bluuebunny/crossref_metadata_2025 huggingface dataset:
Quick and Reliable Procedure for Liquid Limit Determination of Fine-Grained Soils
Authors: Mendoza MJ , Orozco M
Published: February 2009

This paper describes comparative results of liquid limits for fine-grained soils, determined by the percussion-cup standard procedure and alternative techniques with penetrating cones. Microwave oven drying is used as a complement to fall-cone tests. In this way, the liquid limit for a soil sample can be accurate and reliably obtained in about 45 min. The studied cones were the pioneer Swedish cone with 60° angle and 60 g mass, and the English cone with 30° and 80 g. Percussion liquid limits differ from those obtained with the cones; however, results of a comprehensive experimental program evince that there exist linear correlations between their liquid limits.
Laboratory Testing of Concrete-rock Joints in Constant Normal Stiffness Direct Shear
Authors: Seidel JP , Haberfield CM
Published: February 2009

This paper describes the experimental component of an extensive investigation into the shear behavior of joints formed between concrete or cement grout and soft, weak or weathered rock. Understanding the behavior of such joints is important for the prediction of performance of a diverse range of structural elements, such as drilled piers socketed into rock, rock anchors, and dam foundations. The particular tests described in this paper were carried out on joints formed between concrete and an artificial silstone called Johnstone, under conditions of constant normal stiffness, and involved a range of boundary conditions and interface profiles. Interfaces included a series of regular triangular asperities and irregular profiles based on fractal geometry concepts. The authors have included the complete suite of test results in the belief that it will be a significant addition to the literature, which currently contains very few results of constant normal stiffness tests. It also demonstrates the importance of realistically modelling interface roughness. Careful observations made during testing using time-lapse photography have aided in the development of a number of simple theoretical models of behavior, which are published elsewhere.
Permeability of Two-Layer Soils
Authors: Sridharan A , Prakash K
Published: February 2009

The equivalent coefficient of permeability of a stratified soil system calculated theoretically has been observed to be not the same as that directly measured, when the flow is normal to the orientation of the bedding planes. A hypothesis has been proposed in this investigation to explain this deviation according to which the permeability of the exit layer controls whether the measured permeability is greater or lesser than the theoretically calculated value. The proposed hypothesis has been used to successfully and satisfactorily explain the experimental observations made with the two-layer systems. It has been shown that the coefficient of permeability of a soil in a layered system cannot be considered as its property and that it depends upon the permeabilities of adjoining layers, their thicknesses, and the flow direction.
Development of RECP Performance Test Methods
Authors: Joel Sprague C , Carver CA , Allen S
Published: February 2009

The recent growth and development of the Rolled Erosion Control Products (RECP) industry have created the need for a way to compare the wide array of products now available.

The Erosion Control Technology Council (ECTC) identified the need for standardized performance testing for RECPs and initiated a project to develop performance tests that provide economical and efficient product evaluation and which are suitable for the ASTM approval process. The resulting new performance test protocols have been developed:

• “Determination of RECP Performance in Protecting Soil from Rainsplash”

• “Determination of RECP Performance under Shear Stress”

• “Determination of the Biodegradability of RECPs by CO2 Release”

• “Determination of RECP Performance in Encouraging Seed Germination and Vegetation Growth”

This paper documents the developmental process including the design bases for erosion control tests, a review of existing performance test practices, and details the new performance test protocols for RECPs in both slope and channel lining applications. Initial testing using the new test standards has indicated that the tests are practical, cost-efficient, and reproducible.
Stress-Strain Strength Characteristics of a Marine Soil with Different Clay Contents
Authors: Yin J-H
Published: February 2009

It is commonly believed that the clay content has a major influence on the behavior of a soil, among other factors. This technical note presents main results of a series of consolidated undrained (CU) triaxial tests on re-consolidated soft Hong Kong marine deposits (HKMD) with different clay contents. The focus is placed on the influence of the clay content on the stress-strain strength characteristics of the HKMD, including the stress-strain curves, effective stress paths, friction angles, and Young's modulus. The results are discussed and interpreted. New understanding and useful correlations are presented.
Anisotropic Consolidation Behavior of Soft Bangkok Clay
Authors: Seah TH , Koslanant S
Published: February 2009

The anisotropic consolidation behavior of soft Bangkok clay is investigated by means of constant rate of strain consolidation tests with vertical and radial drainage conditions. Conventional oedometer tests were performed to verify the results of constant rate of strain consolidation tests in the vertical flow condition. Better-defined compression curves were obtained from the CRS tests, resulting in better estimation of preconsolidation pressure. A new method of determining the preconsolidation pressure based on the pore pressure ratio gave values close to those obtained from the Casagrande construction of compression curves. The results of CRS tests under different drainage conditions indicated that soft Bangkok clay is slightly anisotropic, with the ratio of coefficients of consolidation and permeability in the horizontal to vertical directions of about unity at in-situ stress. The difference increases with increasing stress due to stress-induced anisotropy of the soil.
Performing Undrained Shear Tests on Saturated Sands in a New Intelligent Type of Ring Shear Apparatus
Authors: Sassa K , Wang G , Fukuoka H
Published: February 2009

The design and construction of an undrained ring shear apparatus, which was newly developed at Disaster Prevention Research Institute, Kyoto University, are presented in detail. This apparatus is suited for undrained shear tests under all types of loading, and enables observing the undrained shear behavior of soils in high-speed motion (maximum rotating speed 2.24 m/s) to an endless displacement level. Using rubber edges and a gap control system, leakage of pore water was effectively prevented, and the friction of rubber edges was controlled with high credibility during shearing. For undrained shearing tests on sand, the related experimental procedures are introduced and the undrained shear behavior of sand in ring shear test is presented. Test results showed that high pore water pressures could be built up in both loose and dense sands, given the shear displacement is great enough.
A Double Cell Triaxial System for Continuous Measurement of Volume Changes of an Unsaturated or Saturated Soil Specimen in Triaxial Testing
Authors: Yin J-H
Published: February 2009

This paper presents an improved Double Cell Triaxial System (DCTS) for continuous measurement of the volume change of an unsaturated or saturated soil specimen in triaxial testing. The DCTS developed by the author overcomes the two critical shortcomings of the conventional triaxial system and has advantages over the existing modified triaxial cells for measuring the volume changes of unsaturated/saturated soils during water flushing, consolidation, and compression. The calibration of the DCTS has been done using both a dummy solid copper specimen and a fully saturated marine clay specimen. The water volume changes of the inner cell and the outer cell are measured and compared on the copper specimen under compression of the inner/outer cell pressure up to 400 kPa. It is found that the volume changes of the outer cell are significant, while the volume changes of the inner cell are negligible. On the saturated marine clay, volume changes of the clay specimen under isotropic consolidation and drained axial compression are measured using two methods: the conventional method (Method A) by measuring the volume of water coming out from inside the specimen and the method (Method B) by using the DCTS to measure the internal cell water volume changes. The volume changes using the two methods are compared. It is found that the differences of the volume changes using the two methods are within 5.6%. The calibration results using both the solid copper specimen and the saturated marine clay specimen show that the DCTS is accurate and reliable for continuously measuring the volume changes of unsaturated or saturated soil specimens during consolidation and compression.
Interface Behavior of Sands from Constant Normal Stiffness Direct Shear Tests
Authors: Porcino D , Fioravante V , Ghionna VN , Pedroni S
Published: February 2009

This paper reports an experimental study concerning the frictional behavior of sand-solid structure interfaces. The study was performed using a constant normal stiffness (CNS) direct shear box. Three natural silica sands and four aluminium plates with different roughnesses were investigated. A comparison between constant normal load (CNL) and CNS tests is reported. The influence of the main factors controlling the frictional behavior of the investigated materials such as constant normal stiffness, roughness of solid surface, particle size, and relative density, and initial effective normal stress are analyzed and discussed.
Compression Tests of Ultra-Soft Soil Using an Hydraulic Consolidation Cell
Authors: Bo MW , Sin WK , Choa V , Ing TC
Published: February 2009

Compression behavior and compression parameters in the ultra-soft soil stage are still not well understood. In ultra-soft soil stage, the process of compression does not follow Terzaghi's unique relationship of deformation and effective stress gain principle, and the large deformation with little or no effective stress gain occurred in this stage. One-step loading compression tests were conducted, using a large diameter hydraulic consolidation cell (Rowe Cell). Vertical displacement and pore pressure behavior were measured during the deformation process. The transition point between slurry and soil stage determined from various methods are discussed. Approximate determination of compression indices in slurry stage from one-step high pressure loading was described in the paper. Step loading compression tests were also carried out with hydraulic consolidation cells on an ultra-soft soil with radial drainage conditions. Based on these test results, new compression parameters C*c1, C*c2, and C*c3 are introduced in this paper. The correlation between e*10 and void ratio at liquid limit eL is proposed. With this information, the total settlement at various loadings can be determined using the proposed equations. The prediction of time-rate of settlement could even be made using the coefficient of large strain consolidation CF estimated from the void ratio-permeability relationship. The computed magnitude and time rate of settlement agreed well with measured data. The dimensionless time factor curves for various radial drainage conditions are also proposed.
Changes in Interface Stresses During Pullout Tests on Geogrid Strip Reinforcement
Authors: Hayashi S , Shahu JT , Watanabe K
Published: February 2009

For a strip geogrid reinforcement, pullout resistance per unit width is known to increase with decreasing specimen width at low applied normal stresses. This phenomenon can be explained by a conceptualized model for a pullout interaction mechanism consisting of combined 2-D and 3-D interaction mechanisms, and the results obtained from laboratory pullout tests can be extended to the field. In this paper, a series of pullout tests on stiff extruded geogrid specimens embedded in dense sandy gravel was carried out and the normal stresses at the soil-reinforcement interface were measured by small-diameter earth pressure cells. On the basis of these tests, the fundamental behavior of soil-geogrid reinforcement interaction is explained and the conceptualized pullout interaction model is corroborated. It is shown that restrained positive dilatancy, observed at low applied normal stresses, results in an increase in actual normal stresses at the soil-reinforcement interface at the edges of the geogrid, thereby increasing the pullout resistance of the reinforcement.
Automated Humidity System for Measuring Total Suction Characteristics of Clay
Authors: Likos WJ , Lu N
Published: February 2009

A computer-automated experimental system for determining total suction characteristic curves using relative humidity control is described. The system is applicable in the relatively high suction range important for fine-grained materials (7000 to 700 000 kPa). The new system has several advantages over existing suction measurement techniques; most notably, it is fully automated, has a much broader measurement range, is capable of determining both wetting and drying characteristics in significantly less time, and requires only one undisturbed sample for testing. Tests are conducted to evaluate the system response and illustrate its use in practice. Total suction characteristic curves are determined for four types of clay, ranging from highly expansive smectite to non-expansive kaolinite. Concurrent characteristic curves are determined using the filter paper method for comparison. Practical applications are demonstrated in two ways. First, select results are analyzed to assess the swelling potential of the four clays using an existing methodology based on total suction testing. Second, aspects related to the adsorption kinetics of expansive soils are evaluated by analyzing the results with a first-order kinetic model.
An Evaluation of Geometric Factors Used in the Two-Stage Borehole Test (ASTM D6391-99) Using the Finite Element Method
Authors: Ratnam S , Soga K
Published: February 2009

Geometric or shape factors are constants used in the interpretation of in-situ hydraulic conductivity tests, such as the Two-Stage Borehole (TSB) test in ASTM D6391-99. The finite boundary condition shape factors used with the TSB test are an extension of those derived by Hvorslev (1951) for infinite boundary conditions. The accuracy of this extrapolation is investigated here, using the finite element method (FEM) as a tool for deriving shape factors for finite boundary conditions. The utilized FEM has been validated against closed-form solutions for other test geometries. The resulting errors from the incorrect use of shape factors with the TSB test are discussed, and new shape factors derived from the FEM are presented in the form of a chart.
Experimental Investigation of Dynamic Response of Compacted Clayey Soils
Authors: Inci G , Yesiller N , Kagawa T
Published: February 2009

A study was conducted to determine the dynamic properties of compacted clayey soils subjected to low amplitude vibration. A fast and simple ultrasonic pulse transmission method was used. Tests were conducted on three clayey soils with low to high plasticity compacted using standard and modified Proctor effort over a range of water contents. The samples were allowed to dry after compaction and P-wave velocity, S-wave velocity, Poisson's ratio, and shear modulus were determined. The effects of soil type, compaction conditions, and degree of saturation on the dynamic response of the soils were investigated. The elastic wave velocities and the dynamic shear modulus increased as the soil plasticity decreased. The velocities and the modulus increased and the Poisson's ratio decreased as the degree of saturation decreased due to drying. Generally, the velocities and moduli increased significantly at the early stages of drying with the changes becoming more gradual as drying progressed. Variations were high for soils compacted with low energy and high water content. The shear moduli of the soils were also estimated using a common empirical equation. Suction values obtained for the test soils in a different study were used as effective stresses in the estimation. The estimated shear moduli agreed well with the measured values.
Horizontally Mounted Bender Elements for Measuring Anisotropic Shear Moduli in Triaxial Clay Specimens
Authors: Pennington DS , Nash DFT , Lings ML
Published: February 2009

Novel horizontally mounted bender element devices capable of high-quality transmission and reception of horizontally propagated shear waves polarized in orthogonal planes across the mid-height of a triaxial clay specimen are described. Mounting of these mini benders, in a T-shaped configuration, is in the pads of a radial strain belt on 100 mm diameter triaxial samples, or alternatively as bender probes (similar in concept to mid-height pore pressure probes) suitable for use on triaxial samples down to 38 mm diameter. This latter type may also be used in bench-top tests or on site. The effective fabrication procedures that have been developed are described. The instrumentation systems used to drive and receive signals are outlined, and estimates of the magnitude of the shear strains developed by the bender elements and the accuracy with which shear wave velocities can be determined are discussed. These new bender elements enable both anisotropic shear moduli to be measured over the same path length on a single triaxial specimen that can be taken to a wide variety of anisotropic stress states. Comparison with measurements using conventional platen-mounted bender elements suggests these may underestimate the shear modulus by up to 20%.
Calibration of Five-Segment Time Domain Reflectometry Probes for Water Content Measurement in High Density Materials
Authors: Wright WC , Yoder RE , Rainwater NR , Drumm EC
Published: February 2009

Time domain reflectometry (TDR) systems are being used widely for in situ measurement of soil water content. Water content is calculated based on the measured dielectric properties of the soil system. TDR systems for water content measurement were originally developed for use in soils with low bulk densities similar to those found in agriculture. Four highway test sites in Tennessee were instrumented with five-segment TDR probes in the soil subgrade and in the unbound aggregate sub-base (Rainwater et al. 1999). These materials are more dense than agricultural soils. After several months of data collection and field verification, the TDR predicted water contents and gravimetric water contents did not coincide. For this reason, a study was performed with the TDR equipment using each of the four test site subgrade soils and an unbound aggregate sub-base sample. Ten previously published TDR water content relationships were evaluated to determine which relationship most accurately predicted water content for the subgrade soils and for the unbound aggregate sub-base using the five-segment probe. During the course of the study, it was necessary to evaluate the manufacturer's relationship between the measured propagation time and the corrected propagation time, which accounts for the epoxy fill between the probe waveguides. The relationship was revised to reduce significant variation in corrected propagation times between segments.

The relationship between inverse signal velocity and soil water content proposed by Herkelrath et al. (1991) most accurately predicted water content for all subgrade soils; however, this relationship required the derivation of a soil-specific slope and intercept. The equation proposed by Baran (1994) most accurately predicted water contents for the unbound aggregate sub-base. Both of these expressions appear to provide a better prediction than the widely used Topp's relationship.
An Internal Instrumentation for Axial and Radial Strain Measurements in Triaxial Tests
Authors: Bésuelle P , Desrues J
Published: February 2009

A measuring device for axial and radial displacements in triaxial tests on soft rock specimens is described. Developed to optimize the detection of strain localization, the transducers have a linear response and a working range of a few percent. After a presentation of the manufacture and properties, detection of strain localization in the specimen during the compression test is discussed.
A Laboratory Apparatus to Measure Chemico-Osmotic Efficiency Coefficients for Clay Soils
Authors: Malusis MA , Shackelford CD , Olsen HW
Published: February 2009

A laboratory apparatus for measuring the chemico-osmotic efficiency coefficient, ω, for clay soils in the presence of electrolyte solutions is described. A chemico-osmotic experiment is conducted by establishing and maintaining a constant difference in electrolyte concentration across a soil specimen while preventing the flow of solution through the specimen. The chemico-osmotic efficiency coefficient is derived from a measured pressure difference induced across the specimen in response to the applied concentration difference. The effective diffusion coefficient (D*) and retardation factor (Rd) of the electrolytes (solutes) also can be determined simultaneously by measuring the diffusive solute mass flux through the specimen until steady-state diffusion is achieved. Experimental results using specimens of a geosynthetic clay liner subjected to potassium chloride solutions indicate that the measurement of ω may be affected by soil-solution interactions, as well as by changes in the induced chemico-osmotic pressure difference due to solute diffusion. As a result, ω should be evaluated using the induced pressure difference at steady state. The time required to achieve a steady-state response in induced pressure difference is related to the time required to achieve steady-state diffusion of all solutes, and may be affected by the circulation rate at the specimen boundaries. The circulation rate should be sufficiently rapid to minimize changes in the boundary concentrations due to diffusion, but sufficiently slow to allow measurement of solute mass flux at the lower concentration boundary for evaluating D* and Rd.
LVDT Based System for the Measurement of the Prefailure Behavior of Geomaterials
Authors: Da Re G , Santagata MC , Germaine JT
Published: February 2009

This paper describes a device that can accurately measure the small strain behavior of geomaterials in the triaxial apparatus. It makes use of two miniature submersible linear variable differential transformers (LVDTs) mounted on a pair of yokes which clamp onto the soil specimen. A highly stable, low noise, custom designed signal conditioning system completes the design. The result is a device capable of consistently resolving displacements of less than 0.1 microns corresponding to strains of less than 0.0002% for standard sized (3.6 cm × 7.6 cm) triaxial specimens. The system is simple in design, can be easily implemented in existing triaxial equipment, and thus may represent a commercially viable solution for the investigation of the small strain behavior of soils in the triaxial apparatus.

Along with a description of the mechanical and electrical system, the paper presents the results of proof testing performed to assess the stability and linearity characteristics of the system under a wide range of temperature and pressure conditions. These tests demonstrate the device's versatility and its ability to measure true axial strains. Recent modifications to the existing triaxial equipment, introduced to improve the investigation of small strain behavior in geomaterials, are also discussed.

Finally, the performance of the device is illustrated with results of tests on Resedimented Boston Blue Clay (RBBC) and frozen Manchester Fine Sand (MFS). These geomaterials differ in stiffness by more than two orders of magnitude and establish a range in behavior that encompasses that of most soils. Test results confirm that the measuring system can provide a detailed characterization of the pre-failure behavior of soils in triaxial compression.
A Potential Model for Compaction Evaluation of Piedmont Soils Using Dynamic Cone Penetrometer (DCP)
Authors: Gabr MA , Coonse J , Lambe PC
Published: February 2009

The potential use of the Dynamic Cone Penetrometer (DCP) as a compaction quality control tool is investigated in this study. The DCP is a simple device and relatively inexpensive to operate. Results from a laboratory testing program performed on three piedmont residual soils with appreciable fine content (> 60%) yielded correlation patterns for the estimation of moisture content (w) and dry unit weight (γdry), based on the DCP penetration rate (PR). The PR-liquidity index (LI) data were best correlated with an equation in the form of LI = A Log PR-Bm. For the test soils, A was equal to 0.65 and Bm = 1.2. On the other hand, the PR-degree of saturation (S) data were best correlated with the equation in the form of S = 1 − eCm*PR with the Cm coefficient estimated equal to −0.065. Using the principles of soil mechanics, w and γdry are calculated based on the predicted LI and S values, respectively. Using the water content and unit weight models, and on the average, the water content was underpredicted by 0.2% and the dry unit weight was overpredicted by 0.3 kN/m3. The developed model parameters are expected to vary for different soil types as well as compaction effort and a field calibration procedure in which moisture contents and dry densities are evaluated by alternative means, on a limited scale, is recommended.
Effects of Installation Method on Sand Compaction Piles in Clay in the Centrifuge
Authors: Lee F-H , Ng Y-W , Yong K-Y
Published: February 2009

The effects of the method of installation of centrifuge model sand compaction piles (SCPs) in soft clay are studied. The comparative study involves the frozen pile method, a 1-g displacement method, and a high-g displacement method. The results show that, although all the SCP-improved models exhibit higher strength compared to the unimproved models, both displacement methods confer additional enhancement in strength to ground improvement, which was not present in the frozen pile models. In addition, wavy settlement patterns were also observed in the frozen pile models, but not in the displacement models. The observed differences were explained by the postulated differences in stress states of the improved models. For the frozen pile models, thawing during reconsolidation was postulated to lead to a reduction in effective lateral stress, resulting in further softening of the clay. On the other hand, the cavity expansion effect caused by the displacement methods was postulated to lead to a set-up in the strength of the clay, thereby resulting in better integrity in the response of the improved ground to loading.
Experimental and Data Analysis Techniques Used for High Strain Rate Tests on Cohesionless Soil
Authors: Abrantes AE , Yamamuro JA
Published: February 2009

Experimental methods used to subject drained triaxial compression axisymmetric test specimens composed of cohesionless soils to very high strain rates and analyze the resulting data are presented. Included is the use of a custom gravity drop-frame loading system to generate the high strain rates and a custom square triaxial cell to minimize optical distortion. Methods to collect and analyze the experimental results are also presented. High-speed film photography, coupled with digital image analysis techniques, are used to capture specimen deformations. Experimental issues such as image analysis of specimens, optical corrections, time synchronization of photographic images with data acquisition, inertial effects, global versus local strain measurements, axisymmetric shape of the specimen during deformation, and membrane compliance are examined by analyzing test results that were performed at high strain rates.
Shear-Wave Velocity to Determine Vertical Stress Share on Column-Sand Samples
Authors: Blewett J , Woodward PK
Published: February 2009

The increased rigidity of vibro-replacement stone columns in liquefiable soils offers the potential for liquefaction mitigation. This paper proposes a laboratory method to facilitate an investigation of this parameter. Shear-wave velocity data are used to obtain the vertical load distribution between loose sand and gravel column in composite columnar triaxial samples under static and cyclic loading. Significant reductions in cyclic stresses applied to the loose sand are obtained, offering the potential for the optimization of the design of vibro-systems to include load share benefits.
A Comparative Evaluation of Various Additives Used in the Stabilization of Expansive Soils
Authors: Al-Rawas AA , Taha R , Nelson JD , Al-Shab BT , Al-Siyabi H
Published: February 2009

This paper investigates the effectiveness of using cement by-pass dust, copper slag, granulated blast furnace slag, and slag-cement in reducing the swelling potential and plasticity of expansive soils. The soil used in this study was brought from Al-Khod (a town located in Northern Oman) where structural damage was observed. The first stage of the experimental program dealt with the determination of the chemical, mineralogical, and geotechnical characteristics of the untreated soil. The soil was then mixed with the stabilizers at 3, 6, and 9% of the dry weight of the soil. The treated samples were subjected to liquid limit, plastic limit, swell percent, and swell pressure tests. Furthermore, the cation exchange capacity, exchangeable cations (Na+, Ca++, Mg++, and K+), and pH of the treated samples were also measured. The study showed that copper slag caused a significant increase in the swelling potential of the treated samples. Other stabilizers reduced the swelling potential and plasticity at varying degrees. The study further indicated that cation exchange capacity and the amount of sodium and calcium cations are good indicators of the effectiveness of chemical stabilizers used in soil stabilization.
Predicting the Shear Strength Envelope of Unsaturated Soils
Authors: Rassam DW , Cook F
Published: February 2009

Determining the shear strength envelope of an unsaturated soil involves a sophisticated and time-consuming testing program. Hence, it is advantageous to minimize the number of tests required to establish the envelope. In this paper, a power additive function is adopted to predict the shear strength envelope of unsaturated soils from knowledge of the unsaturated shear strength at residual suction, the effective stress friction angle for saturated conditions, and the soil-water characteristic curve. Two boundary conditions are required to quantify the two fitting parameters of the function. The first is φb = 0 at residual suction, and the second is the contribution of matric suction to the shear strength at residual suction, which should be experimentally evaluated. The validity of the method is tested for a number of unsaturated shear strength data covering a wide range of suctions. Good agreement was found to exist between the predicted envelopes and the experimental data. The method requires only one experimental evaluation of the unsaturated shear strength and is most suitable for coarse- to medium-grained soils where the residual suction may be achieved reliably in the laboratory.
Determination of Trace Amounts of Sediment in Gas-Oil
Authors: Babitz M , Rocker A
Published: February 2009

The proposed method is suitable for quantitative determination of trace amounts of sediments in gas-oil on the order of 0.001 percent in the presence of water. It is a modification of the ASTM Standard Method of Test for Water and Sediment in Crude Oils and Fuel Oils by Centrifuge (D 1796) and the ASTM Standard Method of Test for Water and Sediment in Distillate Fuels by Centrifuge (D 2709) and uses a 1:1 mixture of toluene and isopropanol as solvent for centrifugation. Its repeatability is on the order of 0.002 percent.
Fatigue Behavior of Copper with Intermediate Surface Layer Removal
Authors: Nakano Y , Sandor BI
Published: February 2009

The effect of single and periodic intermediate surface layer removal on the fatigue behavior of oxygen-free, high-conductivity copper was studied in the life range of 105 to 2 × 106 cycles. The fatigue tests were conducted at room temperature, in tension-compression, under load control, and without mean load. The surface layer removal was accomplished by electropolishing. The variables of the test conditions were the engineering stress range, the average grain size, and the atmosphere (air and argon gas).

A single treatment of removing all the surface markings (caused by fatigue) during the life increased the subsequent fatigue life significantly. The largest increase in life was obtained after the largest period of precycling, which was about 80 percent of the standard life. The average plastic strain ranges after the polishing treatments were measured. The fatigue lives after polishing were strongly dependent upon the depth of the removed surface layer.

Periodic treatments to remove all the surface markings during the life also increased the fatigue life. Removal of all the surface markings after every 80 percent of the standard life increased the life by a factor of ten.
Stress-Relaxation Characteristics in Tension of High-Strength, High-Conductivity Copper and High Copper Alloy Wires
Authors: Fox A
Published: February 2009

The ability of pressure-type electrical connections to remain stable and reliable over long periods of time depends in large measure on the stress-relaxation characteristics of the conductor and the connector material. For applications such as the miniaturized solderless wrapped connection, traditionally made with copper No. C110 (ETP copper), the relaxation of the conductor is far greater than that which occurs in the terminal; hence, for this type of termination the behavior of the conductor material governs the stability of the termination.

Miniaturization of telephone equipment and the associated increase in ambient operating temperatures requires improved conductor materials which, in addition to having adequate tensile strength, ductility, and high electrical conductivity, are able to resist stress relaxation at these higher temperatures. Based on these considerations the tensile stress-relaxation behavior of several 0.255-mm diameter (30 AWG) high-strength, high-conductivity copper and copper alloy conductors were studied in the temperature range 23°C to 149°C (73°F to 300°F) for a time period extending to 10,000 h. Stress-temperature-time relationships are shown to follow Arrhenius behavior, thus permitting a choice of realistic accelerated aging test requirements for connections made with these copper alloy conductors.

Since high-speed production of these conductor materials possibly may require in-line strand annealing procedures, a comparison of the stress-relaxation behavior of commercially processed strand annealed samples with that of laboratory processed batch annealed material, as well as a comparison of the effects of gage size on stress relaxation [0.511-mm (24-AWG) diameter versus 0.255-mm (30-AWG) diameter wires] was included in this study. Since no significant size effects were observed, available stress-relaxation data on a number of 0.511-mm (24-AWG) diameter high-strength, high-conductivity copper and copper alloy conductor materials are also included for convenient reference.
Contact Angle of Zinc on Some Ceramic Materials and Metals
Authors: Kelley JE , Harris HM
Published: February 2009

Measurements were made of the contact angle of molten zinc drops on fifteen ceramic materials and four metals in high-purity helium and carbon monoxide atmospheres. Zinc of 99.9999-percent purity did not wet the oxide materials, glass-type coatings, or graphite; all contact angles were greater than 90 deg at 500 to 700°C in helium and 500 to 800°C in carbon monoxide. Materials tested that were most resistant to wetting by zinc were ZnO sinter, glazed fireclay, graphite, and mullite.
Mechanical Properties of Epoxy Impregnated Concrete
Authors: Whiting DA , Blankenhorn PR , Kline DE
Published: February 2009

Concrete has been impregnated with a particular epoxy system using a combined vacuum-pressure technique. Compressive modulus and compressive strength of these concretes were determined and found to be a function of total porosity. Results are compared with data previously reported for polymer concretes based on other monomer systems.
Dependence of Fatigue Notch Factor on Plasticity and Duration of Crack Growth
Authors: Gowda CVB , Leis BN , Smith KN
Published: February 2009

The effects of several factors which influence the magnitude and variation with life of fatigue notch factor (Kf) are discussed in this paper. Plasticity at the roots of stress raisers is known to have the most dominant influence on the variation of Kf when a failure criterion of fatigue crack initiation is employed. When a failure criterion other than cycles to crack initiation is employed, the duration of crack propagation becomes a significant factor in the determination of magnitude and variation of Kf. The duration of crack propagation is viewed as a primary influence on the magnitude of Kf since the increase in propagation duration with increasing theoretical stress concentration factor (Kf) accounts in part for the decrease in notch sensitivity. New evidence is given to the influence of the above two factors on Kf and an attempt is made to add to the understanding of fatigue process in notched components.
A Test Procedure for Determining the Influence of Stress Ratio on Fatigue Crack Growth
Authors: FitzGerald JH , Wei RP
Published: February 2009

A test procedure is outlined by which the rate of fatigue crack growth over a range of stress ratios and stress intensities can be determined expeditiously using a small number of specimens. This procedure was developed to avoid or circumvent the effects of load interactions on fatigue crack growth, and was used to develop data on a mill annealed Ti-6Al-4V alloy plate. Experimental data suggest that the rates of fatigue crack growth among the various stress ratios may be correlated in terms of an effective stress intensity range, Δ Keff, at given values of Kmax.

This procedure is not to be used, however, for determining the corrosion fatigue crack growth characteristics of alloys when non-steady-state effects are significant.
Tables for Making an Early Decision in Precedence Tests
Authors: Little RE
Published: February 2009

Tables are presented for critical values of Young's nonparametric D statistic, which may permit early termination of statistical precedence tests in accelerated life test comparisons. Use of the tables is explained for acclerated comparisons of the proposed and present designs.
Sources and Magnitude of Errors in the Measurement of Coating Thickness with the Double-Beam Interference Microscope
Authors: Saur RL
Published: February 2009

An analysis was made of three factors (fringe width, phase change, and surface roughness) which contribute to errors in measurement of coating thickness with a double-beam interference microscope. Excluding any unpredictable contributions made by surface roughness, a theoretical analysis based on a literature search revealed that the total of the two remaining errors will not exceed ±0.19 μm (±0.0076 mil) if either the coating or its substrate is a metal. If both are metals, the error will not exceed ±0.12 μm (±0.0048 mil). Measurements were made on a few samples of common coating systems. The errors experienced were much less than the above theoretical values, and would not normally contribute significantly to measurements with the double-beam interference microscope.
The Effect of Cement Properties and the Thermal Compatibility of Aggregates on the Strength of Accelerated Cured Concrete
Authors: Orchard DF , Jones R , AL-Rawi RS
Published: February 2009

Most research work on the effect of the thermal expansion of the constituents of concrete has concentrated chiefly on hardened concrete. Its resistance to heating and cooling and to freezing and thawing has been used for purposes of assessment. The works of different investigators have led to considerable contradiction and no definite conclusion can be drawn on the effect of differences between the coefficients of thermal expansion of the constituents of concrete. Findings show effects on the durability under repeated cycles of freezing and thawing and the compressive strength of concrete subjected to temperature change. There is some evidence that the relative expansions of the constituents of fresh concrete cause a reduction of its ultimate strength under conditions of accelerated curing.

In the present research, when electric curing was adopted, the complete elimination of any temperature gradients throughout the test specimens was effected by precisely controlled conditions. This made it easier to detect small differences as the conditions were changed.

The factors investigated were the ratio of the strengths obtained by (1) one-day accelerated curing and 28-day normal curing and (2) one-day accelerated curing plus 27-day normal curing and 28-day normal curing.

It was found that coarse aggregates having a low coefficient of thermal expansion caused a significant drop in the one-day accelerated cured compressive strength. The coefficient of thermal expansion of the coarse aggregate did not have much effect on the 28-day accelerated cured strength. It was thought that this was due to autogenous healing during the 27 days of normal curing, rectifying any cracking caused through stresses arising from thermal incompatibilities during the one day of accelerated curing. Residual expansion after heating and cooling of certain aggregates was liable to cause decreases in strength. Further evidence is given of the importance of the C3A content of cement in determining the ultimate strength obtained when the concrete is subjected initially to accelerated curing.
The Effects of Composition and Fineness of Cement in Accelerated Testing of Concrete
Authors: Al-Rawi RS
Published: February 2009

The effects of C3A content, fineness, gypsum content, C3S:C2S ratio, and alkali content of the cement on the correlation between 1-day accelerated and 28-day normal strength of concrete were investigated. The accelerated testing method used was that developed by the Institution of Civil Engineers (ICE) Accelerated Testing Committee [1]. Both C3A and alkali content did not affect the correlation between accelerated and 28-day strength. Increased fineness caused the predicted 28-day strength to be less than actual. Increased gypsum content could cause an increase in accelerated strength and at the same time a decrease in 28-day strength. The ICE correlation was not applicable when cements of low C3S:C2S ratio were used.
Some Mechanical Properties of Sintered Fiber Metal Composites
Authors: Rostoker W , Galante JO , Shen G
Published: February 2009

Kinked, short-length, fine wire can be molded by conventional powder metallurgy procedures and sintered to a porous composite with large proportions of interconnecting voids. This material has potential applications for implanted prosthetic systems. The material behaves in a nonlinear elastic fashion which may be approximated as two linear elastic processes. In the strain range of 0 to about 0.5 percent, the elastic modulus can be less than 1 kg/mm2. In a higher strain regime the elastic modulus is about 100 kg/mm2. A total elastic strain range of 1.5 to 4 percent is found.
Contamination Control in the Production of High-Purity Chemicals
Authors: Zief M , Horvath J
Published: February 2009

Contamination problems inherent in the preparation of high-purity chemicals must be recognized and controlled. Major problems such as airborne contamination, leaching from containers, and reagents for ultratrace elemental analysis are reviewed. Trace impurities contributed by electrostatic charges, filtration media, and water are discussed.
A Critical Assessment of the Cantilever Beam Method for the Determination of Dynamic Young's Modulus
Authors: Rosinger HE , Ritchie IG
Published: February 2009

The application of a noncontacting optical transducer for the measurement of flexural resonant frequencies and normal mode shapes of a cantilever beam is described. Results on the resonant frequencies of cantilever beams, gripped at the fixed end by a vise, are compared with the Bernoulli-Euler and Timoshenko beam theories. Although the mode shapes agree well with the theories, there are large discrepancies between the experimental variation of resonant frequency with inverse slenderness ratio and that predicted by the theories. These discrepancies are attributed to imperfect clamping. It is concluded that for accurate Young's modulus calculations from the measured resonant frequencies of cantilever beams, tests must be restricted to long slender beams. For beams which cannot be fabricated to meet this criterion, an empirical method is presented which yields Young's modulus to within ±3 percent on the specimens tested. For increased accuracy the free-free reasonant beam method should be used.
An Acoustical Emission-Damping Fatigue Study of a 17-4 PH Steel
Authors: Willertz LE , Hunter DO
Published: February 2009

The acoustic emissions emitted from a 17-4 PH stainless steel were monitored while the specimen was undergoing fatigue testing in the torsional mode. Below the cyclical stress sensitivity limit (CSSL) of the material no abnormal emissions were detected, while at and above CSSL emissions were detected which could be attributed to fatigue damage which resulted in failure of the specimen. This test was the first in a series which will enable us to learn more about fatigue damage in various materials.
High Cycle Fatigue Crack Propagation Rates in Copper
Authors: Nakano Y , Sandor BI
Published: February 2009

The crack propagation rate was studied on axially loaded specimens of oxygen-free, high conductivity copper tested in the high cycle life region. Fatigue tests were conducted under load control without a mean load. The variables of the test conditions were the engineering stress range, the average grain size, and the atmosphere (air and argon gas). The crack propagation rate during the first 80 percent of the life was determined by using an electropolishing technique. The rate was also measured after final failure of each specimen from the distances of the striations on the fracture surface observed through a scanning electron microscope. The crack propagation rate depended upon the test conditions as well as on the prior stress cycling. The crack propagation was divided into two main stages: the crack nucleation and microcrack development stage, and the crack propagation or macrocrack development stage. Argon gas atmosphere reduced the macrocrack propagation rate, but did not affect the crack nucleation and microcrack development significantly. Increasing the grain size shortened the crack nucleation stage markedly.
Design and Analysis of Corrosion Experiments for Testing Materials Exposed to Gamma Radiation
Authors: Makepeace CE
Published: February 2009

The scope of metallurgical engineering applied research and development of cladding and encapsulation materials has been extended during recent years beyond those materials used in core and cladding and in non-core structural nuclear applications in research and power reactors. Materials for the encapsulation of radioisotopes for medical and commercial uses must also be carefully selected for their suitability for exposure initially up to two years in the reactor followed by four or five years in service. The susceptibility to corrosion of all of these materials is a most important consideration. Conventional weight loss and potentiostatic experiments require careful design of both the physical corrosion assembly and experimental method. In this paper a controlled laboratory experiment using a 50,000-Ci gamma irradiator is used as an example to exemplify the use of Statistical Design of Corrosion Experiments.