estimating the life expectancy of thin asphalt overlays in new … · in this presentation…...

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: alia@rowan.edu

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)

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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

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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

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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

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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

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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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Ayman Ali, Ph.D.Tel: (908) 283-0467

Email: alia@rowan.eduwww.rowan.edu/creates