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Die Dissertationsschrift widmet sich einer systemtheoretischen Untersuchung zur verkehrsabhängigen Steuerung von Lichtsignalanlagen in Straßennetzwerken. Aus einem mathematischen Modell für den Verkehrsablauf auf Knotenzufahrten wird ein Verfahren abgeleitet, mit dem sich Umschaltzeitpunkte und Phasenwechsel flexibel an das tatsächliche Verkehrsgeschehen anpassen lassen. Der Ansatzpunkt ist, die einzelnen Knotenpunkte des Netzwerks lokal zu optimieren. Eine "Grüne Welle" soll sich von selbst einstellen, und zwar genau dann, wenn dadurch lokal Wartezeiten eingespart werden. Indem die lokale Optimierung in ein lokales Stabilisierungsverfahren eingebettet wird, können Instabilitäten aufgrund netzwerkweiter Rückkopplungen ausgeschlossen werden. Das vorgestellte Verfahren setzt sich aus drei Teilen zusammen: (i) einem lokalen Prognoseverfahren zur Bewertung von Schaltzuständen und Phasenübergängen bezüglich zukünftig entstehender Wartezeiten, (ii) einem lokalen Optimierungsverfahren, das jeder Phase einen dynamischen Prioritätsindex zuweist und die Phase mit höchster Priorität zur Bedienung auswählt und (iii) einem lokalen Stabilisierungsverfahren, das zum Einhalten einer mittleren und einer maximalen Bedienperiode korrigierend in die lokale Optimierung eingreift. Indem die Knotenpunkte ausschließlich über die Verkehrsströme gekoppelt sind, ergeben sich die Umschaltzeitpunkte unmittelbar aus den Ankunftszeitpunkten der Fahrzeuge selbst. Die Phasenwechsel stellen sich somit von selbst bedarfsgerecht ein. Simulationsergebnisse machen deutlich, dass sich aufgrund der höheren Flexibilität sowohl die Wartezeiten als auch der Kraftstoffverbrauch senken lassen.

This presented dissertation is focused on the installation technology of green roofs and sustainable long-term stability considering the construction and runoff water management. The main topic of the study and research was the technical layer application, especially the newly developed retention board made of recycled polyester fiber and non woven textiles. Consistent monitoring was performed in the climatic conditions of the Czech Republic and selected installation technology.

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The Portland Cement Association commissioned a research project at Brigham Young University to compare selected laboratory durability tests available for assessing stabilized subgrade materials. Improved understanding of these tests is needed to enable more objective selection of durability tests by design engineers and to facilitate more meaningful comparisons of data obtained for different stabilizer treatments using different evaluation procedures. The laboratory research associated with this project involved two subgrade materials, four stabilizers at three concentrations each, and three durability tests in a full-factorial experimental design. The two subgrade soils used were a silty sand and a lean clay, while the four stabilizer types included Class C fly ash, lime-fly ash, lime, and Type I/II portland cement. The three tests used in this comparative study were the freeze-thaw test, the vacuum saturation test, and the tube suction test. On average, to achieve the same 7-day unconfined compressive strength (UCS) values, the sand required 4.4 times more Class C fly ash than cement, 3.6 times more lime-fly ash than cement, and 6.0 times more lime than cement. Likewise, the clay required 10 times more Class C fly ash than cement, 7.5 times more lime-fly ash than cement, and 1.8 times more lime than cement. Analyses of the test results indicated that the UCS and retained UCS were higher for specimens tested by vacuum saturation than the corresponding values associated with freeze-thaw cycling. This observation suggests that the freeze-thaw test is more severe than the vacuum saturation test for these particular fine-grained materials. Testing also suggested that specimens with 7-day UCS values below 200 psi will generally not survive freeze-thaw cycling. After both freeze-thaw and vacuum saturation testing, the sand specimens treated with lime-fly ash had significantly higher UCS and retained UCS than specimens treated with Class C fly ash, lime, or cement. Similarly, the clay specimens treated with Class C fly ash or lime-fly ash had significantly higher UCS values than specimens treated with cement or lime; however, clay specimens treated with Class C fly ash and lime-fly ash were not significantly different. None of the four stabilizer types were significantly different from each other with respect to retained UCS after vacuum saturation testing. Dielectric values measured in tube suction testing were lowest for specimens treated with lime-fly ash and cement with respect to the sand and for specimens treated with Class C fly ash and cement with respect to the clay. The lime-fly ash and cement successfully reduced the dielectric value of sand specimens to a "marginal" rating, while no stabilizer reduced the moisture susceptibility of the clay to a satisfactory level. A strong correlation was identified between UCS after the freeze-thaw test and UCS after the vacuum saturation test, while very weak correlations were observed between the final dielectric value after tube suction testing and all other response variables. Differences in variability between test results were determined to be statistically insignificant in an analysis of the CVs associated with data collected in this research. Although the freeze-thaw test utilized in this research was determined to be more severe than the vacuum saturation test for materials similar to those tested in this study, the vacuum saturation test is recommended over both the freeze-thaw and tube suction tests because of the shorter test duration, usability for specimens with 7-day UCS values even below 200 psi, and lack of a need for daily specimen monitoring.

The primary objective of this research was to quantify the improvement in service life of a flexible pavement constructed using full-depth reclamation (FDR) in conjunction with cement stabilization when specified reductions in the spatial variability of specific construction-related parameters are achieved. This study analyzed pavement data obtained through field and laboratory testing of a reconstruction project in northern Utah. Data analyses included multivariate regression, Monte Carlo simulation, and mechanistic-empirical analyses of a model pavement structure. The results of the research show a steadily increasing trend in 28-day unconfined compressive strength of the cement-treated base (CTB) layer with increasing reductions in variability for cement content, moisture content, and reclaimed asphalt pavement (RAP) content across each of five different reliability levels. The most significant increases in CTB strength occurred with reductions in the standard deviations of moisture content and RAP content. Decreasing the variability of cement content did not provide significant additional strength to the CTB layer. Therefore, when involved on FDR projects, members of the pavement industry should focus energy on reducing the variability of both moisture content and RAP content, which both significantly impact pavement life, to achieve high-quality, long-lasting pavements.

Full-depth reclamation (FDR) in conjunction with cement stabilization is an established practice for rehabilitating deteriorating asphalt roads. Conventionally, FDR uses dry cement powder applied with a pneumatic spreader, creating undesirable fugitive cement dust. The cement dust poses a nuisance and, when inhaled, a health threat. Consequently, FDR in conjunction with conventional cement stabilization cannot generally be used in urban areas. To solve the problem of fugitive cement dust, the use of cement slurry, prepared by combining cement powder and water, has been proposed to allow cement stabilization to be utilized in urban areas. However, using cement slurry introduces several factors not associated with using dry cement that may affect road base strength, dry density (DD), and moisture content (MC). The objectives of this research were to 1) identify construction-related factors that influence the strength of road base treated with cement slurry in conjunction with FDR and quantify the effects of these factors and 2) compare the strength of road base treated with cement slurry with that of road base treated with dry cement. To achieve the research objectives, road base taken from an FDR project was subjected to extensive full-factorial laboratory testing. The 7-day unconfined compressive strength (UCS), DD, and MC were measured as dependent variables, while independent variables included cement content; slurry water batching temperature; cement slurry aging temperature; cement slurry aging time; presence of a set-retarding, water-reducing admixture; and aggregate-slurry mixing time. This research suggests that, when road base is stabilized with cement slurry in conjunction with FDR, the slurry water batching temperature; haul time; environmental temperature; and presence of a set-retarding, water-reducing admixture will not significantly affect the strength of CTB, provided that those factors fall within the limits explored in this research and are applied to a road base with similar properties. Cement content and cement-aggregate mixing time are positively correlated with the strength of CTB regardless of cement form. Additionally, using cement slurry will result in slightly lower strength values than using dry cement.

The first objective of this research was to investigate temporal trends in the mechanical properties of base materials stabilized with asphalt emulsion and to assess the rate at which emulsion-treated base (ETB) design properties are achieved. The second objective of this research was to identify construction and environmental factors most correlated to specific mechanical properties of ETB layers and to determine which construction factors exhibit the greatest variability. Additional statistical analysis was performed to determine if significant differences existed between different test sections on a given project. In this research, three experimental sections were established along a pavement reconstruction project near Saratoga Springs, Utah. Field tests were performed to assess the structural properties of the ETB immediately following construction and at 2, 3, 7, and 14 days; 4 months; and 1 year. Measured values were plotted against time to determine trends in ETB strength development. Several statistical analyses were then performed on the collected data. Modulus values were consistently low in all three sections during the first two weeks of testing, increased dramatically by 4 months, and then decreased considerably by 1 year. During the first two weeks following construction, the average ETB structural coefficient was 0.04. Only two of the three sections reached the design structural coefficient of 0.25, which occurred after approximately 3 months; however, the average structural coefficient measured for all three sections after 1 year of curing, which included a winter, was only 47 percent of the design strength. The results of this research show that, while pavement capacity is sufficient at 4 months, it is severely reduced during the first two weeks and at 1 year. Trafficking under these reduced capacities is not recommended. Statistical analysis showed that gradation, binder change during emulsion treatment, and moisture content have the most significant impact on ETB structural properties. Gradation and binder change during emulsion treatment also exhibited significant variability; tighter specifications on material gradations and improved uniformity in emulsion distribution should therefore be considered. Because of the negative impacts of moisture on ETB strength development, construction should not be performed in conditions of excess moisture.

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