bluuebunny/crossref_metadata_2025 huggingface dataset:
Constant Flow Method for Concurrently Measuring Soil-Water Characteristic Curve and Hydraulic Conductivity Function
Authors: Lu N , Wayllace A , Carrera J , Likos WJ
Published: March 2009

A constant-flow laboratory testing method (CFM) is presented for concurrently measuring the soil-water characteristic curve (SWCC) and hydraulic conductivity function (HCF) of unsaturated coarse-grained soils. Two computer-automated syringe pumps are employed to control the volumetric water content of a specimen and to periodically impose constant volumetric flow rates through the specimen, respectively. Hydraulic conductivity (k) corresponding to each water content increment is determined from Darcy's law by measuring the steady-state gradient induced by the applied constant flow. Matric suction is maintained by axis translation using elevated pore air pressure and high-air-entry ceramic disks. Diffused air bubbles are removed using unique passive bubble traps. SWCCs and HCFs are obtained for three sandy soil specimens, requiring about 25–35 days to obtain both functions for each soil. The range of the system is demonstrated for k from about 10−4 cm/s to 10−9 cm/s at corresponding matric suction between about 0 kPa (saturated) and 40 kPa. Results are validated by comparison with independent SWCC measurements obtained using Tempe cells and HCFs estimated using a statistical model.
Triaxial Compression of Clay Reinforced with Sand-Coir Fiber Core
Authors: Vinod P. , Bhaskar Ajitha , Lekshmi C. S.
Published: March 2009

This paper describes the results of a study into the undrained response of clay specimens reinforced with sand-coir fiber cores in triaxial tests. Coir, used to reinforce sand, is the processed fiber from the husk of coconuts. Coir combines the properties of biodegradability and fiber strength, and remains an under-utilized material of great potential value for ground improvement in parts of the world where such materials are available in abundance. A thin PVC pipe kept centrally inside a split mold is used to form the core in the triaxial tests. The clay is placed inside the mold around the PVC pipe at maximum dry unit weight—optimum moisture content condition while the sand-coir mixture is placed inside the pipe at the same bulk unit weight as that of clay. Influence of variables such as replacement area ratio (ratio of cross-sectional area of sand-coir fiber core to that of the triaxial test specimen), confining pressure, fiber content, and fiber aspect ratio on the behavior of the composite soil specimen is identified and isolated. It is found that stress-strain strength properties of clay specimens reinforced with sand-coir fiber core is appreciably better not only when compared with untreated clay specimens but with sand core reinforced clay specimens as well. Such an improvement is of importance to allow reduced requirement of sand and increased use of natural fiber. An optimum fiber content of 1 % (by weight) was identified for strengthening of the sand core. The reinforcement effect is found to increase appreciably with increase in replacement area ratio and to a smaller extent with increase in fiber aspect ratio. The larger reinforcement effect observed at higher confining pressures suggests that the proposed method is more effective at greater depths.
Drip Injection of Chemical Grouts: A New Apparatus
Authors: Hayashi S , Chai XJ , Matsunaga K , Toki A
Published: March 2009

The tip structure of conventionally used drip injection apparatus for chemical grouting has the defect that the chemical grouts flow upwards to the ground surface frequently, which reduces the accuracy and efficiency of injection significantly. Normally, cement and bentonite are used for sealing the gap between injection tube and drill hole, the performance of which is not satisfactory. In this study, a balloon cover injection tip (called BCIT) has been developed. The special tip structure of the injection tube prohibits the chemical grout flowing upward to the ground surface. In particular, BCIT can implement down-to-up chemical grouting due to its soft and tight attachment with the drill hole sides. The main advantage of the BCIT is its simplicity, portability, adaptability, and accurate injection quantity management. Further, this can be used effectively for small-scale strengthening and preservation of historical remains with complicated geographic features without spoiling their appearance. In the laboratory, the feasibility of BCIT apparatus has been verified by chemical grouting in model ground, which simulates the practical condition of Funasako kiln sites. A soil hardness tester was used to evaluate the strength of the solidified body.
Shear Strength and Stress-Strain behavior of Contaminated Soils
Authors: Ratnaweera P , Meegoda JN
Published: March 2009

A series of unconfined compression tests performed on fine-grained soils contaminated with varying amounts of chemicals showed a decrease in shear strength and stress-strain behavior. These observations were attributed to changes in dielectric constant and pore fluid viscosity. Consolidated drained triaxial tests performed on a granular soil showed a similar behavior, even though granular soils do not show a physicochemical interaction between soil and pore fluid. This is attributed to mechanical interactions at particle contacts, caused by enhanced lubrication by viscous pore fluids. For fine-grained soils, the observed reduction in shear strength is attributed to physicochemical effects caused by a reduction in dielectric constant and mechanical interactions caused by high pore fluid viscosities. Observations show that the reduced physicochemical interactions seem to have been overshadowed by mechanical interactions. The clayey silt tested showed a marginal reduction in shear strength, indicating that the net effect is insignificant.
A Convenient Graphical Representation of Compaction Data
Authors: Chapuis RP , Mbonimpa M , Aubertin M , Dagenais A-M
Published: March 2009

The results of compaction tests are usually presented as dry density versus molding water content. In the corresponding graph, the curves of levels of saturation appear as hyperbolas. A new graphical presentation is proposed where the inverse of the dry density is plotted against the molding water content. In this convenient representation, all curves of equal degree of saturation become straight lines, which facilitates plotting and interpolation. It appears also more practical to establish a linkage with other graphs, such as those relating mechanical or hydraulic properties, to void ratio.
New Sample Holder for the Preparation of Undisturbed Fine-Grained Soil Specimens for Laboratory Element Testing
Authors: Wijewickreme D , Sanin MV
Published: March 2009

The paper describes a new soil sample holding device, the undisturbed soil sample holder (USSH), which has the ability to minimize potential sample disturbance during the preparation of relatively soft fine-grained cylindrical soil specimens. The USSH is capable of providing suitable external, uniform lateral confinement to a sample of soil extruded from a field sampling tube. The device comprises a split hollow cylindrical aluminum housing that is internally lined with a flexible synthetic foam material. The foam lining allows the diameter of the cylindrical cavity of the USSH to be variable, while maintaining the shape of the cavity cylindrical. The device has the ability to essentially eliminate the sample freestanding period that is commonly associated with conventional preparation methods and to reduce potentially significant soil deformations that occur due to the self-weight of the sample. The effectiveness of the USSH in minimizing sample disturbance is demonstrated using comparative laboratory tests conducted on relatively soft soil specimens prepared with and without the USSH. The observed axial strains during specimen preparation, volumetric strains during consolidation, and stress-strain-pore water pressure response during undrained triaxial shear testing show that the USSH contributes to the preparation of undisturbed soil specimens for element testing.
Viscous Effects on the Stress-Strain Behavior of Gravelly Soil in Drained Triaxial Compression
Authors: AnhDan L , Tatsuoka F , Koseki J
Published: March 2009

A series of special drained triaxial compression tests using a large-scale triaxial apparatus was carried out to study the viscous properties of gravelly soil. To evaluate loading rate effects on the stress-strain behavior, the axial strain rate was changed stepwise during otherwise monotonic loading (ML) at a constant strain, which resulted in a sharp increase or decrease in the deviator stress. Drained creep loading tests were also performed at several deviator stresses during otherwise monotonic loading and unloading along different stress paths. The amount of creep strain increased with an increase in the deviator stresses. The stress-strain behavior was nearly elastic for some stress range immediately after ML was restarted at a constant strain rate following each creep stage. The viscous properties of partially and fully saturated specimens were essentially the same.
Monitoring the Hydraulic Conductivity of Crushing Sands
Authors: Valdes JR , Caban B
Published: March 2009

Crushing occurs when particles are subjected to sufficiently high external stresses. The crushing process leads to the production of fragments and to ensuring changes in void ratio, pore sizes, specific surface, and hydraulic conductivity. This paper presents a study of the changes in hydraulic conductivity that take place during particle crushing in sand specimens. A new one-dimensional compression cell modified for double-ring permeametry was used to measure the hydraulic conductivity of various sands during crushing and is described in detail in this paper. The device, procedures, and data analyses incorporate arching and localized crushing effects, and are presented as a development towards a new testing standard for determining hydraulic conductivity degradation curves that result from crushing of sands subjected to large stresses. Results show that the hydraulic conductivity degradation curve is dependent on sand type, in particular the particle shapes and mineral composition. The role of arching on the compression behavior and the associated post-crushing grain size distribution curves is also addressed.
The Use of Filter-Paper and Suction-Plate Methods for Determining the Soil-Water Characteristic Curve of Undisturbed Colluvium Soils
Authors: Feuerharmel C , Gehling WYY , Bica AVD
Published: March 2009

The relationship between matric or total suction and gravimetric water content, volumetric water content, or degree of saturation is denoted as the soil-water characteristic curve. This relationship has been widely used for predicting the engineering behavior of unsaturated soils. Residual and colluvium soils from tropical and subtropical regions often show bimodal-shaped soil-water characteristic curves, indicating that both micropores and macropores present in these soils govern the inflow and outflow of water. The objective of this paper is to discuss testing methods adequate for obtaining soil-water characteristic curves of bimodal shape, particularly by the combined use of the suction-plate method (suction < 10 kPa) and the filter-paper method (5 kPa < suction < 30 000 kPa). The soil-water characteristic curves of two undisturbed colluvium soils from Southern Brazil are then presented to highlight the application of those methods.
Twin-Cell Stress Path Apparatus for Testing Unsaturated Soils
Authors: Sivakumar R , Sivakumar V , Blatz J , Vimalan J
Published: March 2009

Determination of specific volume changes of unsaturated soils remains a challenging issue in soil testing for a number of reasons. Various attempts have been made over the years to improve the techniques of sample volume change measurement. This technical note reports the benefit of using a fully automated twin-cell stress path apparatus for measuring sample volume change and hence determining the specific volume. The system requires calibration for apparent volume change due to expansion of plastic tubes and connections. The results have shown excellent repeatability of the apparent volume change during the loading and unloading process.
Identification of Collapsible Soil Using the Fall Cone Apparatus
Authors: Ayadat Tahar , Hanna Adel
Published: March 2009

Soils that go through a great loss of volume upon wetting with or without additional loads are identified as collapsible. In recent years, there has been an increasing awareness of this type of soil due to the expansion of urban developments to arid regions. Also man-made earth structures often exhibit collapsing behavior when compacted at water content less than the optimum moisture content.

In the literature, methods can be found to predict this behavior based on field and laboratories test results. These methods, however, are time consuming and developed for the type of soils tested.

This paper presents the results of an experimental investigation on collapsible soils using the fall cone and the oedometer apparatuses. The fall cone method, originally developed to determine liquid and plastic limits of soils, was adopted in this investigation to identify its collapse potential. A cone penetration limit (Plim) is introduced to identify collapsible soil and a correlation between the collapse potential, CP, and the cone penetration, P, was developed and validated with the present experimental results and those available in the literature. Furthermore, a simple procedure is introduced to determine the optimum Proctor Moisture Content for collapsible soils from the results of the cone test. The proposed procedure is simple and fast to evaluate soil collapsibility by a single reading of the cone penetration.
An Improved Experimental Test Set-up to Study the Performance of Granular Columns
Authors: Black J , Sivakumar V , Madhav MR , McCabe B
Published: March 2009

This paper describes an innovative design of a newly developed large test setup for testing the performance of footings supported on soft clay reinforced with granular columns. This advanced testing method is used to examine the settlement of footings supported on granular columns. Two important features of the equipment are (a) the axial loading system which allows samples to be consolidated under Ko condition while the load is applied onto a small foundation area of the sample, and (b) a relatively large sample size of 300-mm diameter and 400-mm high. The system is also equipped with pressure cells located beneath the footing and top cap to measure the pressure distribution with respect to foundation displacement and a lateral strain gage to monitor boundary effects. This paper reports on some of the early findings from the preliminary tests carried out using this equipment. Samples for testing were prepared by consolidating kaolin slurry in a large one-dimensional consolidation chamber. The granular columns were installed using the replacement method by compacting crushed basalt (uniformly graded with 90 % between 1.5–2-mm particle sizes) into a preformed hole. The preliminary tests have yielded promising results, validating the functionality of the equipment and support the prospect of increasing the knowledge with respect to settlement response and design of a footing supported on granular columns.
Centrifuge Modeling of Solid Waste Landfill Systems—Part 2: Centrifuge Testing of Model Waste
Authors: Indrasenan Thusyanthan N , Gopal Madabhushi SP , Singh S
Published: March 2009

This paper presents the use of the model waste developed in the companion paper, “Centrifuge modeling of solid waste landfill systems—Part 1: Development of a model municipal solid waste,” in centrifuge testing. Two centrifuge tests were performed using the model waste to understand the static and dynamic behavior of municipal solid waste (MSW) landfills. First centrifuge test demonstrates the use of model waste to study the settlement profile in a landfill. In the second centrifuge test model earthquake loadings were applied to the model waste to investigate its dynamic behavior. The results were used to obtain shear modulus reduction and damping curves of the model waste. These curves were shown to match with those reported for MSW validating the use of model waste to study the seismic behavior of MSW landfills.
Development of TDR Penetrometer through Theoretical and Laboratory Investigations: 2. Measurement of Soil Electrical Conductivity
Authors: Lin CP , Chung CC , Tang SH
Published: March 2009

A TDR penetrometer was introduced to allow simultaneous measurements of dielectric permittivity and electrical conductivity during cone penetration. This study focused on the theoretical development and experimental evaluation of electrical conductivity measurement using the TDR penetrometer. Theoretical development takes into account the cable resistance and nonconducting cone shaft, leading to a new data reduction equation and calibration procedure. Measurement sensitivity and spatial sampling bias were experimentally evaluated for various probe configurations. The results show that the measurement sensitivity of interest may be controlled by the geometric factor of the probe. The complication and implications of the spatial weighting bias are discussed. A prototype TDR penetrometer was calibrated and used to perform simulated penetration tests in a soil. Experimental results do not show significant errors in electrical conductivity due to the penetration disturbance, verifying the effectiveness of the TDR penetrometer for electrical conductivity measurement.
The Physical Basis for Quantitative Surface Analysis by Auger Electron Spectroscopy and X-Ray Photoelectron Spectroscopy
Authors: Powell CJ
Published: March 2009

A review is given of the physical basis for quantitative surface analysis by Auger electron spectroscopy (AES) and by X-ray photoelectron spectroscopy (XPS) or electron spectroscopy for chemical analysis (ESCA). The principal topics discussed are: the feasibility of surface analysis, approaches to surface analysis, description of models and data for surface analysis by AES and XPS, analytical methods, intensity measurements, practical considerations, applications, and reference materials.
Mechanical and Microstructural Properties Characterization of Heat-Treated, Beta-Extruded Ti-6A1-6V-2Sn
Authors: Ulitchny MG , Rack HJ , Dawson DB
Published: March 2009

The mechanical behavior of β-extruded Ti-6A1-6V-2Sn has been examined after a variety of subtransus heat treatments. Increasing strength has been found to result in a gradual decrease in fracture toughness. The fracture toughness that may be achieved at any given strength level is also a function of prior solution treatment. Optimum toughness at intermediate strength levels (yield strength of approximately 1035 MPa) is associated with lower solution treatment temperatures, while at high strength levels (yield strength of approximately 1200 MPa), the use of higher solution temperatures appears to enhance the maximum achievable toughness. Comparison of the present results with those previously obtained for α-β processed Ti-6A1-6V-2Sn also indicates that, at any given strength level, β processing will result in a higher fracture toughness and a somewhat lower tensile ductility.

Finally, microscopic evidence suggests that the ordering in the primary α phase which occurs after high temperature aging does not play a predominant role in limiting the fracture toughness of high strength α-β titanium alloys; indeed, the deformation limiting characteristics of the interface α phase may be the principal factor controlling the toughness of these alloys.
Influence of Composition, Annealing Treatment, and Texture on the Fracture Toughness of Ti-5A1-2.5Sn Plate at Cryogenic Temperatures
Authors: Van Stone RH , Shannon JL , Pierce WS , Low JR
Published: March 2009

The plane strain fracture toughness (KIc) and conventional tensile properties of two commercially produced 25.4-mm (1-in.) thick Ti-5A1-2.5Sn plates were determined at cryogenic temperatures. One plate was extra-low interstitial (ELI) grade, the other, normal interstitial. Portions of each plate were mill annealed at 1088 K (1500°F) followed by either air or furnace cooling. The tensile properties, flow curves, and KIc of these plates were determined at 295 K (room temperature), 77 K (liquid nitrogen temperature), and 20 K (liquid hydrogen temperature).

The air-cooled ELI plate was the toughest material evaluated. The KIc of the furnace-cooled ELI plate was about 25 percent below that of the air-cooled ELI material. Cooling rate from the annealing temperature had no influence on the toughness of the normal interstitial plates, both of which had a KIc approximately half that of the air cooled ELI plate. The 20 K fracture toughness of the normal interstitial plates varied only slightly with specimen orientation. The LS toughness of both ELI plates was approximately 20 percent greater than the LT toughness.

Based on these results and a study of the microstructural fracture mechanism, it is recommended that Ti-5A1-2.5Sn, which is to be used in applications requiring high fracture toughness, should have the lowest possible interstitial level and be air-cooled from the annealing treatment so as to prevent ordering.
Influence of Test Temperature on the Fracture Toughness and Tensile Properties of Ti-8Mo-8V-2Fe-3A1 and Ti-6A1-6V-2Sn Alloys Heat Treated to High Strength Levels
Authors: Chait R , Lum PT
Published: March 2009

This paper examines the mechanical properties of two high strength titanium alloys as a function of test temperature, namely, the α/β titanium alloy Ti-6A1-6V-2Sn (Ti-662) as well as the metastable β-alloy Ti-8Mo-8V-2Fe-3A1 (Ti-8823). Specifically, the paper characterizes the changes in fracture toughness and tensile properties at low and elevated test temperatures. The variation in fracture toughness is given by KQ and W/A, while for the tensile properties, it is given by the yield and ultimate tensile strength, reduction of area, and elongation. For Ti-8823 material, the characterization was conducted on material that was given either a solution treated-and-aged or an age treatment directly after fabrication. Heat treatments for the Ti-662 alloy were either a solution-treated-and-age or solution-treated-and-overaged. Results are discussed in terms of fractographs taken from broken fracture toughness and tension specimens.
Structural Design Significance of Tension-Tension Fatigue Data on Composites
Authors: Grimes GC
Published: March 2009

Constant cycle tension-tension fatigue and related static tension data have been generated on six single composite material/orientation combinations and twenty-one hybrid composite material/orientation combinations. Anomalies are related to the temperature rise and stopped interval creep, whereas endurance limit stresses (runouts) are associated with static proportional limit values, when they occur, and internal damage. The significance of these room temperature-dry data on the design allowables and weight of aerodynamic structures is discussed. Such structures are helicopter rotor blades and wing and horizontal stabilizer lower surfaces. Typical criteria for turning these data into preliminary allowables are shown, as are examples of such allowables developed from the data. These values are then compared to those that might be used if the structures were made of metal.
Acoustic Emission Response Characteristics of Metal Matrix Composites
Authors: Pipes RB , Ballintyn NJ , Scott WR , Carlyle JM
Published: March 2009

The primary objective of this research was to investigate acoustic emission techniques for nondestructive evaluation of the integrity of boron-aluminum composite materials. The approach taken centered upon the development of acoustic signatures for the unidirectional composite laminae subjected to both biaxial and uniaxial tension states of stress. Acoustic signatures for biaxial states of stress were developed through implementation of the off-axis tensile coupon. Fiber orientations examined include 15, 30, 45, 60 and 75 deg. Acoustic signatures also were obtained for uniaxial tension (0 deg) and transverse tension (90 deg) test specimen geometries. In addition to investigation of the acoustic properties of the boron-aluminum composite, a complete mechanical characterization was performed. Typical acoustic and mechanical characteristics for the boron-aluminum composites are presented.
Compression Testing of Large Gage Length Composite Coupons
Authors: Ryder JT , Black ED
Published: March 2009

A compression testing procedure for composites is described. Using the procedure large gage length, variable thickness specimens were tested. Buckling and end brooming were prevented by the testing procedure, and either extensometers or strain gages were used to record strain. Specimens were gripped on one end and compressed against a bearing plate on the other, but they can be gripped on both ends. The practicality of the testing procedure is demonstrated using compression test results for two different laminates of a graphite/epoxy composite. Types of failure modes are reviewed. The effects of extensometer attachment are discussed and comparisons made between strain readings using extensometers and strain gages.
Effect of Stacking Sequence on the Notched Strength of Laminated Composites
Authors: Whitney JM , Kim RY
Published: March 2009

The effect of laminate stacking sequence on the notched and unnotched tensile strength of quasi-isotropic graphite/epoxy laminates is investigated. Notch geometry includes circular holes and center cracks. Experimental data are presented for two different stacking sequences of quasi-isotropic graphite/epoxy laminates. One stacking sequence produces large interlaminar tensile stresses along straight free-edges of a tensile coupon, while the second yields compression at the same free-edges. Three different notch sizes are used for the circular hole and center crack in conjunction with both stacking sequences. Each data point is represented by a minimum of 15 replicates so that statistical distributions of notched and unnotched strengths can be obtained. The experimental data indicate that unnotched tensile strength is reduced by the presence of interlaminar tensile stresses at the straight free-edge, while notched strength appears to be independent of stacking sequence for notch sizes which produce tensile failure prior to delamination at the straight free-edge.

Experimental results also are compared against theoretical notch strengths obtained from the average stress criterion and the point stress criterion, two recently developed criteria for predicting notch strength of laminated composites.
Effects of Themal Cycling on the Properties of Graphite-Epoxy Composites
Authors: Mazzio VF , Mehan RL
Published: March 2009

There is strong evidence that weaker composites, regardless of fiber content, tend to cleave on a single plane, while stronger specimens exhibit extensive fracture zones as a result of cumulative damage. This type of behavior is the same before and after thermal cycling of specimens up to 500 cycles.

Assessment of the mechanical and thermal cycling behavior of engineering composites has been extended to include transverse tensile, compressive, and flexural properties, as well as the longitudinal tensile properties and short-beam shear strength. After cycling, the 55 volume percent 0-deg tensile modulus exhibits a five percent loss. In 25 volume percent specimens, the effect is less because of the greater bulk of the resin. Compressive strength of 25 and 55 volume percent specimens shows a significant decrease for higher fiber content, while the lower fiber content retains about the same strength after thermal cycling. Flexural strength in high-fiber content specimens shows an increase with increased thermal cycling. Similar behavior is noted for 25 volume percent up to 200 cycles; however, there is a drastic reduction after 200 cycles. There was little change in interlaminar strength with the number of cycles.
Environmental Sensitivity Tests of Graphite-Epoxy Bolt Bearing Properties
Authors: Wilkins DJ
Published: March 2009

Over 200 tests were performed to study the effects of moisture and temperature on typical graphite-epoxy bolted joints. Three test specimen types were used: unnotched control laminates, filled-hole specimens containing an unloaded fastener, and bearing specimens. Five typical laminate orientations were studied. Standard 1/4-in. straight-shank fasteners were used with bolt torques varying from zero to specification values. Two types of moisture conditioning were employed: hygrothermal and conditioning with thermal spikes to 300°F superimposed on the hygrothermal background. Test temperatures were 75 and 200°F. A summary of results shows that many of the test conditions produced no significant effects. The maximum reduction from room temperature, dry performance to hot, wet performance was 18 percent.
Nonflame Atomic Absorption with a Constant Temperature Atomizer
Authors: Woodriff R , Amend JR , Bath DA
Published: March 2009

A short review of the present state of nonflame atomic absorption spectroscopy is provided. The effect of a number of matrix components on the determination of analyte elements in a constant-temperature furnace is discussed. A new method for multielement analysis is described. Components of the analytical apparatus have been used in two different ways to correct for broadband absorption and scatter. Results are reported using these two different methods of background correction with a nonflame atomizer designed by Woodriff.
Some Engineering Problems with Dispersive Clays
Authors: Sherard JL , Dunnigan LP , Decker RS
Published: March 2009

Laboratory tests show that filters containing some fine sand sizes (such as ASTM Specification for Concrete Aggregates (C 33-74a) concrete sand) will generally control piping and seal leaks through dispersive clay. The authors believe that it is reasonable practice to build major embankment dams with cores of dispersive clay with appropriate design details. Existing dams of dispersive clay which have given no trouble are not usually considered unsatisfactory structures. Piping of dispersive clay in dam foundations is believed generally unlikely below the depth where the clay is continuously saturated in nature. Some observations are given on the geologic origin, surface topography, and appearance (color) of deposits of dispersive soil. Damage to canals is described.
Tunnel-Gully Erosion and Urban Development: A Case Study
Authors: Crouch RJ
Published: March 2009

An area of tunnel gully erosion induced by the excavation of a drain through a residential subdivision in Southern New South Wales was examined.

Twelve months after excavation, tunnels extend 7 m from the drain wall and threaten residential blocks only 5 m further away.

A survey of a major tunnel by excavation and probing indicated tunnel formation along soil cracks around large (50 to 100 cm diameter) structural units.

Soil analyses rated the soil as highly dispersible by all the routine tests used by the Soil Conservation Service (SCS) of New South Wales, namely, Emerson's Crumb Test, Ritchie's Dispersal Index, and Floyd's Sticky Point Test, and showed that this dispersibility could be attributed to a high exchangeable sodium percentage (ESP) (mean 10.5). In addition, the soil had a low volume expansion (<5 percent) and was relatively impermeable.

These analyses have been compared with published criteria to show that the soil could have been identified as highly susceptible to tunnel erosion prior to excavation. This would have permitted an improved channel design, with a more gently sloping batter and stressed the need for lime stabilization, topsoiling, and immediate revegetation to minimize the possibility of tunnel development.
Chemical Treatment of a Sensitive, Cemented Clay (Champlain Clay)
Authors: Dascal O , Hurtubise J
Published: March 2009

Significant changes in the geotechnical characteristics of a highly sensitive, cemented, marine clay (Champlain clay) were recorded following its treatment with hydrated lime (by mechanical mixing). Increase of the liquid and plastic limit, decrease of the sensitivity, and also increase of the unconfined compression strength were observed. Following the lime treatment, the clay also became nonerodible. The improvement of the geotechnical characteristics are dependent of the lime concentration; however, it seems that a peak is reached for about 3 to 4 percent lime concentration, above which no significant increase can be detected. These improvements are also curing time dependent.
Field Methods for Determination of Soluble Salts and Percent Sodium from Extract for Identifying Dispersive Clay Soils
Authors: Flanagan CP , Holmgren GGS
Published: March 2009

This paper presents field test procedures for determining the total dissolved salts and the percent sodium in the saturation pore water extract for the purpose of identifying dispersive clay soils. Soluble salts were determined by two methods. The first method used a sodium electrode and chemical reagents, while the second method used a wheatstone bridge. Plots of data and geometric regression analyses were used to determine the relationship between the soluble salts obtained by the two field techniques versus the soluble salts by atomic absorption. The percent sodium was calculated three separate ways using data from the sodium electrode, chemical reagents, and bridge. Plots of data and linear regression analyses were made of the percent sodium by the three methods versus the percent sodium by atomic absorption. In all plots of soluble salts and percent sodium, the atomic absorption data were used as the independent variable.
Conditions Causing Piping in Compacted Clay
Authors: Landau HG , Altschaeffl AG
Published: March 2009

Erosion studies were conducted with laboratory apparatus which produced a piping-type failure within compacted cohesive soil specimens. No artificial opening was preformed in the specimens. The erosion potential was found to be strongly dependent upon the soil type and its chemical properties, the compaction water content, and the chemical composition of the eroding water. Interactions among the variables were important. The combination of wet side compaction and low ion concentration eroding water was found to produce extremely low resistance to erosion for some soil.
Calibration of Radiation Sources for Radiography
Authors: Eisenhower EH
Published: March 2009

A survey was conducted to find and evaluate published national standards for calibration of radiation sources used in industrial radiography. No standards were found on this specific subject, although several standards for medical radiography were discovered and summarized. The latter are inadequate for industrial radiography, but serve as general guidance on the subject. The need for an industrial standard was discussed, and a specific mechanism for developing such a standard was suggested if the need is considered to be sufficient.
Standards for Neutron Radiography
Authors: Haskins J
Published: March 2009

The growth of neutron radiography and the subsequent demand for recommended practices are discussed in terms of their influence on the development of national standards. Included is a discussion of existing standards, an overview of current activities, and a preview of future efforts.
Towards Standards for Acoustic Emission Technology
Authors: Hartman WF
Published: March 2009

Five years ago, acoustic emission monitoring was recognized barely as an emerging nondestructive testing (NDT) method; yet significant progress has been made with respect to the establishment of standards. The NDT experts in acoustic emission technology presently are developing standard terminology, standard measurement procedures, standard calibration techniques, and standard personnel qualifications. The major collective efforts are being coordinated by the American Society for Testing and Materials (ASTM), American Society of Mechanical Engineers (ASME), American Society for Nondestructive Testing (ASNT), and the National Bureau of Standards (NBS). In this paper we review the current status of the developing standards, and we discuss some idealized standards that have not been formulated popularly or even seriously proposed. We also show how some of the limitations and deficiencies of the present state of the art can be removed by the evolving or proposed standards.
An Overview of Magnetic Particle and Liquid Penetrant Methods Documents and Associated Quantitative Measurement Standards Needs
Authors: Borucki JS
Published: March 2009

The magnetic particle and liquid penetrant inspection methods are the most widely used nondestructive testing methods in industry today, as evidenced by the existence of a multitude of worldwide governmental, institutional, and industrial specifications which govern the use of these processes. However, there are some problem areas, that is, inconsistencies, overlaps, omissions, etc., associated with the various documents which control these two recognized test methods.

Of fundamental importance, and in keeping with the theme of this symposium, this presentation will concentrate on the need for and the problems associated with the development of magnetic particle and liquid penetrant physical property standards and physical performance standards. We recognize the need for reproducible, quantitative, physical, and performance measurement standards such as calibrated cracks, artificial defects, magnetic penetrameters, flux density, “black light,” fluorescent brightness, and penetrant removability.

Industry can benefit from the development of such standards. It is our intention, therefore, to discuss this area candidly and seek ways and means of achievement.
Standards for Quantitative Nondestructive Examination
Authors: Tittmann BR , Thompson DO , Thompson RB
Published: March 2009

In this report, the subject of ultrasonic standards is reappraised in terms of history, philosophy of calibration, and future needs. In answer to the critical need for a procedure to calibrate ultrasonic systems for quantitative nondestructive examination (NDE), a new calibration standard and procedure is proposed.

The calibration standard proposed is the far-field sphere (cavity or inclusion embedded in a solid or a ball suspended in a liquid). As a result of recent work, the sphere now is understood well theoretically and experimentally and can be reproduced and fabricated in a solid, for example, by diffusion bonding techniques. A major advantage of the sphere is that it has no preferential orientation, the transducer alignment is not critical, and it allows multipoint checks on a single standard block.

The backbone of the calibration procedure is an equation which relates the transmitter signal to the received signal in a quantitative way. With the help of this equation, the scattering parameters, namely, the angular dependence, frequency dependence, and amplitude of the differential scattering cross section may be determined from data obtained on a calibration standard. The results may be compared then with the invariant theoretical solution to verify the proper operation of the ultrasonic system. A key feature of the development is the G-factor which is a proposed figure of merit for a transducer. The discussion includes a technique for its simple determination and its use in the calibration procedure.
Impact of Pocket Gophers (Thomomys talpoides) on the Quantitative Productivity of Rangeland Vegetation in Southern Alberta: A Damage Assessment Tool
Authors: Alsager DE
Published: March 2009

A quantitative assessment of impact by pocket gophers (Thomomys talpoides) on vegetative production of rangeland in southwestern Alberta, Canada, was obtained. The technique described outlines a method of experimental plot selection, design, treatment, and evaluation over a three-month period, which is relatively simple and has potential for application in other types of rodent damage assessments. The experimental design is particularly useful in that it allows the researcher to correlate the presence of rodents to measurable changes in net vegetation production. In this study, forage production increased 16 percent during the final 60 days of the three-month study on plots where pocket gophers were removed completely. Plots treated with a machine application of rodenticide showed a four and five percent increase in forage production, respectively. During the same period, forage yields on untreated control plots (where pocket gophers were not removed) declined 18 percent (p < 0.001).
Guidelines for Field Evaluations of Repellents to Control Deer Damage to Reforestation
Authors: Campbell DL , Evans J
Published: March 2009

A repellent evaluation process used by the U.S. Fish and Wildlife Service in a research program directed at reducing browsing damage to regenerating Douglas-fir (Pseudotsuga menziesii) by black-tailed deer (Odocoileus hemionus columbianus) in the Pacific Northwest is reviewed. Several methods of repellent testing to control deer damage to commercially valuable trees are being used in the United States. Our procedures to assess deer damage and efficacy of candidate repellents could be used in most of these evaluations to provide uniform data for comparisons of materials and aid in registration of deer repellents needed by land managers.
Effect of Specimen Taper and Machining Processes on Tension Test Results
Authors: Schmieder AK
Published: March 2009

Tension tests on four steels showed that increasing the specimen taper resulted in increased strength values and decreased ductility values. The effect on most properties was small, but elongation was decreased substantially. Specimens were processed by grinding, turning, shot peening, and aging. Within the range used in normal specimen manufacture, few significant effects were observed. Tests were made using manually controlled, as well as computer-controlled, machines. Again, the differences were generally small, but the differences in tensile strength and elongation were statistically significant. These differences were attributed to twofold changes in strain rate and in the cross section area of the specimens. The strength properties from the computer-controlled machine were calculated manually and automatically. The values were not significantly different. Elongation appears to be the most sensitive and reproducible measure of procedural differences.
Pullout Strength of Concrete
Authors: Richards O
Published: March 2009

A proposed method of nondestructive testing for pullout strength of hardened concrete is under consideration by the American Society for Testing and Materials' Committee C-9 on Concrete and Concrete Aggregates. Interest in the method is due to current emphasis on construction safety and recognition that strength of concrete should be measured in structures to determine in-place, load-bearing capacity. The pullout test measures the force required to pull an embedded anchor and accompanying small cone of concrete out of the mass tested. This force is divided by the area of conic fracture to give the pullout strength, which is directly related to other strength measurements to the extent that test masses and curing are comparable. The pullout can be used in the moist room of the standard potential strength cylinder but, more importantly, where potential strength may not apply: in field tests of in-place, load-bearing performance.
The Influence of Intermolecular Interactions on Viscosities at Low Temperatures: Forced-Sphere and Forced-Cylinder Viscometers
Authors: Ensley EK
Published: March 2009

The viscosity of asphalt was found to be dependent upon its thermal history. Asphalt thermally dissociated at 250°C had a lower viscosity than asphalt that had been allowed to associate at 130°C. Viscosities were obtained by forcing a sphere or cylinder (wire) through the asphalt. Temperature range investigated was from 25 to −12°C. Asphalt was examined both as a Newtonian and as a viscoelastic material.
Measurement and Prediction of Asphalt Stiffnesses and Their Use in Developing Specifications to Control Low-Temperature Pavement Transverse Cracking
Authors: Gaw WJ
Published: March 2009

Pavement transverse cracking is a recurring problem in Canada and the northern United States. Field trials and laboratory investigations have confirmed that the major influence on this cracking is the mix stiffness, and consequently asphalt stiffness, at low temperatures. It has been demonstrated that asphalt stiffnesses predicted from van der Poel's nomograph for both waxy and nonwaxy asphalts correlate with low-temperature pavement cracking trends and consequently can be used to develop low-temperature asphalt specifications. A second approach, based on cracking temperatures predicted from a nomograph using asphalt penetrations at 5 and 25°C, is described as the preferred route for low-temperature asphalt specifications. The soundness of this approach is demonstrated in a specific case where the low-temperature properties of a waxy asphalt are improved by air blowing an otherwise highly crack-susceptible vacuum-flashed residue.
Prediction of Low-Temperature Creep and Thermal Strain in Asphalt Concrete Pavements
Authors: Ruth BE
Published: March 2009

Absorptive and nonabsorptive aggregates and different asphalts were used to prepare specimens for indirect tension tests. Fracture and tensile creep tests were used to evaluate the stress-strain behavior of the mixtures at different test temperatures. It was observed that failure strain and stress remained essentially constant when test temperatures were depressed below some critical temperature. Creep strain rates were found to be entirely dependent upon asphalt viscosity and stress ratio. The stress ratio was defined as the applied stress divided by the maximum failure stress below the critical temperature. A creep prediction equation was developed which can be used in predicting thermal stresses and strains of asphalt pavements.
Low-Temperature Ductility in Relation to Pavement Performance
Authors: Kandhal PS
Published: March 2009

The data on changing asphalt properties, especially the low-temperature ductility measured at 39.2 and 60°F (4 and 15.6°C), have been analyzed and related to the performance of ten experimental pavements in Pennsylvania.

It has been observed that aging of the pavement results in progressively lower penetration and higher viscosity. However, the accompanying decrease in low-temperature ductility is an important factor. After the penetration of asphalt drops below 30 due to hardening. the pavements containing asphalt with low ductilities are likely to show poorer service than pavements containing asphalts of the same penetration but with high ductilities. The data also indicate the probable ranges of low-temperature ductility values at which the progressive deterioration of the pavement (such as loss of fines, raveling, cracking, etc.) takes place under Pennsylvania climatic conditions.

At lower temperatures, the ductility values are lower, reproducible, and better defined than the values at higher temperatures determined on long, thin threads of asphalt. Therefore, a specification requirement at a 60°F or lower temperature should provide better criteria.
Rail Wear Under Heavy Traffic Conditions
Authors: Kalousek J , Bethune AE
Published: March 2009

The life of rail in curves under heavy traffic densities and loads is governed either by rail failures or wear. Basic forms of rail wear including rail gage face wear and surface fatigue forms of wear are described and illustrated by metallographical and scanning electron micrographs. The influence of improved rail metallurgical properties and lubrication on wear reduction is discussed. Potential savings arising from the usage of rail with improved metallurgy are estimated.
The Assessment of Rail Steels
Authors: Morton K , Cannon DF , Clayton P , Jones EG
Published: March 2009

Many problems with rails can be attributed to the failure of the steel to withstand the service environment. The successful selection of new and better materials depends upon accurate material evaluation. Realistic laboratory techniques adopted at British Railways for studying material behavior are described in detail, and various results for currently available rail steels are given. The future development of rail steels based on these evaluation methods is discussed.