Browsing by Subject "Highway engineering"
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Item Effect of the chemical composition of compaction water on the performance of soil subgrades and embankments(Texas Tech University, 2004-12) Ayenu-Prah, Albert YawsonThe Texas Department of Transportation (TxDOT) wants to employ the use of other water sources (alternative water) besides potable drinking water for those construction projects that use large amounts of water. This is due to increasing cost of drinking water treatment and, therefore, a consequent scarcity of potable water for construction purposes. The sometimes prohibitive cost of hauling water from remote areas to certain construction sites, and more importantly, issues related to performance are also part of the reason for this research effort. The research deals mainly with the investigation of the potential effects of the chemical composition of compaction water on the performance of soil subgrades and embankments, with an emphasis on the effects of sodium. Shaikh et al. (1988) indicate that the primary factor that influences the erodibility of unsaturated compacted clays is the soil pore-water chemistry. A comprehensive laboratory test program was carried out to ascertain the possible effects that the chemical composition of compaction water could have on engineered soils. Test results from the project would help in developing predictive models to serve as a framework for a preliminary feasibility evaluation, and selection of a particular alternative water source for use among candidate sources. Similarly, appropriate blending ratios could be determined for those water sources to meet design specifications. Varied results have been obtained that would lead to various conclusions. It was observed that even the worst sources of alternative water would have no significant effect on engineered soils.Item Feasibility of using the micro-deval test method as an aggregate production quality control tool(Texas Tech University, 2003-12) Hoare, Appa RaoNot available.Item Prioritization of highway maintenance functions using multi-attribute decision making with fuzzy pairwise comparison(2011-05) Liu, Wenxing, 1987-; Zhang, Zhanmin, 1962-; Machemehl, Randy B.As is the case for most of the Departments of Transportation in the U.S., the Texas Department of Transportation has been experiencing fluctuations of budget for maintaining and preserving its highway infrastructure over the recent years. If the maintenance budget shortfall lasts for an extended period of time, the condition of the highway network would be harmed directly or indirectly since some maintenance work would be deferred or cancelled. Thus, in order to control and minimize the risk caused by maintenance budget reductions, it is important for highway agencies to adjust their maintenance and rehabilitation policies to accommodate budget fluctuations. This thesis presents a methodological framework that helps highway agencies quantify the risks to highway networks, and revise the highway routine maintenance work plans to minimize the impact of budget fluctuations. The proposed methodology aims to assist highway agencies in prioritizing and selecting maintenance functions according to the risk of not performing a specific maintenance activity. Also, this methodology considers the subjective nature of decision makers’ assessments, allowing different levels of confidence and different attitudes toward risk to be captured as the uncertainty and imprecision involved in the decision making process. In the case study, the proposed methodology is tested with a set of data obtained from the Texas Department of Transportation. The result is compared with the outcome obtained from the crisp Analytical Hierarchy Process using the same set of data. The outcomes from the two methodologies are very close, validating the effectiveness of prioritizing highway maintenance functions using Multi-Attribute Analysis with Fuzzy Pairwise Comparison.