George Huntington

Method for Assessing Heavy Traffic Impacts on Gravel Roads Serving Oil- and Gas-Drilling Operations

In cooperation with the Wyoming Department of Transportation and Sheridan, Johnson, and Carbon Counties, the Wyoming Technology Transfer Center conducted a 3-year pilot asset management program. These counties were chosen because of significant impacts on their road networks from oil- and natural gas–drilling activities. One objective of the program was to assess the impacts of drilling activities on the counties’ roads, with the hope that decision makers would achieve a better understanding of these impacts; this assessment is described. Improvements were recommended for roads with inadequate surface conditions for their functional class. The costs of recommended improvements were examined for both the roads that serve predominantly drilling activities (drilling roads) and the rest of the counties’ roads (nondrilling roads), along with the distresses driving the recommendations. From a comparison of the rate at which improvements were recommended on the drilling and nondrilling roads, conclusions were drawn about the impacts of drilling traffic. The portion of roads in substandard condition is much higher for drilling roads than for nondrilling roads. Clearly, the heavy traffic associated with drilling activities has significantly damaged these three counties’ roads beyond what would be anticipated from typical traffic loads. The proposed method could easily be adapted to other road systems experiencing a significant influx of heavy truck traffic to assess the impact of the additional traffic.

Performance of Recycled Asphalt Pavement in Gravel Roads

Because more recycled asphalt pavement (RAP) has become available to use in roadways, the Wyoming Technology Transfer–Local Technical Assistance Program Center and two Wyoming counties saw a need to investigate the use of RAP in gravel roads. The Wyoming Department of Transportation along with the Mountain Plains Consortium funded this study. The investigation explored the use of RAP as a means of dust suppression while considering road serviceability. Test sections were constructed in the two counties and were monitored for dust loss by means of the Colorado State University dustometer. Surface distress evaluations of the test sections were performed following a technique developed by the U.S. Army Corps of Engineers in Unsurfaced Road Maintenance Management (Special Report 92–26). The data collected were statistically summarized and then analyzed. The performance of RAP sections was compared with that of gravel control sections. This comparison allowed fundamental conclusions and recommendations to be made for RAP and its ability to abate dust. It was found that RAP-incorporated gravel roads can reduce dust loss without adversely affecting the roads serviceability. Other counties and agencies can expand on this research to add to the toolbox for dust control on gravel roads.

Gravel Roads Surface Performance Modeling

Twenty gravel road study sections at 10 sites in north-central Wyoming were monitored from September 2005 through June 2006. Windshield or mobile, visual survey ratings of the sections and field measurements were taken weekly. Surfacing gravel samples were collected, and their gradations were determined. Traffic speeds and volumes by class were collected with a two-tube system. (A two-tube system counts traffic by receiving signals from two tubes placed 8 ft apart across the road. By a comparison of the times at which signals are received from each tube, the speed of the traffic can be determined, as can the number and spacing of axles.) Statistical analyses generated regression models that allowed the prediction of the service life of an unmaintained gravel road. Traffic speeds, traffic volumes, and surfacing gravel properties were shown to have the greatest influence on gravel roads’ deterioration rates. For these typical Wyoming county roads with good geometry, good drainage, and adequate gravel thicknesses, the typical failure mode was shown to be either potholes or washboards (corrugations). The typical life of gravel roads without maintenance was shown to be in the range of several months to 1 year. Climatic effects were shown to be related to precipitation more than seasonality, at least in Wyomings dry–freeze climate.

Annualized Road Works Cost Estimates for Unpaved Roads

Providing locally elected officials with reasonable information about the cost of maintaining and improving an unpaved road network is part of the job for those directly responsible for maintaining such a network. This paper describes a simple method for generating estimates of the annualized maintenance and construction costs incurred by small agencies, three Wyoming counties in this case. Several simple inputs are used to estimate the total annualized cost of operating an unpaved road network. Road segments are assigned to one of four functional classes. Treatment costs and frequencies are determined for each functional class. These inputs are used to generate annualized network-level cost estimates for each county. The most difficult aspect of this procedure is generating reasonable treatment cost and frequency information, particularly for rehabilitation and reconstruction costs. The process of generating these inputs, along with the process of assigning roads to functional classes, is described in this paper. Comparisons between the estimates generated using the method presented in this paper and actual costs incurred by two of the counties both demonstrate the feasibility of this method and highlight aspects of this procedure that will benefit from further refinement. Tailoring treatment costs and frequencies to in-place cost tracking methods will make for more precise projection of future costs, particularly for maintenance tasks. The methods presented here are particularly useful for smaller agencies without the resources to undertake highly sophisticated, expensive asset management programs. This methodology may be applied to a wide and diverse range of agencies.

Field and Laboratory Evaluations of Hot-Poured Thermoelastic Bituminous Crack Sealing of Asphalt Pavements

This paper describes the results of field and laboratory tests evaluating four configurations and three materials used for crack surfacing. Crack surfacing, as defined in this paper, is the sealing of cracks over 1 in. (25 mm) wide in asphalt pavements. Laboratory testing using the thermal stress restrained specimen test (TSRST; AASHTO TP 10-93) determines the temperature at which a specimen with its ends restrained fails due to thermal contraction. Field studies evaluate the performance of two materials with the uniform overband configuration on three roads in Wyoming. All crack surfacing materials are commercially available hot-poured thermoelastic bituminous products. Overband configurations are found to be the preferred method for applying crack surfacing, based on the TSRST. Failure modes are evaluated and generally found to propagate from the interface between the surfacing material and the pavement to which it is bonded. Field studies indicate that traffic and snowplowing have a significant influen...

Implementation Guide for the Management of Unsealed Gravel Roads

To address the current lack of a gravel roads management system (GRMS) appropriate for the rural agencies of the Intermountain West and the Great Plains, the Wyoming Technology Transfer Center (T2/LTAP) consulted with a volunteer group of experts and practitioners in the fields of unsealed earth and gravel roads and roadway management to put together a set of recommendations and guidelines for managing unsealed roads. This paper describes and summarizes the gravel roads management methodology developed by T2/LTAP under the guidance of this group. Steps in implementing a GRMS are described, beginning with an assessment stage in which an agency evaluates its current unsealed roads information management and the resources available to improve it. Next, three elements of a GRMS are described: data management, inventory, and data collection. Eight maintenance tasks for unsealed roads are described: blading, reshaping, regraveling, dust control, stabilization, isolated repairs, major work, and drainage maintenance. Primary outputs of a GRMS are described, including cyclic maintenance scheduling, triggered maintenance scheduling, and network-level outputs, including network-level monitoring, financial tables, and road tables and maps. Safety and drainage assessments are described briefly. Recommendations are made for putting these procedures into practice.

Visual Assessment System for Rating Unsealed Roads

During the past decade the Wyoming Technology Transfer Center has developed two complementary guides for visually assessing unsealed roads. The Ride Quality Rating Guide (RQRG) assesses the quality of an unsealed road’s ride as perceived by the traveling public. The Gravel Roads Rating System (GRRS) provides standard evaluations of seven distresses, including potholes, rutting, washboards, loose aggregate, dust, crown, and roadside drainage. These guides have been used by many individuals on several projects. The guides described in this paper have been revised, updated, and improved several times. Manual methods are better than automated systems for assessing the condition of unsealed roads because the conditions can change quickly and sensors provide a measurement only for the path or location on which they are placed. Some methods are too simplified, and others are so complex that they require excessive resources to perform. The RQRG and the GRRS rating systems were developed by combining the use of ph...

Improvement Recommendations for Unsealed Gravel Roads

A method was developed to recommend improvements for unsealed earth and gravel roads that are not up to the standard expected for their functional class. As part of a pilot asset management program carried out by the Wyoming Technology Transfer Center, roads were rated for several distresses, including corrugations–washboards, rutting, potholes, loose aggregate, drainage, dust, and overall condition by using a visual survey method. These ratings were used to calculate a surfacing serviceability index (SSI) for each road section. This SSI was compared with the minimum acceptable SSI for the sections functional class. When the sections SSI was below this threshold value, improvement tasks were selected from a decision matrix, and the most expensive task was recommended to address the sections inadequate surface condition. This process allows an agency to present its elected officials with a list of roads in their network that need improvement, along with an estimate of the cost of these improvements. The method presented in this paper can be used by agencies with extensive unsealed road networks if they perform a visual survey rating various distresses and they develop a decision matrix based on these distresses to establish appropriate improvements to substandard roads.

Management of Unsealed Gravel Roads: State of the Practice in American Counties

This paper provides insights into the current state of the management of unsealed earth and aggregate roads, with a particular emphasis on rural counties of the American West. As part of an effort to develop a methodology for the management of unsealed roads, considerable information about unsealed roads management practices both in the United States and abroad was compiled. The results of two recent surveys also help describe the current state of roadway management by smaller agencies. Legal, accounting, technical, and financial barriers to improving unsealed roads management are discussed, along with ways these problems may be overcome.

Identification of the mineral phases responsible for cementation of Lurgi spent oil shale

ABSTRACT Very large volumes of solid waste are generated during oil shale retorting. The reclamation and use of these wastes are desirable from an environmental and economical point of view. Two of the primary considerations in the disposal of these wastes are their structural integrity and the leaching of toxics into groundwater. The spent shale used in this study was generated from oil shale mined from the Green River Formation in the Piceance Basin of western Colorado. The oil shale was processed using the Lurgi-Ruhrgas method (Schmalfeld 1975). The spent shale was packed in the Harvard miniature apparatus (Soiltest 1964) forming columns using three different water contents. Subsequently, the columns were allowed to cure for periods ranging from one day to eight weeks. Pour types of analyses were performed on the cured columns. X-ray diffraction (XRD), scanning electron microscopy with an energy dispersive X-ray analyzer