bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ground Penetrating Radar Supplements Deflection Testing to Improve Airport Pavement Evaluations
Authors: Eckrose RA 
Published: December 2008

Deflection testing is a common nondestructive test procedure used by pavement engineers to evaluate the structural properties of the pavement structure and the loadbearing capacity of the underlying soil system. In dynamic deflection testing, the most common analytical models are based on linear elastic layer theory. While pavement systems are neither linear nor elastic, these models have been shown to adequately simulate in-situ response of pavement structures.
A critical element in linear elastic layer analysis is accurate determination of individual layer thickness. Minor changes in layer thickness can produce significant changes in analytical results of materials properties.
Traditionally, determination of layer thickness has relied on either construction records or on destructive (coring) calibration. Either method has now been shown to be capable of significant error. Construction records have been shown to vary from actual conditions by an order of magnitude or more, and actual pavement thicknesses have been shown to vary by an order of magnitude within only 100 m, a rate of change not detectable by coring procedures.
Since variations of only about 25 mm (1 in.), in extreme conditions, can skew deflection testing results by 100%, these traditional methods are frequently no longer adequate, and extreme care must be taken to employ methods which assure that accurate layer thicknesses are obtained in order to optimize pavement rehabilitation design.
One nondestructive technique, ground-penetrating radar (GPR), has now been demonstrated to provide such layer thicknesses within tolerances of ±6 mm (1/4 in.), a level of accuracy which lends an increased level of confidence to deflection testing results. In addition, GPR can be used to locate reinforcing steel, dowel bars, and voids, and to evaluate the deterioration of joints and load transfer systems within rigid pavements.
Case histories for a number of airport projects will be used to show the value of coupling GPR to a deflection testing program. Projects included are Des Moines International Airport, El Paso International Airport, and Chicago-O'Hare International Airport.
SASWOPR: A Program to Operate on Spectral Analysis of Surface Wave Data
Authors: Sayyedsadr M , Drnevich VP 
Published: December 2008

The spectral-analysis-of-surface-waves (SASW) method is a nondestructive method for determining elastic properties and thicknesses of pavement systems as well as natural soil deposits.
This method consists of three phases: 1. Collecting data from field testing. 2. Converting these data to a dispersion curve. 3. Determining the shear wave velocity profile by inverting the dispersion curve.
The computer program SASWOPR, developed at the University of Kentucky, performs the second of these three phases.
SASWOPR is an easy-to-use interactive program that provides great flexibility to operate on field data in the process of generating a single dispersion curve (surface wave phase velocity versus frequency or wavelength). This graphics-oriented program is written in compiled BASIC and runs on a personal computer.
Using NDT to Calculate the 1986 AASHTO Guide Subgrade Effective Resilient Modulus
Authors: Lindly JK , White TD 
Published: December 2008

The research reported assessed a major change in the 1986 AASHTO Guide for Design of Pavement Structures. The soil support value was replaced with subgrade effective resilient modulus (MR) in flexible pavement design. MR was introduced into the 1986 AASHTO Guide as part of an overall shift to the use of elastic modulus as the indicator of pavement layer structural capacity. Because subgrade modulus changes when the subgrade moisture content changes or when the subgrade freezes, MR must reflect the combined effect of the modulus values from all seasons of the year. AASHTO suggests that the spring thaw modulus may be as low as 20 to 50% of the summer modulus.
NDT testing was performed during the spring thaw and summer seasons of 1986 on 15 Indiana flexible pavements with subgrades ranging from high plasticity clays to sands. Deflections from sensors 5 ft (152 cm) and 7 ft (213 cm) from the load plate were recorded for use in seasonal subgrade resilient modulus determination as provided by AASHTO. MR for each of the 15 pavements was determined using the following seasonal moduli as inputs: spring thaw and summer moduli as calculated from NDT deflections, spring/fall wet modulus interpolated between spring thaw and summer moduli, and winter modulus estimated as recommended by AASHTO. The research yielded the following findings for the conditions present in Indiana in 1986: contrary to expectations, the typical spring thaw modulus value was not dramatically lower than the summer modulus value; and summer modulus values were close enough to MR values that they may be used to approximate MR if spring thaw, spring/fall wet, and winter data are not available.
Measurement of the Thickness of Extremely Thin Inorganic Coatings of Metals
Authors: Bijlmer PFA 
Published: December 2008

A measuring method for thin inorganic coatings on metals has been developed, based on the capacitance of the coating, using an electrical conductive rubber probe as the electrode, pressed against the surface and the substrate as the counter electrode. The reciprocal value of the capacitance is displayed in Angstrom units as the dielectric thickness and by multiplication with the dielectric constant the geometrical thickness is found. If calibration samples, with known thickness, are used, the variable resistance is set to the value of the sample. Coatings of equal nature can then be measured in terms of the geometrical thickness. The optimal range of the instrument is between 500 and 5000 Å units. Below 500 Å, the meter tends to indicate higher values than measured by other means like electro microscopy. Coatings in excess of 5000 Å can be measured provided a high dielectric constant of the coating exists. Most of the work was carried out on aluminum samples on which oxide layers of various thickness values were created.
Barrier layer anodic oxide layers could be measured from 50 Å (3.5V), and except for the very low values a good correlation with the expected coating thickness was obtained. The thickness of hydrated oxide layers formed in hot water is a good example of the application of the method, finding the critical temperature and immersion time at which the bondability is affected. Clear conversion coatings in Alodine 1000 has been successfully measured and the influence of concentration, temperature, and process time can be studied without the need of laborous gravimetrical methods. Results of measurements of phosphoric acid anodic oxide coatings and the influence of voltage and time on coating formation are shown. The range above 5000 Å can be used for chromic acid and sulfuric acid anodized material although hydration differences on samples with varying thicknesses will interfere with accurate readings of the geometrical thickness.
Testing of Anodic Coatings on Aluminum Alloys: A Review
Authors: Lacey EA , Sonnino C 
Published: December 2008

The test methods will be presented and reviewed for evaluating specific properties and parameters of anodic coatings on aluminum alloys: (1) thickness, (2) hardness, (3) dielectric properties, (4) mechanical continuity, (5) sealing effectiveness, (6) color matching, and (7) color stability. The thickness of the anodic coating is probably considered the most important propety to be determined, because most of the other properties are dependent upon it. The gravimetric, optical, and eddy current methods will be described and discussed. Hardness of çoatings may vary widely; and for many applications involving wear, knowledge of hardness is very important. Hardness tests will be reviewed. Electrical dielectric properties of the anodizing and the determinations of a breakdown voltage of the coating are essential for safety and to insure the proper service conditions and limitations. The testing methods, capable also of determining the leakage existent for elevated voltages, will be discussed.
Where the corrosion protection afforded by the anodic coating is essential (as in anodized cans, and so forth) the mechanical continuity of the coating is of paramount importance because any discontinuity will involve very high corrosion current densities, causing extremely rapid failures. The detection of discontinuities is an essential test that will be reviewed. Also essential to optimize the corrosion protection by the anodizing is the effectiveness of the seal extended by the anodic coating. A simple test will be described applicable to finished items and to periodic control of the continuing effectiveness of the sealing. The use of anodizing for a large variety of esthetic applications, from architecture to costume jewelry, dictates that two important parameters must be controlled: color matching and color stability. Appropriate test methods for these exist and will be described and discussed.
Porosity Testing of Metallic Coatings
Authors: Krumbein SJ , Holden CA 
Published: December 2008

Porosity tests generally make use of the relative corrosivities of the coating and the substrate to determine the integrity of the former. This paper is concerned with coatings, such as gold, that are cathodic to the substrate. Coatings of this type are usually applied to protect the substrate from the environment and provide a surface having other beneficial properties, such as wear resistance, electrical conductivity, and an attractive appearance. Porosity is detrimental to the intended functioning of such coatings in that it provides openings through which atmospheric corrodants can attack the substrate and degrade the integrity of the plating.
Different methods of evaluating such tests are presented, including laboratory investigations of the critical parameters and interlaboratory (“round robin”) comparison testing. These methods are described with reference to the nitric acid vapor and sulfur dioxide porosity tests, respectively. It will also be shown how results and insights from these programs are incorporated into ASTM test specifications.
Electrostatic Charge Decay for Detecting Contamination on Aluminum Surfaces
Authors: Cibula A , Daech A , Silbert L 
Published: December 2008

This paper discusses the theory behind electrostatic charge decay (ECD), parameters that affect the measurements, and how potential primer adhesion problems can be detected before the application of coatings.
ECD, a technique for detecting flaws in dielectric materials, is examined as a method to detect surface cleanliness of aluminum parts before the application of primer coatings. The ECD device was used to measure the contact potential difference (CPD) of a metal. The CPD is the difference in work function of the specimen and that of a gold reference. It is the measure of the ease with which electrons are released from the surface in the absence of external fields. In addition, a corona charger was used to apply 12 kV onto the surface and the rate of electrostatic charge decay (ECD) was monitored. Together, the CPD and ECD measurements can be used to give important information about the metal surface quality.
CPD and ECD measurements are both affected by surface contamination, surface morphology, nature of the oxide film, adsorbed gases and films, as well as the particular metal alloy. Contaminated surfaces exhibit a different electrochemical behavior. Processed 2219-T87 aluminum was examined. By implementing a process delay between acid deoxidation of the aluminum and rinsing, a significant change was seen in the ECD/CPD readings. ESCA/auger surface analysis indicated only small chemical differences. Scanning transmission electron microscopy (STEM), however, showed that the surface profile nearly doubled in depth on the delayed etch panel. Atomic composition remained relatively the same, but the ECD readings reflected the change in morphology. The delay before rinsing expended the deoxidizer, preferentially etching the metal. The deeper profile provided a better surface for paint adhesion.
Lateral Drainage Designs Using Geotextiles and Geocomposites
Authors: Koerner RM , Bove JA 
Published: December 2008

Of the available functions that geosynthetic materials possess, their ability to conduct liquids in the plane of their structure is important in a wide class of drainage applications. The thicker geotextiles (usually needled nonwoven types) and a new generation of high drainage composite materials are most suitable for this purpose.
This design-oriented paper gives the necessary theory and required test data and then proceeds to solve three numeric examples illustrating the procedures. They are slope drainage, consolidating foundation drainage, and drainage behind a retaining wall.
Asphalt-Aggregate Mixtures Analysis System: Philosophy of the Concept
Authors: Von Quintus HL , Scherocman J , Hughes C 
Published: December 2008

This paper presents the philosophy of the asphalt-aggregate mixture analysis system (AAMAS) concept and provides a brief discussion on those factors that must be included in the design of optimum paving mixtures based on performance-related criteria. Typically, the structural design of asphalt concrete pavements is based on assumed material properties (layer stiffness coefficients, resilient modulus, and fatigue or permanent deformation constants or both). After the structural design has been completed, materials are submitted and a mixture design is completed. The question then becomes: Does the as-placed material meet the assumptions used in structural design?
Certainly, asphalt concrete mixture design and analyses need to be related to those factors that affect pavement performance. The AAMAS objective is to predict in-place properties of the asphalt concrete in the laboratory during the mixture design stage to evaluate mixture behavior and performance under traffic and environmental loads. Thus, the focus for the development of AAMAS was to develop new laboratory mixture design procedures or modify existing procedures based on engineering properties, structural behavior and pavement performance, rather than on empirical numbers such as Marshall or Hveem stability.
Specific items addressed in the paper include compaction of laboratory mixtures to simulate the characteristics of mixtures placed in the field, preparation and mixing of materials in the laboratory to simulate the asphalt concrete plant production process, simulation of the long-term effects of traffic and the environment (this includes accelerated aging and densifi-cation of the mixes caused by traffic), and the conditioning of laboratory samples to simulate the effects of moisture-induced damage and hardening of the asphalt.
The AAMAS concept is applicable to hot-mixed asphalt concrete and includes mixture variables such as binders, aggregates, and fillers used in the construction of asphalt concrete pavements. The AAMAS currently excludes such materials or layers as open-graded friction courses and drainage layers.
A Comprehensive Asphalt Concrete Mixture Design System
Authors: Monismith CL , Finn FN , Vallerga BA 
Published: December 2008

The design of an asphalt concrete mix consists, essentially, of the following steps: 1. select type and gradation of aggregate, 2. select type and grade of asphalt, with and without modifier, and 3. select proportionate amount of asphalt in asphalt/aggregate blend.
These steps have been incorporated into a general framework for design, which serves as the basis for the mix design procedure presented in this paper.
Essentially, the system consists of a series of subsystems in which the mix components and their relative proportions are selected in a step-by-step procedure to produce a mix that can then be tested and evaluated to ensure that it will perform adequately in the specific pavement section for which it has been formulated. The latter evaluation phase includes the influence of environmental factors, effects of traffic, and the consequence of the anticipated structural cross-section design at the designated site in the following distress modes: fatigue, rutting, thermal cracking, and raveling.
The paper includes a brief discussion of the important factors associated with the various steps of the design process and recommended test procedures to be followed. Information and data are presented to illustrate a procedure that might be followed to ensure that the laboratory method of specimen preparation and fabrication provides specimens with stress versus strain characteristics similar to those obtained by field compaction. The use of the creep test to assist in the design process is illustrated. Some techniques to reduce the amount of testing associated with the methodology described herein are also described.
The Role of Asphalts in Rational Mix Design and Pavement Performance
Authors: Ruth BE , Tia M , Badu-Tweneboah K 
Published: December 2008

Conceptually, a rational mix design procedure should provide test parameters for input into mechanistic pavement design methods and analytical procedures to predict high and low-temperature pavement performance. It is suggested that high-temperature evaluation be performed to design asphalt concrete mixtures using a gyratory testing machine (GTM) to simulate (1) field compaction at conventional mix temperatures, and (2) traffic densification at 60°C. This would provide a better indication of mixture behavior and sensitivity to changes in aggregate blend and asphalt content than current mix design methods. The major advantage of this approach is that the changes in the shear response of the mix can be evaluated easily over the range from as-compacted to highly densified. Conventional mix design procedures are essentially one-point tests that do not provide information rate of densification or changes in stability when the mix density changes.
Tentative recommendations are presented for quality control and acceptance testing using gyratory testing of plant-produced hot mix. Advantages of this procedure are its sensitivity to combined changes in gradation and asphalt content, simplicity, and potential for more intensive testing of produced hot mix.
The low temperature (&lt;25°C) properties and behavior of asphalt concrete paving mixtures are controlled by the Theological properties of the asphalt concrete. Therefore, it is essential that specifications for asphalts or mixtures or both be established to minimize the potential for excessive age hardening and pavement cracking. Research investigations have found cracking to be related to thermal contraction, thermal gradients that produce pavement rippling, vehicular loads, and the viscosity of the asphalt binder during cooling of the pavement. A stress analysis is presented to illustrate the combined effect of asphalt concrete moduli, underlying pavement support, and heavy wheel loading on the maximum pavement stresses developed at designated low temperatures.
A brief discussion on the selection of asphalts and polymer modification is presented to illustrate the major deficiencies in current test methods and specifications. Most asphalt specifications require only tests at 25°C and higher that neglect behavior at low temperatures. Low-temperature viscosity tests should be incorporated in all asphalt specifications. A comprehensive model asphalt specification is presented that includes viscosity tests at 15 and 25°C. An example is given to demonstrate how the viscosity-temperature relationships enhance our ability to interpret asphalt, polymer modified asphalt, and mix behavior at low temperature.
Hazardous Waste Reduction Efforts in the Department of the Army
Authors: Pomerleau NM , McCarthy JJ , Bandy JT 
Published: December 2008

The Department of the Army generates approximately 102 000 metric tons of hazardous waste each year. Nearly 90% of these wastes are produced by the Army's industrial activities. The typical method of treatment has been land disposal. Because of the costs associated with managing these wastes, both in terms of final disposal and corrective actions, and recent legislation emphasizing waste reduction, the Army began to strengthen its pollution prevention strategy. Beginning in 1984, the Army elevated the management of all wastes to the highest levels; previously, the Army had maintained a decentralized program by individual Army installations. Also, the Army established policy goals for reducing the disposal of solvents, a significant hazardous waste contributor. Similarly, in 1985, Army industrial activities developed waste reduction strategies for all other types of hazardous wastes that also emphasize front-end reduction, using methods such as materials substitution, recycling, and process changes to achieve specific process reduction goals. Hazardous waste audits and economic analyses are also required to identify and rank the appropriate type of reduction options that are economically practicable. Moreover, to develop a strategy for selecting waste management options and to measure progress in achieving program goals, formal committees were established. Committee members represent the various facets of Army activities responsible for the cradle-to-grave management of hazardous wastes.
To further facilitate the Army's hazardous waste reduction objectives, a study is being conducted to assess all hazardous waste reporting requirements, as provided by local, state, Federal, and international regulation and Army policy. The findings and recommendations from this study will support a concurrent study to identify and develop the most appropriate type of computer data base to record the necessary hazardous waste data. This data base will also serve as a useful tool in programming and budgeting for hazardous waste activities. Moreover, two additional studies are being conducted, in concert, to refine a hazardous materials tracking system and to economically evaluate and rank waste reduction options. These studies, in support of on-going waste reduction initiatives, and continuing waste reduction committee forums, will enhance the Army's efforts to meet its hazardous waste reduction objectives and goals.
The Soliroc Process in North America: A Stabilization/Solidification Technology for the Treatment of Metal-Bearing Wastes with Reference to Extraction Procedure Toxicity Testing
Authors: Ezell D , Suppa P 
Published: December 2008

The Soliroc Process is a proven European stabilization/solidification technology which is used in the treatment of liquid wastes containing heavy metals. Tricil has carried out laboratory-scale studies of the Soliroc Process at three of its North American waste treatment facilities and also has contracted an independent consultant to carry out similar studies.
Waste samples at each facility were treated, using the Soliroc technology, and then subjected to the Extraction Procedure Toxicity Test (EP Tox). In all the lab tests, identical waste samples were also treated using a conventional lime precipitation process and compared with the Soliroc results. The results indicated superior performance of the Soliroc process to lime precipitation with respect to the EP Tox test. In addition, chelating agents were found not to adversely affect the EP Tox results of the Soliroc process.