as 4 inches contributed to instability
rutting
 Pavements with an ARMI rutted 20 to 50 times faster
than those without an ARMI
 FEA and lane slices indicated critical stress states
above ARMI and at the tire edge

Contracted research effort initiated to evaluate ARMI
alternatives
11
Rut Resistance of Heavy Polymer
Asphalt Binders

2001 APT evaluation of rutting resistance of a polymer modified PG
76-22 asphalt binder
 Traffic level D roadways (10 to > 30 million ESALs) require PG
76-22 binder on final structural course
 Traffic level E (≥ 30 million ESALs) require PG 76-22 binder in
top two structural courses
 Recommended for use at intersections or other facilities with
slow moving & concentrated truck loads
12
Can We Add More Polymer?

Localized rutting failures still occur at some intersections
and other facilities with low speed and concentrated truck
traffic

Recent studies have indicated a PG 82-22 asphalt binder
could improve rut resistance

Cost of adding polymer vs. PG 67-22 (Fall 2011):
 PG 76-22 is approximately $250/liquid ton more
 PG 82-22 is approximately $350/liquid ton more
13
Experiment Design (Rutting)
2 inch HMA with PG 67-22, PG 76-22 or PG 82-22

Rutting
 Three test track sections: two
2 inch lifts w/ PG 67-22, PG 7622 & PG 82-22 binders
 Loading performed at 120⁰F
(50⁰C)

Fatigue
 Two test pit sections: two 1.5
inch lifts w/ PG 76-22 & PG 8222 asphalt binders
 Loading performed at ambient
temperature
2 inch HMA with PG 67-22, PG 76-22 or PG 82-22
1-inch existing SP -12.5
10.5-inch limerock base
12-inch granular subbase
1.5 inch HMA with PG 76-22 or PG 82-22
1.5 inch HMA with PG 76-22 or PG 82-22
1-inch existing SP -12.5
10.5-inch limerock base
12-inch granular subbase
14
Rut History
As the amount of polymer
increases, rut accumulation
decreases
0.45
0.40
Rut Depth, inch
0.35
0.30
0.25
0.20
0.15
PG 67-22
0.10
PG 76-22
0.05
PG 82-22
0.00
0
20,000
40,000
60,000
HVS Pass
80,000
100,000
Tensile Strain
As the amount of polymer
increases, tensile strain
decreases
600
Previous test with
similar mixture
Tensile Microstrain
500
400
Modified binders offer 20
times greater fatigue
resistance than
unmodified binder
300
PG 67-22
200
PG 76-22
PG 82-22
100
0
0
5
10
15
20
25
30
PG 82-22 binder offers 5
times greater fatigue
resistance
than
35
40 PG 76-22
45
binder
Temperature, ⁰C
16
Summary & Conclusions

APT study showed that PG 82-22 binder increased
rutting and fatigue resistance

To date, two projects have been constructed with PG 8222 binder
 Both have history of significant rutting
17
Current APT Projects

Asphalt rubber (AR) binder
 Alternative to polymer modified (PM) binder in
structural courses
 Must meet PG 76-22 requirements
 Six test tracks

4.75-mm mixture
 Preservation treatment or overbuild

Composite bridge deck
 Alternative to open grid steel decks
18
Asphalt Rubber Binder
PG 76-22 PM
ARB-5
Blend of GTR
and Polymer
PG76-22
ARB
PG76-22
ARB
1.5-inch SP-12.5
1.5-inch SP-12.5
1.5-inch SP-12.5
1.5-inch SP-12.5
1.5-inch SP-12.5
1.5-inch SP-12.5
1.5-inch SP-12.5
1.5-inch SP-12.5
1-inch existing SP-12.5
1-inch existing SP-12.5
1-inch existing SP-12.5
1-inch existing SP-12.5
10.5-inch limerock
base
10.5-inch limerock
base
10.5-inch limerock
base
10.5-inch limerock
base
12-inch granular
subbase
12-inch granular
subbase
12-inch granular
subbase
12-inch granular
subbase
(two binder
suppliers)
(two binder
suppliers)
19
4.75-mm Mixture
4.75-mm w/ PG 67-22
4.75-mm w/ PG 76-22
4.75-mm mixture w/ PG 67-22
4.75-mm mixture w/ PG 76-22
1.5-inch SP-12.5 w/ PG 76-22
1.5-inch SP-12.5 w/ PG 76-22
1.5-inch SP-12.5 w/ PG 67-22
1.5-inch SP-12.5 w/ PG 67-22
10.5-inch limerock base
10.5-inch limerock base
12-inch granular subbase
12-inch granular subbase
4.75-mm thickness ranges from ½ to 1 inch
20
Composite Bridge Deck

Cooperative effort with Structures Research Group

Alternative to open grid steel decks

Must have solid riding surface

Weigh less than 25 lb/ft2
21
Crack Seal Evaluation

Objective: Evaluate cost effectiveness of crack sealing
on flexible pavements

Scope:
 Five projects (Desoto, Baker, Leon, Sumter, Dade)
- Route & seal (AR & PM binders)
- Crack filling (AR & PM binders)
- Control (no treatment)
 Performance
- Crack survey, ride (also rut, friction)
- Monitor for 3 years
- Pre-construction sections have been surveyed
22
Hydroplane Prediction Tool

Objective: Develop design tables and curves for the
prediction of hydroplaning speed for specific pavement
design surfaces and materials.

Approach:
 Obtain Friction Number & macro-texture from
standard FDOT test methods
 Estimate water film thickness (PaveDrain)
 Determine hydroplaning
potential with 3D-FEM
 Tabulate results
23
Wide Spot Laser

Background: FDOT currently uses a single spot laser to
measure pavement smoothness. Diamond ground
surfaces may appear rougher due to influence of surface
texture.

Objective: Evaluate wide spot laser sensors on
longitudinal ground concrete surfaces.

Update
 Field testing 50% complete by end of Feb
24
Pavement Noise

Background: On-board sound intensity
(OBSI) directly measures tire/pavement
noise. Tire/pavement noise is greatest
component of vehicle generated noise at
speeds >25 mph.

Objective:
 Validate & implement OBSI system
 Develop database of pavement texture & noise

Update
 More than 30 field sections measured
 Noise rodeo planned
25
Concrete Test Road

Provide a real-world testing ground
 New construction, rehabilitation, and maintenance
techniques
 New materials and design methods

Develop cost effective long-life concrete pavements
specific for Florida environment

Will be the only full scale concrete pavement test facility
in the Southeast
26
Other Full-Scale Facilities

MnROAD, Minnesota Department of Transportation
 3.5 mile mainline interstate roadway with live traffic
 2.5 mile low volume closed-loop

NCAT, Auburn University
 FDOT funded two sections
 Closed-loop
27
Test Road Location

Northbound US 301 / SR 200
 Minimal side streets
 Minimal impact
 Large truck volume
US-301,
Clay County
- 30% trucks
- 1 million ESALs/year
SMO
28
Concrete Test Road

2.5 mainline miles, parallel to existing NB lanes
 Individual test sections will be 225 ft long
 Test sections will be used to evaluate various design
and construction features

Live traffic will be diverted to the test road
 Traffic will be classified & weighed

Construction planned for 2015/16
29
Objectives

Structural - Thickness, base types, recycled material

Drainage - Edge drains, joint sealant

Construction - Temperature, curing
Asphalt Base
ATPB
Concrete Pavement Slab
(variable thickness)
Concrete Pavement Slab
(variable thickness)
4-inch Type B-12.5
4 inch ATPB
Composite Base
Concrete Pavement Slab
(variable thickness)
2-inch Type SP
4-inch Limerock Base
(LBR 100)
12-inch Stabilized
Subgrade (LBR 40)
12-inch Stabilized
Subgrade (LBR 40)
Embankment
Embankment
Embankment
30
THANK YOU!
James Greene
(352)955-6329
[email protected]
31