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Ranking System for Non- Destructive Testing Devices to Assess Quality of HMA during Construction Ahmed Faheem – Bloom Companies LLC Dr. Robert Schmitt.

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Presentation on theme: "Ranking System for Non- Destructive Testing Devices to Assess Quality of HMA during Construction Ahmed Faheem – Bloom Companies LLC Dr. Robert Schmitt."— Presentation transcript:

1 Ranking System for Non- Destructive Testing Devices to Assess Quality of HMA during Construction Ahmed Faheem – Bloom Companies LLC Dr. Robert Schmitt – UW Platteville Dr. Imad Al-Qadi – UIUC

2 Strategy Define Critical Characteristics of Compaction Identify Non-Destructive Technologies Rank Technologies on Technical Merits, field, portability, training, cost, practicality Goal Investigation and Development of a Non- Destructive System to Evaluate Critical Properties of Asphalt Pavements during the Compaction Process

3 Project Stages Stage 1: ◦Determine critical properties ◦Select promising non-destructive testing technologies Stage 2: Field data collection ◦Select field compaction sites ◦Collect data using proposed NDTs Stage 3: Data Analysis ◦Analyze data ◦Evaluate quality of data collected from each NDT

4 Background and Stage 1 Objective Non-destructive technologies are emerging Move beyond density and smoothness New measures for characterizing pavement Ability to assess entire pavement sections Real-time data retrieval Objective: Rank NDTs to guide agency selection

5 Critical Characteristics  Survey of 12 states by Washington DOT (1999)

6 Critical Characteristics and Impact Agency-specific rank: #1 #2 #3

7 Critical Properties - Characteristics critical to compaction from Lit. Search: 1. Mix segregation 2. In-place compaction 3. Smoothness 4. Temperature segregation 5. Layer thickness 6. Layer bond 7. Pavement modulus - Agency-specific: 1.In-place compaction 2.Temperature segregation 3.Pavement modulus

8 Non-Destructive Technologies: Factors to Consider:  Operational principle  Measures and indicators  Test equipment  Portability of the test  Complexity in the field  Time to conduct test  Environmental limitations  Reliability of collected data  Degree of training required  Cost  States using in practice Available Technologies 

9 Infrared Thermography  Thermal Segregation  $30,000 Washington, Texas 25-50°F corrective action > 50°F suspend, no bonus

10 Intelligent Compactor  Index, CCV, vibration modulus, stiffness  $175,000 to $280,000 (25% above base roller price)

11 GPR  Thickness, segregation, delamination, ASTM  Dry pavement  $40,000 to $80,000 (minus vehicle)

12 Deflectometers  Deflection, stiffness, moduli  <140°F pavement  LWD no states spec for HMA  Layers only; highly variable  $17,000

13 Seismic  Seismic waves, moduli, PSPA portable, SPA discontinued  Temperature dependent  No state specs, TxDOT design manual  $30,000

14 Permeameters  Water = NCAT  No ASTM or state specs  Autocorrelation (repeatability)  <140°F pavement  $800  Air = ROMUS  No ASTM or state specs  More repeatable  <140°F pavement  $6,000

15 NDT vs. Critical Characteristics NDT Continuous coverage? Width Mix Seg. Com- paction Smoo- thness Temp. Seg. Thick- ness BondModuli ThermographyYes, lane  ICYes, drum  GPRYes, 1 ft.  DeflectometerNo  PSPANo  PermeameterNo  Nuclear/EMNo  LaserYes, 1 ft. 

16 Agency Specific: Critical Characteristics vs. NDT NDT Continuous coverage? Width Com- paction Temp. Seg. Moduli Rank123 ThermographyYes, lane  ICYes, drum  GPRYes, 1 ft.  DeflectometerNo  PSPANo  PermeameterNo  Nuclear/EMNo  LaserYes, 1 ft.

17 Ranking System (Scoring)  7 Attributes:  Portability  Complexity  Time  Environmental Sensitivity  Reliability  Training  Price  4 levels: Excellent(4), Good(3), Moderate(2), Poor(1)  Cumulative score is calculated

18 Levels of NDT Attributes LevelPortabilityComplexityReliabilityTraining Excellent Moves rapidly Self-contained Easy to operateHighly accurateMinimal training Good Moves rapidly Attached to a vehicle Multiple steps are required Two or more primary phases Good accuracy but requires continuous calibration Multiple phases, and steps within each phase Fair Moves rapidly Requires trailering Multiple steps within phases Knowledge of calibration Higher testing variability with known bias Requires continuous calibration Capability for data collection and statistical analysis Poor Requires trailering Considerable set up time Requires multiple phases Knowledge of sophisticated equipment Technology considered at experimental phase In-depth understanding of pavement engineering principles

19 Scoring Score for Equipment Characteristics (Cumulative) Score for Agency Objectives Overall Score x=

20 Scoring Example for FWD Objectives Score (Agency Specific): 2 = During Lay down 1 = After Compaction 4 = Compaction 3 = Thermal Seg. 2 = Modulus 1 = Other Measures and Indicators Construction Process Utilization FWD: Objectives ModulusAfter Compaction 21 Objectives Score = 3 Overall Score = 13 x 3 = 39

21 Ranking

22 Ranking Summary: Critical Characteristics NDT Continuous coverage? Width Com- paction Temp. Seg. Moduli Overall Score ICYes, drum  120 ThermographyYes, lane  110 GPRYes, 1 ft.  85 PSPANo  80 LWDNo  68 Nuclear/EM**No  105 FWDNo  39 PermeameterNo  34 LaserYes, 1 ft.30 ** Nuclear Gauges will be used in field for comparison

23 Ranking, Vendors and Prices RankingNDTVendor and Model Price ($k) 1 Intelligent Compaction Sakai SW900 or Bomag BW278AD Infrared Thermography Moba Corporation Pave-IR 28 3 GPRGSSI RADAN PSPA Geomedia R&D PSPA-PU 30 5LWDZorn ZFG-2000A17

24 What Next? Stage 2 1. Field Testing (Completed) Stage 3 1. Analyze collected data. 2. Identify variability. 3. Validate GPR as surrogate density measurement. 4. Identify mix design critical factors affecting constructed quality. Final Report

25 Many Thanks ! Wisconsin Highway Research Program, Presentation may not reflect official views, policies, standard specifications or regulations of Wisconsin DOT or US DOT. Vendors – MOBA, Sakai, GSSI, Geomedia Contractors – Mathy Construction, Payne & Dolan

26 Contact: Questions? Thank You


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