bluuebunny/crossref_metadata_2025 huggingface dataset:
Values of Corrosion Rate of Steel in Concrete to Predict Service Life of Concrete Structures
Authors: Andrade C , Alonso MC
Published: March 2009

Concrete is increasingly being used for encapsulating dangerous wastes although the experience with modern reinforced concrete is not longer than 100 years. In order to predict service lifes of 300–500 years for LLW (low level waste) facilities, some kind of extrapolation is therefore necessary. Due to values of corrosion intensity recorded when steel actively corrodes in concrete, it is not recommended to consider a propagation period in the design of LLW disposals. The design hypothesis should be to keep the steel passive unless unexpected changes in service life, occur. If the steel remains around values of 0.01 μA/cm2 (normal in a passive steel embedded in concrete) the stability of the structure could be provided along the foreseen expected life. A final comment is presented on the erroneous assumption usually made that relates corrosion rates to the oxygen diffusion rate through concrete cover.
Design of Low Activation Austenitic Steels by the d-Electron Concept
Authors: Yukawa N , Morinaga M , Nishiyama K , Matsumoto Y , Murata Y , Ezaki H
Published: March 2009

Low activation austenitic steels of Fe-Cr-Mn-Ni-C-N were designed using the d-electron concept, which was devised on the basis of the molecular orbital calculation of transition-metal based alloys. In this design two calculated parameters are mainly utilized. The one is the d-orbital energy level (Md) of alloying transition elements, and the other is the bond order (Bo) that is a measure of the covalent bond strength between atoms. Alloying effects on the microstructures and physical properties of steels are well understood using these parameters. The phase stability of various austenitic steels containing chromium, manganese, nickel, carbon, and nitrogen were examined experimentally. The results were interpreted using these parameters, and a new phase stability index diagram was proposed for the austenitic steels. In this diagram, the γ/γ + αM and the γ/γ + α(δ) phase boundaries are well represented for solution-treated alloys, and also the γ/γ + σ phase boundary is denned for aged alloys. Here, γ is the face centered cubic (fcc) matrix phase, and αM, α(δ) and σ are the martensite, ferrite, and sigma phases, respectively. Computer-aided design was performed so that the steel could contain the least amount of high activation elements such as nickel and nitrogen, and several alloys were selected as potential materials for fusion reactor.
The Effect of Composition and Phase on Segregation of Fe-Cr Based Alloys
Authors: Takahashi H , Shiba K , Nakahigashi S , Ohnuki S , Kinoshita H , Garner FA
Published: March 2009

The segregation behavior of Fe-Cr-Mn alloys during electron-irradiation was studied using a high-voltage electron microscope at a temperature range between 723 and 823 K. The ferritic Fe-7Cr-3Mn, Fe-5Cr-5Mn, and Fe-3Cr-7Mn alloys and the austenitic Fe-10Cr-15Mn and Fe-10Cr-15Mn-3Al alloys were used. Irradiation-induced segregation was observed for all of the Fe-Cr-Mn alloys. That is, manganese tended to enrich and chromium deplete near grain boundaries. However, both manganese and chromium were enriched to high concentrations not only at grain boundaries but also in the grain so that new phases were formed. Furthermore, the amount of segregation depended on the initial manganese and chromium solute concentration along with the aluminum addition. From these results it is suggested that compositional changes due to enrichment or depletion or both can result in a phase transformation during irradiation, even local phenomena.
Decrease of Ductility Due to Hydrogen in Fe-Cr-Mn Steel
Authors: Igata N , Osada T , Nagato T , Tsunakawa H , Sekiguchf T
Published: March 2009

The decrease of ductility due to displacement damage and nuclear transmutation damage by 14-MeV neutrons are major problems to be considered in the selection of fusion reactor materials. In this study with reduced activation Fe-18Cr-15Mn steel, the effect of hydrogen on ductility was investigated by using an electrolytic charging method as a simulation for the (n,p) transmutation effect. The state of hydrogen was clarified by internal friction, X-ray and electron microscopy. The hydrogen peak was found and its parameters were estimated as τ0 = 5.8 × 10-13 sec and H = 0.52eV. In this solute state, the work hardening coefficient and uniform ductility decreased as the charging time increased. This effect was discussed from dislocation phenomenological theory.
Effects of Irradiation on Low Activation Ferritic Alloys: A Review
Authors: Gelles DS
Published: March 2009

A broad composition range of ferritic alloys exists which satisfy the low activation requirement for fusion reactor materials five hundred years after decommissioning. Low activation bainitic alloys in the Fe-2Cr composition range, martensitic alloys in the Fe-7-to-9Cr range and stabilized martensitic alloys in the Fe-12Cr range have been successfully fabricated and are undergoing testing as demonstrated by efforts in Europe, Japan, and the United States. However, irradiation significantly degrades the properties of bainitic and stabilized martensitic alloys. Bainitic alloys containing vanadium develop severe hardening due to irradiation-induced precipitation at temperatures below 450°C and extreme softening due to carbide coarsening at temperatures above 500°C. Stabilized martensitic alloys which rely on manganese additions to provide a fully martensitic microstructure are embrittled at grain boundaries following irradiation leading to severe degradation of impact properties. The most promising composition regime appears to be the Fe-7-to-9Cr range with tungsten additions in the 2% range where high-temperature mechanical properties and microstructural stability are retained and impact properties are relatively unaffected by irradiation.
Microstructure of Neutron Irradiated Vanadium Alloys
Authors: Ohnuki S , Takahashi H , Kinoshita H
Published: March 2009

To investigate the effect of alloying elements on void formation and precipitation during neutron irradiation, vanadium and vanadium based alloys were irradiated in the experimental fast breeder reactor “JOYO” up to 6 × 1025 n/m2 at 670 to 870 K. Alloying elements were selected on the basis of volume size factors: carbon for an interstitial atom, chromium for an undersized substitutional atom and titanium and molybdenum are oversized ones. Voids were formed in all materials except in V-Ti alloys. The V-Cr alloy shows inhomogeneous void formation, and the swelling was larger compared to other alloys. The void formation was related to the radiation-induced precipitates which nucleated on dislocations. In the matrix of the V-Mo alloy, the precipitation was not confirmed, and homogeneous void formation occurred so the swelling was not large. Void formation and precipitation are discussed on the basis of alloying effects.
Solid State Reactions Between V-Base Alloys and Silicon Carbide at High Temperatures
Authors: Kurokawa K , Miyamoto K , Nagasaki R
Published: March 2009

To clarify the chemical compatibility between vanadium alloys and SiC, the extent of reactions, the products, and the structures of reaction layers in V/SiC, V-15Cr/SiC, and V-15Ti/SiC diffusion couples were studied at temperatures ranging from 1173 to 1523 K in an argon gas stream. The interfacial reactions were mainly dominated by the diffusion of carbon into the metal and alloys leading to the formation of the carbides which are of VC and V2C in the V/SiC and V-Cr/SiC systems and V2C and TiC in the V-Ti/SiC system. The remarkable internal carbides of V2C in the V-Cr alloy and TiC in the V-Ti alloy were also formed. The silicides of V5Si3 and V3Si which were presumably formed by the diffusion of vanadium into SiC side were present in the SiC side of the original interface of SiC and V-metal or alloys. The growth of the reaction layer in each system followed a parabolic rate law. The compatibility between the vanadium alloys and SiC from the standpoint of the growth kinetics of the reaction layer was superior to other metals such as iron and nickel. Furthermore, these reactions were used as a surface treatment in order to improve oxidation resistance of the vanadium alloys. The effect of the surface treatment was especially beneficial for the V-Ti alloy.
ASTM C90 Concrete Masonry Units Using Lightweight Aardelite Aggregate
Authors: Dunstan ER , Hay P
Published: March 2009

This report gives test results for ASTM C90 block produced throughout Central Florida using a new lightweight aggregate. In May 1988, Florida Mining and Materials started producing medium and light weight block using Aardelite. Aardelite consists of pelletized particles produced from a mixture of hydrated lime and fly ash. The Aardelite plant is located at Florida Power's Energy Center near Crystal River, Florida.
The Properties of Masonry Grout in Concrete Masonry
Authors: Hedstrom EG , Hogan MB
Published: March 2009

This paper presents the results of a research project on the properties of masonry grout and grouted concrete masonry. Seventy-two grout specimens were tested to investigate the effect of varying the proportions of grout (cement to aggregate ratio) on the physical properties of grout and grouted concrete masonry including compressive strength and modulus of elasticity. Both fine and coarse aggregate grouts were investigated. The investigation included a comparison of the compressive strength of grout specimens saw cut from grouted hollow concrete masonry units versus the procedures of ASTM C1019 [1]. Compressive strength tests of grouted and ungrouted concrete masonry prisms were also conducted. This experimental investigation concludes that grout having leaner proportions (cement to aggregate ratio) than permitted by ASTM C476 [2] may be more compatible with typical concrete masonry units. It is recommended that the strength requirements of grout be developed as an alternate to the current proportion requirements of ASTM C476 in order to encourage designers to specify grout with properties similar to the properties of the concrete masonry units thus achieving compatibility of the components and improve the structural performance of grouted concrete masonry structures. It was also found that grout specimens molded in accordance to ASTM C1019 can be used to predict the strength of grout in grouted concrete masonry.
Masonry Cements — A Laboratory Investigation
Authors: Ribar JW , Dubovoy VS
Published: March 2009

Effects of masonry cement mortars and clay brick units on flexural bond (ASTM C 1072) and on water penetration of masonry wall assemblies (ASTM C 514) were investigated. The test variables included 20 masonry cements and 11 types of brick, each representing materials produced in different areas of the United States.

Regardless of the composition of individual masonry cements, flexural bond in wall assemblies was generally in excess of 100 psi. Also, single-wythe wall assemblies exhibited satisfactory watertightness.

Flexural bond tests of prisms built with the above materials combinations showed that brick properties such as Initial Rate of Absorption (IRA) and surface texture together with mortar properties are primary factors in the development of bond strength.
A Bentonite Clay Plasticizer in Masonry Mortars
Authors: Dickelman BK
Published: March 2009

Select clays modified in the production of proprietary masonry mortar plasticizers yield masonry mortars with improved workability while retaining other physical characteristics desired for masonry construction. The success of the combination has been demonstrated by increased usage during the past thirty years. Extensive product evaluation indicates the compound is economically and technically competitive with or superior to other masonry mortar plasticizers. This report traces the development of the product, general production of the plasticizer, quality control of product by the manufacturer, performance characteristics of mortars when tested in accordance with ASTM C 270, and other special performance characteristics of the mortar, singly or in masonry prism and wall assemblages.
The Development of Ready Mixed Mortar in the United States
Authors: Gates RE , Nelson RL , Pistilli MF
Published: March 2009

The introduction of Ready-Mixed or Extended-Life Mortar to the masonry industry in the United States in the early 1980's prompted the American Society for Testing and Materials to initiate development of a specification for Ready-Mixed Mortar. The development of this specification was under ASTM Committee C12, on Mortars, and Sub- Committee C12.03, on Specifications. The Sub-Committee commissioned a task group, designated C12.03.7, to develop the specification. The authors of this paper are some of the members of that task group. The data presented is a compilation of information that was submitted by members of the task group in evaluation of ready-mixed mortar. Both laboratory- and field-developed data have been submitted.

Ready-Mixed Mortar is best defined as “Mortar consisting of cementitious materials, aggregate water, and set control admixtures which are measured and mixed at a central location using weight or volume control equipment. This mortar is delivered to a construction site and shall have a workability period in excess of 2-1/2 hours.”.

The data that is presented in this paper represents testing of Ready-Mixed Mortar for basic physical properties such as compressive strength, air content, water retention, and workability. Additional properties such as bond strength of ready-mix mortars to masonry units, bond strength of ready mixed mortar to steel, water permeance, and compressive strength of masonry prisms, employing ready-mixed mortar have also been examined.
Quality Control of Mortars: Cubes vs. Cylinders
Authors: Schmidt S , Brown ML , Tate RD
Published: March 2009

Use of 75×150-mm (3×6-in.) and 100×200-mm (4×8-in.) cylinders was found to be more consistent than 50×100-mm (2×4-in.) cylinders in predicting 50-mm (2-in.) cube compressive strengths. The use of 100-mm (4-in.) cubes generally produced the same results as 50-mm (2-in.) cubes but not in every case. The compressive strength results for cylinders can be conservatively assumed to be 85% of 50-mm (2 in.) cube strengths for all mortars tested except for conventionally-mixed masonry cement mortars, which produced cylinder strengths which were 93% as strong as their companion cube strengths. Ready-mixed mortars produced no difference in the relationship between cylinders and cubes from conventionally-mixed mortars.
Corrosion of Reinforcing Steel and Wall Ties in Masonry Systems
Authors: Haver CA , Keeling DL , Somayaji S , Jones D , Heidersbach RH
Published: March 2009

The corrosion of metal associated with masonry systems is controversial. Little research has appeared on the subject, even though corrosion has been associated with multimillion dollar failures of masonry facades on buildings and other structures.

This report reviews the available literature on corrosion in masonry and compares this literature with the more abundant literature on corrosion in concrete. Corrosion patterns and performance are discussed based on analyses of metal removed from a seawall in California and a building facade in Illinois.
Experimental Investigation of Mortar Compressive Strength Using 5.08 cm. Cubes and 7.62 cm. × 15.24 cm. Cylinders
Authors: Matthys JH , Singh R
Published: March 2009

ASTM C270 “Mortar For Unit Masonry” lists compressive strength requirements under the property specification based on 5.08 cm. cubes. ASTM C780 “Preconstruction and Construction Evaluation of Mortars For Plain and Reinforced Unit Masonry” allows the use of 5.08 cm. × 10.16 cm. cylinders, 7.62 cm. × 15.24 cm. cylinders or 5.08 cm. cubes in determination of mortar compressive strength. The cylinder compressive strength may be considered to be equal to 85% of the cube compressive strength. An experimental investigation of the compressive strength relationship between 5.08 cm. cubes and 7.62 cm. × 15.24 cm. cylinders for (1) laboratory mortars cured in a moist room, (2) job site mortars cured in laboratory air, and (3) job site mortars cured outside has been conducted. The data includes portland cement lime mortar, masonry cemment mortar, and ready mix mortar.
The Effect of Constituent Proportions on Stress — Strain Characteristics of Portland Cement — Lime Mortar and Grout
Authors: Sriboonlue W , Wallo EM
Published: March 2009

The results of an experimental program designed to evaluate the influence of constituent proportions on the stress-strain relationship of Portland cement-lime mortar and grout are reported. Grout specimens consisting of 76 millimeter by 152 millimeter cylinders and mortar specimens of 50 millimeter cubes were cast and tested. Mix variations included lime and sand content. Modulus of elasticity of both mortar and grout specimens using different parts of lime and sand are presented. In addition, the relationship of the ultimate compressive strength and modulus of elasticity for various mixes is presented. Mortar cube specimens were constructed following ASTM C270, Standard Specification for Mortar for Unit Masonry. The water content used in mortar was measured as different percentages of flow of fresh mortar. Grout specimens were made in accordance with the ASTM C476, Standard Specification for Grout for Masonry. The water content was measured as different slumps of the grout. The specimens were tested at age twenty-eight days. The results define trends, resulting from varying the constituents, in the stiffness characteristics of mortar and grout.
A Critical Review of Field Adapting ASTM E 514 Water Permeability Test Method
Authors: Brown MT
Published: March 2009

This paper investigates the use of a field adapted ASTM E 514 water permeability test which is currently used by masonry consultants to document moisture penetration problems in brick masonry. There is a growing debate of whether this adapted test method can appropriately be used to decide if a masonry wall is considered a failure regarding moisture penetration.

It is the intent of this adapted test method to follow the requirements of ASTM's E 514-74 test method except the test is used on in-place walls. However, additional differences between the actual and adapted test methods significantly alter the results and interpretation of the test. Information on the differences between the two test methods is needed by engineers, architects and building owners so that informative decisions can be made on the appropriateness of the field adapted ASTM E 514 water permeability test method.
In-Plane Seismic Resistance of Two-Story Coupled Concrete Masonry Walls
Authors: Merryman M , Leiva G , Antrobus N , Klingner RE
Published: March 2009

To study the in-plane resistance of multi-story masonry coupled walls, 6 full-scale reinforced masonry specimens, each two stories high, are being constructed and tested in the laboratory as part of the U.S.-Japan masonry program (TCCMAR). All specimens are of fully grouted hollow concrete masonry. Four specimens are pairs of walls, coupled by floor slabs with and without lintels. Two other specimens are single walls with door and window openings. In this paper, the design, construction, and testing of two of the coupled wall specimens are described. The specimens were loaded vertically by constant loads representing gravity loads on the shear wall's tributary area, and horizontally by quasi-static, reversed cyclic shear loads applied in the plane of the walls at the two floor levels. Test results are presented, discussed, and compared with analytical predictions of specimen performance. Implications of the results for design and test procedures are discussed.
Masonry Wall Drainage Test — A Proposed Method for Field Evaluation of Masonry Cavity Walls for Resistance to Water Leakage
Authors: Krogstad NV
Published: March 2009

A procedure for the field testing of wall drainage systems is proposed. The procedure combines a new test method called the “Wall Drainage Test” with field adapted versions of ASTM E514 to evaluate new and existing masonry drainage cavities and flashing systems. The wall drainage test introduces water directly into masonry cavities at rates based upon values of water penetration measured in field versions of ASTM E514. To assure that water is introduced uniformly along the back face of the outer wythe during such testing, realistic limits are recommended for several parameters including the velocity and volume of water at points of entry into the cavity as well as limits on the minimum number and maximum spacing of the entry points. Procedures for using the test method as a quality control check for new masonry walls and as an investigative tool to evaluate existing masonry wall leakage problems are discussed.
Aspects of Blast Resistant Masonry Design
Authors: Volkman DE
Published: March 2009

Blast resistant design should be examined for building code incorporation, due to the potential of explosions occurring in an industrial society. Specifically, public and commercial structures of concrete masonry construction need additional building code criteria, since these buildings have high density populations to protect. Presently, blast resistant design is accomplished by using government published manuals, but these do not address industry standard construction. A design procedure is presented to illustrate and regulate the methodology. Using this procedure, a common wall section is shown capable of withstanding an air blast load of 4.54 kg (10 lbs) of TNT, located 0.91 m (3 ft) above ground surface and 30.48 m (100 ft) from a structure. Building code criteria in this order of magnitude is sufficient to protect against blast, resist progressive failure, and yet not be an economic impediment. Design details and adequate inspection must be observed to ensure blast resistant integrity.
Influence of Blast Furnace Slags on the Corrosion Rate of Steel in Concrete
Authors: Valentini C , Berardo L , Alanis I
Published: March 2009

The polarization resistance method was used to measure the corrosion rate of steel bars embedded in mortar specimens. The measurements were carried out on specimens, with different percentages of blast furnace slags (0, 20, 45, and 75% weight relative to the weight of cement). During the first 28 days, all the specimens were cured, immersed in water, and subsequently stored partially immersed at 50 and 100% relative humidity. In addition to the polarization resistance, the corrosion potential and ohmic resistance of the specimens were recorded. The influence of the different storage conditions and the percentage of furnace slags on the corrosion rate of steel bars embedded in the mortar are discussed. An analysis of the correlation between the measured parameters is presented.
An Initial Effort to Use the Corrosion Rate Measurements for Estimating Rebar Durability
Authors: Andrade C , Alonso MC , Gonzalez JA
Published: March 2009

The approach presented here is an attempt to implement the values of corrosion intensity which have been measured in laboratory tests, in the framework of the service life prediction analysis for corroding structures. First of all, the model on service life suggested by Tuuti was considered, and only the propagation period model has been analyzed in this paper.

In order to expand the proposal, different steps were covered: (1) the definition of an unacceptable level of deterioration, taking into consideration the levels suggested by the Comité Eurointernational du Béton (CEB) in its Bulletin No. 162, in order to define the urgency of intervention in a damaged structure; (2) the reduction in bar diameter or bar section was taken as the determining parameter in failure risk, assuming that this decrease in section occurs either in a generalized form or in the zones of the structure in which the load-carrying capacity may be significantly affected; and (3) the ranges of possible corrosion intensity values were introduced in Tuuti's model for calculating the reduction in bar section in function of the life of the structure. Some examples for bars of 10 and 20 mm ϕ were presented. Finally, the limitations and the improvements of the proposal are discussed.
Comparison of the Polarization Resistance Technique to the Macrocell Corrosion Technique
Authors: Berke NS , Shen DF , Sundberg KM
Published: March 2009

Reinforced concrete structures are often subjected to chloride intrusion from deicing salts or marine environments or both. The chloride ions disrupt the normal passivity of steel in concrete initiating corrosion. The corrosion can lead to structural failure of the concrete due to the increased volume of the corrosion products which results in cracking and scaling. Much work is underway to determine the corrosion rate of steel in concrete to determine the benefits of a particular protection system or to ascertain current condition of the steel.

Polarization resistance can be used to compare different protection systems and to determine the corrosion rate at a given time. The technique involves the use of a potentiostat or galvanostat, and ideally means to correct for ohmic resistance in the concrete. Though relatively easy to perform, it requires a potentiostat with a means of correcting for ohmic resistance and occasionally a better than superficial understanding of corrosion theory.

The Macrocell corrosion technique involves the measurement of the galvanic current passing between a layer of steel in a chloride rich top mat and a low chloride bottom mat which acts as a cathode. A resistor is placed between the two mats, and the macrocell current is determined by measuring the voltage drop across the resistor. This technique is most applicable when comparing corrosion protection systems in the laboratory.

In this paper, we compare polarization resistance measurements to macrocell measurements on the same specimens. Whenever the macrocell technique indicates severe corrosion is in progress, the polarization resistance technique also shows corrosion to be occurring. However, the polarization resistance technique is able to determine localized corrosion in addition to the macrocell corrosion effect. In several cases, this is present in the absence of a macrocell current. Furthermore, even when the macrocell technique shows the presence of corrosion, rates can be significantly underestimated due to localized rates. When calcium nitrite is present in the concrete, localized corrosion rates remain low.
Corrosion Measurements of Reinforcing Steel in Partially Submerged Concrete Slabs
Authors: Aguilar A , Sagüés AA , Powers RG
Published: March 2009

The corrosion of reinforcing steel in concrete partially submerged in salt water has been investigated using concrete slabs containing longitudinal rebars divided into elements with independent electrical connections. Open circuit potential, interelement current, concrete conductance, and electrochemical impedance measurements have been conducted while specimens were exposed to water containing chlorides over a period of about one year. Direct observations of corrosion and concrete characteristics were conducted at the end of the experiment. Corrosion tended to initiate at the evaporation zone of the vertical slabs, where chlorides accumulated. Once active corrosion started, a macrocell developed with the small portion of the bar below the water surface acting as an electron source. Evaluations of the damage from macrocell current and electrochemical measurements were in rough agreement with direct estimates of sound metal loss based on after-exposure examination. In bars where the separate elements were kept electrically isolated, corrosion proceeded at a higher rate at those elements near the evaporation zone. The results have been used to propose a mechanism for corrosion initiation and propagation in partially immersed reinforced concrete members.
A Computer-Controlled Automated Test System for Fatigue and Fracture Testing
Authors: Nanstad RK , Alexander DJ , Swain RL , Hutton JT , Thomas DL
Published: March 2009

A computer-controlled system consisting of a servohydraulic test machine, an in-house designed test controller, and a desktop computer has been developed for performing automated fracture toughness and fatigue crack growth testing both in the laboratory and in hot cells for remote testing of irradiated specimens. Both unloading compliance and dc-potential drop can be used to monitor crack growth. The test controller includes a dc-current supply programmer, a function generator for driving the servohydraulic test machine to required test outputs, five measurement channels (each consisting of low-pass filter, track/hold amplifier, and 16-bit analog-to-digital converter), and digital logic for various control and data multiplexing functions. The test controller connects to the computer via a 16-bit wide photoisolated bidirectional bus. The computer, a Hewlett-Packard Series 200/300, inputs specimen and test parameters from the operator, configures the test controller, stores test data from the test controller in memory, does preliminary analysis during the test, and records sensor calibrations, specimen and test parameters, and test data on flexible diskette for later recall and analysis with measured initial and final crack length information. During the test, the operator can change test parameters as necessary.
Fatigue and Fracture Testing Using a Multitasking Minicomputer Workstation
Authors: McKeighan PC , Evans RD , Hillberry BM
Published: March 2009

An automated fatigue and fracture toughness testing control system is described that is based on a Sun 3/180 workstation computer running under the UNIX operating system. Real-time difficulties associated with UNIX have been overcome with a unique combination of software and modified data acquisition hardware that results in a system not requiring conventional analog-to-digital (A/D) and digital-to-analog (D/A) device drivers. The control system software subroutines utilize the multitasking feature of UNIX to permit plotting, computations, and A/D operations to run simultaneously with D/A output. Inputs to the system are primarily through a mouse-driven, menu-based window methodology. The program currently contains four versatile cyclic loading sequences for fatigue crack growth and LEFM and EPFM fracture evaluations that can be applied to five commonly utilized specimen geometries. The software and hardware system has been demonstrated and validated for numerous tests using various materials and specimen types.
Fatigue Crack-Growth Measurement Using Digital Image Analysis Technique
Authors: Redner AS , Voloshin AS , Nagar A
Published: March 2009

A novel approach to the measurement of fatigue crack growth at elevated temperatures based on digital image analysis technology is presented. An operational prototype was designed to demonstrate the feasibility of this technique to measure crack lengths at temperatures up to 1093°C (2000°F). The crack tip image transmission was accomplished using fiber-optic guides and relay lenses. The technique provides a direct (without calibration) measurement of the crack length and position with a resolution better than 0.025 mm (0.001 in.) and a capability for automation. The experimental observations of the crack tip using the digital image analysis system prototype showed that this technique can be applied to crack measurement at temperatures up to 1093°C (2000°F). The method requires further experimental work for verification of crack length accuracy under cyclic and thermal-mechanical spectrum loads, various specimen geometries, and other high temperature materials.
J-R Curve Testing Utilizing the Reversing Direct Current Electrical Potential Drop Method
Authors: Bicego V , Liviero D , Fossati C , Lucon E
Published: March 2009

A Reversing Direct Current Electrical Potential Drop (RDCEPD) method has been implemented at CISE for crack monitoring in laboratory tests on specimens of metallic materials. Convenient features of the method are simple and cheap electronics, good insensitivity to noise from the environment, insensitivity to thermoelectrical potentials, and compensation for current and temperature fluctuations. The method is suitable for low-cycle fatigue crack initiation studies, fatigue, corrosion and creep crack growth tests, and J-integral tests. In the latter case, difficulties in obtaining reliable crack length values, due to resistivity changes in the plastically strained material of the specimen, are discussed on the basis of an experimental analysis on different types of steels.
Automated Variable-Amplitude Fatigue Crack Growth Technology
Authors: Donald JK
Published: March 2009

An automated variable-amplitude fatigue crack growth system has been developed that provides arbitrary waveform generation of either an endpoint or block spectrum using either a triangular or sinusoidal waveform. Up to 90 000 endpoints or 1000 blocks may be supported on a 640 K computer system. A constant peak-to-peak loading rate with upper and lower frequency limits may be specified. The block mode allows testing for a given number of cycles between specified load levels. Ramps, hold-times, and breakpoints may be incorporated in the block mode. The breakpoint feature allows changing to the next block at specified crack lengths. The spectrum may be also scaled as a function of crack length to provide for increasing K, decreasing K, or constant K. Custom hardware and software provide simultaneous command and feedback verification, as well as data acquisition to monitor the crack length. The command-feedback features of this system provide typical load errors of less than 0.2% of range with a guarantee of less than 1%. Either compliance or electric potential drop may be used for nonvisual monitoring of crack growth rates.
Use of Automated Ball Indentation Testing to Measure Flow Properties and Estimate Fracture Toughness in Metallic Materials
Authors: Haggag FM , Nanstad RK , Hutton JT , Thomas DL , Swain RL
Published: March 2009

A field indentation microprobe (FIM) apparatus was developed (and patented) to evaluate, nondestructively in situ, the integrity of metallic structures. This study investigated the applicability of using a new automated ball indentation (ABI) test, which is a major part of the FIM, to measure the flow properties of metallic materials including those exhibiting Lüders or inhomogeneous strains (carbon steels, titanium alloys, aluminum alloys, etc.) and to estimate their fracture toughness. The ABI test is based on multiple indentations (at the same penetration location) of a polished metallic surface by a spherical indenter. Automation of the test, where a computer and test controller were used in innovative ways to control the test as well as to analyze test data, made it simple, rapid, accurate, economical, and reproducible. Results of ABI tests on different base metals, welds, and irradiated materials are presented and discussed in this paper. Excellent agreement was obtained between ABI-derived data and those from standard ASTM uniaxial tension and fracture toughness tests.
Automated Fatigue and Fracture Laboratory with Multiple Load Frames and Single Host Computer System
Authors: Sunder R
Published: March 2009

An automated fatigue and fracture laboratory was recently set up at the National Aeronautical Laboratory. Six servohydraulic load frames are connected to a single multi-user, time-sharing computer system, through dedicated microprocessor-based interfaces. The host computer system includes resources for post processing of test data, output of test results and their storage and retrieval.

Application software was developed for automated crack growth testing under a variety of constant-amplitude and spectrum load test conditions including K-control and on-line fatigue cycle analysis. Automated crack length measurement is through unloading compliance.
Design, Construction and Testing of Sand Compaction Piles
Authors: Barksdale RD , Takefumi T
Published: March 2009

Sand compaction piles can be used to improve marginal sites for stability, liquefaction, and settlement applications. They have been employed extensively in Japan for many years to improve land reclaimed from the sea. The advantages and disadvantages of using sand compaction piles are compared with other vibro-compaction techniques such as stone columns. Methods are described for construction of sand compaction piles on land and over water. Design theories are summarized for the utilization of sand compaction piles at sites underlain by both cohesionless and cohesive soils. Practices and design criteria are presented.
Shearing Characteristic of Composite Ground and Its Application to Stability Analysis
Authors: Enoki M , Yagi N , Yatabe R , Ichimoto E
Published: March 2009

Shearing characteristics of composite ground, that is clayey soft ground improved by stone or sand columns, are studied. Triaxial compression tests and simple shear tests on composite ground elements are carried out. The result suggests that sand and clay fail individually when the element fails, and that the element has anisotropy of shear strength parameters. Stabilities of embankments on several composite grounds are analyzed by the proposed method in which anisotropy of shear strength parameters is Introduced. The result shows that the proposed method gives lower safety factor than the conventional method.
Present State of Sand Compaction Pile in Japan
Authors: Aboshi H , Mizuno Y , Kuwabara M
Published: March 2009

The sand compaction pile method (hereinafter abbreviated as SCP method) has been developed in Japan as an improvement method for soft ground. One of the reasons of the above is that SCP method can be applied to both sandy and clayey soil. Complicated soil strata in Japan have also contributed to the development of this method. This paper evaluates and verifies the applicability of the design procedure of SCP method to sandy and clayey grounds by comparing the measured data with designed values. Moreover the latest technolgy of SCP method, that is the Mechatronic Consolidation System which can set up sand compaction piles in accordance with the variation of soil properties, is also introduced.
Bearing Capacity of Improved Ground by Sand Compaction Piles
Authors: Terashi M , Kitazume M , Minagawa S
Published: March 2009

Bearing capacity of the ground improved by sand compaction pile method is investigated primarily by a series of centrifuge model tests. Bearing capacities obtained under the various loading conditions are well explained by the simple stability analysis which has been commonly employed in Japan. The effectiveness of a simple construction control diagram is confirmed based on the deformation of the ground. These findings are also verified by the full scale load test leading to failure of the improved ground.
The Testing and Instrumentation of Stone Columns
Authors: Slocombe BC , Moseley MP
Published: March 2009

The vibro replacement technique for constructing stone columns was first used in Europe in the late 1950's and has been used extensively for ground improvement work in the United Kingdom for over twenty five years. Testing of ground improvement work is a vital ingredient of the construction process, and this paper sets out current British developments.
Use of Stone Columns to Support I-90 Cut and Cover Tunnel
Authors: Allen TM , Harrison TL , Strada JR , Kilian AP
Published: March 2009

A case history is presented describing the use of stone columns to support a portion of a cut and cover tunnel. The tunnel was intended to be supported on spread footings founded on dense granular glacial soil. Inspection and testing of the bottom of the footing excavation revealed the presence of soil below the footing level inadequate for the design loads. A number of alternatives were evaluated. Stone columns were chosen, resulting in a savings of over $350,000 when compared to the next lowest cost alternative. Performance measures were used to ensure that the stone columns improved ground performance sufficiently to result in less than 5.1 cm (2.0 in.) of footing settlement under a maximum load of 290 kN/m2 (6 ksf). Two plate load tests were performed on the stone columns, and instrumentation was placed in the ground and on the structure. Data are presented indicating structure induced pressures in the foundation soil, settlement at four depths below footing level, and rotation of the footing.
Dynamic Compaction/Stone Columns - Test Sections for Construction Control and Performance Evaluation at an Uncontrolled Landfill Site
Authors: Snethen DR , Homan MH
Published: March 2009

Completion of a portion of the highway loop around Tulsa, Oklahoma, required that State Highway 11 (SH-11) cross an old strip mine/uncontrolled landfill area located in north central Tulsa. A grade separation was required where SH-11 crossed Yale Avenue, a major city street. The entire project involves the bridge structure, approach embankments with a maximum height of approximately 9 m and the roadway paving. The foundation conditions varied from remnants of intact shale existing between the strip mined areas to layers of disturbed shale covering layers of trash varying in thickness from approximately 1 m to nearly 6 m. At both ends of the project, ground water was present.

Dynamic compaction was selected over other options (i.e. grouting or elevated roadway) to prepare the foundation material to support the embankments. As part of the dynamic compaction quality assurance program, three instrumented field test sections were constructed to verify the adequacy of dynamic compaction. In the portion of the project where the thickness of the trash layers was the greatest, the potential for additional settlement following dynamic compaction seemed large, so it was decided to support that section of the embankment on stone columns constructed using the dynamic compaction process. An on-site evaluation of different impact sequences was conducted to determine the most efficient method for stone column construction. Approximately 95 stone columns were constructed, using the selected procedure, in the area with the thickest trash. Following completion of the embankment, several locations were instrumented (settlement gages and piezometers) to observe the long term settlement performance of the embankment.

Dynamic compaction of the materials resulted in average settlement over the approximately 9 hectare site of 66 cm. Reasonable strength improvements were measured at each of the test sites. Settlement records show a maximum settlement of approximately 30 cm since completion of the embankment in Spring 1986. The major portion of the settlement occurred rather quickly (i.e. in a few months) with subsequent settlement being minimal.
Lateral Static Densification at Monaco Design, Construction and Testing
Authors: Gambin MP
Published: March 2009

The so-called “Compaction Grouting” technique is now being used in France under various names. Due to a large research programme launched a few years ago, Soletanche was in a position to develop a more scientific approach to this process when it is used as a soil improvement method.

This paper describes the various rules used for design with their background and gives an example of a lateral static densification job.

The positive role of microshearing in sandy soil and that of solid mortar columns in clayey soils is described.
Deep Chemical Injection for Protection of an Old Tunnel
Authors: Munfakh GA
Published: March 2009

The foundation of a 19th Century brick-lined railroad tunnel was reinforced by a deep chemical stabilization scheme which allowed successful construction of two new tunnels about 7 ft. (2 m) below its invert. After evaluation of several protection schemes which included ground freezing, reinforcement with micro piles and conventional structural underpinning, chemical grouting of the foundation soils was selected based on technical and economical merits. Laboratory and field grouting tests were performed in conjunction with the grouting design to select the appropriate type of grout and determine the grouting specifications. The successful application of the chemical grouting scheme allowed construction of the new tunnels with a minimum impact on the existing tunnel.
Deep Soil Compaction Using Vibratory Probes
Authors: Massarsch KR
Published: March 2009

A new approach to deep compaction of granular soils is presented, which makes it possible to take into account the site-specific conditions in the design of the compaction process. Special vibratory probes have been developed, the shape and dynamic properties of which are chosen to achieve optimal transfer of the compaction energy to the soil. The operating frequency of the vibrator, which is attached to the top of the probe, can be varied to achieve optimal soil densification. Results from extensive field measurements from compaction projects are presented. Settlements after compaction range between 5 and 10 % of layer thickness. An increase of penetration resistance of between 50 and 300 % has been observed. A rational design concept for the resonant compaction technique is presented.
Densification of Sand Using a Variable Frequency Vibratory Probe
Authors: Neely WJ , Leroy DA
Published: March 2009

The first application of a new vibratory compaction method in North America is described. A variable frequency piling vibrator is used to insert a probe of Y-shaped cross section into the soil to be densified. A unique feature of the system is that on-site monitoring can be used to ‘tune’ the probe so that compaction is carried out at optimum frequency, vibration time and spacing of treatment point locations. The method is simple, fast and economical and, in contrast to other conventional methods, no material is added during the compaction process.
Field Results of Hydrocarbon Vapor Monitoring to Detect Leaking Tanks
Authors: Durgin PB , Michelson RW
Published: March 2009

Vapor monitoring for leak detection around underground storage tanks (UST) is generally regarded as being plagued by false alarms. Examples of field data from six sites are provided. Vapor monitoring indicates real leak or spill events but methods are needed to differentiate between the two. Site assessment, appropriate installation of monitoring points, overfill/spill protection, and data analysis are all important factors for a well-operating vapor monitoring system. Vapor monitoring may gain importance over time as systems are improved, subsurface contamination is reduced, and demands increase for providing assurance that sites are clean.
How Well Do Leak Detection Methods Work?: Preliminary Results from the EPA Test Procedures
Authors: Young TM
Published: March 2009

In 1990, EPA released a series of “Standard Test Procedures for Evaluating Leak Detection Methods” to define consistent, rigorous procedures for determining the performance of underground storage tank leak detection methods. Each test procedure outlines one or more ways to evaluate the performance of a class of leak detection devices. Liquid- and vapor-phase detectors are tested for their ability to detect the presence of petroleum components in controlled laboratory settings. Pipeline leak detectors, tightness testing methods and automatic tank gauging systems are tested for their ability to reliably differentiate between non-leaking systems and systems with simulated leaks of specified sizes. Statistical inventory reconciliation methods are tested using real inventory data from tight tanks, including some simulated leaks. The results of these preliminary evaluations are discussed and compared. The test procedures allow manufacturers to demonstrate the effectiveness of their methods and help tank owners to ensure that the equipment or service they purchase complies with applicable regulatory requirements.