bluuebunny/crossref_metadata_2025 huggingface dataset:
Virtual Triaxial Test Simulation Based on Discrete Element Method for Shear Resistance Property Assessment of Asphalt Mixtures
Authors: Yang Jun , Wang KeLi
Published: January 2013

In this paper, the shear resistance of asphalt mixtures, which accounts for the permanent deformation characteristics of flexible pavements to a large extent, is analyzed based on the discrete element (DE) method from a microscopic perspective. This study first considered the processes used to obtain the microscopic parameters for the DE model, which typically simulated an asphalt mixture based on its three components. Then the study employed Burger’s model to simulate the rheological behavior of asphalt sand mastics (fine aggregates, fines, and asphalt binder). A random generation algorithm was also developed to generate coarse aggregate elements in the DE model complying with the realistic gradations of asphalt mixtures. So as to more precisely model the rheological characteristics of asphalt sand mastics, the microscopic parameters of Burger’s model were calibrated via simulations of uniaxial tests in the DE model. Finally, meaningful conclusions were achieved by analyzing the simulation result and the laboratory result. The simulation result was consistent with the laboratory test result, so the use of the established DE model to evaluate the shear resistance property of asphalt mixtures is feasible.
The Effects of Accelerated Heat and Light Aging on Textiles Marked with Fabric Marking Pens
Authors: Evenson Janet , Crews Patricia Cox
Published: January 2013

Temporary fabric marking pens are popular products among quilters and home sewers. However, no published studies exist concerning long-term effects of temporary marking pens to help consumers make informed decisions. The purpose of this study was twofold: (1) to determine whether temporary marking pens in combination with ink removal treatments contribute to degradation or discoloration of fabrics over time, and (2) to determine whether marking pen ink that remains on fabric for 30 days can be successfully removed and thereby avoid discoloration of quilts or other home sewing projects. Specimens were marked with one of three brands of marking pen (Dritz, Clover and Crayola) and subjected to ink removal treatments (eraser pen, water, or no treatment), followed by heat or light aging. Changes in color and strength were measured. Results showed that the water immersion ink removal treatment was the most effective method for removing marking pen ink and was associated with much less discoloration than eraser pen ink removal treatments. Eraser pens caused statistically significant discoloration following both light and heat aging on both fabric types. They proved to be an undesirable ink removal treatment. Temporary marking pen inks, if rinsed out thoroughly using a water immersion treatment, do not result in discoloration or strength losses when exposed to heat and light aging. This suggests that consumers should use marking pens only if they launder their newly completed projects. Results also show that consumers may complete quilting and sewing projects over a period of several weeks without concern about ink removal because marked fabric specimens given a water immersion treatment within 30 days exhibited no more discoloration than the control specimens. Results of this study could influence the ink removal recommendations that manufacturers list on the packaging and the practices of quilters and home sewers who use the products.
White OLED Weibull Life Prediction Using Maximum Likelihood Estimation
Authors: Zhang Jian-ping , Wu Jiong-lei , Liu Yu , Wu Helen , Zhou Aixi , Wu Wen-li
Published: January 2013

A theoretical model using Weibull distribution and maximum likelihood estimation (MLE) was established to statistically analyze the test data, which were obtained by three groups of constant stress accelerated life tests. The life prediction software was applied to simplify the calculation and achieve organic light-emitting device (OLED) life estimation. The results indicate that the Weibull distribution is fit to describe white OLED life, and the precise accelerated parameter β is particularly useful to predict the white OLED life within a shorter time, which provides significant guidelines to help engineers make decisions in design and manufacturing strategy from the aspect of reliability life.
An Investigation of Hydrogen Environment Effect on the Strain Aging of Low-Carbon Steel through Vickers Hardness Test
Authors: Lee Dongsun , Yamamoto Aki-nori , Oda Yasuji , Noguchi Hiroshi
Published: January 2013

In recent years, increasing attention has been paid to the effect of a hydrogen environment on the fatigue limit of hydrogen-power systems and infrastructure. In carbon steel, strain aging is one of the important factors influencing non-propagating crack behavior, which is related to the fatigue limit. In the present study, to investigate the effects of hydrogen on the strain aging of low-carbon steel (0.13 % carbon steel), Vickers hardness tests were carried out on the carbon steel. A couple of 0.13 % carbon steel specimens with a large-scale plastic zone were aging heat-treated; one was a hydrogen-charged specimen, whereas the other was an uncharged specimen. The Vickers hardness of the hydrogen-charged specimen was found to be lower than that of the uncharged specimen. This observation implies that hydrogen inhibits strain-aging hardening of low-carbon steel. The observation also suggests that hydrogen could affect the non-propagating crack behavior through the inhibition of strain aging.
Effect of Electrical Discharge Machining (EDM) on Charpy Test Results from Miniaturized Steel Specimens
Authors: Lucon Enrico
Published: January 2013

Electrical discharge machining (EDM) is a manufacturing process whereby a desired shape is obtained through electrical discharges between an electrode and a workpiece, which are separated by a dielectric fluid. EDM produces a recast layer on the surface of the workpiece, which in carbon steels is typically harder and more brittle than the base metal, and is often characterized by microcracks. This type of damage, particularly in the notch region of a steel specimen, can adversely affect impact test results. The objective of this investigation is to assess the possible influence of EDM on miniaturized Charpy test results. We tested Kleinstprobe (KLST)-type Charpy specimens of two reactor pressure vessel (RPV) steels, machined with different combinations of two machining processes (EDM and milling). Comparison of the impact results, combined with metallographic observations and microhardness measurements on the recast layers and the base metals, indicated no detrimental effect of EDM on the impact toughness of the materials investigated. The maximum thickness of the recast layer was about 16 μm, and the magnitude of the EDM-induced hardening varied between 34 % and 84 % with respect to the hardness of the base material, depending on the carbon content of the steel. No microcracks were observed.
Lubricant Properties and Characterization
Authors: Henderson Kenneth O. , May Chris J.
Published: January 2013

Lubricant physical properties are important in determining their suitability for the intended application and for comparing fluids. Some properties also provide insight into the remaining useful life of a fluid in service. In this chapter, we first review the components that go into making a lubricant. This is followed by a review of the most common ASTM International standard test methods used to measure a lubricant's physical properties. More information on the significance of tests for petroleum can be found in ASTM Manual 1, Significance of Tests for Petroleum Products, edited by Sal Rand [1].
The Drivetrain System
Authors: Simner Dave
Published: January 2013

The aim of this chapter is to review the technology that might be found within the drivetrain of a vehicle and make the link to the lubricants used within those units. The lubricant is arguably the most important single component within the drivetrain, although it is often the most difficult to improve, modify, or develop. However, in investigating the drivetrain of the vehicle, some boundaries need placing around the problem. Before starting, it is also worth pointing out that the reader may well come across or be familiar with the term “driveline”. It is probably reasonable to say that “drivetrain” and “driveline” are terms that are interchangeable, although some engineers may have some subtle distinction between the two.
Problems and Opportunities Regarding the Lubrication of Modern Automotive Engines
Authors: Yamaguchi E. S. , Tanaka G. A. , Matsumoto K.
Published: January 2013

For those readers who have been involved with diesel and passenger car engine oils for many years, this chapter may not seem to cover all aspects of this broad topic in great detail. However, for those readers who are interested in the topic and who have not lived through the development of engine oil categories, this chapter is meant to convey an understanding of the challenges and the excitement that practitioners are now facing. The goals of this chapter are to give the reader a full understanding of the lubrication of diesel and gasoline engine oils and their present U.S. categories, and then to concentrate on what makes these oils perform so well today. That role is fulfilled by the additives that are put into these oils, and this chapter will describe the function of these remarkable components.
Current and Future Specification of Lubricant Performance
Authors: Fox Malcolm F.
Published: January 2013

For the past 50 years the specification and testing of lubricant performance has successfully protected engines and powertrains against wear, internal deposit formation, and corrosion while reducing friction. Lubricant systems have systematically evolved in concert with increased performance requirements arising from

• Higher engine operating temperatures from increased power densities and reduced aerodynamic cooling;

• Extended service drain periods in response to consumer expectation and market expansion;

• Improvements and changes in fuel quality, mainly for reductions in sulfur but also gradual reformulations, then inclusion of biofuels at (currently) low percentages; and

• The consequences of increasingly stringent environmental emission controls.
Design for Reduced Wear
Authors: Lewis Roger , Slatter Tom
Published: January 2013

Wear is the progressive damage, involving material loss, which occurs on the surface of a component as a result of its motion relative to the adjacent working parts. Most contacting components in an engine are provided with a supply of lubricant to avoid excessive wear and subsequent damage, which may occur if they were allowed to contact in dry conditions. The consequences of wear in an engine can be severe and can lead to complete engine failure in some cases. Other effects can be loss of performance, an increase in oil consumption, a decrease in fuel economy, and an increase in emissions.
Tribology and Fine Automotive Mechanical Systems
Authors: Stehr Werner Friedrich
Published: January 2013

The laws and findings of tribology as an applied science are also applicable to the entire field of mechanics, from the bearing arrangement of a brown coal excavator with a diameter of 1 m to the bearing in a miniature gear with a diameter of only 0.1 mm. According to one definition, precision mechanics begins with bearing diameters of less than 5 mm (Figure 21.1), but this definition is purely arbitrary. The difference between the classical mechanics of mechanical engineering and precision mechanics consists only of the dimensions of the components. However, downscaling creates typical problems and particulars. This is also true in the automobile.
Analysis of In-Service Automotive Engine Oils
Authors: Fitch Jim C.
Published: January 2013

Most oil analysis performed in North America is done on diesel engine crankcase oils, primarily for large fleets in the transportation and off-road equipment industries. Ranking second would be the analysis of lubricants used in stationary industrial machinery including compressors, turbines, gearing, bearing lubes, and hydraulics. Far down the list is engine oil analysis performed on crankcase lubes from automotive fleets or privately owned cars and trucks.
Evaluating the Impact of a Surprise Silicone Additive to a Synthetic Hydrocarbon Lubricant
Authors: Hanks J. T. , Smith D. W. , Stevens C. J. , Winkel R. E.
Published: January 2013

A fractional percentage of a silicone compound was inadvertently introduced in one lot of Rheolube synthetic hydrocarbon grease used in the spin bearings of our momentum control systems. As a result, a decision had to made in a very short time as to whether the grease would meet the performance and life requirements. To accomplish this, a series of tests were undertaken to compare the performance of the subject grease or oil extracted from it to compare to the baseline lubricant. These tests represented each phase of bearing life: vibration, beginning of life, normal operational life, and end of life. Included were two different wettability tests, two different types of elastohydrodynamic lubrication tests and two different types of boundary tests. Acceptance test data of existing units with and without the subject grease were also used to determine how operational performance was affected. In addition to this test data, the Honeywell/Hanks lubricant life model was used to conclude that the subject grease would support our requirements.
Dual-mode Analytical Permeation System for Precise Evaluation of Porous and Nonporous Chemical Protective Materials
Authors: MacTaggart Douglas L. , Farwell Sherry O. , Cai Zhongtao , Smith Pauline
Published: January 2013

The reliable determination of the permeation characteristics of chemical protective materials and material systems is vital for the development and assessment of effective personal protective clothing and equipment. ASTM F739 describes the necessary capabilities for rigorous testing of the permeation characteristics of protective materials. Currently available technologies are limited in their ability to test chemical protective materials for permeability to certain classes of hazardous substances such as toxic industrial chemicals, chemical warfare agents (CWAs), and CWA simulants. In an effort to overcome these limitations, a dual-mode Compact Integrated Analytical Swatch Testing System (C-IASTS) has been developed that combines an advanced test cell design with rigorous temperature, flow, and pressure control. The automated, dual-mode, five test cell instrument allows both convective (dynamic) and static tests of porous and nonporous chemical protective materials in a manner that is compliant with the requirements of ASTM F739. Performance characterization of the new dual-mode C-IASTS demonstrated sufficient detectability, measurement precision, and time resolution to allow the determination of breakthrough time, steady state and maximum permeation rates, and cumulative permeation and an ability to produce a well-defined permeation curve. Current development and testing has been directed toward CWA simulants and military protective material systems, as well as commercial polymers, textiles, and other chemical selective barriers.
Garment Specifications and Mock-ups for Protection from Steam and Hot Water
Authors: Yu Sihong , Strickfaden Megan , Crown Elizabeth , Olsen Sara
Published: January 2013

This work is part of a larger project to develop improved, innovative textiles and garments for workers in the oil industry. Use of steam and hot water in extracting bitumen from oil sands, in oilfields, and in plants has become extensive in recent years. Personal protective equipment (PPE) is currently well designed to protect against hazards such as flash fire and radiant thermal exposures; however, due to an increase in workplace injuries reported in the last five years, including incidents of steam and hot water burns, further protection for workers is considered a priority. Steam used at sites is up to 375°C and under extreme pressures of up to 13 500 kPa; hot water is under significantly less pressure but is 80°C–90°C, which is well above temperatures that result in partial thickness burns. This research presents several stages of the design process: (1) identifying specific tasks which expose workers to steam and hot water; (2) setting the criteria for determining the needs addressed in specific types of PPE; (3) developing specifications for PPE garment design; and (4) presenting a preliminary mock-up garment. A multi-method research approach was taken that included observing, photographing, interviewing, and analyzing the movements of workers in western Canada. Results indicate extreme workplace conditions both indoors (up to 40°C in summer) and outdoors (down to −30°C in winter). Hazardous activities include steam quality sampling, cleaning filters and sludge traps, loading and unloading hot water, opening traps and high pressure steam valves, working very close to hot valves and pipes, and spraying steam onto wellheads. Specifications for improved garment design and mock-up garments were developed based on analysis of interviews and observations. This work also contributes insights into the process for understanding the complexities of a workplace environment with specific hazards and worker needs.
Analysis of Test Parameters and Criteria for Characterizing and Comparing Puncture Resistance of Protective Gloves to Needles
Authors: Gauvin Chantal , Darveau Olivier , Robin Charlotte , Lara Jaime
Published: January 2013

Needlestick injuries that expose workers to infection by blood-borne pathogens can be prevented by the use of appropriate protective gloves. Recently, an F23 ASTM task group developed the test method ASTM F2878-10, which defines needle puncture resistance as the maximum force recorded during tests using one of three hypodermic needle gauges. This study has two objectives: (1) to assess the effect of needle gauge on the ranking of glove puncture performance using the ASTM F2878-10 standard test method, and (2) to analyze the correspondence between maximum puncture force and puncture-through using an electrical detection device during needle penetration in protective gloves made of reinforced and multilayer composite materials. Two series of experiments were performed. In the first one, seven glove materials were characterized as described in the ASTM test method. The glove puncture resistance results were ranked after testing with the 21, 25, and 28 needle gauges. In the second experiment, a test device was used to electrically detect the force at which the needle tip punctures the material. Puncture tests were performed on seven glove materials following the ASTM F2878-10 test method and using this electrical device. The maximum force and force at puncture-through criteria are discussed. In the first experiment, the needle puncture resistance ranking of the gloves was almost equivalent for all three needle gauges. For glove selection purposes, the use of a single needle gauge provides sufficient information on needle puncture resistance for a comparison of the performance of the protective glove materials. In the second experiment, for two of the seven glove models, needle puncture-through was detected before the maximum force was reached. For those cases, the force at puncture-through criterion provides additional information on the material resistance that is not fully captured by the maximum force criterion alone, but it requires a more complex experimental setup.
Non-destructive Test Methods to Assess the Level of Damage to Firefighters' Protective Clothing
Authors: Rezazadeh Moein , Torvi David A.
Published: January 2013

During the service life of firefighters' protective clothing, individual aspects of its performance change due to factors such as thermal exposure. Although there are some standards for the inspection of firefighters' protective clothing, test methods that could be used to completely determine the level of damage and the remaining service life of such clothing have not yet been developed. In order to develop these test methods, it is necessary to understand how individual aspects of the performance of protective clothing deteriorate after exposure to fireground conditions. In this project, specimens consisting of an outer shell, a moisture barrier, and a thermal liner were thermally aged and tested using 20 kW/m2 exposures in a cone calorimeter. Two different outer shell fabrics, one undyed (light brown in color) and one dyed (black), were tested. Changes in the tensile strength of the outer shell resulting from single and multiple exposures were measured. Changes in the color of the outer shell were also measured using digital image analysis. The study demonstrates that multiple exposures to this heat flux level were less destructive than a single exposure of the same total duration. Color measurements showed good potential as a possible nondestructive means of evaluating the condition of the outer shell fabric, as these color measurements could be correlated to the loss in tensile strength of the outer shell. Possible future work to evaluate other aspects of the performance of these materials is discussed.
Assessing User Needs and Perceptions of Firefighter PPE
Authors: Barker Jessica , Boorady Lynn M. , Lin Shu-Hwa , Lee Young-A , Esponnette Beth , Ashdown Susan P.
Published: January 2013

The purpose of this study was to evaluate user perceptions of firefighter personal protective equipment (PPE) to determine ways to improve PPE design and function for both male and female firefighters. No previous studies have included both male and female firefighters in identifying user needs. It is critical to consider the entire PPE that a firefighter wears in his or her work environments, due to the various items worn simultaneously, to ensure a system that is fully functional and minimizes impact on wearer work performance and comfort. A total of 12 focus group interviews were conducted of career and volunteer firefighters, utilizing 67 males and 22 females. Urban and rural companies were represented from five different states. To obtain more in-depth data than the focus group interviews allowed, three firefighters participated in individual follow-up interviews. All interviews were recorded, transcribed, and analyzed using thematic analysis methods to draw comparisons of perceptions and user needs shared by both male and female firefighters. Both male and female firefighters identified a number of similar concerns such as excessive weight of the PPE, heat stress, overprotection for non-fire calls, garment fit and restricted mobility, compression burns, and problems donning the PPE quickly. They also indicated concern about specific firefighter clothing features that did not function well for them, including pockets, fasteners, knee and suspender padding, as well as the durability of the materials used in the PPE. Further study is needed to determine optimum design changes that can improve firefighter PPE to maximize wearer protection, performance, and comfort.
Evaluation of Thermal Comfort of Fabrics Using a Controlled-Environment Chamber
Authors: Pierce John D. , Hirsch Stephen S. , Kane Sara Beth , Venafro John A. , Winterhalter Carole A.
Published: January 2013

A critical characteristic of garments is thermal comfort, the ability to remain comfortable under conditions of elevated temperature and humidity. The traditional approach for assessing thermal comfort has required participants to exercise under conditions of elevated temperature and humidity while garbed in the candidate garments. The participants are subjected to stress, sophisticated equipment is required, and the measures, which have to be obtained in considerable numbers, require substantial time. In the present work, we report on the development of a potential alternate methodology to evaluate thermal comfort. Participants wore arm stockings of candidate fabrics and inserted their arms past the elbow in a controlled-environment chamber (CEC; Electro-tech Systems, Inc., Glenside, PA) under conditions of elevated temperature (40.5°C) and relative humidity (75 %). Participants assessed mittens made from eight different fabrics in 20-min testing sessions. Participants provided comfort ratings and judgments of specific perceptual experiences (such as warmth, sweatiness, stickiness, etc.) at separate specified times during the trial. Results revealed that fabric type was a significant predictor of thermal comfort ratings, with significant differences emerging after 10 min in the CEC. Further, thermal comfort was predicted by perceptual experiences of warmth, sweatiness, and stickiness. These results demonstrate the feasibility of the CEC approach in assessing relative fabric comfort as a viable alternative to whole-body testing under significant heat stress in an environmental chamber. This approach has further advantages of being more rapid, less stressful to participants, and not as complex as existing approaches.
Surface Deflections of Perpetual Pavement Sections
Authors: Gedafa Daba S. , Hossain Mustaque , Miller Richard , Steele Douglas A.
Published: January 2013

Structural evaluation provides valuable information at the network level of pavement management for project evaluation and prioritization purposes. However, due to the expenses involved in data collection and analysis, structural capacity is usually not evaluated at the network level. A rolling-wheel deflectometer (RWD), which measures surface deflections at highway speed, can be an alternate, faster method of pavement deflection evaluation for network-level data collection. This study was initiated in order to assess the feasibility of using an RWD for network-level pavement deflection measurements. RWD deflection data were collected under an 80 kN axle load and at a highway speed of about 88 km/h on four perpetual pavement sections in Kansas. Falling-weight deflectometer (FWD) data were also collected concurrently. The FWD first-sensor deflections were normalized to a load of 40 kN and then corrected to a temperature of 20° C. The RWD deflections were also corrected for temperature. FWD and RWD center deflections were then compared statistically. The results show that the deflections measured by RWD and the center (first sensor) deflections from the FWD are statistically similar. Furthermore, there is a linear relationship between FWD and RWD center deflections for all sections.
Measurement and Control Methodology for the Flowability of Lime Fines in Steel Injection Systems
Authors: McKinney David , Wolfe Larry D. , Belcastro Philip , Derby James
Published: January 2013

In recent years, injection technology in steel making has evolved from a means to inject oxygen and carbon into an electric arc furnace to a preferred technology for the introduction of calcium and dolomitic lime fines into the furnace. In optimizing this process, flowability is an important factor. Literature searches reveal that there are few useful methodologies for measuring the flowability characteristics of materials in the desired size range of 10 mm × 0 mm. Therefore, control standards need to be developed for measuring the desired quality of lime fines for injection systems. A methodology has been developed based on the key characteristics of “compressibility” and “cohesiveness,” which can be used to evaluate lime suitability in injection systems. The traits that help define these characteristics are the loose and packed density and the angle of repose. The results of these measurements are used as criteria for setting the control limits for flowability. Adhering to these control limits has mitigated problems in the field encountered when injecting lime fines into steel furnaces. This article describes the methods developed and how control limits can be determined for approving lime fines for injection into steel furnaces.
Impact of Lime and Liquid Additives on Life-Cycle Cost of Asphalt Pavements
Authors: Sebaaly Peter E. , Hajj Elie Y. , Sathanathan Thileepan , Shivakolunthar Sivakulan
Published: January 2013

An extensive laboratory experiment was conducted to evaluate the impact of liquid and lime additives on the life-cycle cost of asphalt mixtures from five different sources around the United States: Alabama, California, Illinois, South Carolina, and Texas. Three types of mixtures were evaluated from each source: un-treated, liquid-treated, and lime-treated. The types of liquid additive were selected by the participating state agency (i.e., mix source) and were added at the rate of 0.5 % by weight of binder. A single hydrated lime source was used for all five sources at the rate of 1 % by dry weight of aggregates. The mechanical properties of the 15 asphalt mixtures at the undamaged and moisture-damaged stages were evaluated in the laboratory in terms of: strength (i.e., dynamic modulus), resistance to rutting, and resistance to fatigue cracking. The measured strength and resistances to rutting and fatigue cracking were used in the AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) to assess the impact of the strength and mechanical properties of the various mixtures on the final performance of asphalt pavements. The results of the MEPDG were used to conduct comparative life-cycle cost analyses (LCCA) for asphalt pavements constructed with untreated, liquid-treated, and lime-treated asphalt mixtures from each of the five sources. The results of the LCCA showed that using hydrated lime in asphalt mixtures led to significant savings to the owner agency 100 % of the time, whereas using liquid anti-strip in the same asphalt mixtures may lead to significant cost increase to the owner agency.
Evaluating Polish Resistance of Tennessee Bituminous Surface Aggregates
Authors: Crouch L. K. , Brown Heather J.
Published: January 2013

The Tennessee Dept. of Transportation (TDOT), as part of an overall plan to achieve minimum HMA resurfacing cycle goals of 8 yr on inter-states and 12 yr on state routes, initiated a project to pair aggregate polish resistance with pavement functional needs. A new pre-evaluation procedure for aggregate polish resistance was developed and named the Tennessee Terminal Textural Condition Method (T3CM). Thirty-two bituminous surface projects were selected for the T3CM evaluation. The projects selected included both test strips and in-service bituminous surfaces. Further, several projects contained coarse aggregates from the same source. When possible, the coarse aggregates used in the projects were sampled at the HMA cold-feed stockpile rather than the aggregate source to ensure that the exact aggregates placed in the bituminous surface course were tested. The aggregates were subjected to two physical tests: T3CM and British polishing wheel/British pendulum, as well as three chemical/mineralogical tests: Percent silica ASTM C25, percent silica by x-ray diffraction, and loss-on-ignition (LOI). In addition, the bituminous surface courses containing these aggregates were monitored for skid resistance (i.e., polish resistance) by TDOT personnel using the locked-wheel trailer. A plot of project skid data versus time was considered to have a terminal skid number if the later skid results were stable or increasing. No project was considered to have had a terminal skid number unless more than three skid data points were available. Correlation coefficients between laboratory test methods and terminal skid numbers of bituminous surface aggregates were 0.705, 0.065, 0.076, 0.366, and 0.116 for the T3CM, the British Pendulum and British Wheel Method, ASTM C25 percent silica, LOI, and x-ray diffraction percent silica, respectively. Information is also presented on aggregate variability characterized by the T3CM, the British Pendulum, and British Wheel Method, and ASTM C25 percent silica.
Ascertaining Parametric Correlations between Lock-Wheel Friction-Testing and Fixed-Slip Friction-Testing Devices on Louisiana Highways
Authors: Gaspard Kevin , Zhang Zhongjie
Published: January 2013

Pavement friction testing originated in the 1950s and has been studied internationally. There are four major types of friction-testing methods: lock-wheel test (LWT), fixed slip (FXSL), variable slip, and side force. The Federal Highway Administrator solicited the Louisiana Transportation Research Center (LTRC) to participate in a national study to evaluate fixed-slip testers that it had purchased from Dynatest International (FXSLD) and Findlay Irvine (FXSLG). LTRC developed a testing program where the fixed-slip testers were correlated to its LWT. Eight roadways were assessed with each device at 80.5 kph within a 2-h interval. Approximately 2286 m were assessed on each roadway. Testing with the LWT included both the smooth (LWTS) and ribbed tires (LWTR). The regression analysis between fixed-slip testers and a lock-wheel tester (ribbed and smooth tire) indicated that statistically viable correlations exist for the roadway surfaces and friction number (FN) ranges assessed in this study. More comprehensive testing should be conducted to validate the trend found in this study prior to establishing equations to be utilized on a statewide basis. The one-way analysis of variance (ANOVA) results indicated that a statistical difference exists between the FN maximum (μmax) values obtained by all devices used in this study. In the authors' opinion, this is a significant issue that must be addressed by the friction-testing community and regulation industry. Though both FXSL devices were calibrated in accordance with their manufacturer's recommendations, different FN maximums (μmax), as well as precisions (variances), were discovered. Such a scenario would make it unfeasible to establish investigatory or intervention friction criteria for a roadway network using FXSL testers under these conditions.
Golden-Car Simulation Speed and Its Implications to the Relevance of the IRI
Authors: Karamihas Steven M.
Published: January 2013

The road-monitoring community is considering alternatives to the International Roughness Index (IRI) that are based on the Golden-Car model, but perform the simulation at a speed other than standard value of 80 km/h. Many state and federal highway agencies apply pay adjustments to new road and road resurfacing contracts based on the IRI, but expect significantly higher prevailing travel speeds on very smooth limited-access roads. Inertial profilers also continue to propagate as a tool for monitoring pavement conditions on lower-speed roads, where the posted speed limit or the prevailing traffic speed may be much lower than 80 km/h. The broad application of the IRI to higher and lower-speed roads has created interest by practitioners in the issue of Golden-Car model simulation speed. Changing the simulated forward speed causes predictable changes in the frequency response of the Golden-Car model: the temporal frequency response changes very little, but the spatial frequency response shifts in proportion to speed. However, the quantitative effect on the resulting index values and their relationship to other relevant responses, such as tire load variations and passenger acceleration, are less obvious. This paper explores the potential consequences of changes to the Golden-Car model simulation speed, including changes to the output roughness values and meaning of the roughness scale and roughness threshold values. Most of the discussion relies on numerical and theoretical analysis, with some sample measurements provided for elucidation.
Performance of Exposed Aggregate Surface of Composite Pavements at MnROAD
Authors: Izevbekhai Bernard , Akkari Alexandra
Published: January 2013

This paper summarizes the construction and early performance assessment of an exposed aggregate surface on a composite pavement test cell (cell 72) at MnROAD. Although exposed aggregate surfaces and composite pavement systems have become extremely popular in Europe, they are a relatively new concept in the United States. The performance of the exposed aggregate surface is compared to that in the two other composite pavement cells at MnROAD: cell 70, hot mix asphalt (HMA) over a recycled aggregate concrete, and cell 71, diamond grind concrete over recycled aggregate concrete. The strength, tire pavement noise (on board sound intensity), sound absorption, friction, texture, and international roughness index were tested. The results suggest that the exposed aggregate concrete surface does not provide significant noise reduction. Innovative diamond grinding of composite pavements might be beneficial for noise reduction. Exposed aggregate surfacing can provide more than adequate friction for driver safety, but it does not show any improvement relative to typical HMA or diamond ground surfaces. Exposed aggregate surfaces have a texture (or mean profile depth) similar to that of traditional diamond ground surfaces but might be detrimental to the ride quality. Continued monitoring of these test cells will aid the development of a wide understanding of exposed aggregate surfaces and composite pavements needed for more effective design and accurate service life models.
Treatment of Marine Clay with Hydrated Lime and Quicklime
Authors: Kavak Aydin , Tüylüce Füsun
Published: January 2013

The objective of this research is to improve dredged marine sediments with lime for potential use in earthfill works. Dredging work is usually necessary for coastal construction work and this material should be removed in an economical way. Marine clay samples used in the study were dredged in Gemlik Bay near Bursa, in Turkey. Geotechnical tests were conducted to determine the properties of the natural clay samples, including classification tests, unconfined compression (UC) and California bearing ratio (CBR) tests. The optimum lime content by weight was determined as 5 % using the Eades and Grim pH method, Atterberg limits and unconfined compression strength tests. Standard and modified Proctor tests were conducted to determine optimum water content and maximum dry density of the soil. Maximum dry density values decreased, optimum water content values increased, and Proctor curves becomes flatter with the addition of lime. Because the natural water content of the clay is around 40 % and the optimum water content of the samples with lime is around 16 %, not only hydrated lime but also quicklime is used for the improvement and drying of the marine clay soil. The original unconfined compressive strength and CBR value of the dredging soil were close to zero because of high water content. One month after improvement by lime, the unconfined compressive strength value reached 550 kPa and soaked CBR value was 35 without swelling. Unconfined compressive tests and CBR test results demonstrate that this type of marine clay can be improved with lime and can be economically utilized as a fill material in earthfill works.
Methods for Measuring the Grip Performance of Structural Firefighting Gloves
Authors: Ross Kevin , Barker Roger , Watkins Jessica , Deaton A. Shawn
Published: January 2013

Grip evaluation methods are compared in tests made on structural firefighter gloves selected to represent a range of materials and constructions. An investigation of the effects of pulling force orientation and wetting on grip performance in rope and rod-type grip tests is discussed. A new method developed to measure grip by measuring torque generated in twisting an acrylic glass rod with gloved hands is described. Comparative studies show that the newly developed torque test provides lower subject variability and enhanced resolution among different gloves based on measured grip performance. Factors of glove construction that influence performance in the torque grip test are discussed, including slip-stick phenomena observed in tests on some wet gloves.
Variability of Fresh and Hardened Voids of Pervious Concrete
Authors: Crouch L. K. , Hendrix John P. , Sparkman Alan , Badoe Daniel
Published: January 2013

ASTM C1688-08 currently contains only a single-operator standard deviation for the density criterion for determining allowable range. The adequacy of this criterion was put to the test in recent research undertaken for the Tennessee Concrete Association (TCA). Twenty replications of three pervious mixtures were used. The control mixture had 356-kg/m3 (600-lb/yd3) of cementing materials with a 0.3 w/cm ratio, 1533-kg/m3 (2584-lb/yd3) of No. 89 limestone coarse aggregate and no fine aggregate. The second mixture had 3.5 % river sand replacement of the coarse aggregate (by total aggregate volume) and a 0.31 w/cm ratio. The third mixture had 7 % river sand in the combined aggregate gradation and a w/cm ratio of 0.32. Coarse aggregate content was reduced to accommodate the changes in the second and third mixtures. Twenty replications of each TCA mixture yielded coefficients of variation of ASTM C1688 density values of 0.3, 0.5, and 0.7 %, respectively for the control mixture, the 3.5 % sand mixture, and the 7 % sand mixture. All three mixtures met current allowable ASTM C1688 range criteria based on ASTM C670-03 multipliers. However, the variability in density increased substantially as sand and w/cm ratios were increased, possibly indicating that the variability criterion for density may need to be revised. Other findings include a good correlation between C1688 voids and pervious properties such as effective (water accessible) voids (ASTM D7063-05) and compressive strength (ASTM C39-06) indicating that C1688 voids may be useful as a mix design and adjustment tool. Twenty replications of each TCA mixture yielded coefficients of variation of ASTM C1688 void values of 1.1, 2.5, and 3.6 %, respectively, for the control mixture, 3.5 % sand mixture, and 7 % sand mixture. Information on compressive strength and effective void variability is also provided.
Translation between Heat Loss Measured Using Guarded Sweating Hot Plate, Sweating Manikin, and Physiologically Assessed Heat Stress of Firefighter Turnout Ensembles
Authors: Ross Kevin , Barker Roger , Deaton A. Shawn
Published: January 2013

Sweating skin models and instrumented thermal manikins are commonly used to assess the heat stress potential of materials used in protective clothing. This research describes the relationship observed between heat loss through firefighter turnout ensembles measured using a sweating thermal manikin and that measured with a guarded sweating hot plate. Materials and garment level instrument measures are compared on the basis of their ability to predict human physiological responses related to heat stress in firefighter turnout systems. Sweating hot plate and manikin test results for selected firefighter turnout ensembles are compared to human wear studies in which firefighter turnout ensembles were worn in different environmental conditions. Sweating manikin tests are used to explain differences in the human physiological response and how these measures are related to turn-out heat transfer properties measured using a sweating hot plate. This study confirms the utility of sweating manikins in characterizing the effects of clothing design, fit, and layers on heat and moisture transfer. Thermal manikins are shown to be valuable tools for evaluating the distribution of heat loss through different areas of protective gear.
Development of a New Test Method for Assessing the Potential Raveling Resistance of Pervious Concrete
Authors: Offenberg Matthew
Published: January 2013

One of the key concerns with pervious concrete is the material's surface durability, specifically, its resistance to raveling. As the market for pervious concrete grew, this was one of the hurdles in the way of broader adoption of the technology. This paper documents the process of developing a test method to determine the potential raveling resistance of a pervious concrete mixture. The process included a study that used lab cast cylinders to compare the raveling resistance potential of pervious concrete mixtures containing different aggregates, varying cement contents, and basic chemical admixtures. A refined version of the test method was developed after an unsuccessful ASTM round robin evaluation. The results from this new method will provide the industry with beginning correlations between basic mix ingredients and the surface durability of a finished pervious concrete pavement.
Performance of Pervious Portland Cement Concrete by Field and Laboratory Testing, Including Void Structure, Unit Weight, Compressive and Flexural Strength
Authors: Denison William B.
Published: January 2013

Titan Virginia Ready Mix (TVRM) sponsored a study involving field and laboratory testing on numerous placement segments of the 4700 yd3 (8 acres) of pervious pavement supplied to the Prime Outlet Mall project in Williamsburg, Virginia, 2008. The intent of the study was to gather a statistically sufficient quantity of test data of plastic and hardened properties using ASTM test standards from a project large in square footage to provide such data. The TVRM approach involved representative sampling, plastic and hardened density testing, void % determination, thickness measurements, and compressive and flexural strength testing. The hardened test specimens were obtained by coring and sawing from precast panels cast onsite during pavement production. The test panels measuring 3 ft × 3 ft × 6 in. in depth had supporting bottoms and was cast from composite samples obtained at the project site. The test panels were cast and cured in the same manner as the pervious pavement, one test panel for every 150 to 200 yd3. The test panels were cured a minimum of 7 days to promote the necessary aggregate/ cement paste bond development as is referenced in ACI 522.1-08 [ACI 522-1, “Specification for Pervious Concrete Pavement,” American Concrete Institute, Farmington Hills, MI, 2008]. Once the curing was complete the pervious test panels were cushioned, and transported to the TVRM laboratory for further curing and hardened strength and density testing. The TVRM objective was to compile enough raw data with consistent test results to help designers and specifiers in designing for future pervious projects.
Lime in Papermaking: A Historic Review
Authors: Doelle Klaus
Published: January 2013

Paper making is one of the largest industries in the United States. The application of lime in the paper manufacturing process can be traced back almost 2000 years. Constant improvements over time have made it possible for lime today to have applications in pulping, papermaking, and paper mills' energy and environmental sectors, leading to a demand for well over 2 × 106 tons of lime products annually. Currently, the most promis ing sector for lime applications in papermaking is the filler sector. Today, paper products require the use of approximately 3.5 × 106 tons of filler material annually, with an estimated 5 % annual increase. Fillers are less expensive than fiber, allowing for reduced production costs while improving optical paper properties, dimensional stability, sheet formation, and printability. Fillers will also allow the paper industry to reduce its energy use and reduce the use of acidic materials in the bleaching process.
A Survey of Particle Characterization Techniques for Lime and Other Powders
Authors: Thornton Anthony W.
Published: January 2013

The behavior of many materials can be readily predicted based on the measurement of various physical properties. This is often much quicker, easier, and less expensive than performing functional tests with the material, especially because the relationship between the measured physical properties and the material is usually known from past experience. Often it is necessary only to make sure that a current lot of material has the same properties, within acceptable tolerances, as a previous lot, and that a new lot prepared in the future will also behave as expected if it has the same values for these measurable properties. In this paper, several currently used methods for determining the physical properties of lime and other powders are presented, along with an explanation of the principles of measurement and sample preparation.