Louisiana's Experience with Open-Graded Friction Course Mixtures

2012 ◽  
Vol 2295 (1) ◽  
pp. 63-71 ◽  
Author(s):  
M. Sharear Kabir ◽  
William King ◽  
Christopher Abadie ◽  
Patrick Icenogle ◽  
Samuel B. Cooper
Keyword(s):  
Traffic Safety ◽  
Comprehensive Evaluation ◽  
Field Performance ◽  
Performance Standards ◽  
Field Evaluation ◽  
The United States ◽  
Field Analysis ◽  
Mix Design ◽  
Test Field ◽  
Open Graded Friction Course

The Louisiana Department of Transportation and Development (DOTD) began developing open-graded friction course (OGFC) mixtures in the late 1960s and early 1970s. Then, in the late 1980s, a moratorium was imposed on their use because of some early failure issues. However, OGFC mixture performance and service life have improved significantly since a new generation of OGFC mixture was promoted in the United States in the late 1990s. Inspired by the success of other state agencies, the Louisiana DOTD modified the earlier mix design and constructed four new OGFC sections during the past decade to evaluate pavement performance and safety benefits. This paper includes a comprehensive evaluation of Louisiana OGFC mixtures based on their laboratory and field performance. Laboratory work entailed material and mixture design in addition to numerous laboratory tests, namely permeability, draindown, tensile strength ratio, and loaded wheel test. Field evaluation involved visual inspection, pavement condition survey, skid resistance, and traffic safety. With few exceptions in the laboratory, the selected OGFC mixtures showed the potential to meet current Louisiana DOTD specifications, as well as various performance standards established by previous studies. The field analysis indicated that the OGFC test sections showed improved rutting, cracking, and skid performance when compared with typical Superpave® roadway sections. This performance evaluation will likely support the ongoing use of OGFC mixtures in the state of Louisiana. Additionally, the evaluation provides an opportunity to continually improve the current OGFC specification and mix design procedures adopted by the Louisiana DOTD.

Refinement of New-Generation Open-Graded Friction Course Mix Design

2003 ◽  
Vol 1832 (1) ◽  
pp. 78-85 ◽  
Author(s):  
Donald E. Watson ◽  
Kathryn Ann Moore ◽  
Kevin Williams ◽  
L. Allen Cooley
Keyword(s):  
United States ◽  
Design Procedure ◽  
The United States ◽  
Mix Design ◽  
Superpave Gyratory Compactor ◽  
Open Graded Friction Course ◽  
Compactive Effort ◽  
And Performance ◽  
New Generation ◽  
Air Void

Open-graded friction course (OGFC) has been used in the United States for more than 50 years. In 2000, National Center for Asphalt Technology (NCAT) research led to a recommended mix design procedure for a new-generation OGFC, but the work involved only one aggregate source. Therefore, NCAT is in the process of refining this design procedure to ensure that it is applicable to other aggregate types used in surface mixes throughout the United States. The objectives of NCAT's current research are to refine and field validate the new-generation OGFC mix design procedure. This work has led to several experiments. Several objectives have been identified that need to be addressed. Superpave® technology and use of the Superpave gyratory compactor (SGC) need to be incorporated into the mix design procedure. The Cantabro test for durability and resistance to stone loss needs to be adapted to SGC-prepared specimens and performance parameters established. The asphalt draindown test (AASHTO T 305-97), which was developed for stone-matrix asphalt mixtures, also needs to be evaluated for applicability to OGFC mixtures. In addition, a method for effectively evaluating air void criteria needs to be investigated. On the basis of the research conducted in this study, 50 gyrations of the SGC was selected as the design compactive effort during mix design. Also, the use of SGC-prepared samples during the Cantabro test appears to be a reasonable alternative to use of Marshall-compacted samples.

Five-Year Performance of Improved Open-Graded Friction Course on the NCAT Pavement Test Track

2019 ◽  
Vol 2673 (2) ◽  
pp. 544-551 ◽  
Author(s):  
Zhaoxing Xie ◽  
Nam Tran ◽  
Donald E. Watson ◽  
Lyndi Davis Blackburn
Keyword(s):  
Design Procedure ◽  
Field Performance ◽  
Weather Conditions ◽  
Mix Design ◽  
Department Of Transportation ◽  
Test Track ◽  
Research Cycle ◽  
Laboratory Test Results ◽  
Life Issues ◽  
Open Graded Friction Course

Open Graded Friction Course (OGFC) mixtures are used as the final riding surface on roadways as they offer many benefits, such as reducing hydroplaning, reducing splash and spray behind vehicles for improved driver visibility, improving wet-pavement friction, and reducing surface reflectivity during wet-weather conditions. Despite these benefits, the use of OGFC has diminished over the years due to durability and service-life issues. The typical OGFC pavements in Alabama have exhibited premature distresses (e.g., raveling) after approximately six or seven years in service. Therefore, there is a need to change the current OGFC mix design procedure to improve the mix durability. In this study, three modified OGFC mixtures were designed based on a 12.5-mm OGFC mix design previously approved by the Alabama Department of Transportation (ALDOT) and paved in three test sections (E9A, E9B, and E10) on the National Center for Asphalt Technology pavement test track to evaluate possible changes to ALDOT’s OGFC mix design procedure. The ALDOT-approved mix design lasted less than 20 million equivalent single-axle loads (ESALs) on I-85, a few miles from the test track, whereas the three modified OGFC mixtures lasted more than 20 million ESALs and remained in place for another research cycle (10 millions ESALs) on the test track. The three modified OGFC mixtures also showed improved laboratory performance characteristics compared with those of the ALDOT-approved OGFC mixture. Based on the field and laboratory test results, adjustments made in the three modified OGFC mixtures can potentially improve the long-term field performance of OGFC mixtures in Alabama.

Field Performance of Stress-Laminated Timber Bridges

2000 ◽  
Vol 1740 (1) ◽  
pp. 96-103 ◽  
Author(s):  
Michael A. Ritter ◽  
Sheila Rimal Duwadi ◽  
James P. Wacker
Keyword(s):  
United States ◽  
Monitoring Program ◽  
Field Performance ◽  
Forest Products ◽  
Field Evaluation ◽  
The United States ◽  
Load Test ◽  
Department Of Agriculture ◽  
Condition Evaluation ◽  
Timber Bridges

Stress-laminated timber bridges were introduced into the United States in the late 1980s. Since then this concept has been used for more than 500 bridges constructed on roadways throughout the United States. To evaluate the performance of these bridges, the Forest Products Laboratory of the U.S. Department of Agriculture Forest Service and FHWA initiated a nationwide bridge-monitoring program. A field evaluation and the results obtained through that monitoring program for stress-laminated bridges that have been continuously monitored for 2 or more years after installation are presented. Included are discussions related to bridge design and construction, moisture content, stressing bar force, vertical creep, load test behavior, and condition evaluation. On the basis of the monitoring program results, the performance of stress-laminated timber bridges is generally satisfactory, although there are areas in which performance can be improved.

A Commented Synopsis of the Report of the Committee for the National Tire Efficiency Study4

2007 ◽  
Vol 35 (2) ◽  
pp. 70-93
Author(s):  
Marion G. Pottinger ◽  
Joseph D. Walter ◽  
John D. Eagleburger
Keyword(s):  
Traffic Safety ◽  
Rolling Resistance ◽  
The United States ◽  
Final Report ◽  
Highway Traffic ◽  
National Academy Of Sciences ◽  
Scrap Tire ◽  
National Highway Traffic Safety ◽  
Fuel Savings ◽  
Time Required

Abstract The Congress of the United States petitioned the Transportation Research Board of the National Academy of Sciences to study replacement passenger car tire rolling resistance in 2005 with funding from the National Highway Traffic Safety Administration. The study was initiated to assess the potential for reduction in replacement tire rolling resistance to yield fuel savings. The time required to realize these savings is less than the time required for automotive and light truck fleet replacement. Congress recognized that other factors besides fuel savings had to be considered if the committee’s advice was to be a reasonable guide for public policy. Therefore, the study simultaneously considered the effect of potential rolling resistance reductions in replacement tires on fuel consumption, wear life, scrap tire generation, traffic safety, and consumer spending for tires and fuel. This paper summarizes the committee’s report issued in 2006. The authors, who were members of the multidisciplinary committee, also provide comments regarding technical difficulties encountered in the committee’s work and ideas for alleviating these difficulties in further studies of this kind. The authors’ comments are clearly differentiated so that these comments will not be confused with findings, conclusions, and recommendations developed by the committee and contained in its final report.

Field evaluation of tissue-cultured bananas in south-eastern Queensland

1990 ◽  
Vol 30 (4) ◽  
pp. 569 ◽  
Author(s):  
RA Drew ◽  
MK Smith
Keyword(s):  
Callus Culture ◽  
Field Performance ◽  
Field Evaluation ◽  
Ratoon Crop ◽  
Musa Sp ◽  
Planting Material ◽  
Lateral Buds ◽  
Conventional Material ◽  
Banana Cultivar ◽  
Plant Crop

Field performance is described for tissue cultured plants and conventional propagules of planting material of banana cultivar 'New Guinea Cavendish' (Musa sp., AAA group, Cavendish subgroup). Tissuecultured plants were produced by either regeneration of plants from callus culture or by micropropagation of plants following the release of dormant buds at the leaf axils of explants. The conventional material consisted of suckers and 'bits' (lateral buds and associated corm material). Tissue-cultured plants established more quickly, were taller, and had a shorter time to bunch emergence and harvest of plant crop than conventional planting material. They had significantly (P<0.05) higher yields in terms of bunch weight, which was a function of greater numbers of fingers and hands. These advantages did not extend to the ratoon crop. Sucker production on tissue-cultured plants was significantly (P<0.01) higher up to 8 months after planting, equal to conventional material from 8 months to harvest, and then significantly lower. Twenty-two per cent of the plants derived from callus were off-types compared with 3% in the line produced by axillary bud proliferation. No off-types were observed in conventional planting material.

Athletic Scholarships in Intercollegiate Football

2011 ◽  
Vol 13 (5) ◽  
pp. 515-535 ◽  
Author(s):  
Joshua D. Pitts ◽  
Jon Paul Rezek
Keyword(s):  
High School ◽  
Intercollegiate Athletics ◽  
Negative Binomial ◽  
Negative Relationship ◽  
Field Performance ◽  
The United States ◽  
Football Players ◽  
High School Football ◽  
Football Coaches ◽  
Athletic Scholarships

Despite the financial and cultural importance of intercollegiate athletics in the United States, there is a paucity of research into how athletic scholarships are awarded. In this article, the authors empirically examine the factors that universities use in their decision to offer athletic scholarships to high school football players. Using a Zero-Inflated Negative Binomial (ZINB) model, the authors find a player’s weight, height, body mass index (BMI), race, speed, on-the-field performance, and his high school team’s success often have large and significant impacts on the number of scholarship offers he receives. There is also evidence of a negative relationship between academic performance and scholarship offers. In addition, the authors find evidence of a scholarship premium for players from Florida and Texas. The results also show that running backs, wide receivers, and defensive backs appear to generate the most attention from college football coaches, other things equal.

Pedestrian Behavior at Signalized Intersection Crosswalks: Observational Study of Factors Associated with Distracted Walking, Pedestrian Violations, and Walking Speed

2018 ◽  
Vol 2672 (35) ◽  
pp. 1-12 ◽  
Author(s):  
Brendan J. Russo ◽  
Emmanuel James ◽  
Cristopher Y. Aguilar ◽  
Edward J. Smaglik
Keyword(s):  
Traffic Safety ◽  
Walking Speed ◽  
The United States ◽  
Ordinary Least Squares ◽  
Signalized Intersections ◽  
Video Data ◽  
High Definition ◽  
Pedestrian Behavior ◽  
Factors Associated ◽  
Walking Speeds

In the past two decades, cell phone and smartphone use in the United States has increased substantially. Although mobile phones provide a convenient way for people to communicate, the distraction caused by the use of these devices has led to unintended traffic safety and operational consequences. Although it is well recognized that distracted driving is extremely dangerous for all road users (including pedestrians), the potential impacts of distracted walking have not been as comprehensively studied. Although practitioners should design facilities with the safety, efficiency, and comfort of pedestrians in mind, it is still important to investigate certain pedestrian behaviors at existing facilities to minimize the risk of pedestrian–vehicle crashes, and to reduce behaviors that may unnecessarily increase delay at signalized intersections. To gain new insights into factors associated with distracted walking, pedestrian violations, and walking speed, 3,038 pedestrians were observed across four signalized intersections in New York and Arizona using high-definition video cameras. The video data were reduced and summarized, and an ordinary least squares (OLS) regression model was estimated to analyze factors affecting walking speeds. In addition, binary logit models were estimated to analyze both pedestrian distraction and pedestrian violations. Ultimately, several site- and pedestrian-specific variables were found to be significantly associated with pedestrian distraction, violation behavior, and walking speeds. The results provide important information for researchers, practitioners, and legislators, and may be useful in planning strategies to reduce or mitigate the impacts of pedestrian behavior that may be considered unsafe or potentially inefficient.

scholarly journals Bella Abzug, queer rights, and disrupting the status quo

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Trevor G Gates ◽  
Margery C Saunders
Keyword(s):  
Civil Rights ◽  
Social Action ◽  
Public Discourse ◽  
Historical Context ◽  
The United States ◽  
Status Quo ◽  
Working Environment ◽  
Field Analysis ◽  
The Public ◽  
The Status

Workers who are lesbian, gay, bisexual, transgender, and queer (LGBTQ)-identified have always been a part of the workplace in the United States, yet there has been a lack of awareness about how to advocate for the needs of these people. This lack of awareness was challenged by Congresswoman Bella Abzug. Abzug’s campaign for creating an equal working environment for sexual minorities initiated gradual changes in the public discourse concerning workplace and other broad equality measures for these communities. To frame these gradual transformations within a historical context, we use Lewin’s force field analysis framework to examine the change efforts of Abzug. Abzug had beginning success in thawing the status quo yet her visions for equality for LGBTQ people have yet to be realized. Using Abzug’s social action as an example, this article concludes that allies must continue to challenge societal oppression, power, and privilege and to demand civil rights protections for LGBTQ individuals.

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