NCAT Pavement Test Track
NCAT Pavement Test Track
7.8M ESALs
• Sustainable Technologies in Thin Overlays
Background • Cost of mix materials continues to increase • “Screenings” stockpiles are accumulating • Smaller NMAS mixes used for light traffic • Can “screenings” mixes support heavier traffic? • Can “screenings” mix sustainability be improved?
APAI – 12/2/08
2
2003 NCAT Pavement Test Track
4.75 NMAS Mix in West Curve
4
Rutting 25
Average Rut Depth (mm)
20
15
10
5
0 0
2,500,000
5,000,000
7,500,000
10,000,000 12,500,000 15,000,000 17,500,000 20,000,000 22,500,000
Traffic Accumulation (ESALs) 4.75
5
9.5
12.5
Roughness International Roughness Index (m/km)
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0.00 0
2,500,000
5,000,000
7,500,000
10,000,000 12,500,000 15,000,000 17,500,000 20,000,000 22,500,000
Traffic Accumulation (ESALs) 4.75
6
9.5
12.5
Raveling 1.0 0.9 y = 2E-08x + 0.3174 R² = 0.8095
Mean Texture Depth (mm)
0.8 0.7 0.6 y = 7E-09x + 0.3731 R² = 0.6398
0.5 0.4
y = 1E-08x + 0.1908 R² = 0.8871
0.3 0.2 0.1 0.0 0
2,500,000 5,000,000 7,500,000 10,000,000 12,500,000 15,000,000 17,500,000 20,000,000 22,500,000 25,000,000 27,500,000
Traffic Accumulation (ESALs) 4.75
7
9.5
12.5
9.5 mm NMAS Cracking
8
Thin-Lift Asphalt Pavement
9
Preservation Sections on Lee Road 159
18
19
20
21
22
23
24
25
Cape
67
CCPR
76
Bond
RAP
RAS
HiMA
Laboratory Rut Depths
11
Rut Depths on Lee Road 159
Cape
Neat
Base
SBS
12
Bonded RAP
RAS
HiMA
Friction on Lee Road 159
13
Macrotexture Concerns
14
Conclusions & Recommendations • • • • • •
Track Performance comparable to both 9.5 & 12.5 Durability of 4.75 NMAS actually better than 9.5 Passed ultimate torture test in winter 2013 High volume road applications are possible Sustainability improved with neat AC, RAP, RAS Good thin overlay performance on Lee Road 159…
APAI – 12/2/08
15
www.pavetrack.com
16
End-of-Cycle Track Conference
Questions ?
Dr. R. Buzz Powell, PE Assistant Director & Test Track Manager
277 Technology Parkway Auburn, AL 36830 Phone: (334) 844-6857 Cell: (334) 750-6293 Email: [email protected] Web: www.pavetrack.com Twitter: www.twitter.com/pavetrack
18
7.8M ESALs
• Sustainable Technologies in Thin Overlays
Background • Cost of mix materials continues to increase • “Screenings” stockpiles are accumulating • Smaller NMAS mixes used for light traffic • Can “screenings” mixes support heavier traffic? • Can “screenings” mix sustainability be improved?
APAI – 12/2/08
2
2003 NCAT Pavement Test Track
4.75 NMAS Mix in West Curve
4
Rutting 25
Average Rut Depth (mm)
20
15
10
5
0 0
2,500,000
5,000,000
7,500,000
10,000,000 12,500,000 15,000,000 17,500,000 20,000,000 22,500,000
Traffic Accumulation (ESALs) 4.75
5
9.5
12.5
Roughness International Roughness Index (m/km)
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0.00 0
2,500,000
5,000,000
7,500,000
10,000,000 12,500,000 15,000,000 17,500,000 20,000,000 22,500,000
Traffic Accumulation (ESALs) 4.75
6
9.5
12.5
Raveling 1.0 0.9 y = 2E-08x + 0.3174 R² = 0.8095
Mean Texture Depth (mm)
0.8 0.7 0.6 y = 7E-09x + 0.3731 R² = 0.6398
0.5 0.4
y = 1E-08x + 0.1908 R² = 0.8871
0.3 0.2 0.1 0.0 0
2,500,000 5,000,000 7,500,000 10,000,000 12,500,000 15,000,000 17,500,000 20,000,000 22,500,000 25,000,000 27,500,000
Traffic Accumulation (ESALs) 4.75
7
9.5
12.5
9.5 mm NMAS Cracking
8
Thin-Lift Asphalt Pavement
9
Preservation Sections on Lee Road 159
18
19
20
21
22
23
24
25
Cape
67
CCPR
76
Bond
RAP
RAS
HiMA
Laboratory Rut Depths
11
Rut Depths on Lee Road 159
Cape
Neat
Base
SBS
12
Bonded RAP
RAS
HiMA
Friction on Lee Road 159
13
Macrotexture Concerns
14
Conclusions & Recommendations • • • • • •
Track Performance comparable to both 9.5 & 12.5 Durability of 4.75 NMAS actually better than 9.5 Passed ultimate torture test in winter 2013 High volume road applications are possible Sustainability improved with neat AC, RAP, RAS Good thin overlay performance on Lee Road 159…
APAI – 12/2/08
15
www.pavetrack.com
16
End-of-Cycle Track Conference
Questions ?
Dr. R. Buzz Powell, PE Assistant Director & Test Track Manager
277 Technology Parkway Auburn, AL 36830 Phone: (334) 844-6857 Cell: (334) 750-6293 Email: [email protected] Web: www.pavetrack.com Twitter: www.twitter.com/pavetrack
18
