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Asphalt mixture variations that result from moisture fluctuations in aggregate stockpiles pose a serious problem at dryer-drum plants. The moisture content of a stockpile is infrequently measured, if at all. If the proportion of aggregate is not adjusted to account for its moisture content, an improper mix will result. This project looked at identifying a practical and accurate field method or probe for measuring the moisture content of aggregates, testing the probe in a hot-mix plant, and developing a control strategy for asphalt oil addition to the mix. Researchers identified a suitable commercial probe by reviewing past research and conducting laboratory studies. Testing in the plant showed that this probe could rapidly measure aggregate moisture in plant conditions at the same level of accuracy as gravimetric measurements. Researchers also developed a control strategy for the asphalt oil addition. Testing showed the effectiveness of this control, in conjunction with commercial probe moisture measurements in the feed bin. A problem with probe operations robustness was identified.

This report outlines the development of a suite of computer codes collectively referred to as MnDrain. These codes, embedded in a standard spreadsheet program, provide a user-friendly environment in which the consequences of an edge drain design decision can be investigated. The purpose of an edge drain is to remove moisture from the granular base of the road system. The rate at which moisture is removed will depend on the geometry and materials used in the base and the soil type in the subgrade. MnDrain allows for evaluation of a given drain design against Federal Highway Administration requirements. In MnDrain, the user can chose from three basic scenarios, select material types and adjust geometries for each scenario, and calculate the moisture removal versus time curve over a two-hour drainage time. The work in this report shows that MnDrain is easy to use, flexible, and produces accurate approximate solutions of the Richard's model of variable saturated flow in a layered media. MnDrain also offers the advantage of offering free access to all source codes, which means that MnDrain can be reconfigured to deal with a large array of pavement drainage issues.

The objective of this report is to complete work undertaken at the University of Minnesota in the mid 1990's. This work was directed at developing an understanding of frost heaves in relationship to the lifting of buried objects such as shallow sewers. The critical findings in the field investigation were detailed in a 1995 final report by Ray Sterling, "Progressive Lifting of Shallow Sewers: Field Investigation." Preliminary details of the modeling work were provided in an interim project report and complete details were provided in the MS thesis of Lingjun Hou, "An Investigation of a Lumped Parameter Frost Heave Model," published by the University of Minnesota in January 1994. The objective of the current report is to outline the critical findings in the modeling work detailed in the previous interim report and Hou's thesis. This document should be seen as a complement to the original final report submitted by Sterling in 1995. The central objective of the modeling study is the investigation of the lumped parameter frost heave model developed by Blanchard and Fremond. The work in this report shows that a lumped porosity model can generate an accurate comparison with experiments and is a feasible tool for the investigation of the effect of freeze thaw on buried infrastructure.

Across the state of Minnesota, asphalt roads under the jurisdiction of counties, cities and townships have been controlled by restrictions that limit the total weight of each truck that uses those roads during the spring thaw period. During this time, the pavement weakens and the bearing capacity of the roadway is reduced. These policies vary from county to county and from road to road, depending on the capacity of the roads - typically, 5, 7 and 9 tons. While spring load restrictions serve to extend the useful life of the road, they also add significant burdens to truckers who are forced to re-route their vehicles and/or increase the number of trips in order to adhere to the policies. This study assesses the economic impact of lifting all vehicle restrictions during the spring thaw period. Economic benefits of lifting the bans include reduced cost to carriers; potential cost includes reduced pavement life. Their research concludes that if the policy is changed, the costs of additional damage could be recovered from those who use the roads. Recovering those costs could take the form of annual fees, appropriate fuel taxes and/or user charges paid by vehicle operators.