Bridge monitoring and maintenance is an expensive yet essential task in maintaining a safe national transportation infrastructure. Traditional monitoring methods use visual inspection of bridges on a regular basis and often require inspectors to travel to the bridge of concern and determine the deterioration level of the bridge. Automation of this process may result in great monetary savings and can lead to more frequent inspection cycles. One aspect of this automation is the detection of cracks and deterioration of a bridge. This paper provides a comparison of the effectiveness of four crack-detection techniques: fast Haar transform (FHT), fast Fourier transform, Sobel, and Canny. These imaging edge-detection algorithms were implemented in MatLab and simulated using a sample of 50 concrete bridge images (25 with cracks and 25 without). The results show that the FHT was significantly more reliable than the other three edge-detection techniques in identifying cracks.

Analysis of edge-detection techniques for crack identification in bridges

Evaluating skid resistance of different asphalt concrete mixes

Different techniques for measuring pavement surface macrotexture and their application in pavement management are discussed. The main applications of surface macrotexture are to measure the frictional properties of the pavement surface and to detect hot-mix asphalt (HMA) construction segregation or nonuniformity. Since surface macrotexture can be measured quite efficiently using noncontact technologies and provides important information regarding pavement safety and HMA construction quality, this parameter may be included in the quality assurance or control procedures. Correlations between different measuring devices were investigated utilizing different HMA wearing surfaces. Excellent correlation was found between the circular track meter and sand patch measurements. In addition, the macrotexture determined using a laser profiler correlates well with that determined with sand patch measurements. Consistent with previous studies, it was found that the skid number gradient with speed is inversely proportional to the pavement macrotexture. However, there was a noticeable difference in speed dependency when smooth and ribbed tires were used. Oscillations in the percent normalized gradient with time due to seasonal variations were also observed. Macrotexture measurements hold great promise as tools to detect and quantify segregation for quality assurance purposes. A standard construction specification was proposed in a recent NCHRP study. However, the equation proposed for computing the nonsegregated estimated (mean) texture depth could not be applied to the mixes studied. An alternative equation has been proposed, which estimates the surface macrotexture using the mix nominal maximum size and voids in the mineral aggregate. The study was based on the mixes used at the Virginia Smart Road. Further investigation using other mixes is recommended.

Pavement Surface Macrotexture Measurement and Applications

Maintenance engineers have been applying treatments to both flexible and rigid pavements ever since there have been these types of pavements. The types and application of various treatments for both corrective and preventive maintenance have been the subject of research studies over a number of years, and many publications have reported these findings. FHWA recently initiated an effort to encourage departments of transportation at all levels to begin, or extend, the practice of preventive maintenance, since there simply is not enough money available to continue the types of maintenance currently employed. Flexible pavement preventive maintenance is specifically addressed, including the types of pavements that are candidates for preventive maintenance, the available treatments, where and when they should be used, their cost-effectiveness, factors to be considered in selecting the appropriate treatment strategy, and a methodology to determine the most effective treatment for a particular distress.

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Selecting a Preventive Maintenance Treatment for Flexible Pavements

We integrate ground spectrometry, imaging spectrometry, and in situ pavement condition surveys for assessment of asphalt road infrastructure. There is strong spectral evidence for asphalt aging and deterioration. Several spectral measures derived from field and image spectra correlate well with pavement quality indicators (e.g., a pavement condition index). However, the potential for mapping is limited by fine spatial resolution requirements (as fine as 0.5 m) and by the spectral confusion between pavement material aging and asphalt mix erosion on the one hand and structural road damages (e.g., cracking) on the other.

Spectral characteristics of asphalt road aging and deterioration: implications for remote-sensing applications

This book focuses on the process of pavement management, from data acquisition and evaluation to network level priority programming to project level design, construction and maintenance, and on the principles, methods and technology which enable the process to become a working system Examples of working systems are provided, as well as guidelines for implementation Research management, future issues, special problems, new technologies and innovation opportunities are also addressed

John P Zaniewski

Papers

Modern pavement management