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Asphalt Concrete Fatigue Crack Monitoring and Analysis Using Digital Image Analysis Techniques

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ABSTRACT

This paper describes the method of crack detection, monitoring, and data extraction employed by the University of California, Berkeley Pavement Research Center as part of its accelerated pavement testing program (CAL/APT). The method employs digital imaging techniques, which enable the conversion of images to data on the location, orientation, and length of fatigue cracks on pavement test sections. Crack data is presented from three pavement sections tested using the Heavy Vehicle Simulator (HVS). These sections are identified as 502CT, 503RF, and 515RF. The crack density (cm/cm2) data from these sections is correlated with data obtained from other instrumentation on these sections, including nuclear gage, multi-depth deflectometer, road surface deflectometer, and falling weight deflectometer. Crack density is also correlated with the load distribution caused by the wander pattern of the HVS test wheel.

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Road Asphalt Pavements Analyzed by Airborne Thermal Remote Sensing: Preliminary Results of the Venice Highway

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Abstract:

This paper describes a fast procedure for evaluating asphalt pavement surface defects using airborne emissivity data. To develop this procedure, we used airborne multispectral emissivity data covering an urban test area close to Venice (Italy).For this study, we first identify and select the roads’ asphalt pavements on Multispectral Infrared Visible Imaging Spectrometer (MIVIS) imagery using a segmentation procedure. Next, since in asphalt pavements the surface defects are strictly related to the decrease of oily components that cause an increase of the abundance of surfacing limestone, the diagnostic absorption emissivity peak at 11.2μm of the limestone was used for retrieving from MIVIS emissivity data the areas exhibiting defects on asphalt pavements surface.The results showed that MIVIS emissivity allows establishing a threshold that points out those asphalt road sites on which a check for a maintenance intervention is required. Therefore, this

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Effects Of Runway Grooving On Aircraft Tire Spin-up Behavior

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SUMMARY

An experimental study was conducted to compare the spin-up behavior of an aircraft tire during touchdown on grooved surfaces with the corresponding behavior on similar ungrooved surfaces. The study involved the impact of 49 X 17, type VII aircraft tires at several inflation pressures upon dry grooved and ungrooved concrete and asphalt surfaces at ground speeds up to approximately 110 knots. The results of this study indicate that grooving a runway generally reduces wheel spin-up time but does not appreciably affect the maximum wheel spin-up drag loads, at least for the ground speeds of these tests. Tire-tread damage in the form of chevron cutting was observed on the grooved surfaces under some test conditions and appeared to be dependent upon ground speed, tire inflation pressure, and the runway surface material.

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Use Of Close Range Terrestrial Photogrammetry To Assess Accelerated Wear Of Asphalt Concrete Surface Course Mixes

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ABSTRACT:

This paper reports the initial findings of a study to assess the use of close range terrestrial photogrammetry to model the wear of asphalt surface course mixes. Slabs of 10mm asphalt concrete were subjected to accelerated wear under laboratory conditions using the University of Ulster Road Test Machine. Macro-texture profiles were generated from photo stereo pairs. The output data was compared to texture depth change determined using the conventional volumetric sand patch test. The initial findings suggest that this methodology based on digital imagery can be used to model highway surface change and provide improved understanding of the processes at the tyre road surface interface

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