Using X-Ray Fluorescence to Assess Soil Subgrade Stabilization Competency During Construction Inspection

ODOT SPR Item Number 2310A large portion of transportation corridor projects use lime and other calcium-based stabilizers to reduce soil plasticity, increase shear strength, reduce compressibility, and reduce volume changes when subjected to variations in water content. While design and construction practices for subgrade stabilization have been standardized, there is no extant quality control measures, particularly measures that are timely, cost effective, and accurate. Therefore, this study was undertaken to evaluate the ability of portable handheld X-ray fluorescence (PXRF) to detect calcium stabilizers in soil samples. The accuracy of Whole Rock XRF (WXRF) was evaluated and used to verify a variety of PXRF measurement techniques, including scan duration, particle size, and sample type. Additionally, the viability of PXRF in measuring soil sulfate content was investigated. It was concluded that the WXRF method is highly accurate in detecting both calcium and sulfate in soils, with average magnitude of deviation between WXRF-determined stabilizer content and actual stabilizer content of 0.3%. While the PXRF method found to be less accurate than WXRF, the average magnitude for clay samples was 2.1% and 10.6% for sand samples. Moreover, the existing calibration libraries do not require slope correction for calcium contents in lower ranges, but do not accurately measure calcium content in higher ranges. The calibration libraries for sulfate detection are able to accurately detect sulfate contents in the range of 0 to 8%, but require individual calibration coefficients

Demonstration of the Applicability of the New CPTU/SCPTU Correlations With Soil Parameter Evaluation

ODOT SPR Item Number 2308Nine test sites across the state of Oklahoma were investigated using the Seismic Cone Penetration Test with pore water pressure measurement (SCPTu). Field testing was conducted during wet and dry periods to observe the effect of moisture conditions on the data collected from the field. Disturbed and undisturbed samples were collected at each site to conduct laboratory tests and determine the properties of the soils tested. Using the field and laboratory data, correlations proposed in the literature to predict various soil properties were tested for their applicability to Oklahoma Soils. Results showed that some existing and new correlations may provide reasonable first approximations of soil properties. However, there is considerable uncertainty with these correlations based on scatter observed in the comparisons to SCPTu and laboratory test data gathered in this current study. Additionally, it was observed that the moisture conditions at the time of SCPTu has a considerable influence on predicted soil properties

Guidelines for the Use of Fiber Reinforced Soil (FRS) in Highway Construction

DTRT13-G-UTC36Fiber Reinforced Soil (FRS) is essentially polypropylene fibers mixed with soil to reinforce the soil mass against shear or tensile failure. This concept has been in use in one form or another throughout history such as clay bricks and mud roofs reinforced with straw in traditional construction in many parts of the world. However, despite its proven record, long history, affordability and ease of construction, this technology has been underutilized, primarily because until relatively recently, extensive laboratory testing, usually in the form of time-consuming and complex triaxial and direct shear tests, was required in order to determine an appropriate application rate. In other words, if an engineer was interested in using FRS, extensive testing was required for each fiber type and range of concentrations of possible interest. However, with significant developments in theoretical models, laboratory testing and field application and verification in the recent years, soil and fiber properties can be used as input values in mathematical models to predict the magnitude of increase in shear strength of the FRS relative to the unreinforced (i.e. raw) soil, and use the resulting data in stability analysis programs to obtain the desired factors of safety in the earthwork project at hand. When the engineer is satisfied with a potential fiber type and application rate, targeted verification tests can be performed as necessary to improve confidence in design. FRS is applicable to a wide range of projects (e.g. retaining walls, slopes, foundations, and pavement subgrades). However, the focus of this study was on its application in repairing shallow slope failures. This report contains a brief review of different slope stabilization techniques beyond soil reinforcement, followed by descriptions of major discrete models developed for FRS, sample preparation and testing procedures in the laboratory, important concepts, and field implementation. Two case studies are also provided together with detailed slope stability calculations, which illustrate alternative methods of using commonly available slope stability analysis programs in combination with FRS data from spreadsheet calculations vs. special programs which can accept fiber properties and application rate as input values in their algorithms. The case study projects included in this report constitute the largest applications of FRS in the United States

A Systems Approach for Design, Construction, and Maintenance of Bridges and Adjacent Roadways

ODOT SPR Item Number 2307Previous research projects funded by the Oklahoma Department of Transportation, Federal Highway Administration, and other agencies have revealed that many problems faced by bridges, such as expansion joints closing, are related to how the interfaces between a bridge and the adjacent roadway are designed, constructed, and maintained. Design, construction, repair, and maintenance guidelines to alleviate some of the problems related to the interactions between bridges and adjacent roadways are developed. The recommendations are based on published literature, adopted regional practices, field observations, field monitoring, and computer simulations. Pressure relief joints for excessive pavement pressure were installed and monitored at three bridges. The efficacy of ultra-high performance concrete (UHPC) as a possible solution for bridge expansion joint headers was also studied. To better understand the behavior of tall bridge approach embankments constructed on soft soils, computer simulations were performed using the finite element software PLAXIS 2D. To ensure satisfactory bridge performance, it is necessary to put pressure relief joints in rigid pavements leading up to bridges. When bridge embankments are built on soft foundation soils, and especially for taller embankments, the potential for lateral deformation of the embankment should be considered. A water barrier should be incorporated in the abutment backfill design to keep infiltrated water from short circuiting the backfill drainage system. UHPC is a viable alternative for joint headers and has excellent durability. Additional recommendations for conventional, semi-integral, and integral bridges are also presented

Design and Monitoring of Non-Proprietary UHPC Joints of Precast Elements

ODOT SPR Item Number 2313This project included collection of UHPC connection details utilized by other states and examination of those details for applicability to use with the OU J3 non-proprietary UHPC, examination of different fiber sources and the effect of those fibers on properties of the OU J3 UHPC mix, consultation on and monitoring of UHPC projects in Oklahoma, and development of materials for using in training ODOT personnel relative to UHPC mix design and construction. UHPC connection details used in several different states were examined for applicability to use in Oklahoma with non-proprietary UHPC. The research team provided input on upcoming and ongoing bridge projects utilizing UHPC and UHPC connections in one ongoing project and several completed projects were monitored throughout the project. The steel fibers used in previous studies on locally developed J3 non-proprietary UHPC are no longer available and mechanical response and durability of J3 UHCP with varying fiber contents of a new source of straight steel microfibers and long hooked-end fibers intended for use in structural applications were measured. A series of PowerPoint presentations providing an introduction to UHPC, description of non-proprietary UHPC mix design, training on UHPC mixing, placement, and testing, and results of research on non-proprietary UHPC were prepared. These presentations were used to conduct two workshops and one free in-depth web training in conjunction with the Accelerated Bridge Construction University Transportation Center

Water reuse in a paper reprocessing plant /

Includes appendices.Prepared by School of Civil Engineering & Environmental Science, University of Oklahoma, Norman Okla., and Big Chief Roofing Company, Ardmore, Okla., under grant S-801206.Includes bibliographical references (pages 67-71).Mode of access: Internet