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A data filtering system for the MnROAD temperature database was designed and implemented. Fourteen inter-dependent quantitative tests were developed to identify and flag erroneous, questionable, or exceptional data. Four of the tests identify missing and intermittent data streams. Three of the tests analyze the time series from individual sensors and identify outliers. Three of the tests compare data streams of similar sensors; "similar" implies identical pavement type, general location, and sensor depth. The remaining four tests are summary tests that identify periods of unreliable data. The specific analysis and quantitative results are based upon the 471,178,324 data records from 1,313 thermocouple sensors in 48 MnROAD test cells collected from 1 January 1996 through October 2007. The considered test cells include both hot mix asphalt and Portland cement concrete sections from both the Mainline and Low Volume Road. The majority of the sensors performed very well: 714 of the 1,282 operational sensors produced reliable data more than 99 percent of the time. Only 18 of 1,282 operational sensors produce reliable data less than 50 percent of the time. Only 31 of the original 1,313 sensor were wholly non-operational. A wide variety of statistical tables and graphical representation were produced in a digital format for the considered data. Although this project focuses on a particular set of data, the concepts and tools developed in this project are designed to be extensible to accommodate the filtering of the ongoing and future data collection efforts at MnROAD.

Benefits from a potential significant correlation between distresses and slab thickness can be broadly applied in all stages of highway development from design and construction to maintenance decisions. In order to comprehensive explore this possibility, thickness data and existing distresses were related for three highway projects in Minnesota. Thickness was obtained through non-destructive ultrasonic testing, while distresses were recorded for the same location with a distress image software. Significant thickness variation was observed in both longitudinal and transverse directions. The combined results of thickness, shear wave velocity and distresses analysis revealed that an increase in shear wave velocity was coincident with a less damaged pavement area within a section. An in-depth statistical analysis confirmed this observation showing that shear surface velocity variation was better correlated with overall pavement performance than thickness variation. Differences in cracking behavior within a section were traced back to changes in construction and design practices, showing the potential of using shear velocity analysis for pavement maintenance. A survey and analysis procedure for shear wave velocity testing of concrete pavements is proposed.

Subgrade modulus values for roads around the State of Minnesota can be effectively modelled as spatially correlated lognormal random variables. Based upon this geostatistical model, this report presents guidelines and nomographs for selecting the preliminary sample spacing for assessing the subgrade modulus. The maximum sample spacing to achieve a required precision is represented as a function of the average, standard deviation, and correlation length.

This report presents a detailed statistical analysis and graphical presentation of more than 120,000 subgrade modulus values from Minnesota state roads and highways. These subgrade modulus values are based on Falling Weight Deflectometer measurements collected by the Minnesota Department of Transportation between 1983 and1993. The report gives a one-page summary for each road in each district where measurements exist. This summary page contains a plot of the modulus versus the reference post, modulus versus year when a measurement is collected, modulus histogram, and a number of state-wide summaries. The one-page summaries are accompanied by a number of district and state-wide summaries, and nomograms for the selection of sample spacing, to form the state of Minnesota subgrade modulus Atlas. In addition to this report, a Microsoft Windows-based computer program, the Minnesota Subgrade Modulus Atlas--Online, allows for the detailed analysis of the subgrade modulus along state roads and highways. This analysis can be carried out on a state-wide scale, on a small project scale of less than one mile, or any scale in between. This electronic form of the Atlas can be easily upgraded as additional measurements become available.

This report analyzes frost heave data collected by MnROAD personnel using elevation of frost pins embedded in pavements over four years. In particular, the researchers looked at the long-term changes in ride quality due to frost heave and found that MnROAD flexible pavements deteriorated faster than rigid pavements.

This project identifies, quantifies, and statistically characterizes the components of asphalt pavements that may lead to spatial variability of pavement performance. Researchers analyzed extensive data sets at the Minnesota Road Research Project (Mn/ROAD) project, including Falling Weight Deflectometer (FWD) data, Ground Penetrating Radar (GPR) data, core analysis, and loading history data on 22 asphalt test sections. On the average, the as-built thickness is slightly thicker than the design. However, even at this carefully constructed site, there is a significant chance that the as-built pavement thickness can be in error by more than 2.5 cm ( one inch). Spatial statistics indicate that overly thin zones will occur in areas on the order of 101s of square meters, on the average. While the more heavily traveled lane shows a consistent increase in the measures of pavement distress--for example, rutting depths--a quantitative and predictive conclusion is impossible from currently available data. At the time of this study, the pavement structures have not degraded sufficiently to clearly correlate long-term pavement performance with the available measures of pavement stiffness.