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The estimation of future year traffic volumes is a key component in the overall process of designing roadways. Reliable traffic projections are required to estimate construction needs and to develop cost estimates. Methods used by the Minnesota Department of Transportation (Mn/DOT) to project future year traffic volumes have been found to be statistically unreliable. The purpose of this study was to evaluate the procedure used by Mn/DOT, to examine and evaluate other available methods, and to develop a more reliable and accurate method to project traffic volumes

Man-made floatable litter (MMFL) appears commonly in area rivers. The litter consists of plastic containers, Styrofoam, and other materials. It has been found along river banks, at hydroelectric power plant intakes, and at other locations on the river. It is expected that this litter is derived from recreational and commercial uses of the river and from street litter which is transported to the river by storm sewers and creeks. The goals of this project were to: estimate the volume of man-made floatable litter which enters the Mississippi River from the Twin Cities Metropolitan Area, estimate the portion of litter which is contributed by storm sewers, and evaluate possible techniques for reducing the litter problem. The project included three main work tasks, which were: a literature search, a telephone survey of regulatory agencies in other parts of the country, and a field investigation.

Permanent deformation in asphalt concrete pavements manifests itself as depression along the wheelpaths; rutting. The prediction of the depth of rutting requires a knowledge of materials characteristics that relate the asphalt concrete permanent strains to stress and temperature. In this report the existing test methods are reviewed to understand the mechanisms of permanent deformation in asphalt concrete. Based upon this information, the uniaxial compression creep/recovery tests are designed to characterize the mechanical behavior of the asphalt concrete. The characteristics of permanent strains are analyzed as inferred from test results. It is shown that the separation of the strains into the time independent elastic and plastic strains and the time dependent viscoelastic strains requires tests with various unloading times. The analysis is illustrated with results of a series of tests on one asphalt concrete mixture. The tested material exhibits temperature dependent elastic and plastic strains that are proportional to the level of stress. The time and temperature dependent viscoelastic strains are nonlinearly related to the stress level and stress history. An approximate constitutive equation which disregards this nonlinearity is presented.

It is estimated that the production of new roofing shingles generates approximately 1,000,000 tons of waste annually in the US., and about 36,000 tons of this waste is in the Twin Cities Metro Area of Minnesota. With another 8.5 million tons of waste materials which are similar to those used in asphalt concrete, it seems viable that their use in hot-mix would be an attractive alternative to disposing of them in landfills. This report presents the results of an effort to evaluate the use of roofing waste generated by manufacturers and from reconstruction projects. It was shown that up to 5%, by weight of mixture, manufacturing waste roofing shingles could be used in asphalt concrete with a minimum impact on the properties of the mixture. At a level of 7.5%, a noticeable softening of the mixture occurs, and this might be detrimental to pavement performance. The use of shingles from roof reconstruction projects resulted in the embrittlement of the mixture which may be undesirable for low temperature cracking of pavements. The manufactured shingle waste seems to work well in stone mastic asphalt mixtures.

Many chemical additives designed to inhibit the corrosive effect of salt on rebars are being marketed. Their effort on Portland Cement Concrete is neither known or understood. This study is an attempt to determine if there is an effect and to understand the nature and results of the effects

Nine experimental joint sealants were installed in a one-mile long section of Interstate 94 near Sauk Centre, Minnesota. The sealants were evaluated for five years, beginning on 1988, and compared for performance against Dow Corning 888, the only silicone joint sealant currently approved for use on transverse joints by the Minnesota Department of Transportation. The sealants tested included three silicones, one urethane, one polyurethane, one nitrile rubber, one rubberized polypropylene, one polysulfide and one hot-pour asphaltic sealant . An additional section evaluated consisted of several joints sealed with Dow Corning 888 in 1976. Inspections were generally done in the winter and summer. The sealants were evaluated based on adhesion, cohesion and effectiveness of preventing the entry of moisture and incompressibles into the joint. A goal of this research project was to identify products that would provide effective long-term performance, hopefully for up to ten years. This report describes the changes in performance of the sealants during the evaluation period. Also included is a rating procedure for quantitatively evaluating joint sealants.

This report shows the results of tests done to determine the efficiency of various types of pre-wetting in the Metro Division during the Winter of 1992-1993

The transportation facilities and services available to Minnesota exporters to export to Pacific area countries were identified. This included the modes of transportation, individual carriers, third parties, and ocean ports and airports available to Minnesota shippers. The service provided was evaluated as were its accessibility to Minnesota exporters and the ability of the system to handle a substantial increase in exports from Minnesota. Included were international water and air transportation and domestic railroad, motor truck, and intermodal railroad-truck transportation. The conclusions drawn were that (1) the transportation service from Minnesota to the Pacific area is sufficient in quantity and quality in all modes, with some problems with lack of enough air freight service at Minneapolis-St. Paul; (2) the transportation service is satisfactory in terms of cost for water and motor truck service, with less satisfaction with the cost of the other modes; (3) the transportation service is generally accessible to Minnesota exporters; and (4) the transportation system for the most part should be able to handle a major increase in the quantity of exports to the Pacific region from Minnesota, the possible exception is air freight transportation in terms of both carrier capacity and airport capacity.

The testing of various deicing chemicals (salt and salt substitutes) and their effect on metal corrosion is a phenomenon that has not been studied very extensively. This study was conducted under laboratory conditions to evaluate the various chemicals and their effect on rebar corrosion under various conditions (room temperature, high temperature, wet-dry, excess oxygen (bubbled and stirred). The results show that the various chemicals react to different tests with varying results. No one chemical deicer was successful in all tests.

Accelerated soil erosion and the sedimentation caused by it pose serious problems for the construction industry and state and local agencies. Runoff from construction sites has high sediment loads which may contain various pollutants, including oil, chemicals, and soil wastes. Natural erosion in ditches and along roadways may result in sedimentation that may result in costly damage to water and land. Drainage channels, culverts, and storm sewers may be filled and plugged by sediment, resulting in frequent and costly maintenance. This report addresses those problems and outlines methods for controlling erosion both during and after construction. Structural and vegetative practices for reducing sedimentation are given, and turf establishment techniques for native grasses and wildflowers are discussed. Information regarding the National Pollution Discharge Elimination System (NPDES) Storm Water Permit Requirements is also given.