Stabilization of Subgrade Soil using Hydrated Lime Product

The Carbide/Graphite Group Inc. requested the University of Kentucky, Kentucky Transportation Center to do a feasibility study to determine if a hydrated lime product produced at their Calvet City, Kentucky facility can be used as a soil subgrade stabilizing agent

Embankment Construction Using Shale

Shales have been used extensively in the construction of highway embankments, and other earthen structures, because of the vast amounts of these materials located in many areas of the country and the lack of economical and alternate available materials. Because shales exhibit a wide range of engineering properties and behaviors, many problems have occurred. Numerous shale embankment failures have occurred generally some 1 to 10 years after construction. Settlements of 1 to 3 feet (0.3 - 0.9 m) have been observed in many old embankments and required numerous asphaltic overlays. Shale embankments that settle continuously have been observed to fail eventually. Each year millions of dollars are spent repairing embankments built with shales. This report presents a discussion of some of the research conducted by the University of Kentucky Transportation Center in the seventies and eighties and attempts to address some of the problems that arise in constructing shale embankments. A brief overview of the engineering properties of shales located in Kentucky is presented. Some important factors that need to be considered in designing and building shale embankments are briefly discussed. Finally, a description of the construction of three experimental shale embankments in 1986 is given. These embankments were constructed to evaluate a special shale compaction provision adopted by the Kentucky Transportation Cabinet to avoid large long-term settlements and instabilities. Observations of long-term settlements of the embankments are presented

Use of Hydrated Lime Byproduct for Stabilization of Subgrade Soils

In January 1998, Minteck Resources requested that the Kentucky Transportation Center at the University of Kentucky perform a feasibility study to determine if a hydrated lime byproduct produced at the Carbide/Graphite facility in Calvet City, Kentucky can be used as a substitute for hydrated lime as a soil subgrade stabilizing agent. According to personnel of Carbide/Graphite Group, Incorporated, the byproduct contains a high percentage of hydrated lime

Stabilization of an Airport Subgrade using Hydrated Lime and Fly Ash

A 457-m (1,500-ft) runway pavement extension is planned for the Georgetown-Scott County Airport (Marshall Field). The clay subgrade of the existing paved runway was stabilized with six percent (dry weight) hydrated lime. A request was made by the Kentucky Transportation Cabinet, Division of Aeronautics, to determine the feasibility of replacing a percentage of the hydrated lime stabilizer with fly ash for the extended runway subgrade. Kentucky Highway Investigative Task No. 27 was issued by the Transportation Cabinet to fund a laboratory study to determine the effects of partially replacing lime with Type F fly ash (FA). Using fly ash to replace lime could potentially, reduce stabilization cost and provide a means of using fly ash as a byproduct in lieu of landfill disposal. The subgrade extension was previously constructed to final grade with clay soils. A thin layer of topsoil and grass currently covers the subgrade. Stabilization of the extended runway is planned during pavement construction

MIUS integration and subsystems test program

The MIUS Integration and Subsystems Test (MIST) facility at the Lyndon B. Johnson Space Center was completed and ready in May 1974 for conducting specific tests in direct support of the Modular Integrated Utility System (MIUS). A series of subsystems and integrated tests was conducted since that time, culminating in a series of 24-hour dynamic tests to further demonstrate the capabilities of the MIUS Program concepts to meet typical utility load profiles for a residential area. Results of the MIST Program are presented which achieved demonstrated plant thermal efficiencies ranging from 57 to 65 percent

Rockfall Mitigation Measures

Highways in Kentucky contain numerous rock slopes and rockfall from these slopes represent potential dangers to motorists. As these highway rock cut slopes age and deteriorate because of weathering, the potential for rockfall and rock slides increases. Some bodily injuries and traffic fatalities have been reported in past years. The general aims of this study were to establish a highway rock cut slope policy and devise a statewide system of dealing with this problem. This study represents the start of an effort by the Kentucky Transportation Cabinet to develop a proactive stance and policy toward preventing, minimizing, or mitigating the rockfall problem on the Cabinet\u27s highways and to establish a rockfall risk management program. As this study shows, the vast majority of rockfall problems in Kentucky occur in counties located east of Interstate 75. Preliminary rockfall hazardous ratings of all rock cut slopes­ – some 5270 slopes – on the Interstates, Parkways, and most Primary routes were performed using the rockfall hazardous rating system (RHRS) devised by Pierson and Vickle of Oregon DOT. This approach appears to be a good system for rating the potential for rockfall at a given highway rock cut location. Some 180 slopes were identified as hazardous. Detailed numerical ratings were performed at those locations. Differential weathering and structural characteristics – jointing and unfavorable orientations – were the major causes of rockfall. Few mitigation measures have been used on Kentucky\u27s highways. For the sedimentary rock strata in Kentucky, benching of rock slopes appears to be very effective in preventing, or mitigating, rockfall on Kentucky\u27s highways. The rock cut slope design guidelines used by the Cabinet appear to be sound. The basic problem is not design standards, but the fact that many of the highway rock slopes are aging, weathering, and deteriorating. With aging, rockfall problems will continue to increase with time. The computer rockfall simulation program devised by Colorado engineers was used to analyze several case studies of rockfall. This program appears to a very good analytical tool for assessing the stability and safety of existing rock slopes and newly designed rock slopes and will be useful in devising remedial and mitigating plans at rockfall sites

Long-Term Performance of Flexible Pavements Located on Cement-Treated Soils

Long-term performance of flexible pavements located on cement-treated soils and the longevity of soil-cement subgrades are examined at sections of four highway routes. Ages of the soil-cement subgrades range from 6 to 30 years. Field and laboratory studies were conducted at each section. Generally. the soil-cement subgrades were non-plastic and were classified as SM, or sandy silt, according to the Unified Soil Classification System, although the classification of the untreated soil subgrades located below the treated layers ranged from CL (clay) to GC (clayey gravel). Plasticity index of the untreated soils ranged from non-plastic to 44 percent. Generally, the untreated soils were moderately plastic. In situ bearing ratios of the soil-cement subgrades were generally very large. Based on a percentile test curve, the in situ bearing ratios of the cement-treated subgrades at the 90th and 50th percent test values were about 24 and 90, respectively. Based on overlay histories of the routes, flexible pavements located on the soil-cement subgrades have performed well. In the older sections, overlays had been constructed every 11 to 14 years. Use of cement to construct stabilized subgrades represents a good design alternative when compared with other stabilizing methods and other design alternatives