15 research outputs found
Experimental Approach Embankments at Salt Fork River Bridges on US 177 and Their Initial Performance
This paper presents preliminary findings based on the initial performance evaluation of five approach embankments used in a bridge replacement project over the Salt Fork of the Arkansas River on US Highway 177 in Noble and Kay Counties, Oklahoma. The research involved instrumentation and measurement of four experimental approach embankments and one control approach embankment, all with similar dimensions. Instrumentation inc1uded total pressure cells to measure lateral earth pressure against the abutment wall, inclinometer casings to measure lateral movement of the backfill material and abutment walls, telescoping couplings on the inclinometer casings to measure settlement of the backfill and foundation, amplified liquid settlement gages for measurement of foundation settlement, and piezometers to measure pore water pressure. The four experimental backfills used were geotextile reinforced granular backfill, controlled low strength material backfill, dynamically compacted granular backfill, and flooded and vibrated granular backfill. The control section was unclassified borrow material placed at the contractor\u27s discretion as long as density requirements were met. This paper documents and presents summaries of the preliminary findings regarding initial performance and construction cost of each approach embankment
Subgrade moisture variations interim report IX Effectiveness of existing highway designs
The purpose of this study was to determine which existing Oklahoma highway designs give acceptable performance and why/how they resist the effects of subgrade moisture variations. After a review of pertinent factors to be considered in evaluating both pavement performance and subgrade moisture conditions, a study of designs existing at 50 field research sites was made to determine which designs were performing well and the relations between particular design performance and observed subgrade moisture conditions. Results of the study indicate that the type of wearing surf ace had little effect on either pavement performance or subgrade moisture conditions, with underlying components being responsible for both. In general, the best performance was obtained from designs incorporating improved shoulders, flexible, impervious, or semi-pervious base materials continuous under pavement and shoulder, subbases, and adequate drainage.Interim Report IXN
Evaluation of dynamic compaction in Tulsa, Oklahoma (FHWA-OK-86-3) 2141
This report describes the installation and monitoring of three test sections
to evaluate dynamic compaction as it was applied as a foundation
treatment for the approach fills of an interchange on the Gilcrease Expressway
(SH 11) in north central Tulsa. The test sections were monitored
to assess the performance of dynamic compaction and to provide the
data base for recommending changes to the construction process as foundation
conditions varied.
Evaluation of the results obtained from the three test sections monitored
during the dynamic compaction process indicated that the process improves
the strength characteristics of strip mining spoil containing clay with
shale fragments and trash. The most consistent improvement occurred in
areas where the thickness of the trash was less than a few feet. The presence
of a groundwater table did not appear to adversely affect the results.
In areas of thicker trash layers, stone columns were successfully
constructed using dynamic compaction. With the exception of the inclinometers,
all instrumentation performed well and provided very good data to
evaluate the dynamic compaction procedure.Final ReportN
VALIDATION AND REFINEMENT OF CHEMICAL STABILIZATION PROCEDURES FOR PAVEMENT SUBGRADE SOILS IN OKLAHOMA – VOLUME II (FHWA-OK-11-02(2))
For projects involving a chemically stabilized layer as a part of the structural design of the pavement, it is typical to conduct a mix design to assess the additive content needed to achieve a certain unconfined compressive strength (UCS) and to determine the resilient modulus (MR) of the stabilized soil. However, there is considerable uncertainty regarding whether the strength and resilient modulus of the field stabilized soil are consistent with design values determined in the laboratory. A purpose of this study was to compare results of field tests and laboratory tests on chemically stabilized soil at different curing times to assess whether a relationship exists between field and laboratory measurements. The goal was to determine if a field testing method could be used to assess whether the strength and stiffness in the field are consistent with laboratory measurements used for design. In addition, numerous other physical and chemical tests were conducted on the soils with an aim to enhance interpretation of UCS and MR and comparisons to field tests.
Field testing included three devices that are portable, quick, and easy to use. These devices include: the Dynamic Cone Penetrometer (DCP), the PANDA penetrometer, and the Portable Falling Weight Deflectometer (PFWD). Laboratory testing was conducted to determine the unconfined compressive strength (UCS) and resilient modulus (MR) of laboratory specimens prepared using additive contents that were similar to samples taken from field test locations. To estimate the additive contents in the field samples, a mineralogical test method known as “whole rock analysis” using x-ray fluorescence (XRF) was investigated. Samples mixed in the laboratory were tested to determine the UCS and MR after curing times of 1, 3, 7, 14, & 28 days. Field tests were conducted at each of the five test sites after curing times that fell within the 1 to 28 day time frame; however, because of construction logistics and weather conditions it was not always possible to match the curing times of laboratory tests or conduct field tests over the full 28 days at every site. Nevertheless, sufficient field data was collected to make meaningful comparisons with laboratory test data.
Mineralogical, electrical, chemical, physical and index property testing (Atterberg Limits, linear shrinkage, Total Specific Surface Area (SSA), etc.) was conducted on the natural soils and the stabilized cured samples to observe the relationship of these properties to stabilized soil strength and stiffness. The effect of curing temperature on stabilized strength gain of soils was also examined. The UCS samples were cured at both room temperature (68°F) and at 40°F, which is the minimum ambient temperature specified for chemical stabilization of subgrades.
Correlations were examined and involved basic soil measurements (mineralogical, electrical, chemical and index properties) and mechanical properties (UCS and MR), and field test results (DCP, PANDA, and PFWD). Some of the various correlations developed show promise as methods for predicting UCS and MR based on more simply measured soil properties. Relationships between field and laboratory tests also show promise as a means to evaluate strength and stiffness gains in field stabilized soils. Additionally, lower curing temperatures were observed to have an adverse affect on more reactive clayey soils.Final Report, October 2007-December 2010N
VALIDATION AND REFINEMENT OF CHEMICAL STABILIZATION PROCEDURES FOR PAVEMENT SUBGRADE SOILS IN OKLAHOMA – VOLUME I FINAL REPORT (FHWA-OK-11-02 2207)
Additions of byproduct chemicals, such as fly ash or cement kiln dust, have been shown to increase the unconfined compression strength (UCS) of soils. To be considered effective, the soil must exhibit a strength increase of at least 50 psi. Many current design methods base chemical additive percentage recommendations on the results of Atterberg Limit tests which do not always properly characterize the soil stabilization response. For example, Atterberg limit tests may reveal the same AASHTO classification of soil at two different sites, but one site may require more than twice the additive percentage of a chemical to achieve the desired UCS increase.
This study examined the relationship between soil physico-chemical parameters and unconfined compression strength in various fine-grained soils to determine if other soil parameters have significant effects on predicting the strength of a soil treated with a given additive and additive content. The results of this study suggest that the surface area and shrinkage properties of the soil, combined with the Atterberg limit results, present a better picture of a given soil and will allow for better predictions of the amount of chemical stabilizer needed to adequately stabilize the soil.Final Report, October 2007-December 2010N
Winter performance and thermal environment of swine in a modified open-front house
Digitized by Kansas Correctional Industrie
Depressed transverse cracks in asphalt pavements in Oklahoma (FHWA-OK-92-1) 2166
Transverse cracking of asphalt pavements is a costly pavement distress occurring in states that experience cold/freezing temperatures during the winter months. The cracks are caused by low temperature-induced tensile stresses that exceed the tensile strength of the pavement material. The majority of these cracks occur in the transverse direction relative to the pavement and with regular frequency along the roadway. The'majbr objectives of this research included: 1. Determine the nature and extent of transverse cracking in asphalt pavements in Oklahoma. 2. Conduct a field and laboratory investigation of pavement materials and highway features to determine and evaluate the various factors that influence transverse cracking. 3. Review ODOT practices for dealing with transverse cracking of asphalt pavements. The results of the research project confirm that the transverse cracking of pavements is a thermally-induced problem. Based on evaluation of collected data, the number of cracks increased and the average spacing decreased as the average low monthly temperature decreased. De pressions associated with transverse cracks were influenced by subgrade moisture conditions; specifically, as the average subgrade moisture content increased, the occurrence and severity of the depressions increased. Transverse cracking and particularly depressed transverse cracks appear to be more of a problem on fine-grained soil subgrades. Transverse cracking of asphalt pavements is a problem across the state of Oklahoma with severity of the problem varying from division to division based on such factors as pavement age, pavement cross section, traffic, asphalt properties, and maintenance procedures. Although maintenance and remedial procedures vary across the state, ODOT's procedures are consistent with those reported by surrounding states.Final Report, February-September 1998, September 1988-July 1991N
Depressed transverse cracks in asphalt pavements in Oklahoma (FHWA-OK-91-__) 2159
Transverse cracking of asphalt pavements is a costly pavement distress occurring in states that experience cold/freezing temperatures during the winter months. The cracks are causedˆ by low temperature-induced tensile stresses that exceed the tensile strength of the pavement material. The majority of these cracks occur in the transverse direction relative to the pavement and with regular frequency along the roadway. The major objectives of this research included: 1. Determine the nature and extent of transverse cracking in asphalt pavements in Oklahoma. 2. Conduct a field and laboratory investigation of pavement m ateri als and highway features to determine and evaluate the various factors that influence transverse cracking. 3. Review ODOT practices for dealing with transverse cracking of asphalt pavements. The results of the research project confirm that the transverse cracking of pavements is a thermally-induced problem. Based on evaluation of collected data, the number of cracks increased and the average spacing decreased as the average low monthly temperature decreased. Depressions associated with transverse cracks were influenced by subgrade moisture conditions; specifically, as the average subgrade moisture content increased, the occurrence and severity of the depressions increased. Transverse cracking and particularly depressed transverse cracks appear to be more of a problem on fine-grained soil subgrades. Transverse cracking of asphalt pavements is a problem across the state of Oklahoma with severity of the problem varying from division to division based on such factors as pavement age, pavement cross section, traffic, asphalt properties, and maintenance procedures. Although maintenance and remedial procedures vary across the state, ODOT's procedures are consistent with those reported by surrounding states.Final Report February-September 1988. September 1988-July 1991.N