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Regional Issues North Central Superpave Center Update
Rebecca McDaniel, NCSC OAPC/NCAUPG Technical Conference February 2, 2011
Today’s Topics Regional Issues NCSC Activities
Research Areas RAP ETG Training Lab Services Communication
Regional Issues Economy Recycling Warm Mix Asphalt Compaction – longitudinal joints Quality and Performance Safety
NCSC Focus Areas Recycling RAP ETG RAP Evaluation and CIR Mix Design RAP in Surface Courses
Surface Characteristics Use of Local Materials Quiet Pavements Friction in Pavement Management
NCSC Focus Areas Pavement Performance Porous Friction Course Performance Low Void Mixes Longitudinal Joints Continued Evaluation of SPS9 Project
Planned New Research Projects Effects of Foaming in WMA Mixes Optimizing Lab and Field Compaction Frictional Performance of 4.75mm Mixes Tire-Pavement Noise Monitoring
And more!
National Interest in RAP Strong incentives to increase RAP use Material and energy costs Binder costs rose over 300% in 2007 & 2008
Material supply issues Environmental concerns
Growing demand RAP in more mixes (i.e. surfaces) Higher RAP quantities
Major research efforts nationwide
HMA Recycling ETG FHWA initiated in May 2007 Purpose – Coordinate, develop national
guidance and recommendations on RAP use Demo projects, document performance,
share info, best practices, research
RAP mixes can perform as well as or better than virgin mixes.
RAP ETG wants to show states how to successfully use 25% RAP and more.
NCSC Study on RAP Plant Mixes
Reclaimed Asphalt Pavement
Binder Grade 0% 15% 25% 40%
PG 58-28 X X
PG 64-22 X X X X
Five plants and five sets of materials studied.
The RAP mixes were not as stiff as expected.
High, intermediate and low temperatures
The binder did not stiffen linearly with increasing RAP content.
In most cases, dropping the virgin grade to PG58-28 for 25% RAP was not necessary.
Results
One Example
100
1000
10000
100000
1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
Log
|E*|,
MPa
Log Reduced Frequency, Hz
PG64-22 versus PG58-28
MixC (25% RAP)
MixE (25% RAP)
MixD (40% RAP)
MixF (40% RAP)
IDT Strength Example 1
-28
-22
-16
-10
2000
2500
3000
3500
JH-A JH-B JH-C JH-D JH-E JH-F
Pvmt. C
racking Tem
perature, °C
Stre
ngth
, kPa
Mixes
Strength
Temperature
IDT Stiffness Example 2
-22
-16
-10
20
30
40
EB-A EB-B EB-C EB-D EB-E EB-F
Pvmt. C
racking Tem
perature, °C
Stiff
ness
, GPa
Mixes
Stiffness
Temperature
For these materials Grade change at 15% not necessary
Low, intermediate and high temperature
properties acceptable to 25%
Pretty good blending of RAP and virgin binders to 25% RAP
Based on this research And testing RAP sources from across
the state
INDOT increased RAP contents to: 25% with no change in grade
40% with a grade change
Spec change has been adopted
RAP in Surface Courses Evaluate effect of poor quality RAP on
friction Lab study of “crummy” RAP blended with
steel slag, ACBF slag, crushed gravel Field evaluation of RAP surfaces on low
volume roads Data analysis underway; report by Spring
Surface Characteristics
Surface Characteristics/Performance RAP in Surface Courses Friction – NMAS, aggregate type,
gradation Use of Local Aggregates in Surfaces Friction in Pavement Management System Thermoplastic Pavement Marking Material Evaluation of new aggregate sources
Porous Asphalt Surfaces New Generation Open Graded Friction
Courses Porous European Mix Porous Friction Course
For noise control and safety Reduced splash and spray High friction (macrotexture)
Pavement Porosity
Long Term Field Evaluation I74 Eastbound East of Indianapolis Constructed August 2003
Comparison of SMA, PFC and HMA Texture Friction Noise Performance
The Materials 9.5mm mixtures, Steel Slag and PG76-22
PFC designed at 18-22% air voids Old OGFC designed at 12-15% voids Polymer modified binder and fiber
Design Gradations
0
control points
20
40
60
80
100
Sieve
Cum
ulat
ive
% P
assi
ng
PFC
SMA
HMA
0.075 0.15 0.6 1.18 2.36 4.75 9.5 12.5
SMA vs. PFC
Conventional HMA
Changes in Noise vs. Traffic
747576777879808182
0 10 20 30 40 50 60no. of axle passes, 10^6
SPL,
dB
(A)
PFC at 100 km/hSMA at 100 km/hDGA at 100 km/h
10/2006
6/2005
5/2006
10/2006
10/20065/2006
5/2006
6/2005
6/2005
4/2007 5/2007
5/2007
7/2007
7/2007
7/2007
10/2007
10/2007
10/2007
8/2008
8/20088/2008
Changes in Texture
0.0
0.5
1.0
1.5
2.0
0 10 20 30 40 50 60no. of axle passes, 10^6
MPD
, mm
PFCSMADGA
10/2008
9/20035/2006
11/2006
8/2005 11/2005 10/2006
9/2003
4/2007
4/2007
8/2007
10/20077/200
10/2007
10/2008
Changes in Friction (F60)
0.1
0.2
0.3
0.4
0.5
0.6
0 10 20 30 40 50 60no. of axle passes, 10^6
F60
PFCSMADGA9/2003
8/2005 11/2005 10/2006
5/2006
11/2006
9/20034/2007
4/2007
7/2007
10/2007
10/2007
8/2007
For SMAFor PFC
10/2008
10/200
After Five Years Texture decreased slightly after two years then
stabilized Noise increased slightly, now steady PFC significantly quieter PFC and SMA friction the same PFC reduced splash and spray PFCs can hold up in Midwestern applications
(when used properly) Did require somewhat more salt
Other Studies Quiet Pavements European style surfaces in American terms Extensive lab study FHWA funded
Low Void Mixes How low is too low? NCAT Track performance, Accelerated
Pavement Testing and lab testing
Training Activities Customized training on request Our place or yours Example – Wisconsin Project Manager (Field
Personnel) Training Five sites around the state Half day classroom, afternoon plant/project tour
Webinars Perpetual Pavements More planned
Laboratory Services AMRL Accredited Lab Binder, Mixture, Aggregates
Third Party Testing Research Testing New Product Evaluations Test Equipment/Protocol Evaluations
Communications Newsletter Publication resuming in Spring Free distribution On-line versions available
Website Searchable database Technical information Calendar of events
Communications Presentations Recycling Best Practices Pavement Design Factors Affecting Durability Effect of Low Air Voids Research Updates - National, Regional, Local
More info:
Rebecca S. McDaniel Technical Director North Central Superpave Center P. O. Box 2382 West Lafayette, IN 47906 765/463-2317 ext. 226 [email protected] https://engineering.purdue.edu/NCSC