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Module 3. The Nuts and Bolts of Thermal Profiling with Pave-IR. Basis of Pave-IR Implementation. TxDOT Spec: One profile per sublot Engineer may reduce testing frequency Engineer may also obtain as many thermal profiles as deemed necessary Tex-244-F profiled 150 feet of paving
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Module 3 The Nuts and Bolts of Thermal Profiling with Pave-IR
Basis of Pave-IR Implementation • TxDOT Spec: • One profile per sublot • Engineer may reduce testing frequency • Engineer may also obtain as many thermal profiles as deemed necessary • Tex-244-F profiled 150 feet of paving • Essentially Pave-IR profiles each 150 foot segment of paving
General Data Processing Approach • Automated data processing methods selected to mimic structure of existing Tex-244-F • Remember the primary goal of testing • Detect thermal signatures in the placement operation such as • Truck Ends • Streaks • Random cold spots within truckloads
Review of Historical Tex-244-F • Excludes the outer 2 feet toward the edges • Determines “maximum baseline temperature” in first 20 feet of paving • This temperature will generally not be the absolute maximum from within a profile’s limits • This approach reduces the contractor’s risk • Tex-244-F determines the minimum profile temperature over 150 feet • Locations of paver stops > 10 sec. excluded from analysis
Incorporating Pave-IR into Existing Tex-244-F • Must ignore outer 2 ft toward edges • Must mimic risk structure in terms of leniency on the “maximum” temperature • Must ignore paver stops • Must not produce false positives • Must automatically process data
Ignoring Outer 2 Feet • Sensors to ignore selected prior to initiating data collection • In most cases these are the outer 2 sensors on each side • Pave-IR stores which sensors to ignore, and reports which sensors were not used in the temp. differential determination
Determining Maximum Temperature • Researchers manually evaluated 380 profile segments • The hottest spot in the first 20 ft is typically 98.5% of the hottest spot in the entire profile segment Pave-IR ignores 1.5% of the hottest temperatures to determine the maximum baseline temperature
Handling Paver Stops in Pave-IR • Paver stop defined as > 10 seconds idle time • Reviewed over 30 paver stops from 4 different projects • Ignore 2 ft prior to stop • Ignore 8 ft after stop • Using this approach eliminated irregular thermal signatures attributable to the paver stops in all cases examined
Example of Paver Stops Ignored Red bars beneath profile are limits ignored due to paver stop.
Preventing False Positives • External factors could create artificial cold spots in data log files • Hand work, cooler spills Artificial cold spot from hand work
Preventing False Positives • A “single point” approach for determining the minimum profile temperature would artificially inflate the temp. differential when these external factors are present in a profile Pave-IR ignores the coldest 1% of temperatures to determine the minimum profile temperature
Summary of Automated Processing Approach • Operator selects which sensors are within 2 ft of edges. These sensors are ignored from calculations • For each 150 ft segment • Data 2 ft prior, and 8 ft after paver stops lasting > 10 seconds are ignored • Omit hottest 1.5% of measurements to determine maximum baseline temperature • Omit coldest 1% of measurements to determine minimum profile temperature • Profile temp. differential = max - min
Manually Reviewing Data • Pave Project Manager (PPM) allows for automated reporting and manual data review
Demonstration of PPM • Opening a data file • Changing the color map scale • Viewing the thermal profile • Scrolling through the profile • Profile view options • Ignored sensors and profile length • Tooltip and spots of interest • Properties, Time, Speed, and Temperature Class Diagrams • Illustration with 2 project files
Current Usage of Pave-IR • Texas – 15 Units • Other users: • Minnesota • Wisconsin • NCAT • Other interested regions: • Alaska • Quebec • Ohio • Michigan • Germany • China
For more Pave-IR Info… Moba Corporation Paul Angerhofer 678-817-9646 770-634-0058 (cell) p.angerhofer@moba.de Moba Corporation James Lano 678-817-9646 678-557-0951 (cell) jlano@moba.de Moba Corporation Gary Motak 678-817-9646 770-842-1579 (cell) g.motak@moba.de