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Estimating the Life Expectancy of Thin Asphalt Overlays in New Jersey
Ayman Ali, Ph.D.Manager, Center for Research and Education in Advanced
Transportation Engineering Systems (CREATEs)Rowan University
109 Gilbreth ParkwayMullica Hill, NJ 08062Tel: (908) 283-0467
Email: [email protected]
Acknowledgement Dr. Hashim Rizvi Ms. Caitlin Purdy Mr. Ian Sennstrom Mr. Andrae Francoise Ms. Eileen Sheehy Ms. Susan Gresavage Mr. Paul Hanczaryk Mr. Robert Blight Dr. Giri Venkiteela Ms. Kimbrali Davis
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In this presentation… Why Thin Overlays? Study Goals & Objectives Research Approach Construction of Sections &
Instrumentation HVS Testing Plan Preliminary Testing Results Final Remarks Questions
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Why Thin Asphalt Overlays?
Why Thin Asphalt Overlays? Around 50% of NJDOT’s roads are
PCC pavements. These roads are generally in poor
condition. Thin overlays are typically used to
extend the life of these pavements. However, these overlays have been
performing poorly in the field.
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Goals and Objectives
Goals Conduct accelerated full-scale
pavement testing to evaluate theperformance of thin asphalt overlaytreatments used on Portland CementConcrete (PCC) pavements.
Analyze testing results to estimatethe expected life of thin asphaltoverlays applied over PCCpavements.
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Research Approach
Research Approach
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Conduct A Comprehensive Literature Review1
Evaluate Current Condition of PCC Pavements in NJ2
Identify Major Factors Affecting Life Expectancy of Thin Asphalt Overlays3
Construct Full-Scale PCC Sections Overlaid with Thin Asphalt Overlays.4
Research Approach
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Apply Accelerated Loading Using a Heavy Vehicle Simulator (HVS)5
Monitor Performance of Thin Asphalt Overlays as Loading Progresses6
Analyze Testing Results7
Provide NJDOT with Findings and Recommendations8
Overlays Considered
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A 9.5 mm. NMAS Superpave Mix (Control)
12.5 mm. NMAS Stone Matrix Asphalt (SMA)
High Performance Thin Overlay (HPTO)
Binder Rich Intermediate Course (BRIC)
B
C
D
Full-Scale Pavement Sections
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A total of six sections wereconstructed at CREATEs acceleratedpavement testing facility.
Combinations of the four overlayswith varying thicknesses.
The supporting PCC pavementstructure was similar for all sections.
Full-Scale Pavement Sections
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The sections were instrumented using aset of sensors including: Thermocouples Soil Compression Gauges Pressure cells Asphalt Strain Gauges LVDTs
The goal was to compare fieldperformance (rutting and reflectivecracking).
Full-Scale Sections
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Binder Rich Intermediate Course (1 inch)9.5 mm. NMAS Superpave (3 inches)
PCC Layer (8 inches)
Subbase Layer (16 inches)
Compacted Natural Soil (12 inches)
Natural Soil
Section No. 1: 9.5 mm. NMAS Superpave Control Section
Full-Scale Sections
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12.5 mm. NMAS SMA (3 inches)
PCC Layer (8 inches)
Subbase Layer (16 inches)
Compacted Natural Soil (12 inches)
Natural Soil
Section No. 2: 12.5 mm. NMAS SMA A Specialty NJDOT Overlay mix
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High Performance Thin Overlay (2 inches)
PCC Layer (8 inches)
Subbase Layer (16 inches)
Compacted Natural Soil (12 inches)
Natural Soil
Section No. 3: High Performance Thin Overlay A Specialty NJDOT Overlay mix
Full-Scale Sections
Full-Scale Sections
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9.5 mm. NMAS Superpave (2 inches)Binder Rich Intermediate Course (1 inch)
PCC Layer (8 inches)
Subbase Layer (16 inches)
Compacted Natural Soil (12 inches)
Natural Soil
Section No. 4: A combination of 9.5 mm.
Superpave and Binder Rich Intermediate Course (BRIC) Mixes.
BRIC is a Specialty NJDOT Overlay mix
Full-Scale Sections
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12.5 mm. NMAS SMA (2 inches)Binder Rich Intermediate Course (1 inch)
PCC Layer (8 inches)
Subbase Layer (16 inches)
Compacted Natural Soil (12 inches)
Natural Soil
Section No. 5: A combination of 12.5 mm.
SMA and BRIC Mixes.
Full-Scale Sections
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High Performance Thin Overlay (1 inch)Binder Rich Intermediate Course (1 inch)
PCC Layer (8 inches)
Subbase Layer (16 inches)
Compacted Natural Soil (12 inches)
Natural Soil
Section No. 6: A combination of HPTO and
BRIC Mixes.
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Construction of Full-Scale Sections
Construction Phase-I (Facility)
21Construction Site: Work Begins
Construction Phase-I (Facility)
22Construction Site: Foundations
Construction Phase-I (Facility)
23Construction Site: Steel Structure
Construction Phase-I (Facility)
24Construction Site: Fabric Cover
Construction Phase-I (Facility)
25Construction Site: Fabric Cover
Construction Phase-I (Facility)
26Construction Site: Fabric Structure (Inside)
Construction Phase-I (Facility)
27Construction Site: Infrastructure
Construction Phase-I (Facility)
28Construction Site: Completed Facility
Construction Phase-II (NJDOT Sections)
29NJDOT Sections: Marking Sections Locations
Construction Phase-II (NJDOT Sections)
30NJDOT Sections: Milling Existing Pavement
Construction Phase-II (NJDOT Sections)
31NJDOT Sections: Milling Existing Pavement
Construction Phase-II (NJDOT Sections)
32NJDOT Sections: Concrete Forms
Construction Phase-II (NJDOT Sections)
33NJDOT Sections: Concrete Placement (Slabs)
Construction Phase-II (NJDOT Sections)
34NJDOT Sections: Final PCC Slabs
Construction Phase-II (NJDOT Sections)
35NJDOT Sections: HMA Overlays Paving
Construction Phase-II (NJDOT Sections)
36NJDOT Sections: HMA Overlays Paving
Construction Phase-II (NJDOT Sections)
37NJDOT Sections: HMA Overlays Paving
Construction Phase-II (NJDOT Sections)
38NJDOT Sections: HMA Overlays Paving
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Instrumentation of Sections
Goals of Instrumentation
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Assess the impact of reflectivecracking on performance of thinasphalt overlays.
Assess the impact of joint verticalmovements on performance of thinasphalt overlays.
Characterize rutting potential in thinasphalt overlays.
Instrumentation Plan
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Longitudinal Asphalt Strain Gauge (Total: 2)
Pressure Cell (Total: 1)
LVDT (Total: 2)
Soil Compression Gauge (Total: 2)
HMA Temperature Sensor (Total: 3 T-type Thermocouples)
Type T thermocouples will be used for temperature measurements.
3”
11”
26”
31”
5 ft.5 ft.5 ft.5 ft.5 ft.5 ft.
Natural Soil
Compacted Natural Soil
I-3 (Layer -2)
PCC
HMA
I-3 (Layer -1)
5 ft.5 ft.5 ft.5 ft.5 ft.5 ft.
Instrumentation
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Pressure Cells (Geokon Inc.) To measure
pressure in sub-base (I-3) layer at both sides of transverse joints of PCC slabs
6 pressure cells have been installed in NJDOT sections
Instrumentation
43Instrumentation of NJDOT Sections: Pressure Cells
Instrumentation
44Instrumentation of NJDOT Sections: Leveling
Instrumentation
45Instrumentation of NJDOT Sections: Covering
Instrumentation
46Instrumentation of NJDOT Sections: Locating
Instrumentation (Thermocouples)
47
Thermocouples(Omega) To measure
temperature in subbase and overlays at various depths (2” interval for subbase and 0.5” interval in overlays)
48 thermocouples were installed in six Test sections
Instrumentation
48Instrumentation of NJDOT Sections: Preparation and Testing
Instrumentation
49Instrumentation of NJDOT Sections: Installation
Instrumentation
50Instrumentation of NJDOT Sections: Installation
Instrumentation
51Instrumentation of NJDOT Sections: Installation
Instrumentation
52Instrumentation of NJDOT Sections: Thermocouples
Thermocouple Installation (Surface Layer)
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Thermocouple bed preparation, installation, and manual compaction
Instrumentation
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Soil Compression Gauges (CTL Group) To measure vertical
deformation in sub-base (I-3) layer at both sides of transverse joints
12 soil compression gauges have been installed in NJDOT sections
Instrumentation
55Instrumentation of NJDOT Sections: Soil Compression Gauges
Instrumentation
56Instrumentation of NJDOT Sections: Soil Compression Gauges
Instrumentation
57Instrumentation of NJDOT Sections: Soil Compression Gauges
Instrumentation
58
Two LVDTs have been installed in PCC slabs
LVDTs used to measure lateral movement of the PCC slabs under accelerated loading.
Linear Variable Differential Transducers (LVDTs)
Instrumentation
59Instrumentation of NJDOT Sections: LVDTs
Instrumentation
60Instrumentation of NJDOT Sections: LVDTs
Instrumentation
61Instrumentation of NJDOT Sections: LVDTs
Instrumentation
62
12 strain gauges have been installed in NJDOT sections
Strain gauges utilized to simultaneously measure longitudinal and transverse strains in asphalt layer.
Asphalt Strain Gauges(Tokyo Sokki KM-100HAS H-gauge)
Instrumentation
63Instrumentation of NJDOT Sections: Wire trenches
Instrumentation
64Instrumentation of NJDOT Sections: ASGs
Instrumentation
65Instrumentation of NJDOT Sections: ASGs
Instrumentation
66Instrumentation of NJDOT Sections: ASGs
All Sections
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Testing Plan
HVS Testing Protocol One section, out of the six, will be subjected to loading
using the HVS until failure (i.e., failing one section at atime).
Air Temp. around section is controlled using CREATEsCooling/Heating System (25oC).
Therefore, HVS loading will be conducted in thefollowing sequence: Section 1 loaded until failure,followed by Section 2, followed by Section 3, and soon.
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9.5ME SMA HPTO 95/BRIC SMA/BRIC HPTO/BRIC
1 to 2 Months
1 to 2 Months
1 to 2 Months
1 to 2 Months
1 to 2 Months
1 to 2 Months
Testing Plan
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Field Testing Steps
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Verify Sensor Condition
Mark Loading Zone Cover Test Section
Perform HWD Testing
Field Testing Steps
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Perform Profile Testing
Apply Sealing in HVS Station Cooling Trailer
Field Testing Steps
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Ensure Testing Strip is Aligned
Station HVS on Section
Install Thermostat for Heaters Heat Control Thermostat
Field Testing Steps
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Set-up Data Acquisition Station
Apply Side Insulation
Apply Rain Covers Attach Cooling Hoses
Heating System
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Contains infrared heating elements.
Heating angle can be adjusted depending ondesired heating coverage within the section.
Used for controlling the air temperature aroundsection (within sealed enclosure).
Temperature Range:
Depends on ambient temperature.
On average, it can maintain the air temperaturearound the pavement to up to 120oF.
Heating System
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Cooling System
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Based on a vapor compression refrigeration cycle(i.e., uses a refrigerant to cool).
Works by cycling air through the enclosure coveringthe HVS. As a result, it is also used for controllingthe air temperature around section (within sealedenclosure).
Temperature Range:
Depends on ambient temperature.
On average, it can maintain the air temperaturearound the pavement to (comfortably) 32oF.
Cooling System
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Cooling System
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Data Collection Protocol The CREATEs cDAQ system will be utilized
to collect data from all sensors after theapplication of the following load passes:
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Data Sampling Frequency1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175,200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900,1000, 1200, 1400, 1600, 1800, 2000, 2500, 3000, 3500,4000, 4500, 5000, 6000, 7000, 8000, 9000, 10000, …
Incremented by 5,000 after 10k Incremented by 10,000 after 40k
Incremented by 20,000 after 100k Incremented by 40,000 after 200k
A field test that is typicallyconducted evaluate thestructural integrity ofpavements.
The HWD “drops” (freefall) aweight on a particularlocation.
Geophones (seven) are used tomeasure deflections at variouslocations: Forming a DeflectionBasin.
HWD Testing
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HWD Testing
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Heavy Weight Deflectometer (HWD)testing will be conducted before HVSloading and after failure.
Six locations will be tested on eachsection.
5 ft.5 ft.5 ft.5 ft.5 ft.5 ft.
12 ft
.
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HWD Test ConfigurationsParameter Types No. of Drops Stress (psi) Load (lbf)
Load
Seating 3 60, 85,110, 140 7k, 9.5k, 12.5k, 16kDrop height 1 4 60 7kDrop height 2 4 85 9.5kDrop height 3 4 110 12.5kDrop height 4 4 140 16k
Loading Plate Diameter 12 in.
HWD Testing
Transverse Laser Profilometer Characterizes the transverse profiles of
pavements. Uses a laser distance measuring device and
collect data every 2 mm. Useful in measuring permanent deformation
(rutting) within the pavement structure.
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Transverse Laser Profilometer
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Transverse profiles will be measuredusing a laser profilometer on daily basis.
Seven locations will be tested as shown inthe schematic below:
5 ft.5 ft.5 ft.5 ft.5 ft.5 ft.
12 ft
.
Visual Inspection and Mapping
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In addition, visual inspection will beconducted to collect information about thesection.
That is, crack maps and pictures of cracksas loading progresses.
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Visual Inspection and Mapping
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Visual Inspection and Mapping
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Preliminary Testing Results
Section Temperature (Before Testing)
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12 ft.
1 ft.
2 ft.
4 ft.
7 ft.
Temperature (Surface Thermocouples)
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12 ft.
1 ft.
2 ft.
4 ft.
7 ft.
Temperature (HMA Embedded Thermocouples)
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Load
ing
Soil Compression Gauge (Gauge 1)
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Load
ing
Soil Compression Gauge (Gauge 2)
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Load
ing
Soil Compression Gauge (Gauge 2)
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Loading
Slab 1 Slab 2
LVDT 1 (Horizontal Joint Opening)
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Load
ing
LVDT 2 (Horizontal Joint Opening)
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Load
ing
Pressure Cell
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Load
ing
HWD Testing (Deflection Basins)
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5 ft.
5 ft.
5 ft.
5 ft.
5 ft.
5 ft.
12 ft.
12
3
4
5
6
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Final Remarks
Final Remarks
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The Heavy Vehicle Simulator is capable ofsimulating damage applied by truck andaircraft wheels in an accelerated fashion.
Full-Scale accelerated testing of pavementsprovides valuable information about fieldperformance.
Data extracted from sensors can be used todevelop performance measures forevaluating pavement performance.
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