WorldWideScience
1

Pavement distress detection and severity analysis  

Science.gov (United States)

Automatic recognition of road distresses has been an important research area since it reduces economic loses before cracks and potholes become too severe. Existing systems for automated pavement defect detection commonly require special devices such as lights, lasers, etc, which dramatically increase the cost and limit the system to certain applications. Therefore, in this paper, a low cost automatic pavement distress evaluation approach is proposed. This method can provide real-time pavement distress detection as well as evaluation results based on the color images captured from a camera installed on a survey vehicle. The entire process consists of two main parts: pavement surface extraction followed by pavement distress detection and classification. In the first part, a novel color segmentation method based on a feed forward neural network is applied to separate the road surface from the background. In the second part, a thresholding technique based on probabilistic relaxation is utilized to separate distresses from the road surface. Then, by inputting the geometrical parameters obtained from the detected distresses into a neural network based pavement distress classifier, the defects can be classified into different types. Simulation results are given to show that the proposed method is both effective and reliable on a variety of pavement images.

Salari, E.; Bao, G.

2011-03-01

2

Wavelet-aided pavement distress image processing  

Science.gov (United States)

A wavelet-based pavement distress detection and evaluation method is proposed. This method consists of two main parts, real-time processing for distress detection and offline processing for distress evaluation. The real-time processing part includes wavelet transform, distress detection and isolation, and image compression and noise reduction. When a pavement image is decomposed into different frequency subbands by wavelet transform, the distresses, which are usually irregular in shape, appear as high-amplitude wavelet coefficients in the high-frequency details subbands, while the background appears in the low-frequency approximation subband. Two statistical parameters, high-amplitude wavelet coefficient percentage (HAWCP) and high-frequency energy percentage (HFEP), are established and used as criteria for real-time distress detection and distress image isolation. For compression of isolated distress images, a modified EZW (Embedded Zerotrees of Wavelet coding) is developed, which can simultaneously compress the images and reduce the noise. The compressed data are saved to the hard drive for further analysis and evaluation. The offline processing includes distress classification, distress quantification, and reconstruction of the original image for distress segmentation, distress mapping, and maintenance decision-making. The compressed data are first loaded and decoded to obtain wavelet coefficients. Then Radon transform is then applied and the parameters related to the peaks in the Radon domain are used for distress classification. For distress quantification, a norm is defined that can be used as an index for evaluating the severity and extent of the distress. Compared to visual or manual inspection, the proposed method has the advantages of being objective, high-speed, safe, automated, and applicable to different types of pavements and distresses.

Zhou, Jian; Huang, Peisen S.; Chiang, Fu-Pen

2003-11-01

3

A Novel Pavement Distress Image Filtering Algorithm  

Directory of Open Access Journals (Sweden)

Full Text Available Combined the Nonsubsampled Contourlet Transform (NSCT with compressed sensing de-noising theory, this study proposed a compressed sensing image filtering algorithm in the NSCT transform domain. This algorithm adopted the transform domain filtering method. Firstly, the NSCT was used to do multi-scale and multi-directional transform on the input noisy pavement distress Image which was mapped to the transform domain. Then the compressed sensing theory was used to filter the high-frequency sub-band coefficients. The experiment results show that this algorithm improves the effectiveness and timeliness of the pavement distress image filtering.

Feng Xin

2013-01-01

4

Wavelet-based pavement distress detection and evaluation  

Science.gov (United States)

An automated pavement inspection system consists of image acquisition and distress image processing. The former is accomplished with imaging sensors, such as video cameras and photomultiplier tubes. The latter includes distress detection, isolation, classification, evaluation, segmentation, and compression. We focus on wavelet-based distress detection, isolation, and evaluation. After a pavement image is decomposed into different-frequency subbands by the wavelet transform, distresses are transformed into high-amplitude wavelet coefficients and noise is transformed into low-amplitude wavelet coefficients, both in the high-frequency subbands, referred to as details. Background is transformed into wavelet coefficients in a low-frequency subband, referred to as approximation. First, several statistical criteria are developed for distress detection and isolation, which include the high-amplitude wavelet coefficient percentage (HAWCP), the high-frequency energy percentage (HFEP), and the standard deviation (STD). These criteria are tested on hundreds of pavement images differing by type, severity, and extent of distress. Experimental results demonstrate that the proposed criteria are reliable for distress detection and isolation and that real-time distress detection and screening is currently feasible. A norm for pavement distress quantification, which is defined as the product of HAWCP and HFEP, is also proposed. Experimental results show that the norm is a useful index for pavement distress evaluation.

Zhou, Jian; Huang, Peisen S.; Chiang, Fu-Pen

2006-02-01

5

LDPE and CRMB Utilization in Bituminous Concrete Pavement Surfaces  

OpenAIRE

The road traffic and the traffic intensity are also increasing. Thus the load bearing capacities of the road is to be increased. There are two types of roads - flexible pavements (bitumen roads) and rigid pavements (concrete roads). Flexible pavements (bitumen roads) comprise of the major portion of all surfaced roads. In India, bituminous surfaced flexible pavements comprise of majority of the roads. Distress symptoms, such as cracking, rutting, etc., are being increasingly caused earlier by...

Payal Bakshi

2013-01-01

6

Automated real-time pavement distress detection using fuzzy logic and neural network  

Science.gov (United States)

Conventional visual and manual pavement distress analysis approaches are very costly, time-consuming, dangerous, labor-intensive, tedious, subjective, having high degree of variability, unable to provide meaningful quantitative information, and almost always leading to inconsistencies in distress detail over space and across evaluations. In this paper, a novel system for multipurpose automated real-time pavement distress analysis based on fuzzy logic and neural networks will be studied. The proposed system can: provide high data acquisition rates; effectively and accurately identify the type, severity and extent of surface distress; improve the safety and efficiency of data collection; offer an objective standard of analysis and classification of distress; help identify cost effective maintenance and repair plans; provide images and examples through information highway to other user/researchers; provide image/sample back for training or as the benchmark for testing new algorithms. The proposed system will reduce the cost for maintenance/repair greatly, and can contribute to other research in pavement maintenance, repair and rehabilitation.

Cheng, Heng-Da

1996-11-01

7

LDPE and CRMB Utilization in Bituminous Concrete Pavement Surfaces  

Directory of Open Access Journals (Sweden)

Full Text Available The road traffic and the traffic intensity are also increasing. Thus the load bearing capacities of the road is to be increased. There are two types of roads - flexible pavements (bitumen roads and rigid pavements (concrete roads. Flexible pavements (bitumen roads comprise of the major portion of all surfaced roads. In India, bituminous surfaced flexible pavements comprise of majority of the roads. Distress symptoms, such as cracking, rutting, etc., are being increasingly caused earlier by high traffic intensity, over loading of vehicles and significant variations in daily and seasonal temperature of the pavement. Investigations have revealed that modifiers can be used to improve rheological properties of bitumen and bituminous mixes to make it more suitable for road construction. Bituminous-mix design involves mixing various aggregate sizes and bitumen contents in optimum proportions. For a given aggregate gradation, the optimum bitumen content is estimated by satisfying a number of mix design parameters. Badly compacted bituminous mixtures develop low stiffness, bad fatigue resistance, bad durability, etc. which are undesirable characteristics for a good pavement. Modified Bitumen is one of the important construction materials for flexible pavements. Use of plastic waste (LDPE and Crumb Rubber in the construction of flexible pavement is gaining importance. The modified bitumen show better properties for road construction.

Payal Bakshi

2013-08-01

8

Improving a pavement-watering method on the basis of pavement surface temperature measurements  

CERN Document Server

Pavement-watering has been studied since the 1990's and is currently considered a promising tool for urban heat island reduction and climate change adaptation. However, possible future water resource availability problems require that water consumption be optimized. Although pavement heat flux can be studied to improve pavement-watering methods (frequency and water consumption), these measurements are costly and require invasive construction work to install appropriate sensors in a dense urban environment. Therefore, we analyzed measurements of pavement surface temperatures in search of alternative information relevant to this goal. It was found that high frequency surface temperature measurements (more than every 5 minutes) made by an infrared camera can provide enough information to optimize the watering frequency. Furthermore, if the water retaining capacity of the studied pavement is known, optimization of total water consumption is possible on the sole basis of surface temperature measurements.

Hendel, Martin; Diab, Youssef; Royon, Laurent

2014-01-01

9

Durability of Ring-Road II asphalt pavement - Phase I report on forensic analysis of Ring-Road II pavement distresses  

OpenAIRE

This report presents findings from prematurely failed pavement of Ring-Road II (Kehä II) in Espoo, Finland. The road had excessive potholes, cracking, raveling and stripping only five years after construction. Core samples taken for this study revealed also that pavement layers were partially separated due to the lack of bonding. Research focus was to determine the causes of Stone Mastic Asphalt surface layer failure. Documentation of mix design, construction and material quality analysis, p...

Pellinen, Terhi; Makowska, Michalina; Olmos, Pablo; Laukkanen, Olli-ville

2013-01-01

10

Evaluation of multilayered pavement structures from measurements of surface waves  

Science.gov (United States)

A method is presented for evaluating the thickness and stiffness of multilayered pavement structures from guided waves measured at the surface. Data is collected with a light hammer as the source and an accelerometer as receiver, generating a synthetic receiver array. The top layer properties are evaluated with a Lamb wave analysis. Multiple layers are evaluated by matching a theoretical phase velocity spectrum to the measured spectrum. So far the method has been applied to the testing of pavements, but it may also be applicable in other fields such as ultrasonic testing of coated materials. ?? 2006 American Institute of Physics.

Ryden, N.; Lowe, M.J.S.; Cawley, P.; Park, C.B.

2006-01-01

11

Thin, applied surfacing for improving skid resistance of concrete pavements  

Science.gov (United States)

The use of select aggregate in a thin wearing surface of portland cement mortar to prolone or restore a concrete pavement's ability to develop high friction was accomplished. Two fine aggregates, blast furnace slag and lightweight expanded shale were found to exhibit skid resistance greater than the other aggregates evaluated. The British polishing wheel was used in the laboratory evaluation of aggregate to simulate wear. The need for a method of restoring friction to a worn, but otherwise sound concrete pavement led to a field evaluation of several different techniques for placing a very thin overlay. The successful method was a broomed, very thin layer of mortar, 3 mm thick.

Scholer, C. F.

1980-12-01

12

Propagation Mechanisms for Surface Initiated Crackingin Composite Pavements  

Directory of Open Access Journals (Sweden)

Full Text Available The primary objective of this study was to identify the mechanisms for the development and propagation of longitudinal cracks that initiate at the surface of composite pavement. In this study the finite element program ANSYS version (5.4 was used and the model worked out using this program has the ability to analyze a composite pavement structure of different layer properties. Also, the aim of this study was modeling and analyzing of the composite pavement structure with the physical presence of crack induced in concrete underlying layer. The results obtained indicates that increasing the thickness of the asphalt layer tends to decrease the stress intensity factor, which may be attributed to the rapidly decrease of horizontal tensile stress in the asphalt layer. The cracks initiate at the surface due to high vertical stress and shear stress from wheel loads tends to propagate downward due tensile stress generated at the bottom of the asphalt layer or near crack tip, and the whole process occur at the same location of the existing cracks in underlying concrete layer rather than travel up from existing crack. As the load position varies from the crack zone, this result in tensile stresses or tension at the crack tip, leading to increase the stress intensity factor and intern result in crack propagation further into the depth of the pavement.

Duraid Ali Al Khafagy

2009-01-01

13

Development and evaluation of the model for the surface pavement temperature prediction  

OpenAIRE

This paper examines the existing models for predicting pavement temperatures and formulates a new one using a regression equation to predict the minimum and maximum pavement surface temperatures depending on the air temperature. Also, the paper presents a model for pavement temperature prediction according to the Superpave methodology and conducts the validation of the model for measured temperatures.

Matic?, B.; Tepic?, J.; Sremac, S.; Radonjanin, V.; Matic?, D.; Jovanovic?, P.

2012-01-01

14

Development and evaluation of the model for the surface pavement temperature prediction  

Directory of Open Access Journals (Sweden)

Full Text Available This paper examines the existing models for predicting pavement temperatures and formulates a new one using a regression equation to predict the minimum and maximum pavement surface temperatures depending on the air temperature. Also, the paper presents a model for pavement temperature prediction according to the Superpave methodology and conducts the validation of the model for measured temperatures.

B. Mati?

2012-07-01

15

23 CFR 970.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...the physical pavement features including...functional classification, and shoulder...roughness, distress, rutting...and vehicle classification (as appropriate... (i) A pavement condition analysis...roughness, distress,...

2010-04-01

16

Improving a pavement-watering method on the basis of pavement surface temperature measurements  

OpenAIRE

Pavement-watering has been studied since the 1990's and is currently considered a promising tool for urban heat island reduction and climate change adaptation. However, possible future water resource availability problems require that water consumption be optimized. Although pavement heat flux can be studied to improve pavement-watering methods (frequency and water consumption), these measurements are costly and require invasive construction work to install appropriate senso...

Hendel, Martin; Colombert, Morgane; Diab, Youssef; Royon, Laurent

2014-01-01

17

Pavement Aging Model by Response Surface Modeling  

Directory of Open Access Journals (Sweden)

Full Text Available In this work, surface course aging was modeled by Response Surface Methodology (RSM. The Marshall specimens were placed in a conventional oven for time and temperature conditions established on the basis of the environment factors of the region where the surface course is constructed by AC-20 from the Ing. Antonio M. Amor refinery. Volatilized material (VM, load resistance increment (?L and flow resistance increment (?F models were developed by the RSM. Cylindrical specimens with real aging were extracted from the surface course pilot to evaluate the error of the models. The VM model was adequate, in contrast (?L and (?F models were almost adequate with an error of 20 %, that was associated with the other environmental factors, which were not considered at the beginning of the research.

Manzano-Ramírez A.

2011-10-01

18

Automatic Pavement Crack Detection Using Texture and Shape Descriptors  

Directory of Open Access Journals (Sweden)

Full Text Available Pavement distress detection and analysis is the most important part of automated pavement -inspection -systems. Due to the circumstances such as complex texture, uneven illumination, and nonuniform -background, pavement distress detection is not a simply edge detection process. Over the past 30 years, lots of methods were proposed to detect pavement distresses, especially cracks. In this letter, a novel automatic pavement crack detection approach based on texture analysis and shape descriptors is proposed. Pavement surface is seen as a texture surface, and distresses are defined as inhomogeneities occurring in the texture surface. Six texture features and two translation-invariant shape descriptors were used here as discriminate features against irregular texture and uneven illumination. By using a SVM classifier, all sub-images are classified as crack or non-crack. Final results were obtained after post-processing, which includes segmentation, fake-crack eliminating, and crack-measuring methods. Compared with a traditional edge detector such as a Canny operator, experimental results demonstrated that all cracks are correctly detected by the proposed method, even in a strong texture background or in the surface with uneven illumination.

HU Yong

2010-01-01

19

Effect of pavement temperature on the macrotexture of a semidense asphalt surface  

OpenAIRE

The temperature of the softening point of most bitumen is above 35ºC. Increasing the pavement temperature could change the texture surface of the pavement. The aim of this work is to analyze the influence of the surface temperature on the macrotexture of a semidense asphalt pavement located in an urban area and a semidense asphalt sample in laboratory. The superficial macrotexture profiles at different surface temperatures were measured with the LaserStaticPG-LA2IC and a texture s...

Luong, J.; Bueno, M.; Va?zquez, V. F.; Vin?uela, U.; Paje, S. E.

2012-01-01

20

Morphological Algorithms For The Analysis Of Pavement Structure  

Science.gov (United States)

The applicability of morphological image processing techniques for the description of condition and analysis of pavement surfaces is examined. Morphological techniques can be used in the measurement of pavement media consisting of grain (aggregates) and binding substances (bituminous or Portland cement mixtures). Measurements of size and size distributions on surface features related to texture and distresses can be obtained via morphological opening and closing transformations and distributions. When correlated with actual physical measurements of such quantities, the presented morphological measures of size and size distributions may prove to be useful in characterizing the surface condition of both asphalt and concrete pavement structures.

Grivas, Dimitri A.; Skolnick, Michael M.

1989-11-01

21

Laser Scanning on Road Pavements: A New Approach for Characterizing Surface Texture  

OpenAIRE

The surface layer of road pavement has a particular importance in relation to the satisfaction of the primary demands of locomotion, such as security and eco-compatibility. Among those pavement surface characteristics, the “texture” appears to be one of the most interesting with regard to the attainment of skid resistance. Specifications and regulations, providing a wide range of functional indicators, act as guidelines to satisfy the performance requirements. This paper describes an expe...

Gabriele Bitelli; Andrea Simone; Fabrizio Girardi; Claudio Lantieri

2012-01-01

22

3D Surface Profile Equipment for the Characterization of the Pavement Texture - TexScan  

OpenAIRE

Loads from vehicles alter the functional and structural characteristics of road pavements that directly affect the loss of resistance of the pavement and the users’ comfort and safety. Those alterations require constant observation and analysis of an extensive area of road surface with high precision. For such it was developed a new scanning prototype machine capable of acquiring the 3D road surface data and characterize the road texture through two algorithms that allows calculate the E...

Vilac?a, Joa?o L.; Fonseca, Jaime C.; Pinho, A. C. Marques; Freitas, Elisabete F.

2010-01-01

23

Automatic Pavement Crack Detection Using Texture and Shape Descriptors  

OpenAIRE

Pavement distress detection and analysis is the most important part of automated pavement -inspection -systems. Due to the circumstances such as complex texture, uneven illumination, and nonuniform -background, pavement distress detection is not a simply edge detection process. Over the past 30 years, lots of methods were proposed to detect pavement distresses, especially cracks. In this letter, a novel automatic pavement crack detection approach based on texture analysis and shape descriptor...

Hu, Yong; Zhao, Chun-xia; Wang, Hong-nan

2010-01-01

24

Fusing complementary images for pavement cracking measurements  

Science.gov (United States)

Cracking is a major pavement distress that jeopardizes road serviceability and traffic safety. Automated pavement distress survey (APDS) systems have been developed using digital imaging technology to replace human surveys for more timely and accurate inspections. Most APDS systems require special lighting devices to illuminate pavements and prevent shadows of roadside objects that distort cracks in the image. Most artificial lighting devices are laser based, and are either hazardous to unprotected people or require dedicated power supplies on the vehicle. This study was aimed to develop a new imaging system that can scan pavement surface at highway speed and determine the level of severity of pavement cracking without using any artificial lighting. The new system consists of dual line-scan cameras that are installed side by side to scan the same pavement area as the vehicle moves. Cameras are controlled with different exposure settings so that both sunlit and shadowed areas can be visible in two separate images. The paired images contain complementary details useful for reconstructing an image in which the shadows are eliminated. This paper intends to present (1) the design of the dual line-scan camera system, (2) a new calibration method for line-scan cameras to rectify and register paired images, (3) a customized image-fusion algorithm that merges the multi-exposure images into one shadow-free image for crack detection, and (4) the results of the field tests on a selected road over a long period.

Yao, Ming; Zhao, Zuyun; Yao, Xun; Xu, Bugao

2015-02-01

25

Pavement Management System  

OpenAIRE

All kinds of motorways enable motor vehicles to travel. Pavement structures and pavement surfaces are exposed to various loadings (traffic, climate etc.) which cause deformations and deterioration (changes of condition). Pavement deteriorations effect the driving quality and user costs. Therefore Pavement Management Systems (PMS) are applied. PMS is an activity where the administrator with optimal financial investments maintains an appropriate condition of pavements. The appropriate condition...

S?traus Kavs?ek, Simona

2007-01-01

26

Pavement cracking measurements using 3D laser-scan images  

International Nuclear Information System (INIS)

Pavement condition surveying is vital for pavement maintenance programs that ensure ride quality and traffic safety. This paper first introduces an automated pavement inspection system which uses a three-dimensional (3D) camera and a structured laser light to acquire dense transverse profiles of a pavement lane surface when it carries a moving vehicle. After the calibration, the 3D system can yield a depth resolution of 0.5 mm and a transverse resolution of 1.56 mm pixel?1 at 1.4 m camera height from the ground. The scanning rate of the camera can be set to its maximum at 5000 lines s?1, allowing the density of scanned profiles to vary with the vehicle's speed. The paper then illustrates the algorithms that utilize 3D information to detect pavement distress, such as transverse, longitudinal and alligator cracking, and presents the field tests on the system's repeatability when scanning a sample pavement in multiple runs at the same vehicle speed, at different vehicle speeds and under different weather conditions. The results show that this dedicated 3D system can capture accurate pavement images that detail surface distress, and obtain consistent crack measurements in repeated tests and under different driving and lighting conditions. (paper)

27

A 3D study of the contact surface developed by the contact between the tires and the structural pavements  

OpenAIRE

The basic aim in this work is to present a new technique to analyze the contact surfaces developed by the contact between the tires and the structural pavements by numerical simulations, using 3D finite element formulations with contact mechanics. For this purpose, the Augmented Lagrangian method is used. This study is performed just putting the tires on the structural pavement. These tires and the structural pavement are discretized by finite elements under large 3D elastoplastic deformation...

Alex Alves Bandeira; Rita Moura Fortes; Edlio Merighi, Jo U. E. O. Virg U.

2008-01-01

28

Surface runoff from full-scale coal combustion product pavements during accelerated loading  

Energy Technology Data Exchange (ETDEWEB)

In this study, the release of metals and metalloids from full-scale portland cement concrete pavements containing coal combustion products (CCPs) was evaluated by laboratory leaching tests and accelerated loading of full-scale pavement sections under well-controlled conditions. An equivalent of 20 years of highway traffic loading was simulated at the OSU/OU Accelerated Pavement Load Facility (APLF). Three types of portland cement concrete driving surface layers were tested, including a control section (i.e., ordinary portland cement (PC) concrete) containing no fly ash and two sections in which fly ash was substituted for a fraction of the cement; i.e., 30% fly ash (FA30) and 50% fly ash (FA50). In general, the concentrations of minor and trace elements were higher in the toxicity characteristic leaching procedure (TCLP) leachates than in the leachates obtained from synthetic precipitation leaching procedure and ASTM leaching procedures. Importantly, none of the leachate concentrations exceeded the TCLP limits or primary drinking water standards. Surface runoff monitoring results showed the highest release rates of inorganic elements from the FA50 concrete pavement, whereas there were little differences in release rates between PC and FA30 concretes. The release of elements generally decreased with increasing pavement loading. Except for Cr, elements were released as particulates (>0.45 {mu} m) rather than dissolved constituents. The incorporation of fly ash in the PC cement concrete pavements examined in this study resulted in little or no deleterious environmental impact from the leaching of inorganic elements over the lifetime of the pavement system.

Cheng, C.M.; Taerakul, P.; Tu, W.; Zand, B.; Butalia, T.; Wolfe, W.; Walker, H. [Western Kentucky University, Bowling Green, KY (United States)

2008-08-15

29

Investigation of frictional properties on wire combed PCC (Portland Cement Concrete) pavement surfaces  

Science.gov (United States)

This report involves PCC Pavements constructed with surface textures produced by a wide variety of wire combs. A small amount of testing was also performed on PCCP with other textures as a follow up of previous research on frictional properties. A limited amount of noise evaluation by rating panels and sound level (dbA) meters was conducted to assist in selection of an optimum the spacing for wire combs on future PCC Pavement projects. Included in this report is a brief description of each major project with summaries of friction number tests, standpatch texture depth tests, and sound level measurements.

1982-09-01

30

Methods to Use Surface Infiltration Tests in Permeable Pavement Systems to Determine Maintenance Frequency  

Science.gov (United States)

Currently, there is limited guidance on selecting test sites to measure surface infiltration rates in permeable pavement systems to determine maintenance frequency. The ASTM method (ASTM C1701) for measuring infiltration rate of in-place pervious concrete suggest to either (1) p...

31

Vehicle-Pavement Interaction  

OpenAIRE

Several aspects of vehicle-pavement interaction have been studied and discussed in this thesis. Initially the pavement response is studied through a quasi-static and a dynamic computationally efficient framework under moving traffic loads. Subsequently, a non-stationary stochastic solution has been developed in order to account for the effect of pavement surface deterioration on pavement service life.The quasi-static procedure is based on a superposition principle and is computationally favou...

Khavassefat, Parisa

2014-01-01

32

23 CFR 971.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...the physical pavement features including...functional classification, and shoulder...includes ride, distress, rutting...and vehicle classification (as appropriate... (i) A pavement condition analysis...includes ride, distress,...

2010-04-01

33

23 CFR 973.208 - Indian lands pavement management system (PMS).  

Science.gov (United States)

...the physical pavement features including...functional classification, and shoulder...includes ride, distress, rutting...and vehicle classification (as appropriate... (i) A pavement condition analysis...includes ride, distress,...

2010-04-01

34

23 CFR 972.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...the physical pavement features including...functional classification, and shoulder...includes ride, distress, rutting...and vehicle classification (as appropriate... (i) A pavement condition analysis...includes ride, distress,...

2010-04-01

35

Pavement Preservation for Elected Officials: The Inside Story of Pavement Deterioration  

OpenAIRE

This session is intended to provide elected officials and practitioners with an introduction to the concept of pavement preservation and its applicability within public agencies. Topics include definitions, budget planning, pavement life, road networks, alternative strategies, pavement distresses, guidelines and preservation treatments.

Olson, Jim

2012-01-01

36

Laser Scanning on Road Pavements: A New Approach for Characterizing Surface Texture  

Directory of Open Access Journals (Sweden)

Full Text Available The surface layer of road pavement has a particular importance in relation to the satisfaction of the primary demands of locomotion, such as security and eco-compatibility. Among those pavement surface characteristics, the “texture” appears to be one of the most interesting with regard to the attainment of skid resistance. Specifications and regulations, providing a wide range of functional indicators, act as guidelines to satisfy the performance requirements. This paper describes an experiment on the use of laser scanner techniques on various types of asphalt for texture characterization. The use of high precision laser scanners, such as the triangulation types, is proposed to expand the analysis of road pavement from the commonly and currently used two-dimensional method to a three-dimensional one, with the aim of extending the range of the most important parameters for these kinds of applications. Laser scanners can be used in an innovative way to obtain information on areal surface layer through a single measurement, with data homogeneity and representativeness. The described experience highlights how the laser scanner is used for both laboratory experiments and tests in situ, with a particular attention paid to factors that could potentially affect the survey.

Gabriele Bitelli

2012-07-01

37

Unified Analysis of Road Pavement Profiles for Evaluation of Surface Characteristics  

Directory of Open Access Journals (Sweden)

Full Text Available The research deals with the measure and evaluation of the unevenness and texture of road pavements, by means of unified procedures both for surveys and processing of acquired data, with the aim to represent the surface characteristics as a spectrum in the domain of spatial frequencies (or wavelengths. The texture properties, in fact, can be referred to many aspects of pavements performances, so allowing to establish thresholds for the acceptability of new construction or to ensure good working conditions for existing road infrastructures. The advantages of the proposed unified procedures are that the measurements are taken with modern and advanced equipment, minimizing the impact on the normal road exercise; moreover, it is possible to propose an optimized area in the frequency vs. texture level graph, where the spectrum has to fall into, in order to balance some conflicting requirements. The boundaries of the area can be also referred to the specific characteristics of the examined infrastructures; if a spectrum fits into the area, an optimal behaviour of the surface is ensured, respect to the interaction phenomena between tires and pavement which are influenced by surface texture. The proposal was tested with a case study, in which thresholds of performance parameters and boundaries of the optimized area were decided onto the basis of correlations between road indexes and texture properties, coming from the scientific literature or proposed on the basis of empirical results.

Giuseppe Loprencipe

2013-07-01

38

Laser scanning on road pavements: a new approach for characterizing surface texture.  

Science.gov (United States)

The surface layer of road pavement has a particular importance in relation to the satisfaction of the primary demands of locomotion, such as security and eco-compatibility. Among those pavement surface characteristics, the "texture" appears to be one of the most interesting with regard to the attainment of skid resistance. Specifications and regulations, providing a wide range of functional indicators, act as guidelines to satisfy the performance requirements. This paper describes an experiment on the use of laser scanner techniques on various types of asphalt for texture characterization. The use of high precision laser scanners, such as the triangulation types, is proposed to expand the analysis of road pavement from the commonly and currently used two-dimensional method to a three-dimensional one, with the aim of extending the range of the most important parameters for these kinds of applications. Laser scanners can be used in an innovative way to obtain information on areal surface layer through a single measurement, with data homogeneity and representativeness. The described experience highlights how the laser scanner is used for both laboratory experiments and tests in situ, with a particular attention paid to factors that could potentially affect the survey. PMID:23012535

Bitelli, Gabriele; Simone, Andrea; Girardi, Fabrizio; Lantieri, Claudio

2012-01-01

39

DRAINAGE AND FLEXIBLE PAVEMENT PERFORMANCE  

Directory of Open Access Journals (Sweden)

Full Text Available Providing adequate drainage to a pavement system has been considered as an important design consideration to prevent premature failures due to water related problems such as pumping action, loss of support, and rutting, among others. Most water in pavements is due to rainfall infiltration into unsaturated pavement layers, throughjoints, cracks, shoulder edges, and various other defects, especially in older deteriorated pavements. Water also seep upward from a high groundwater table due to capillary suction or vapour movements, or it may flow laterally from the pavement edges and side ditches. Providing adequate drainage to a pavement system has been considered as an important design consideration to ensure satisfactory performance of the pavement, particularly from the perspective of life cycle cost and serviceability. To minimize premature pavement distresses and to enhance the pavement performance, it is imperative to provide adequate drainage to allow infiltrated water to drain out from the base and sub-base, thus avoiding saturation of base and subgrade soils. This paper deals with the analysis of the impact of subsurface drainage on pavement system performance. The requirement ofeffective subsurface drainage for pavement performance is also discussed.

SIDDHARTHA ROKADE

2012-04-01

40

Review of the development of concrete pavement surface types and their acoustic performance with time  

Science.gov (United States)

Roadways have been constructed out of concrete pavements in the United States since the late 1800s. Numerous surface textures have been produced including burlap drag, astroturf, uniformly and random transverse tined, longitudinally tined, and both profile and whisper diamond grinding processes. Each surface evolved for specific reasons during the historical development of Portland Cement Concrete Pavements (PCCP).This paper reviews the development of these various surface texture types and the reasons for their evolution. In addition, results from both far field and near field acoustic testing are presented to evaluate the ``acoustic'' performance of these surfaces over time.For five surface types, 1/24 octave analysis were conducted on CPX data obtained with a single tire. The spectrum of each of these surface types is presented for comparison. For three of the surfaces, speed gradient testing, ranging between 25-75 MPH was conducted. 1/24 octave analysis of each of these runs was conducted so that that any speed induced spectrum shifts could be observed.The results to date indicate that the adverse tonal properties of some PCCP surfaces can be eliminated through diamond grinding and prevented by not constructing transverse tined PCCP.

Scofield, Larry A.

2005-09-01

41

EFFECTS OF PAVEMENT SURFACE TEMPERATURE ON THE MODIFICATION OF URBAN THERMAL ENVIRONMENT  

Directory of Open Access Journals (Sweden)

Full Text Available Urban centres continue to experience escalating average summer temperature over the last fifty years. Temperature in the urban core cites have been rising due to rapid growth of urbanization in the latter half of the twentieth century (Akbari et al., 1989. Outdoor experiments were conducted to investigate the effects of different movement of materials on the urban thermal environment. Meteorological conditions such as air temperature, pavement surface temperature, Relative humidity and wind velocity were recorded to determine temperature differences among Asphalt/concrete, interlocking bricks and grass surfaces.

SARAT, Adebayo-Aminu

2012-01-01

42

Improving rutting resistance of pavement structures using geosynthetics: an overview.  

Science.gov (United States)

A pavement structure consists of several layers for the primary purpose of transmitting and distributing traffic loads to the subgrade. Rutting is one form of pavement distresses that may influence the performance of road pavements. Geosynthetics is one type of synthetic materials utilized for improving the performance of pavements against rutting. Various studies have been conducted on using different geosynthetic materials in pavement structures by different researchers. One of the practices is a reinforcing material in asphalt pavements. This paper intends to present and discuss the discoveries from some of the studies on utilizing geosynthetics in flexible pavements as reinforcement against permanent deformation (rutting). PMID:24526919

Mirzapour Mounes, Sina; Karim, Mohamed Rehan; Khodaii, Ali; Almasi, Mohammad Hadi

2014-01-01

43

A 3D study of the contact surface developed by the contact between the tires and the structural pavements  

Directory of Open Access Journals (Sweden)

Full Text Available The basic aim in this work is to present a new technique to analyze the contact surfaces developed by the contact between the tires and the structural pavements by numerical simulations, using 3D finite element formulations with contact mechanics. For this purpose, the Augmented Lagrangian method is used. This study is performed just putting the tires on the structural pavement. These tires and the structural pavement are discretized by finite elements under large 3D elastoplastic deformation. The real loads (of aircrafts, trucks or cars are applied directly on each tire and by contact mechanics procedures, the real contact area between the tires and the pavement surface is computed. The penetration conditions and the contact interfaces are investigated in details. Furthermore, the pressure developed at the contact surfaces is automatically calculated and transferred to the structural pavement by contact mechanics techniques. The purpose of this work research is to show that the contact area is not circular and the finite element techniques can calculate automatically the real contact area, the real geometry and its stresses and strains. In the end of this work, numerical resultsin terms of geometry, stress and strain are presented and compared to show the ability of the algorithm. These numerical results are also compared with the numerical results obtained by the commercial program ANSYS.

Alex Alves Bandeira

2008-01-01

44

Evaluation of Surface Infiltration Testing Procedures in Permeable Pavement Systems  

Science.gov (United States)

The ASTM method (ASTM C1701) for measuring infiltration rate of in-place pervious concrete provides limited guidance on how to select testing locations, so research is needed to evaluate how testing sites should be selected and how results should be interpreted to assess surface ...

45

GIS Based Pavement Maintenance: A Systematic Approach  

OpenAIRE

Abstract According to 2008 Federal Highway Administration (FHWA) statistics, there are 2,734,102 miles of paved public roads in the United Sates, with an additional 1,324,245 miles of unpaved public roads. Road conditions deteriorate with time as the result of weather effects, deicing salts, and vehicle loads. The most common pavement distress includes cracking, rutting, and potholes. These pavement defects must be repaired to restore the pavement to a satisfactory service level for roa...

Kmetz, Robert J.

2011-01-01

46

Fast simulated annealing inversion of surface waves on pavement using phase-velocity spectra  

Science.gov (United States)

The conventional inversion of surface waves depends on modal identification of measured dispersion curves, which can be ambiguous. It is possible to avoid mode-number identification and extraction by inverting the complete phase-velocity spectrum obtained from a multichannel record. We use the fast simulated annealing (FSA) global search algorithm to minimize the difference between the measured phase-velocity spectrum and that calculated from a theoretical layer model, including the field setup geometry. Results show that this algorithm can help one avoid getting trapped in local minima while searching for the best-matching layer model. The entire procedure is demonstrated on synthetic and field data for asphalt pavement. The viscoelastic properties of the top asphalt layer are taken into account, and the inverted asphalt stiffness as a function of frequency compares well with laboratory tests on core samples. The thickness and shear-wave velocity of the deeper embedded layers are resolved within 10% deviation from those values measured separately during pavement construction. The proposed method may be equally applicable to normal soil site investigation and in the field of ultrasonic testing of materials. ?? 2006 Society of Exploration Geophysicists.

Ryden, N.; Park, C.B.

2006-01-01

47

Weak interlayers in flexible and semi-flexible road pavements: Part 1  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english Weak layers, interlayers, laminations and/or interfaces in the upper structural layers of road pavements are specifically prohibited in most road-building specifications. However, such layers are extremely common and often lead to premature pavement distress. In Part 1 of this two-part set of papers [...] , it is shown that from experience with heavy vehicle simulator (HVS) and dynamic cone penetrometer (DCP) testing, the presence of such layers and/or conditions at any depth in the structural layers of a flexible or semi-flexible pavement is far more deleterious than is commonly appreciated. In Part 2 the effects of these weak layers are further modelled and discussed using various examples based an HVS testing and mechanistic pavement analyses. In particular, a weak upper base course of a cemented pavement under a thin bituminous surfacing may lead to severe surfacing (and upper base) failure within a matter of weeks to months after opening to traffic, not excluding failure even during construction. In this paper (Part 1), the causes of weak layers, interlayers, laminations and/or interfaces, together with simple methods for their detection during construction and analyses of their effects on the structural capacity of flexible and semi-rigid (cemented) road pavements, are briefly discussed.

F, Netterberg; M, de Beer.

2012-04-01

48

Weak interlayers in flexible and semi-flexible road pavements: Part 1  

Directory of Open Access Journals (Sweden)

Full Text Available Weak layers, interlayers, laminations and/or interfaces in the upper structural layers of road pavements are specifically prohibited in most road-building specifications. However, such layers are extremely common and often lead to premature pavement distress. In Part 1 of this two-part set of papers, it is shown that from experience with heavy vehicle simulator (HVS and dynamic cone penetrometer (DCP testing, the presence of such layers and/or conditions at any depth in the structural layers of a flexible or semi-flexible pavement is far more deleterious than is commonly appreciated. In Part 2 the effects of these weak layers are further modelled and discussed using various examples based an HVS testing and mechanistic pavement analyses. In particular, a weak upper base course of a cemented pavement under a thin bituminous surfacing may lead to severe surfacing (and upper base failure within a matter of weeks to months after opening to traffic, not excluding failure even during construction. In this paper (Part 1, the causes of weak layers, interlayers, laminations and/or interfaces, together with simple methods for their detection during construction and analyses of their effects on the structural capacity of flexible and semi-rigid (cemented road pavements, are briefly discussed.

F Netterberg

2012-04-01

49

Experimental Evaluation of Anti-Stripping Additives Mixing in Road Surface Pavement Materials  

Directory of Open Access Journals (Sweden)

Full Text Available Most road surfaces in Taiwan are paved with asphalt concrete but the phenomena of rutting, cracking and stripping of the pavement are frequently occurring due to the effects of traffic flow, thermal variation and water erosion caused by rain. In this study, a series of experiments were performed to examine the effectiveness of anti-stripping fillers, which include; rock flour, rock flour with 1% lime and rock flour with 1% cement, respectively, in the mixture of asphalt concrete. The experimental mixing results showed that the case of rock flour with 1% lime has a relatively better performance in several categories including stability value, flow value, retained strength, wrapped asphalt rate in grains, resilient modulus, dynamic stability and rate of rutting deformation. The evaluated information implies that this filler can increase the asphalt concrete’s abilities to resist rutting deformation and stripping of the road surface, thus increasing the durability. The results also provide a good reference for using in road construction with similar regional characteristics to Taiwan.

Tienfuan Kerh

2005-01-01

50

Effects of using silica fume and polycarboxylate-type superplasticizer on physical properties of cementitious grout mixtures for semiflexible pavement surfacing.  

Science.gov (United States)

Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout. PMID:24526911

Koting, Suhana; Karim, Mohamed Rehan; Mahmud, Hilmi; Mashaan, Nuha S; Ibrahim, Mohd Rasdan; Katman, Herdayati; Husain, Nadiah Md

2014-01-01

51

Centerline rumble stripes as an alternative to raised pavement markers  

OpenAIRE

A raised pavement marker is a retroreflective lens on a substrate attached to the pavement so as to protrude slightly above the pavement surface. Raised pavement markers (RPMs) have been used in the United States for decades to improve lane delineation in low light conditions. In areas subject to winter snowfall, the retroreflective lens is protected by a cast iron body embedded into the roadway to protect the lens from snowplow blades. There is empirical evidence that raised pavement markers...

Mitkey, Stuart Richard

2012-01-01

52

A Framework for Quantification of Effect of Drainage Quality on Structural and Functional Performance of Pavement  

OpenAIRE

Drainage quality is an important parameter which affects the highway pavement performance. Excessive water content in the pavement base, sub-base, and sub-grade soils can cause early distress and lead to a structural or functional failure of pavement. Thus, when selecting appropriate maintenance strategies the cost of pavement maintenance needs to be compared with the cost of improving the quality of drainage. Hence, there is a need to quantify the effect of va...

Jitendra Gurjar, Pradeep Kumar Agarwal

2013-01-01

53

Determination of the heating temperature of potholes surface on road pavement in the process of repairs using hot asphalt concrete mixes  

Directory of Open Access Journals (Sweden)

Full Text Available In the process of roads construction the necessary transport and operational characteristics should be achieved, which depend on the quality of the applied, material and technologies. Under the loads of transport means and the influence of weather conditions on the road pavement deformations and destructions occur, which lead to worsening of transport and operational characteristics, decrease of operational life of the road and they are often the reason of road accidents. According to the data of the Strategic Research Center of "Rosgosstrah" more than 20 % of road accidents in Russia occur due to bad quality of road pavement. One of the main directions in traffic security control and prolongation of operational life for road pavement of non-rigid type is road works, as a result of which defects of pavement are eliminated and in case of timely repairs of high quality the operational life of the road increases for several years. The most widely used material for non-rigid pavement repairs is hot road concrete mixes and in case of adherence to specifications they provide high quality of works. The authors investigate the problems of hot asphalt concrete mixes for repairs of road surfaces of non-rigid type. The results of the study hot asphalt concrete mix’s temperature regimes are offered in case of repair works considering the temperature delivered to the work site and the ambient temperature depending on the type of mix and class of bitumen.

Giyasov Botir Iminzhonovich

2014-12-01

54

Pavement Performance Modeling – A Case Study  

Directory of Open Access Journals (Sweden)

Full Text Available Pavement deterioration is a complex process. It involves not only structural fatigue but also many functional distresses of pavement. It results from the interaction between traffic, climate, material and time. Deterioration is the term used to represent the change in pavement performance overtime. The ability of the road to satisfy the demands of traffic and environment over its design life is referred to as performance. Due to the great complexity of the road deterioration process, performance models are the best approximate predictors of expected conditions. In this study main distresses were identified from the selected road stretches. Regression models are then developed using SPSS (Statistical packages for social sciences package. T test is used to check the reliability of the model.

Saranya Ullas

2013-08-01

55

Technical and Economic Sustainability of Concrete Pavements  

Directory of Open Access Journals (Sweden)

Full Text Available Economic evaluation of road pavements is as important as their technical and structural design: often only initial construction costs are calculated to assess economic project sustainability. Instead, forgetting maintenance costs exposes society to unacceptable risks of expensive and incorrect decisions. Road pavements design and construction solutions affect maintenance works during service life, which not only entail economical and financial expenditures, but also damage service regularity for users and affect environmental impact. The analysis of pavement distress and the study of its evolution during service life can contribute to find the financially most advantageous solution. This paper shows a software program developed to analyze structural, functional and financial performances of road concrete pavements both doweled slabs and continuously reinforced.

Laura Moretti

2014-04-01

56

An experience on street pavement maintenance program in small region- (Bafq city  

Directory of Open Access Journals (Sweden)

Full Text Available This paper reports an experience on Pavement Maintenance plan of the Research Team of the Islamic Azad University- Bafq Branch. The City of Bafq streets are failing at a growing rate, despite all the efforts of Pavement Management, improved efficiencies in street maintenance operations, contracted work and sharing equipment with other agencies. Pavements in this range show some form of distress or wear that requires more than a life extending achievement. In this group, a well-designed pavement will have served at least 75% of its life and the authority of the pavement has dropped by about 40%.

Khabiry Mehdi

2009-05-01

57

In situ determination of layer thickness and elastic moduli of asphalt pavement systems by spectral analysis of surface waves (SASW) method  

International Nuclear Information System (INIS)

Spectral analysis of surface waves (SASW) is a non-destructive and in situ method for determining the stiffness profile of soil and pavement sites. The method consists of generation, measurement, and processing of dispersive elastic waves in layered systems. The test is performed on the pavement surface at strain level below 0.001%, where the elastic properties are considered independent of strain amplitude. During an SASW test, the surface of the medium under investigation is subject to an impact to generate energy at various frequencies. Two vertical acceleration transducers are set up near the impact source to detect the energy transmitted through the testing media. By recording signals in digitised form using a data acquisition system and processing them, surface wave velocities can be determined by constructing a dispersion curve. Through forward modeling, the shear wave velocities can be obtained, which can be related to the variation of stiffness with depth. This paper presents the results of two case studies for near?surface profiling of two different asphalt pavement sites. (Author)

58

A model for the pavement temperature prediction at specified depth  

OpenAIRE

This paper examines the existing models for predicting pavement temperatures at a certain depth and formulates a new one using the regression equation to predict the minimum and maximum pavement temperatures at the specified depth depending on the surface pavement temperature and its depth.

Matic?, B.; Matic?, D.; C?osic?, ?.; Sremac, S.; Tepic?, G.; Ranitovic?, P.

2013-01-01

59

A model for the pavement temperature prediction at specified depth  

Directory of Open Access Journals (Sweden)

Full Text Available This paper examines the existing models for predicting pavement temperatures at a certain depth and formulates a new one using the regression equation to predict the minimum and maximum pavement temperatures at the specified depth depending on the surface pavement temperature and its depth.

B. Mati?

2013-10-01

60

Analysis of pavement serviceability for the Aashto Design Method: The Chilean Case  

International Nuclear Information System (INIS)

Serviceability is an indicator that represents the level of service a pavement provides to the users. This subjective opinion is closely related to objective aspects, which can be measured on the pavement's surface. This research aims specifically at relating serviceability results obtained by a 9-member evaluation panel, representing general public as closely as possible to parameters (particularly of roughness) measured within instruments on 30, 25 and 11 road sections of asphalt concrete, Portland cement concrete and asphalt overlay respectively. Results show that prediction of serviceability is quite accurate based on roughness evaluation, while also revealing that, by comparison to studies in more developed countries, Chileans are seemingly more tolerant, in that they assign a somewhat high rating to ride quality. Furthermore, visible distress does not have a significant influence on serviceability values for Chilean users. A ratio between International Roughness Index (IRI) and Serviceability, as defined by AASHTO, was developed and may be used in this design method. Results for the final pavement condition of urban pavements were obtained (IRI-asphalt final=5.9, IRI-concrete final=8.1). (author)

61

Low-temperature influence in the predicted of pavement overlay  

OpenAIRE

This paper describes a study of the influence of temperature variation in the pavement overlay life, using finite-element methodology that considers the most predominant type of overlay distress observed in the field: the reflective cracking. The temperature variation has a significant influence on thermally induced stresses that, in turn, affects the overlay predictive service life. This paper presents a three-dimensional (3D) finite element analysis used to predict the pavement overlay life...

Minhoto, Manuel; Pais, Jorge; Pereira, Paulo; Picado-santos, Lui?s

2003-01-01

62

Pavement management and rehabilitation of portland cement concrete pavements  

Science.gov (United States)

Pavement management and rehabilitation projects and techniques are discussed. The following topics are discussed: economic analyses and dynamic programming in resurfacing project selection; implementation of an urban pavement management system; pavement performance modeling for pavement management; illustration of pavement management: from data inventory to priority analysis; rehabilitation of concrete pavements by using portland cement concrete overlays; pavement management study: Illinois tollway pavement overlays; resurfacing of plain jointed-concrete pavements; design procedure for premium composite pavement; model study of anchored pavement; prestressed concrete overlay at O'Hare International Airport: in-service evaluation; and, bonded portland cement concrete resurfacing.

Zegeer, C. V.; Agent, K. R.; Rizenbergs, R. L.; Curtayne, P. C.; Scullion, T.; Pedigo, R. D.; Hudson, W. R.; Roberts, F. L.; Karan, M. A.; Haas, R.

63

Modeling Deflection Basin Using Neurofuzzy in Backcaluculating Flexible Pavement Layer Moduli  

OpenAIRE

Flexible pavement surface condition date play a principle role in the evaluation of pavement structural capacity and in the design of pavement rehabilitation programs. Flexible pavements are affected by moving vehicles, climate and other environmental factors. As a result of these factors, the pavement starts to deteriorate. In order to prevent further deterioration, a maintenance program should be carried out at right time and right places. For the determination of the structural carrying ca...

Mehmet Saltan

2002-01-01

64

Evaluation of Performance and Design of Ultra-Thin Whitetopping (Bonded Concrete Resurfacing) Using Large-Scale Accelerated Pavement Testing  

OpenAIRE

Ultra-Thin Whitetopping (UTW) is a pavement rehabilitation technique that involves the placement of a thin Portland Cement Concrete (PCC) overlay, 2 inches (50 mm) to 4 inches (100 mm) thick, over a distressed Hot Mix Asphalt (HMA) pavement. Typically, the HMA pavement is milled and cleaned which helps to create a bond between the existing HMA pavement and the PCC overlay. The bond between the two layers promotes composite action of the pavement section and as a result has a direct impact on ...

Newbolds, Scott Andrew

2008-01-01

65

Evaluation of performance and design of Ultra-Thin Whitetopping (bonded concrete resurfacing) using large-scale accelerated pavement testing  

OpenAIRE

Ultra-Thin Whitetopping (UTW) is a pavement rehabilitation technique that involves the placement of a thin Portland Cement Concrete (PCC) overlay, 2 inches (50 mm) to 4 inches (100 mm) thick, over a distressed Hot Mix Asphalt (HMA) pavement. Typically, the HMA pavement is milled and cleaned which helps to create a bond between the existing HMA pavement and the PCC overlay. The bond between the two layers promotes composite action of the pavement section and as a result has a direct impact on ...

Newbolds, Scott Andrew

2007-01-01

66

Permeable Pavement Research - Edison, New Jersey  

Science.gov (United States)

This presentation provides the background and summary of results collected at the permeable pavement parking lot monitored at the EPA facility in Edison, NJ. This parking lot is surfaced with permeable interlocking concrete pavers (PICP), pervious concrete, and porous asphalt. ...

67

Full Scale Tests for the Assessment of Wear of Pavement Surfaces  

OpenAIRE

The paper deals with the assessment of wear of road surfaces subjected to traffic. Full-scale tests were performed by means of LCPC Carousel facilities to simulate passages of truck tires under pure cornering maneuver. Three types of road surface were tested. Up to 800 000 passages were performed and measurements of tire and road characteristics were carried out at different wear stages. Results were presented in term of evolution of skid resistance as well as macro- and microtexture of road ...

Do, Minh Tan; Kerzreho, Jean Pierre; Balay, Jean Maurice; Gothie, Michel

2003-01-01

68

A real-time 3D scanning system for pavement rutting and pothole detections  

Science.gov (United States)

Rutting and pothole are the common pavement distress problems that need to be timely inspected and repaired to ensure ride quality and safe traffic. This paper introduces a real-time, automated inspection system devoted for detecting these distress features using high-speed transverse scanning. The detection principle is based on the dynamic generation and characterization of 3D pavement profiles obtained from structured light measurements. The system implementation mainly involves three tasks: multi-view coplanar calibration, sub-pixel laser stripe location, and pavement distress recognition. The multi-view coplanar scheme was employed in the calibration procedure to increase the feature points and to make the points distributed across the field of view of the camera, which greatly improves the calibration precision. The laser stripe locating method was implemented in four steps: median filtering, coarse edge detection, fine edge adjusting, stripe curve mending and interpolation by cubic splines. The pavement distress recognition algorithms include line segment approximation of the profile, searching for the feature points, and parameters calculations. The parameter data of a curve segment between two feature points, such as width, depth and length, were used to differentiate rutting, pothole, and pothole under different constraints. The preliminary experiment results show that the system is capable of locating these pavement distresses, and meets the needs for real-time and accurate pavement inspection.

Li, Qingguang; Yao, Ming; Yao, Xun; Yu, Wurong; Xu, Bugao

2009-08-01

69

Pavement Management for Local Agencies: How to do More with less with the Three Legged Stool System  

OpenAIRE

Pavement management is important for agencies to maintain their critical infrastructure. By using the core principles of asset management, pavement assessment, and candidate selection, an agency is able to address pavement distresses with routine maintenance and prevent good and fair roads from becoming bad roads. This presentation discusses the many ways agencies have successfully managed their way to an improved overall road network even during the most challenging times.

Barnhardt, Blair

2013-01-01

70

Rough thin pavement thickness estimation by GPR  

OpenAIRE

In civil engineering, usually the methods used to estimate the thickness of thin pavements consider flat interfaces for simplification. In this paper, the roughness of the surfaces is taken into account. First, the amplitudes of the first two echoes from the rough thin pavement are calculated from a rigorous electromagnetic method, the PILE method. A comparison is then made with the flat interface case, and their differences in the electromagnetic backscattering are highlighted. Eventually, t...

Pinel, Nicolas; Le Bastard, Ce?dric; Liu, Limei; Bourlier, Christophe; Wang, Yide

2009-01-01

71

A Study of Load Responses towards the Pavement Edge  

OpenAIRE

A major part of the national and county road network in Norway consists of two-lane roads with relatively narrow shoulders. The width of the roadway is limited, forcing heavy trucks to drive close to the pavement edge. This represents a considerable deteriorating effect on these pavements, which typically consist of granular base materials and thin asphalt surfacing. The result is often premature cracking and deformations along the pavement edge.

Despite the fac...

Aksnes, Jostein

2002-01-01

72

Energy equivalents for selected pavement materials: Their production and placement  

Science.gov (United States)

Energy requirements for selected pavement surfaces are discussed. Energy requirements for hot-mixed bituminous recycling and portland cement concrete recycling projects are presented along with conventional pavement methods. Energy requirements for conventional thin surface treatments are also discussed. Environmental analyses involving both air and noise quality measurement are included for various recycling and conventional paving options.

Lane, K. R.

1981-03-01

73

Hybrid green permeable pave with hexagonal modular pavement systems  

International Nuclear Information System (INIS)

Modular permeable pavements are alternatives to the traditional impervious asphalt and concrete pavements. Pervious pore spaces in the surface allow for water to infiltrate into the pavement during rainfall events. As of their ability to allow water to quickly infiltrate through the surface, modular permeable pavements allow for reductions in runoff quantity and peak runoff rates. Even in areas where the underlying soil is not ideal for modular permeable pavements, the installation of under drains has still been shown to reflect these reductions. Modular permeable pavements have been regarded as an effective tool in helping with stormwater control. It also affects the water quality of stormwater runoff. Places using modular permeable pavement has been shown to cause a significant decrease in several heavy metal concentrations as well as suspended solids. Removal rates are dependent upon the material used for the pavers and sub-base material, as well as the surface void space. Most heavy metals are captured in the top layers of the void space fill media. Permeable pavements are now considered an effective BMP for reducing stormwater runoff volume and peak flow. This study examines the extent to which such combined pavement systems are capable of handling load from the vehicles. Experimental investigation were undertaken to quantify the compressive characteristics of the modular. Results shows impressive results of achieving high safety factor for daily life vehicles.h safety factor for daily life vehicles.

74

Hybrid green permeable pave with hexagonal modular pavement systems  

Science.gov (United States)

Modular permeable pavements are alternatives to the traditional impervious asphalt and concrete pavements. Pervious pore spaces in the surface allow for water to infiltrate into the pavement during rainfall events. As of their ability to allow water to quickly infiltrate through the surface, modular permeable pavements allow for reductions in runoff quantity and peak runoff rates. Even in areas where the underlying soil is not ideal for modular permeable pavements, the installation of under drains has still been shown to reflect these reductions. Modular permeable pavements have been regarded as an effective tool in helping with stormwater control. It also affects the water quality of stormwater runoff. Places using modular permeable pavement has been shown to cause a significant decrease in several heavy metal concentrations as well as suspended solids. Removal rates are dependent upon the material used for the pavers and sub-base material, as well as the surface void space. Most heavy metals are captured in the top layers of the void space fill media. Permeable pavements are now considered an effective BMP for reducing stormwater runoff volume and peak flow. This study examines the extent to which such combined pavement systems are capable of handling load from the vehicles. Experimental investigation were undertaken to quantify the compressive characteristics of the modular. Results shows impressive results of achieving high safety factor for daily life vehicles.

Rashid, M. A.; Abustan, I.; Hamzah, M. O.

2013-06-01

75

Indiana Pavement Preservation Program  

OpenAIRE

State highway agencies are facing immense pressure to maintain roads at acceptable levels amidst the challenging financial and economic situations. In recent years, pavement preservation has been sought as a potential alternative for managing the pavement assets, believing that it would provide a cost-effective solution in maintaining infrastructural conditions and meeting user expectations. This study explores the potential of pavement preservation concepts in managing the agency‘s pavemen...

Ong, Ghim Ping; Nantung, Tommy E.; Sinha, Kumares C.

2010-01-01

76

Assessment of porous asphalt pavement performance: hydraulics and water quality  

Science.gov (United States)

The objective of this study is to focus on the water quality treatment and hydraulic performance of a porous asphalt pavement parking lot in Durham, New Hampshire. The site was constructed in October 2004 to assess the suitability of porous asphalt pavement for stormwater management in cold climates. The facility consists of a 4-inch asphalt open-graded friction course layer overlying a high porosity sand and gravel base. This base serves as a storage reservoir in-between storms that can slowly infiltrate groundwater. Details on the design, construction, and cost of the facility will be presented. The porous asphalt pavements is qualitatively monitored for signs of distress, especially those due to cold climate stresses like plowing, sanding, salting, and freeze-thaw cycles. Life cycle predictions are discussed. Surface infiltration rates are measured with a constant head device built specifically to test high infiltration capacity pavements. The test measures infiltration rates in a single 4-inch diameter column temporarily sealed to the pavement at its base. A surface inundation test, as described by Bean, is also conducted as a basis for comparison of results (Bean, 2004). These tests assess infiltration rates soon after installation, throughout the winter, during snowmelt, after a winter of salting, sanding, and plowing, and after vacuuming in the spring. Frost penetration into the subsurface reservoir is monitored with a frost gauge. Hydrologic effects of the system are evaluated. Water levels are monitored in the facility and in surrounding wells with continuously logging pressure transducers. The 6-inch underdrain pipe that conveys excess water in the subsurface reservoir to a riprap pad is also continuously monitored for flow. Since porous asphalt pavement systems infiltrate surface water into the subsurface, it is important to assess whether water quality treatment performance in the subsurface reservoir is adequate. The assumed influent water quality is derived from that which is entering the stormwater treatment system in the adjacent parking lot. Since the facility is new, parking has been less intensive here, and influent concentrations will be adjusted down accordingly. Several wells have been installed in and around the facility. Screened intervals are at two levels; in the reservoir and beneath the facility. One well in the facility is continually monitored for basic water quality parameters (temperature, specific conductivity, pH, dissolved oxygen) and level, and is also sampled with an automated refrigerated sampler. Grab samples are collected from the other wells as a basis for comparison. Water samples are collected during several storm events and during interstorm periods to assess water quality treatment performance. The samples are analyzed for nutrients, metals, petroleum hydrocarbons, and pathogens. The potential for leaching of pollutants from the asphalt binder will also be assessed during these storm events. Water quality treatment performance is compared to those of several other studies. Updates on spring 2005 data are also included in the presentation.

Briggs, J. F.; Ballestero, T. P.; Roseen, R. M.; Houle, J. J.

2005-05-01

77

FUEL CONSUMPTION & ENERGY DISSIPATION THROUGH ROAD PAVEMENT CHARACTERISTIC  

Directory of Open Access Journals (Sweden)

Full Text Available This thesis estimates the effect of pavement characteristic on energy dissipation of a rolling vehicle tyre. On objective of this study is to compare the relative amount of energy dissipated in pavement by the rolling depending on the pavement materials surface condition & environmental condition also. The study also assesses the effect of the vertical deflection, induced by the tyre, on overall energy dissipation in pavement. A comprehensive literature was carried out to prove a wide background for the study. Field measures and laboratory tests were discussed to provide basis for analyses. Results indicate that energy dissipated in pavement significantly depend on the characteristic of pavement. An obvious influence of speed on energy dissipation can be found only when the stiffness in a low level.

Dipanjan Mukherjee

2014-06-01

78

Field Evaluation of Nondestructive Tests in Measuring the Pavement Layers Density  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was field evaluation of nondestructive devices in measuring the density of road layers. Density may be considered as a reliable criterion for evaluating pavement quality and has a high level of importance in that it can ensure the proper performance of pavement at least prior the period of life-time. At present time, the most current and also accurate method to determine in-situ density of asphalt mixture is core sample method, however it has some disadvantages. As well as being costly and time consuming, core sample method causes some distress on the pavement surface and it is not possible to repeat the test for a specific location. In view of this, some attempts were made to develop new methods as alternatives for core sample method. And as such, nondestructive tests have grown into a huge area over the last few years. These tests including nuclear and nonnuclear nondestructive tests do not have the limitations of core sample method. In this study, field evaluation in a new constructed part of a highway was conducted using pavement quality indicator (PQI301 and Troxler nuclear gauge (Model HS-5001EZ. According to the results of validation tests for nondestructive devices (PQI and Nuclear devices, PQI device has sufficient reliability to determine density of asphalt mixture layer but Nuclear device is not reliable to determine density. The obtained results from validation of nuclear device revealed that it has sufficient reliability to determine density of soil layers. Also it was found that the role of calibration procedure in obtaining correct readings From PQI device is highly critical.

H. Divandary

2010-01-01

79

Vehicle dynamic response due to pavement roughness  

Directory of Open Access Journals (Sweden)

Full Text Available The goal of the present study is the development of a spectral method to obtain the frequency response of the half-vehicle subjected to a measured pavement roughness in the frequency domain. For this purpose, a half-vehicle dynamic model with a two-point delayed base excitation was developed to correlate with the spectral density function of the pavement roughness, to obtain the system spectral transfer function, in the frequency domain. The vertical pavement profile was measured along two roads sections. The surface roughness was here expressed in terms of the spectral density function of the measured vertical pavement profile with respect to the evenness wave number of the pavement roughness. A frequency response analysis was applied to obtain the vertical and angular modal vehicle dynamic response with the excitation of the power spectral density (PSD of the pavement roughness. The results show that at low speed, the vehicle suspension mode is magnified due to the unpaved track signature. At 120 km/h in an undulated asphalted road, the first vehicle vibration mode has a significant motion amplification, which may cause passenger discomfort.

Roberto Spinola Barbosa

2011-09-01

80

Vehicle dynamic response due to pavement roughness  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The goal of the present study is the development of a spectral method to obtain the frequency response of the half-vehicle subjected to a measured pavement roughness in the frequency domain. For this purpose, a half-vehicle dynamic model with a two-point delayed base excitation was developed to corr [...] elate with the spectral density function of the pavement roughness, to obtain the system spectral transfer function, in the frequency domain. The vertical pavement profile was measured along two roads sections. The surface roughness was here expressed in terms of the spectral density function of the measured vertical pavement profile with respect to the evenness wave number of the pavement roughness. A frequency response analysis was applied to obtain the vertical and angular modal vehicle dynamic response with the excitation of the power spectral density (PSD) of the pavement roughness. The results show that at low speed, the vehicle suspension mode is magnified due to the unpaved track signature. At 120 km/h in an undulated asphalted road, the first vehicle vibration mode has a significant motion amplification, which may cause passenger discomfort.

Roberto Spinola, Barbosa.

2011-09-01

81

A model for the pavement temperature prediction at specified depth using neural networks  

OpenAIRE

Earlier researches have established that the ambient temperature is one of the most important factors for pavement temperature analysis.This paper examines the existing models for predicting pavement temperatures at specified depth and formulates a new one using neural networks depending on the surface pavement temperature and depth. It was also conducted the validation of the model comparing predicted with measured temperatures.

Matic?, B.; Matic?, D.; Sremac, S.; Radovic?, N.; Vi?ikant, P.

2014-01-01

82

Asphalt in Pavement Maintenance.  

Science.gov (United States)

Maintenance methods that can be used equally well in all regions of the country have been developed for the use of asphalt in pavement maintenance. Specific information covering methods, equipment and terminology that applies to the use of asphalt in the maintenance of all types of pavement structures, including shoulders, is provided. In many…

Asphalt Inst., College Park, MD.

83

The influence of temperature variation in the prediction of the pavement overlay life  

OpenAIRE

This paper describes a study of the influence of temperature variation in the pavement overlay life, using finite-element methodology to consider the most predominant type of overlay distress observed in the field: reflective cracking. The temperature variation has a significant influence on thermally induced stresses that, in turn, affects the overlay predictive service life. This paper presents a three-dimensional (3D) finite element analysis to predict the pavement overlay l...

Minhoto, Manuel J. C.; Pais, Jorge C.; Pereira, Paulo A. A.; Santos, Lui?s Picado

2005-01-01

84

A Framework for Quantification of Effect of Drainage Quality on Structural and Functional Performance of Pavement  

Directory of Open Access Journals (Sweden)

Full Text Available Drainage quality is an important parameter which affects the highway pavement performance. Excessive water content in the pavement base, sub-base, and sub-grade soils can cause early distress and lead to a structural or functional failure of pavement. Thus, when selecting appropriate maintenance strategies the cost of pavement maintenance needs to be compared with the cost of improving the quality of drainage. Hence, there is a need to quantify the effect of various types of drainage quality on performance of the pavement. However, very few studies have investigated to what extent quality of drainage affects the performance of pavement. Therefore, this study identifies a simple framework for quantification of effect of drainage quality on structural as well as functional performance of the pavement. The proposed framework presents the structural and functional performance of the pavement is predicted in terms of deflection and roughness respectively. It is expected that this study will useful to reduce the maintenance cost of highway pavement system and hence will be useful to preserve huge highway network in India.

Jitendra Gurjar, Pradeep Kumar Agarwal, Manoj Kumar Sharma

2013-07-01

85

Modeling the Pavement Present Serviceability Index of Flexible Highway Pavements Using Data Mining  

Directory of Open Access Journals (Sweden)

Full Text Available The term present serviceability was adopted to represent the momentary ability of pavement to serve traffic and the performance of the pavement was represented by its serviceability history in conjunction with its load application history. Serviceability was found to be influenced by longitudinal and transverse profile as well as the extent of cracking and patching. The amount of weight to assign to each element in the determination of the over-all serviceability is a matter of subjective opinion. In the present study, a regression tree model has been presented for determining flexible pavement surface layer thickness. The model, RT was selected as estimating method. Results show that wearing course thickness of flexible pavement regression values of the regression tree model is better than that of the AASHO model. This approach can be easily and realistically performed to solve the optimization problems which do not have a formulation or function about the solution.

Serdal Terzi

2006-01-01

86

Studies of the effect of aging of ``quiet'' pavements on tire/pavement noise  

Science.gov (United States)

One of the issues with using quieter pavements to abate traffic noise is their continued acoustic performance over the life cycle of the surface. Aging effects can be assessed in two manners: (1) long term monitoring of the noise performance of an individual section of roadway; (2) measurement of multiple sections of pavement of the same construction, but different ages. Long term monitoring of Interstate 80 near Davis (I-80 Davis) began in 1998, just prior to the placement of a dense graded leveling course and open graded asphalt overlay. The pavement surface is now approaching 7 years old and continues to show a traffic noise reduction of about 5 dBA over the existing condition. As support of the Arizona Quiet Pavement Program (QPPP), similarly constructed sections of asphalt rubber friction course (ARFC) on Arizona's interstate highways were measured for tire/pavement performance using the close proximity (CPX) method and the on-board sound intensity method. The construction dates for the pavements ranged from 1988 to 1999. The total range in noise level was 7 dB with some indication of degrading performance with age.

Reyff, James A.; Donavan, Paul

2005-09-01

87

Overview of the Arizona Quiet Pavement Program  

Science.gov (United States)

The Arizona Quiet Pavement Pilot Program (QP3) was initially implemented to reduce highway related traffic noise by overlaying most of the Phoenix metropolitan area Portland cement concrete pavement with a one inch thick asphalt rubber friction coarse. With FHWA support, this program represents the first time that pavement surface type has been allowed as a noise mitigation strategy on federally funded projects. As a condition of using pavement type as a noise mitigation strategy, ADOT developed a ten-year, $3.8 million research program to evaluate the noise reduction performance over time. Historically, pavement surface type was not considered a permanent solution. As a result, the research program was designed to specifically address this issue. Noise performance is being evaluated through three means: (1) conventional roadside testing within the roadway corridor (e.g., far field measurements within the right-of-way) (2) the use of near field measurements, both close proximity (CPX) and sound intensity (SI); and (3) far field measurements obtained beyond the noise barriers within the surrounding neighborhoods. This paper provides an overview of the program development, presents the research conducted to support the decision to overlay the urban freeway, and the status of current research.

Donavan, Paul; Scofield, Larry

2005-09-01

88

Experimental AC (Asphalt Concrete) overlays of PCC pavement  

Science.gov (United States)

A series of experimental asphalt concrete (AC) overlays was constructed over an existing distressed portland cement concrete pavement on Interstate 80 near Boca, California. The experimental overlays included rubberized dense-graded AC, rubberized open-graded AC, a rubber flush coat interlayer, dense-graded AC with short polyester fibers and Bituthene interlayer strips. The report presents a description and discussion of AC mix batching, construction observations, laboratory testing, overlay covering, and initial performance evaluation.

Smith, R. D.

1983-11-01

89

Pervious Pavement System Evaluation  

Science.gov (United States)

Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, grade...

90

Runway Operability under Cold Weather Conditions. Tire-pavement friction creation by sand particles on iced pavements, and non-contacting detection of sand particles on pavements  

OpenAIRE

Airports that operate under cold weather conditions face major challenges in ensuring that runways, taxiways and aprons provide sufficient tire-pavement friction to the operating aircraft. This thesis is motivated by two practical problems: (1) maintaining or improving the pavement surface conditions in an, for airline companies, acceptable state and (2) accurately reporting the actual surface conditions to the relevant actors (pilots, air traffic control, winter maintenance services). The pr...

Klein-paste, Alex

2007-01-01

91

Formulação probabilística para análise de tabuleiros de pontes rodoviárias com irregularidades superficiais Probabilistic formulation for the analysis of highway bridge decks with irregular pavement surface  

Directory of Open Access Journals (Sweden)

Full Text Available Apresenta-se uma metodologia de análise com o objetivo de avaliarem-se os efeitos de irregularidades superficiais no tabuleiro sobre o comportamento de pontes rodoviárias submetidas à passagem de veículos. A resposta do sistema veículo-estrutura é obtida no domínio da freqüência segundo modelo probabilístico. Simula-se o tabuleiro das pontes com modelo de elementos finitos unidimensionais com massas discretizadas nos nós, o veículo por um sistema de massas, molas e amortecedores, e as irregularidades da pista são definidas por modelo não-determinístico com base na densidade espectral do perfil do pavimento. O carregamento é constituído por uma sucessão infinita de veículos igualmente espaçados deslocando-se com velocidade constante sobre o tabuleiro e a atenção é concentrada na fase permanente da resposta do sistema. Deduzem-se as expressões das densidades espectrais dos elementos da resposta a partir da densidade espectral do perfil irregular do pavimento e integram-se numericamente tais expressões para se chegar às médias quadráticas desses elementos. Observa-se a resposta do modelo matemático, com base em uma ponte rodoviária de concreto armado simplesmente apoiada, com seção tipo caixão e inércia constante, em termos de deslocamentos e esforços nas seções onde ocorrem os efeitos máximos. As conclusões versam sobre a adequação da metodologia desenvolvida e do modelo matemático empregado.An analysis methodology is proposed to evaluate the dynamical effects, displacements and stresses, on highway bridge decks, due to vehicles crossing on the rough pavement surfaces defined by a probabilistic model. To this purpose, the methodology is developed to evaluate the vehicle-structure response under a full probabilistic formulation, running in the frequency domain. The mathematical model assumes a finite element representation of the beam like deck and the vehicle simulation uses concentrated parameters of mass, stiffness and damping. The deck surface roughness is defined by a well known power spectrum density of road pavement profiles. The moving load is formed by an infinite succession of equally spaced vehicles moving with constant velocity. Only steady-state response is considered. Response data are produced on concrete box girder elements assembled as a simple beam. Conclusions are concerned with the fitness of the developed analysis methodology and the mathematical model adequacy.

José Guilherme Santos da Silva

1999-09-01

92

Classificação híbrida: pixel a pixel e baseada em objetos para o monitoramento da condição da superfície dos pavimentos rodoviários / Hybrid classification: pixel by pixel and object based to monitor the surface conditions of road pavements  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Monitorar a condição de uso de toda a extensão das rodovias brasileiras é tarefa dispendiosa e demorada. Este trabalho trata de novas técnicas que permitem o levantamento da condição da superfície dos pavimentos rodoviários de forma ágil utilizando imagens hiperespectrais de sensor digital aeroembar [...] cado. Nos últimos anos, um número crescente de imagens de alta resolução espacial tem surgido no mercado mundial com o aparecimento dos novos satélites e sensores aeroembarcados de sensoriamento remoto. Propõe-se uma metodologia para identificação dos pavimentos asfálticos e classificação das principais ocorrências dos defeitos na superfície do pavimento. A primeira etapa da metodologia é a identificação da superfície asfáltica na imagem, utilizando uma classificação híbrida baseada inicialmente em pixel e depois refinada por objetos. A segunda etapa da metodologia é a identificação e classificação das ocorrências dos principais defeitos nos pavimentos flexíveis que são observáveis nas imagens de alta resolução espacial. Esta última etapa faz uso intensivo das novas técnicas de classificação de imagens baseadas em objetos. O resultado final é a geração de índices da condição da superfície do pavimento a partir das imagens que possam ser comparados com os indicadores vigentes da condição da superfície do pavimento já normatizados pelos órgãos competentes no país. Abstract in english Monitoring every Brazilian road use condition is an expensive and time consuming task. This research deals with new techniques which will yield a quick survey of road surface pavement condition by using hyperspectral images from airborne remote sensing. Recently, an increasing number of images with [...] high spatial resolution has emerged on the world market with the advent of new remote sensing satellites and airborne sensors. Hyperspectral images from digital airborne sensor have been used in this work. A new identification methodology for a pavement surface and also for classification of the main defects of the surface has been devised. The first step of the methodology is the identification of the asphalt surface in the image, by using hybrid classification based on pixel initially and then improved by objects. The second step of the methodology is the identification and classification of the main defects of pavement surface that are observable in high spatial resolution imagery. This step makes intensive use of new techniques for classification of images based on objects. The goal is the generation of pavement surface condition index from the images which can be compared to quality index of pavement surface already managed by the regulatory agency in the country.

Marcos Ribeiro, Resende; Liedi Légi Barianni, Bernucci; José Alberto, Quintanilha.

2012-09-01

93

DRAINAGE AND FLEXIBLE PAVEMENT PERFORMANCE  

OpenAIRE

Providing adequate drainage to a pavement system has been considered as an important design consideration to prevent premature failures due to water related problems such as pumping action, loss of support, and rutting, among others. Most water in pavements is due to rainfall infiltration into unsaturated pavement layers, throughjoints, cracks, shoulder edges, and various other defects, especially in older deteriorated pavements. Water also seep upward from a high groundwater table due to cap...

SIDDHARTHA ROKADE; Agarwal, P. K.; RAJNISH SHRIVASTAVA

2012-01-01

94

Calculating condition of pavement structure  

OpenAIRE

In XX century, Pavement Management System has became obligatory to be used by road agencies. Need of serviceable road system demands the proper maintenance and rehabilitation plans and at that point, Pavement Performance Models step in. They are used to predict the future condition of pavement structure, basing mostly on road, climate and traffic data.The following thesis describes the attempts to implement modern Pavement Performance Models in Norway. With their help, it would be possible to...

Romanowska, Daria Krystyna

2012-01-01

95

A real-time 3D scanning system for pavement distortion inspection  

International Nuclear Information System (INIS)

Pavement distortions, such as rutting and shoving, are the common pavement distress problems that need to be inspected and repaired in a timely manner to ensure ride quality and traffic safety. This paper introduces a real-time, low-cost inspection system devoted to detecting these distress features using high-speed 3D transverse scanning techniques. The detection principle is the dynamic generation and characterization of the 3D pavement profile based on structured light triangulation. To improve the accuracy of the system, a multi-view coplanar scheme is employed in the calibration procedure so that more feature points can be used and distributed across the field of view of the camera. A sub-pixel line extraction method is applied for the laser stripe location, which includes filtering, edge detection and spline interpolation. The pavement transverse profile is then generated from the laser stripe curve and approximated by line segments. The second-order derivatives of the segment endpoints are used to identify the feature points of possible distortions. The system can output the real-time measurements and 3D visualization of rutting and shoving distress in a scanned pavement

96

Analysis of the functional quality of pavements from texture measurements  

OpenAIRE

The surface texture of a pavement, including uneveness, is largely determinant of drivers’safety and comfort. It is undoubtedly a major cause of road traffic accidents all over the world. Statistics show that one million killed and 50 million injured are reported every year by Competent Authorities. The effect of traffic noise has also become a critical public issue. On the road networking the surface characteristics of pavements also contributed to nearly 80-90% of roadway traffic no...

Freitas, Elisabete F.; Pereira, Paulo A. A.

2007-01-01

97

Improvement of the functional pavement quality with asphalt rubber mixtures  

OpenAIRE

Skid resistance and texture are important safety characteristics which need to be considered in flexible pavement design, maintenance and rehabilitation. The main objective of this paper is to optimize surface texture characteristics in asphalt rubber pavements, mainly macrotexture to reduce splash, spray and hydroplaning and microtexture to increase friction at low and high speeds. The objective was accomplished by measuring the friction surface with two different tests: (i) B...

Fontes, Liseane P. T. L.; Pereira, Paulo A. A.; Pais, Jorge C.; Triche?s, Glice?rio

2006-01-01

98

Road Asphalt Pavements Analyzed by Airborne Thermal Remote Sensing: Preliminary Results of the Venice Highway  

OpenAIRE

This paper describes a fast procedure for evaluating asphalt pavement surface defects using airborne emissivity data. To develop this procedure, we used airborne multispectral emissivity data covering an urban test area close to Venice (Italy).For this study, we first identify and select the roads’ asphalt pavements on Multispectral Infrared Visible Imaging Spectrometer (MIVIS) imagery using a segmentation procedure. Next, since in asphalt pavements the surface defects are strict...

Rosa Cavalli; Maurizio Poscolieri; Angelo Palombo; Cristiana Bassani; Simone Pascucci

2008-01-01

99

Evaluation of pavement texture  

Science.gov (United States)

A system for pavement macrotexture measurement was evaluated. The system utilizes the principle of depolarization of reflected polarized light. The output of the system, the depolarized light number (DPN), is compared with other measures of pavement texture: sand-patch mean texture depth (MTD), British pendulum number (BPN), and outflow meter time (OFT) for 22 asphalt concrete sites and 5 portland cement concrete sites. The prediction of texture data from simultaneous measurements of ribbed and blank-tire skid resistance data was investigated. Using the two-tire data, it is possible to predict sand-patch mean texture depth (MTD) and Bristish pendulum number (BPN). Comparison of the two-tire data at accident sites demonstrates the potential to screen for wet weather accident sites by means of pavement surveys with the two tires.

Henry, J. J.; Wambold, J. C.; Huihua, X.

1984-10-01

100

Pavement Snow Melting  

Energy Technology Data Exchange (ETDEWEB)

The design of pavement snow melting systems is presented based on criteria established by ASHRAE. The heating requirements depends on rate of snow fall, air temperature, relative humidity and wind velocity. Piping materials are either metal or plastic, however, due to corrosion problems, cross-linked polyethylene pipe is now generally used instead of iron. Geothermal energy is supplied to systems through the use of heat pipes, directly from circulating pipes, through a heat exchanger or by allowing water to flow directly over the pavement, by using solar thermal storage. Examples of systems in New Jersey, Wyoming, Virginia, Japan, Argentina, Switzerland and Oregon are presented. Key words: pavement snow melting, geothermal heating, heat pipes, solar storage, Wyoming, Virginia, Japan, Argentina, Klamath Falls.

Lund, John W.

2005-01-01

101

Asphalt pavement temperature prediction  

OpenAIRE

A 3-D finite element model (FEM) was developed to calculate the lemperature of an asphtalt rubber pavement localed in the Northeast of Portugal. The goal of the case study presented in this paper is to show the good accuracy temperature prediction tha can be obtained with this model when compared with the field pavement thermal condition obtained during a year. lnput data to the model are the hourly values for solar radiation and temperature and the mean daily value of wind speed obtained fr...

Minhoto, Manuel; Pais, Jorge; Pereira, Paulo

2006-01-01

102

Modeling Deflection Basin Using Neurofuzzy in Backcaluculating Flexible Pavement Layer Moduli  

Directory of Open Access Journals (Sweden)

Full Text Available Flexible pavement surface condition date play a principle role in the evaluation of pavement structural capacity and in the design of pavement rehabilitation programs. Flexible pavements are affected by moving vehicles, climate and other environmental factors. As a result of these factors, the pavement starts to deteriorate. In order to prevent further deterioration, a maintenance program should be carried out at right time and right places. For the determination of the structural carrying capacity of the pavement, non-destructive testing equipments are used. In such a process, the most important thing is to analyse the collected data. A backcalculation procedure is carried out for back-calculation elastic modules for each layer effective in the pavement life. The input data are usually restricted to the pavement surface deflection or its basin obtained by Nondestructive testing as the Falling Weight Deflectometer (FWD. Generally, linear elastic and finite element based programs are used for back-calculating, but they are both time consuming. It is also important to simulate deflection basin realistically in backcalculating pavement layer moduli. For this purpose, NeuroFuzzy method is used for simulation deflection basin during the course of this study. Results indicate that the NeuroFuzzy can be used for backcalculation of flexible pavement layer moduli with great improvement and accuracy.

Mehmet Saltan

2002-01-01

103

The impact of material characteristics on tire pavement interaction noise for flexible pavements  

Science.gov (United States)

Noise pollution has recently been one of the growing problems all over the world. While there are many sources of the noise, traffic noise is the main contributor to the total environmental noise. Although there are different sources for traffic noise, the tire pavement interaction noise is the most dominant component within most city and highway limits. One of the ways to reduce the tire pavement noise is to improve the material characteristics of the pavements such that they produce less noise. In this study, the relationship between basic material characteristics (e.g., Hot Mix Asphalt (HMA) volumetrics) and sound generation and absorption characteristics of flexible pavements was investigated. In addition, the effect of linear visco-elastic properties (e.g., dynamic modulus (|E*|) and phase angle (delta)) on sound absorption was studied. In order to focus only on impact of material characteristics and overshadow the effect of surface texture, a novel laboratory tire pavement noise measurement simulator (TIPANOS) was developed. The statistical analysis results showed that although the individual material characteristics do not have appreciable influence on sound absorption, there is a significant correlation between sound pressure levels (SPL) and combination of several material and linear visco-elastic parameters.

Kocak, Salih

104

Pervious Pavement System Evaluation  

Science.gov (United States)

Pervious pavement is a low impact development stormwater control. The Urban Watershed Management Branch of the U.S. Environmental Protection Agency in Edison, NJ, is evaluating concrete pavers as a popular implementation. The pollutant removal of a bench-scale permeable interlo...

105

Use of lime cement stabilized pavement construction  

Energy Technology Data Exchange (ETDEWEB)

Expansive clay is a major source of heave induced structural distress. Swelling of expansive soils causes serious problems and produce damages to many structures. Many research organizations are doing extensive work on waste materials concerning the feasibility and environmental suitability. Fly ash, a waste by product from coal burning in thermal power stations, is abundant in India causing severe health, environmental and disposal problems. Attempts are made to investigate the stabilization process with model test tracks over expansive subgrade in flexible pavements. Cyclic plate load tests are carried out on the tracks with chemicals like lime and cement introduced in fly ash subbase laid on sand and expansive subgrades. Test results show that maximum load carrying capacity is obtained for stabilized fly ash subbase compared to untreated fly ash subbase.

Kumar, M.A.; Raju, G.V.R.P. [JNTU College of Engineering, Kakinada (India). Dept. of Civil Engineering

2009-08-15

106

Predicting in-service fatigue life of flexible pavements based on accelerated pavement testing  

Science.gov (United States)

Pavement performance prediction in terms of fatigue cracking and surface rutting are essential for any mechanistically-based pavement design method. Traditionally, the estimation of the expected fatigue field performance has been based on the laboratory bending beam test. Full-scale Accelerated Pavement Testing (APT) is an alternative to laboratory testing leading to advances in practice and economic savings for the evaluation of new pavement configurations, stress level related factors, new materials and design improvements. This type of testing closely simulates field conditions; however, it does not capture actual performance because of the limited ability to address long-term phenomena. The same pavement structure may exhibit different response and performance under APT than when in-service. Actual field performance is better captured by experiments such as Federal Highway Administration's Long-Term Pavement Performance (LTPP) studies. Therefore, to fully utilize the benefits of APT, there is a need for a methodology to predict the long-term performance of in-service pavement structures from the results of APT tests that will account for such differences. Three models are generally suggested to account for the difference: shift factors, statistical and mechanistic approaches. A reliability based methodology for fatigue cracking prediction is proposed in this research, through which the three models suggested previously are combined into one general approach that builds on their individual strengths to overcome some of the shortcomings when the models are applied individually. The Bias Correction Factor (BCF) should account for all quantifiable differences between the fatigue life of the pavement site under APT and in-service conditions. In addition to the Bias Correction Factor, a marginal shifty factor, M, should be included to account for the unquantifiable differences when predicting the in-service pavement fatigue life from APT. The Bias Correction Factor represents an improvement of the currently used "shift factors" since they are more general and based on laboratory testing or computer simulation. By applying the proposed methodology, APT performance results from a structure similar to an in-service structure can be used to perform four-point bending beam tests and structural analysis to obtain an accurate estimate of the necessary Bias Correction Factor to estimate in-service performance.

Guo, Runhua

107

POROUS PAVEMENT: RESEARCH; DEVELOPMENT; AND DEMONSTRATION  

Science.gov (United States)

This paper discusses the U.S. Environmental Protection Agency's porous pavement research program along with the economics, advantages, potential applications, and status and future research needs of porous pavements. Porous pavements are an available stormwater management techniq...

108

Asphalt Pavement Deflection due to a Circular Load and Temperature Modified Coefficient  

OpenAIRE

This study proposed an approximate computation method of pavement deflection due to a circular and regression formulas among temperature modified coefficient to deflection, the average temperature of surface course and pavement structure parameters. Based on theoretical solution of pavement deflection which is beneath the center of the load due to a circular load applied on a homogeneous half-space, by introducing structure parameter modified coefficient &zeta, approximate computation method ...

Hu Honglong

2014-01-01

109

New disclosures at pavement and maintenance treatment design on existent roads  

OpenAIRE

In the field of pavement design and maintenance treatment design on existent roads a significant progress was achieved in Slovenia in recent years. Condition of pavement surfaces and structures is continuously monitored and on roads with comparable deterioration (fatigue) similar maintenance treatments are designed. Essential knowledge, arising from years of experience in the field of pavement design and maintenance treatment design, are brought together in this work. The work is divided in t...

Cezar, Joz?ica

2007-01-01

110

A model for the pavement temperature prediction at specified depth using neural networks  

Directory of Open Access Journals (Sweden)

Full Text Available Earlier researches have established that the ambient temperature is one of the most important factors for pavement temperature analysis.This paper examines the existing models for predicting pavement temperatures at specified depth and formulates a new one using neural networks depending on the surface pavement temperature and depth. It was also conducted the validation of the model comparing predicted with measured temperatures.

B. Mati?

2014-10-01

111

High Performance Concrete for Pavement  

OpenAIRE

Highly loaded concrete pavements need to be constructed with a sufficient serviceability and load bearing capacity during the target service life. High Performance Pavement Concrete with a water/cement-ratio of 0.35 build in with a slip-form paver is having an increased flexural strength up to 80 % above the required level intended for ordinary pavement concrete. A part of this profit due to load bearing capacity is reduced according to coincident altered concrete properties, especially to an...

Beckhaus, Karsten

2007-01-01

112

Comparative Study on Pavement Temperature Features of Bridge Deck and Road Pavement  

OpenAIRE

The objective of this study was to comparatively analyze the difference of pavement temperature of bride deck and road pavement. The asphalt pavement temperature of road pavement and bride deck were tested in Guozigou area of Xinjiang, China. And the air temperature, wind speed, humidness and sunlight radiation were collected. Further, the distribution features of asphalt pavement of bridge deck and road pavement were comparatively analyzed. At last, the predictive model of pavement temperatu...

Yueqin Hou; Nanxiang Zheng; Yiluo Zhang

2013-01-01

113

Impact of Vehicle Class and Tire Pressure on Pavement Performance in MEPDG  

Directory of Open Access Journals (Sweden)

Full Text Available The new Mechanistic-Empirical Pavement Design Guide (MEPDG design and analysis procedures defines the exact traffic loading by defining the specific number of each vehicle class and the use of axle load distribution factors instead of the equivalent single axle load (ESAL. The number of traffic inputs (parameters in MEPDG was found to be 17024. This research aimed to evaluate the sensitivity of the predicted flexible pavement distress to vehicle class and tire pressure in MEPDG. To evaluate the impact of vehicle (truck class on pavement sections, different cases of loading were analyzed. For each case, the MEPDG Ver. 1.1 was used to evaluate the effect of tire pressure by solving each case for a tire pressure of 120 and 140 psi. The effect of the traffic parameters on asphalt pavement (AC rutting, base rutting, subgrade rutting, international roughness index (IRI, longitudinal cracking and fatigue (alligator cracking were investigated. It was found that vehicle class distribution (VCD would cause clear impact (comparable to the effect of AADTT level only if the major traffic is of specific class (very light or very heavy. If this is not the case, the vehicle class distribution will not be a significant factor that affects the final design because most of the trucks had similar impact on flexible pavement distresses. The impact of tire pressure is clear on longitudinal cracking, fatigue cracking and AC rutting, and have no significant impact on both base and subgrade rutting.

Mohamed I. E. Attia

2014-10-01

114

Engineering properties of resin modified pavement (RMP) for mechanistic design  

Science.gov (United States)

The research study described in this report focuses on determining the engineering properties of the resin modified pavement (RMP) material relating to pavement performance, and then developing a rational mechanistic design procedure to replace the current empirical design procedure. A detailed description of RMP is provided, including a review of the available literature on this relatively new pavement technology. Field evaluations of four existing and two new RMP project sites were made to assess critical failure modes and to obtain pavement samples for subsequent laboratory testing. Various engineering properties of laboratory-produced and field-recovered samples of RMP were measured and analyzed. The engineering properties evaluated included those relating to the material's stiffness, strength, thermal properties, and traffic-related properties. Comparisons of these data to typical values for asphalt concrete and portland cement concrete were made to relate the physical nature of RMP to more common pavement surfacing materials. A mechanistic design procedure was developed to determine appropriate thickness profiles of RMP, using stiffness and fatigue properties determined by this study. The design procedure is based on the U.S. Army Corps of Engineers layered elastic method for airfield flexible pavements. The WESPAVE computer program was used to demonstrate the new design procedure for a hypothetical airfield apron design. The results of the study indicated that RMP is a relatively stiff, viscoelastic pavement surfacing material with many of its strength and stiffness properties falling between those of typical asphalt concrete and portland cement concrete. The RMP's thermal and traffic-related properties indicated favorable field performance. The layered elastic design approach appeared to be a reasonable and practical method for RMP mechanistic pavement design, and this design procedure was recommended for future use and development.

Anderton, Gary Lee

1997-11-01

115

Neonatal respiratory distress syndrome  

Science.gov (United States)

... distress syndrome (IRDS); Respiratory distress syndrome in infants; RDS - infants ... Neonatal RDS occurs in infants whose lungs have not yet fully developed. The disease is mainly caused by a ...

116

Influence of binder and mixture properties on the performance of AC pavements  

OpenAIRE

This study was conducted as a part of an on-going program to validate the SUPERPAVE binder selection program introduced in the U.S. in 1995. The SUPERPAVE system recognizes that the behavior of hot mix asphalt (HMA) depends on the temperature, loading and aging conditions and allow for material selection process that aids in the prevention of premature pavement distress. To validate the binder selection process and to study the influence of binder grade on performance of HMA pavements, a stud...

Shah, Ayesha

2004-01-01

117

Mechanistic-Empirical Pavement Design  

OpenAIRE

Fiscal constraints can limit the analysis that can be done prior to pavement design. The falling weight deflectometer offers a fast and cost effective solution to obtaining information to assist in these processes. This presentation discusses its use and inputs into the new Mechanistic-Empirical Pavement Design Guide Darwin-ME software adopted by INDOT.

Gemayel, Chuck; Maurovich, Mike

2013-01-01

118

Advanced Pavement Evaluation & Design Methods  

OpenAIRE

Fiscal constraints can limit the analysis that can be done prior to pavement design. The falling weight deflectometer offers a fast and cost effective solution to obtaining information to assist in these processes. This presentation discusses its use and inputs into the new Mechanistic-Empirical Pavement Design Guide Darwin-ME software adopted by INDOT.

Gemayel, Chuck; Maurovich, Mike

2013-01-01

119

Photocatalytic pavement blocks. Air purification by pavement blocks. Final results of the research at BRRC  

International Nuclear Information System (INIS)

The use of materials can influence to a large extent the environmental impact of traffic and of road infrastructure. Especially in urban areas, where the risk on smog formation during hot summer days is high, the use of photocatalytic pavement blocks can reduce the air pollution significantly. A project on environmental friendly concrete pavement blocks is conducted at the Belgian Road Research Centre. The use of photocatalytic material in the surface of pavement blocks to obtain air purifying materials is investigated. In contact with light, TiO2 as photocatalyst, is able to reduce the NO and NO2 content in the air, caused by the exhaust of traffic. The efficiency is tested on pavement blocks, but the technique can as well be applied on other road elements (e.g. noise reducing walls, linear elements) or as a coating on new materials or existing structures. At the previous TRA conference in Gotenborgh, Sweden, the principle of photocatalysis was presented. In this paper, emphasis will be put on the final results of the 4-year project obtained in laboratory as well as on site at the Leien of Antwerp (10,000 m2). The results indicate a durable efficiency towards NOx reduction, which is in favour for the diminishing of the risk on ozone formation. However, the precise translation from the laboratory towards the site is still in question. The results obtained during the project are discussed in this paper

120

Pavement Subgrade Performance Study : Part II: Modeling Pavement Response and Predicting Pavement Performance  

DEFF Research Database (Denmark)

The report describes the second test in the Danish Road Testing Machine (RTM) under the International Pavement Subgrade Performance Study. Pavement response was measured in different layers, and compared to different theroretical values. Performance in terms of plastic strains, rutting and roughness was measured and theoretical prediction models were developed.

Zhang, Wei; Ullidtz, Per

1998-01-01

121

Measuring Clogging with Pressure Transducers in Permeable Pavement Strips  

Science.gov (United States)

Two issues that have a negative affect on the long term hydrologic performance of permeable pavement systems are surface clogging and clogging at the interface with the underlying soil. Surface clogging limits infiltration capacity and results in bypass if runoff rate exceeds in...

122

Nondestructive testing of pavements and pavement bases (a bibliography with abstracts). Report for 1964--Dec 1975  

International Nuclear Information System (INIS)

Eighty references on nondestructive methods for quality assurance of pavements and pavement bases are presented. Vibration, nuclear activation, radiometry, and acoustic detection are among the various techniques employed

123

Image Preprocessing Methods to Identify Micro-cracks of Road Pavement  

Directory of Open Access Journals (Sweden)

Full Text Available Standards of highway conservation and maintenance are improved gradually following the improvement of requirements of road service. Before obvious damage such as obvious cracking (block?transverse, longitudinal and rutting emerge, inconspicuous distress (micro-cracks, polishing, pockmarked is generated previously. These inconspicuous distresses may provide basis and criteria for pavement preventive maintenance. Currently most of preventive conservation measures are determined by experienced experts in maintenance and repair of road after site visits. Thus method is difficult in operation, and has a certain amount of instability as it is based on experience and personal knowledge. In this paper, camera and laser were used for automated high-speed acquisition images. Methods to preprocess pavement image are compared. The pretreatment method suitable for analyze micro-cracks picture is elected, an effective way to remove shadow is also proposed.

Hui Wang

2013-06-01

124

Design prediction of pavement skid resistance from laboratory tests  

Science.gov (United States)

Methods for preevaluating aggregates and paving mixtures so that predictions can be made covering skid resistance properties of proposed and in service pavement types are discussed. A correlation was established between the field testing using the data from the British Portable Tester and the Locked Wheel Pavement Friction Trailer at speeds of 40 and 55 mph. Core samples were extracted from the Locked Wheel Tester Skid Path and subjected to wear on the small wheel circular track with periodic surface friction testing. The final step was to remix and remold the cored pavement samples or make samples with new materials to obtain an 'as new' surface and again subject these samples to wear on the small wheel circular track with periodic testing.

Parcells, W. H.; Metheny, T. M.; Maag, R. G.

1980-08-01

125

Wavelet-based pavement image compression and noise reduction  

Science.gov (United States)

For any automated distress inspection system, typically a huge number of pavement images are collected. Use of an appropriate image compression algorithm can save disk space, reduce the saving time, increase the inspection distance, and increase the processing speed. In this research, a modified EZW (Embedded Zero-tree Wavelet) coding method, which is an improved version of the widely used EZW coding method, is proposed. This method, unlike the two-pass approach used in the original EZW method, uses only one pass to encode both the coordinates and magnitudes of wavelet coefficients. An adaptive arithmetic encoding method is also implemented to encode four symbols assigned by the modified EZW into binary bits. By applying a thresholding technique to terminate the coding process, the modified EZW coding method can compress the image and reduce noise simultaneously. The new method is much simpler and faster. Experimental results also show that the compression ratio was increased one and one-half times compared to the EZW coding method. The compressed and de-noised data can be used to reconstruct wavelet coefficients for off-line pavement image processing such as distress classification and quantification.

Zhou, Jian; Huang, Peisen S.; Chiang, Fu-Pen

2005-08-01

126

Consideration of pavement roughness effects on vehicle-pavement interaction  

OpenAIRE

Paper presented at the 20th Annual South African Transport Conference 16 - 20 July 2001 "Meeting the transport challenges in Southern Africa", CSIR International Convention Centre, Pretoria, South Africa. ABSTRACT: Current mechanistic pavement design and analysis techniques use several simplifications to enable the process to be practical and cost-effective. These include equivalent vehicle loads, linear elastic analysis and static vehicle load and pavement response analysis. These simplifica...

Steyn, Wynand J. Vdm; Visser, Alex T.

2001-01-01

127

Spills on Flat Inclined Pavements  

Energy Technology Data Exchange (ETDEWEB)

This report describes the general spill phenomenology for liquid spills occurring on relatively impermeable surfaces such as concrete or asphalt pavement and the development and application of a model to describe the time evolution of such spills. The discussion assumes evaporation and degradation are negligible and a homogeneous surface. In such an instance, the inherent interfacial properties determine the spatial extent of liquid spreading with the initial flow being controlled by the release rate of the spill and by the liquids resistance to flow as characterized by its viscosity. A variety of spill scenarios were simulated and successful implementation of the model was achieved. A linear relationship between spill area and spill volume was confirmed. The simulations showed spill rate had little effect on the final spill area. Slope had an insignificant effect on the final spill area, but did modify spill shape considerably. However, a fluid sink on the edge of the simulation domain, representing a storm drain, resulted in a substantial decrease in spill area. A bona fide effort to determine the accuracy of the model and its calculations remain, but comparison against observations from a simple experiment showed the model to correctly determine the spill area and general shape under the conditions considered. Further model verification in the form of comparison against small scale spill experiments are needed to confirm the models validity.

Simmons, Carver S.; Keller, Jason M.; Hylden, Jeff L.

2004-03-01

128

Pervious Pavement System Evaluation- Abstract  

Science.gov (United States)

Porous pavement is a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete pavers as a popular implementation. The pavers themselves are impermeable, but the spaces between the pavers are backfilled with washed, gra...

129

Stormwater quality of spring-summer-fall effluent from three partial-infiltration permeable pavement systems and conventional asphalt pavement.  

Science.gov (United States)

This study examined the spring, summer and fall water quality performance of three partial-infiltration permeable pavement (PP) systems and a conventional asphalt pavement in Ontario. The study, conducted between 2010 and 2012, compared the water quality of effluent from two Interlocking Permeable Concrete Pavements (AquaPave(®) and Eco-Optiloc(®)) and a Hydromedia(®) Pervious Concrete pavement with runoff from an Asphalt control pavement. The usage of permeable pavements can mitigate the impact of urbanization on receiving surface water systems through quantity control and stormwater treatment. The PP systems provided excellent stormwater treatment for petroleum hydrocarbons, total suspended solids, metals (copper, iron, manganese and zinc) and nutrients (total-nitrogen and total-phosphorus) by reducing event mean concentrations (EMC) as well as total pollutant loadings. The PPs significantly reduced the concentration and loading of ammonia (NH4(+)+NH3), nitrite (NO2(-)) and organic-nitrogen (Org-N) but increased the concentration and loading of nitrate (NO3(-)). The PP systems had mixed performances for the treatment of phosphate (PO4(3-)). The PP systems increased the concentration of sodium (Na) and chloride (Cl) but EMCs remained well below recommended levels for drinking water quality. Relative to the observed runoff, winter road salt was released more slowly from the PP systems resulting in elevated spring and early-summer Cl and Na concentrations in effluent. PP materials were found to introduce dissolved solids into the infiltrating stormwater. The release of these pollutants was verified by additional laboratory scale testing of the individual pavement and aggregate materials at the University of Guelph. Pollutant concentrations were greatest during the first few months after construction and declined rapidly over the course of the study. PMID:24681366

Drake, Jennifer; Bradford, Andrea; Van Seters, Tim

2014-06-15

130

Analysis of Pavement for National Highway-N.H.1  

Directory of Open Access Journals (Sweden)

Full Text Available Rigid pavements are those which posses note worthy flexural strength or flexural rigidity. The stresses are not transferred from grain to grain to the lower layers as in the ease of flexible pavements layers the rigid pavements are made of Portland cement concrete-either plain, reinforced or prestressed concrete[1]. This paper shows the required to evaluate the strength characteristics of the soil subgrade, this helps the designer to adopt the suitable values of the strength parameter for design purposes and in case this supporting layer does not come upto the expectations, the same is treated or conditioned to suit the requirementsThe plain cement concrete slabs are expected to take up about 40 kg/cm2 flexural stress. As the rigid pavements slab has tensile strength, tensile stresses are developed due to the bending of the slab under wheel load and temperature variations thus the type of stress develop and their distribution within the cement concrete slab are quit different. The rigid pavement does not get deformed to the shape of the lower surface as it can bridge the minor variation of lower layer[2].

Arvind Dewangan

2012-02-01

131

Design of Rigid and Flexible Pavements by Various Methods & Their Cost Analysis of Each Method  

Directory of Open Access Journals (Sweden)

Full Text Available Highway and pavement design plays an important role in the DPR projects. The satisfactory performance of the pavement will result in higher savings in terms of vehicle operating costs and travel time, which has a bearing on the overall economic feasibility of the project. This paper discusses about the design methods that are traditionally being followed and examines the “Design of rigid and flexible pavements by various methods & their cost analysis by each method”. Flexible pavement are preferred over cement concrete roads as they have a great advantage that these can be strengthened and improved in stages with the growth of traffic and also their surfaces can be milled and recycled for rehabilitation. The flexible pavements are less expensive also with regard to initial investment and maintenance. Although Rigid pavement is expensive but have less maintenance and having good design period. The economic part are carried out for the design pavement of a section by using the result obtain by design method and their corresponding component layer thickness. It can be done by drawing comparisons with the standard way and practical way. This total work includes collection of data analysis various flexible and rigid pavement designs and their estimation procedure are very much useful to engineer who deals with highways.

Saurabh Jain

2013-09-01

132

Solar-reflective coating as a cooling overlay for asphalt pavement  

Science.gov (United States)

Rutting is one of the most serious problems on asphalt pavements. Decrease the surface temperature of the asphalt pavement is an effective method to solve the rutting problem on asphalt pavements. In this study, nano sized particles filled polymer composite was developed as an overlay to reflect the solar energy and decrease the surface temperature of asphalt pavements. The overlay was composed of acrylic or epoxy resin filled with nano TiO2 or nano TiNO2. The solar reflection of the nano particle filled polymers was tested and the results showed that solar reflection effectiveness of the epoxy/TiO2 composite reached the highest value. The results of outdoor temperature test indicate that the solar-reflective overlay could decrease the surface temperature of asphalt pavements about 10 °C when the pavement temperature is about 60 °C. Pavement skid resistance was also tested, which expressed by micro/macrotexture depth and the results of which showed that both matrix was qualified after coated with aggregates on the surface.

Wang, He; Xu, Geng; Feng, Decheng; Zhong, Jing; Xie, Ning

2012-04-01

133

Development of Performance Models for a Typical Flexible Road Pavement in Nigeria  

Directory of Open Access Journals (Sweden)

Full Text Available The results of a study conducted to facilitate the development of road pavement performance models that are appropriate for Nigeria and similar developing countries andcould predict the rate of deterioration over their lifespan have been presented. Comprehensive investigations were carried out on the expressway linking Lagos (the economic nerve centre of Nigeria with Ibadan (the largest city in West Africa - apparently one of the most heavily trafficked roads in the country. Data relating to traffic characteristics, pavement condition ratings, distress types, pavement thickness, roughness index, rainfall and temperature, were collected. Models were developed to determine Pavement Condition Score (PCS and International Roughness Index (IRI. Stepwise Regression was used to analyse the data and quantify the impact of key input parameters on the PCS and IRI. Parameters such as depth of ruts and area of pot holes were found to be statistically significant in predicting PCS while number of patches, length of longitudinal cracks and depth of ruts were statistically significant in predicting IRI. The models can be used for planning road maintenance programs, thus minimizing the need for comprehensive data collection on pavement condition before the maintenance exercise, which is costly and time consuming.

Adebayo Oladipo Owolabi

2012-09-01

134

Pervious Pavement System Evaluation-Poster  

Science.gov (United States)

Pervious pavement is a low impact development stormwater control. The Environmental Protection Agency's Urban Watershed Management Branch is evaluating interlocking concrete pavingstone pervious pavement systems. The pavingstones themselves are impermeable, but the spaces between...

135

Asphalt Pavement Deflection due to a Circular Load and Temperature Modified Coefficient  

Directory of Open Access Journals (Sweden)

Full Text Available This study proposed an approximate computation method of pavement deflection due to a circular and regression formulas among temperature modified coefficient to deflection, the average temperature of surface course and pavement structure parameters. Based on theoretical solution of pavement deflection which is beneath the center of the load due to a circular load applied on a homogeneous half-space, by introducing structure parameter modified coefficient &zeta, approximate computation method of pavement deflection due to a circular applied to a two-layer or multilayer pavement was given. Most regression formulas of temperature modified coefficient to deflection were dependent of testing data, we studied on influence factors of temperature modified coefficient to deflection from a theoretical view and then established an approximate formula among modified coefficient K, the average temperature of surface course T and pavement structure parameters are then established. The results show that temperature modified coefficient to deflection was dependent of the average temperature of surface course and pavement structure parameters. The calculation results using regression formulas in this study can be satisfied with engineering precision requirements.

Hu Honglong

2014-02-01

136

Generating enhanced site topography data to improve permeable pavement performance assessment methods - presentation  

Science.gov (United States)

Permeable pavement surfaces are infiltration based stormwater control measures (SCM) commonly applied in parking lots to decrease impervious area and reduce runoff volume. Many are not optimally designed however, as little attention is given to draining a large enough contributin...

137

Generation mechanisms of tire-pavement noise  

OpenAIRE

Tire-pavement noise is the dominant source of traffic noise at highway speeds. It is the result of a combination of several noise generation mechanisms, including tire carcass vibration and tread block vibration. Because multiple mechanisms are involved, it is difficult to predict the effects of changes in pavement parameters on tire-pavement noise. In this research, a set of experimental techniques were developed to decompose a measured tire-pavement noise spectrum into a set of constituent ...

Dare, Tyler P.

2012-01-01

138

High Performance Concrete Pavement in Indiana  

OpenAIRE

Until the early 1990s, curling and warping of Portland cement concrete pavement did not concern pavement engineers in many transportation agencies. Since beginning construction of the interstate system in the United States in the late 1950s through the late 1980s, the performance of Portland cement concrete pavement has been associated with properties of concrete as a pavement material. In those years developed standards and design guidelines emphasized better concrete materials and construct...

Nantung, Tommy E.

2011-01-01

139

Pavement thickness evaluation using ground penetrating radar  

OpenAIRE

Accurate knowledge of pavement thickness is important information to have both at a network and project level. This information aids in pavement management and design. Much of the time this information is missing, out of date, or unknown for highway sections. Current technologies for determining pavement thickness are core drilling, falling weight deflectometer (FWD), and ground penetrating radar (GPR). Core drilling provides very accurate pin point pavement thickness information; however, it...

Harris, Dwayne Arthur

2006-01-01

140

Reducing Your Cost for Asphalt Pavements  

OpenAIRE

This session will discuss of how local government decision-makers can achieve greater value without sacrificing quality or service life. The session will touch upon use of Higher Recycled Asphalt Pavement (RAP), Recycled Asphalt Shingles (RAS), Asphalt Mix Design for Heavy Traffic vs. Light Traffic, Speed of Construction, Perpetual Pavement and Pavement Rehabilitation Strategies.

Evans, Alvin

2012-01-01

141

Making "Magic" Sidewalks of Pervious Pavement  

Science.gov (United States)

Students use everyday building materials—sand, pea gravel, cement and water—to create and test pervious pavement. They learn what materials make up a traditional, impervious concrete mix and how pervious pavement mixes differ. Groups are challenged to create their own pervious pavement mixes, experimenting with material ratios to evaluate how infiltration rates change with different mix combinations.

Water Awareness Research and Education (WARE) Research Experience for Teachers (RET),

142

Pavement Subgrade Performance Study in the Danish Road Testing Machine  

DEFF Research Database (Denmark)

Most existing pavement subgrade criteria are based on the AASHO Road Test, where only one material was tested and for only one climatic condition. To study the validity of these criteria and to refine the criteria a co-operative research program entitled the "International Pavement Subgrade Performance Study" was sponsored by the FHWA with American, Finnish and Danish partners. This paper describes the first test series which was carried out in the Danish Road Testing Machine (RTM).The first step in this program is a full scale test on an instrumented pavement in the Danish Road Testing Machine. Pressure gauges and strain cells were installed in the upper part of the subgrade, for measuring stresses and strains in all three directions. During and after construction FWD testing was carried out to evaluate the elastic parameters of the materials. These parameters were then used with the theory of elasticity to calculate the stresses and strains at the position of the gauges and to compare these values to the stresses and strains recorded under the rolling wheel load.Plastic strains resulting from 50 000 applications of each of two load levels (20 kN and 40 kN) were recorded, as well as the permanent deformation of the pavement surface. A simple model describing the plastic strain has been developed.The test showed that currently used subgrade strain criteria are conservative if used with the measured strains in the subgrade. If used with strains calculated from FWD tests using linear elastic theory, however, the strain criteria seem to give a reasonably good prediction of the bearing capacity of the pavement.The differences between measured and theoretical values appear to be due to inhomogeneities in the pavement, to the non-linear elastic subgrade modulus and to a modulus gradient in the subgrade.

Ullidtz, Per; Ertman Larsen, Hans JØrgen

1997-01-01

143

Texture and noise features for road pavement identification and classification  

OpenAIRE

Road planners and road administrators frequently face the problem of insufficient knowledge of the correlation between the type of road surface and the resulting noise emission. The aim of this research is to establish the relationship between road surface characteristics, such as macrotexture, and tire/pavement noise emission, in order to identify and classify road surfaces by using statistical learning methods, which is a non-destructive approach. For this purpose, several road sections wit...

Paulo, Joel; Freitas, Elisabete F.; Coelho, J. L. Bento

2010-01-01

144

Geo synthetic-reinforced Pavement systems  

International Nuclear Information System (INIS)

Geo synthetics have been used as reinforcement inclusions to improve pavement performance. while there are clear field evidence of the benefit of using geo synthetic reinforcements, the specific conditions or mechanisms that govern the reinforcement of pavements are, at best, unclear and have remained largely unmeasured. Significant research has been recently conducted with the objectives of: (i) determining the relevant properties of geo synthetics that contribute to the enhanced performance of pavement systems, (ii) developing appropriate analytical, laboratory and field methods capable of quantifying the pavement performance, and (iii) enabling the prediction of pavement performance as a function of the properties of the various types of geo synthetics. (Author)

145

Comparative Study on Pavement Temperature Features of Bridge Deck and Road Pavement  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this study was to comparatively analyze the difference of pavement temperature of bride deck and road pavement. The asphalt pavement temperature of road pavement and bride deck were tested in Guozigou area of Xinjiang, China. And the air temperature, wind speed, humidness and sunlight radiation were collected. Further, the distribution features of asphalt pavement of bridge deck and road pavement were comparatively analyzed. At last, the predictive model of pavement temperature field for bridge deck and road pavement was set up. The results show that the pavement temperature and air temperature change synchronously. The pavement temperature of bridge deck is usually 66~13ºC higher than the air temperature and keeps close to it in winter. Compared with road pavement temperature, the temperature of bridge deck is characterized by being higher lowest-temperatures in winter, greater in temperature changes and lasting for longer time when it keeps its high temperature in summer. The predictive model of pavement temperature field for bridge deck and road pavement is proposed utilized linear function with five factors, namely air temperature, wind speed, humidness, sunlight radiation and pavement depth. The developed model was proved to be more accurate and closer to the measured temperature compared with LTPP and SHRP model.

Yueqin Hou

2013-12-01

146

ICP experiments more durable pavements  

International Nuclear Information System (INIS)

A new asphalts technology that will make more durable the pavement in the highways and roads of the cities of Colombia investigates the Colombian Institute of the Petroleum ICP. The project that will have important incidence in the solution of one of the main problems in the roads of cities like Bogota, is only one of the 35 investigation programs and application of new technologies that with relationship to the sector of the hydrocarbons and its influence branches the ICP advances. The investigation looks for to elevate the current average of useful life of the pavements, with that it would be reached a standard that has the developed countries in this field

147

Superfícies estriadas no embasamento granítico e vestígio de pavimento de clastos neopaleozóicos na região de Salto, SP Neopaleozoic striated surfaces in the granitic basement and clast pavement remains of Salto, SP  

Directory of Open Access Journals (Sweden)

Full Text Available Nas proximidades da Cerâmica Guaraú, localizada a sudoeste da cidade de Salto, Estado de São Paulo, dois afloramentos de granito, distantes algumas dezenas de metros um do outro, exibem superfícies estriadas neopaleozóicas. Essas superfícies estão em contato com diamictitos do Subgrupo Itararé. As estrias correspondem a sulcos subparalelos com espaçamento e profundidade milimétrica, possuindo uma direção média de N48°W e mergulhos variando entre 12° e 42° para SE. As feições observadas e a sua associação com diamictitos indicam uma origem por abrasão glacial devido ao movimento de massas de gelo de sudeste para noroeste. A aproximadamente 1,8 km a este da cidade de Salto foi encontrado, no topo de afloramentos de granito, material inconsolidado contendo abundantes clastos de quartzito facetados e estriados. Esses clastos foram interpretados como vestígios de um pavimento de castos.Near Guaraú Ceramic, localized southwest of Salto city in the State of São Paulo, two granite outcrops, distant some tens of meters from each other, display Neopaleozoic striated surfaces. These surfaces are in contact with diamictites from the Itararé Subgroup. The striae correspond to sub parallel grooves with millimetric spacing and depth, oriented about N48E and dipping 12° to 42° towards SE. Observed features and association with diamictites indicate an origin by glacial abrasion due to ice movement from southeast towards northwest. About 1.8 km east of Salto, unconsolidated material containing flat-iron-shaped and striated clasts was found on top of granite outcrops, interpreted as clast pavement remains.

Annabel Pérez-Aguilar

2009-03-01

148

The Concrete and Pavement Challenge  

Science.gov (United States)

The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as…

Roman, Harry T.

2012-01-01

149

Cooler reflective pavements give benefits beyond energy savings: durability and illumination  

Energy Technology Data Exchange (ETDEWEB)

City streets are usually paved with asphalt concrete because this material gives good service and is relatively inexpensive to construct and maintain. We show that making asphalt pavements cooler, by increasing their reflection of sunlight, may lead to longer lifetime of the pavement, lower initial costs of the asphalt binder, and savings on street lighting and signs. Excessive glare due to the whiter surface is not likely to be a problem.

Pomerantz, Melvin; Akbari, Hashem; Harvey, John T.

2000-06-01

150

Cooler reflective pavements give benefits beyond energy savings: durability and illumination  

International Nuclear Information System (INIS)

City streets are usually paved with asphalt concrete because this material gives good service and is relatively inexpensive to construct and maintain. We show that making asphalt pavements cooler, by increasing their reflection of sunlight, may lead to longer lifetime of the pavement, lower initial costs of the asphalt binder, and savings on street lighting and signs. Excessive glare due to the whiter surface is not likely to be a problem

151

Adaptive Road Crack Detection System by Pavement Classification  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a road distress detection system involving the phases needed to properly deal with fully automatic road distress assessment. A vehicle equipped with line scan cameras, laser illumination and acquisition HW-SW is used to storage the digital images that will be further processed to identify road cracks. Pre-processing is firstly carried out to both smooth the texture and enhance the linear features. Non-crack features detection is then applied to mask areas of the images with joints, sealed cracks and white painting, that usually generate false positive cracking. A seed-based approach is proposed to deal with road crack detection, combining Multiple Directional Non-Minimum Suppression (MDNMS with a symmetry check. Seeds are linked by computing the paths with the lowest cost that meet the symmetry restrictions. The whole detection process involves the use of several parameters. A correct setting becomes essential to get optimal results without manual intervention. A fully automatic approach by means of a linear SVM-based classifier ensemble able to distinguish between up to 10 different types of pavement that appear in the Spanish roads is proposed. The optimal feature vector includes different texture-based features. The parameters are then tuned depending on the output provided by the classifier. Regarding non-crack features detection, results show that the introduction of such module reduces the impact of false positives due to non-crack features up to a factor of 2. In addition, the observed performance of the crack detection system is significantly boosted by adapting the parameters to the type of pavement.

Alejandro Amírola

2011-10-01

152

Adaptive road crack detection system by pavement classification.  

Science.gov (United States)

This paper presents a road distress detection system involving the phases needed to properly deal with fully automatic road distress assessment. A vehicle equipped with line scan cameras, laser illumination and acquisition HW-SW is used to storage the digital images that will be further processed to identify road cracks. Pre-processing is firstly carried out to both smooth the texture and enhance the linear features. Non-crack features detection is then applied to mask areas of the images with joints, sealed cracks and white painting, that usually generate false positive cracking. A seed-based approach is proposed to deal with road crack detection, combining Multiple Directional Non-Minimum Suppression (MDNMS) with a symmetry check. Seeds are linked by computing the paths with the lowest cost that meet the symmetry restrictions. The whole detection process involves the use of several parameters. A correct setting becomes essential to get optimal results without manual intervention. A fully automatic approach by means of a linear SVM-based classifier ensemble able to distinguish between up to 10 different types of pavement that appear in the Spanish roads is proposed. The optimal feature vector includes different texture-based features. The parameters are then tuned depending on the output provided by the classifier. Regarding non-crack features detection, results show that the introduction of such module reduces the impact of false positives due to non-crack features up to a factor of 2. In addition, the observed performance of the crack detection system is significantly boosted by adapting the parameters to the type of pavement. PMID:22163717

Gavilán, Miguel; Balcones, David; Marcos, Oscar; Llorca, David F; Sotelo, Miguel A; Parra, Ignacio; Ocaña, Manuel; Aliseda, Pedro; Yarza, Pedro; Amírola, Alejandro

2011-01-01

153

Preliminary evaluation of the lifecycle costs and market barriers of reflective pavements; TOPICAL  

International Nuclear Information System (INIS)

The objective of this study is to evaluate the life cycle costs and market barriers associated with using reflective paving materials in streets and parking lots as a way to reduce the urban heat island effect. We calculated and compared the life cycle costs of conventional asphalt concrete (AC) pavements to those of other existing pavement technologies with higher reflectivity-portland cement concrete (PCC), porous pavements, resin pavements, AC pavements using light-colored chip seals, and AC pavements using light-colored asphalt emulsion additives. We found that for streets and parking lots, PCC can provide a cost-effective alternative to conventional AC when severely damaged pavements must be completely reconstructed. We also found that rehabilitating damaged AC streets and intersections with thin overlays of PCC (ultra-thin white topping) can often provide a cost-effective alternative to standard rehabilitation techniques using conventional AC. Chip sealing is a common maintenance treatment for low-volume streets which, when applied using light-colored chips, could provide a reflective pavement surface. If the incremental cost of using light-colored chips is low, this chip sealing method could also be cost-effective, but the incremental costs of light-colored chips are as of yet uncertain and expected to vary. Porous pavements were found to have higher life cycle costs than conventional AC in parking lots, but several cost-saving features of porous pavements fellt-saving features of porous pavements fell outside the boundaries of this study. Resin pavements were found to be only slightly more expensive than conventional AC, but the uncertainties in the cost and performance data were large. The use of light-colored additives in asphalt emulsion seal coats for parking lot pavements was found to be significantly more expensive than conventional AC, reflecting its current niche market of decorative applications. We also proposed two additional approaches to increasing the reflectivity of conventional AC, which we call the chipping and aggregate methods, and calculated their potential life cycle costs. By analyzing the potential for increased pavement durability resulting from these conceptual approaches, we then estimated the incremental costs that would allow them to be cost-effective compared to conventional AC. For our example case of Los Angeles, we found that those allowable incremental costs range from less than dollar 1 to more than dollar 11 per square yard (dollar 1 to dollar 13 per square meter) depending on street type and the condition of the original pavement. Finally, we evaluated the main actors in the pavement market and the existing and potential market barriers associated with reflective pavements. Apart from situations where lifecycle costs are high compared to conventional AC, all reflective paving technologies face a cultural barrier based on the belief that black is better. For PCC, high first costs were found to be the most significant economic barrier, particularly where agencies are cons trained by first cost. Lack of developer standards was found to be a significant institutional barrier to PCC since developers are often not held accountable for the long-term maintenance of roads after initial construction, which creates a misplaced incentive to build low first-cost pavements. PCC also faces site-specific barriers such as poorly compacted base soils and proximity to areas of frequent utility cutting

154

Effects of thermal properties on temperature and moisture profiles and the performance of PCC pavements  

Directory of Open Access Journals (Sweden)

Full Text Available To understand the effects of thermal properties on temperature and the moisture profile in Portland cement concrete (PCC pavements, an Enhanced Integrated Climatic Model (EICM analysis was performed for a typical PCC pavement section in Louisiana. The EICM analysis showed that the temperature in the middle layer of PCC pavement decreased as thermal conductivity increased, and the temperature remained constant for higher thermal conductivity values. Temperature was measured at several depths of a concrete block embedded in soil and was compared to the temperature profile predicted by the EICM. Measured temperatures inside the concrete block were higher than the temperatures predicted by the EICM. The measured temperatures reached a peak hour temperature gradient on the hottest time of day, but the EICM model did not predict the peak hour temperature gradient. MEPDG analysis was performed to estimate the effect of thermal properties on the distress of PCC pavements. From the analysis it was found that thermal cracking increased with the decrease of thermal conductivity. It was also noticed that an Integrated Climatic Model (ICM stability failure occurred for a set of thermal conductivity and heat capacity readings in the MEPDG analysis. A passing line is proposed to separate the ICM stability passing zone and failure zone.

Upender Kodide M.S.

2011-12-01

155

Removable Urban Pavements: An innovative, sustainable technology  

OpenAIRE

Removable Urban Pavements: An innovative, sustainable technology By definition, a Removable Urban Pavement (RUP) can be quickly opened and closed, using lightweight equipment, for easy access to underground networks. While no such pavement appears to have ever been constructed, the premises of the concept can be found in certain military paths or industrial soils. A survey conducted among French municipal authorities has revealed the potential benefit of the RUP concept in decreasing the publ...

Larrard, Franc?ois; Sedran, Thierry; Balay, Jean Maurice

2012-01-01

156

DESIGN OF PAVEMENTS REINFORCED WITH GEOGRID  

OpenAIRE

This work includes a selection of most suitable compound of pavement construction at regional road section R3-682/1441 Loke – Ledinš?ica from km 8+200 to 10+080 and describes comparison of structural design of pavement construction with and without geogrid. Pavement construction is designed under the basic design requirements as traffic loads, quality of materials, hydrologic and climatic circumstances. Following that are described geosynthetics and comparative analysis of structural desi...

Pajk, Primoz?

2009-01-01

157

Flexible pavement drainage monitoring, performance and stability  

OpenAIRE

Pavement subsurface drainage is increasingly included in pavement designs. Typically, the subdrainage components consist of a drainage layer, edge collection system and outlet. Questions have developed relative to use of bound and unbound aggregate in the drainage layers as well as drainage layer location within the section. ^ The current study is a continuation of the study HPR-2078, “Locating the Drainage Layer for Flexible Pavements”. In this previous study, three test sections were ...

Feng, Aiwen

1999-01-01

158

Comparative field permeability measurement of permeable pavements using ASTM C1701 and NCAT permeameter methods.  

Science.gov (United States)

Fully permeable pavement is gradually gaining support as an alternative best management practice (BMP) for stormwater runoff management. As the use of these pavements increases, a definitive test method is needed to measure hydraulic performance and to evaluate clogging, both for performance studies and for assessment of permeability for construction quality assurance and maintenance needs assessment. Two of the most commonly used permeability measurement tests for porous asphalt and pervious concrete are the National Center for Asphalt Technology (NCAT) permeameter and ASTM C1701, respectively. This study was undertaken to compare measured values for both methods in the field on a variety of permeable pavements used in current practice. The field measurements were performed using six experimental section designs with different permeable pavement surface types including pervious concrete, porous asphalt and permeable interlocking concrete pavers. Multiple measurements were performed at five locations on each pavement test section. The results showed that: (i) silicone gel is a superior sealing material to prevent water leakage compared with conventional plumbing putty; (ii) both methods (NCAT and ASTM) can effectively be used to measure the permeability of all pavement types and the surface material type will not impact the measurement precision; (iii) the permeability values measured with the ASTM method were 50-90% (75% on average) lower than those measured with the NCAT method; (iv) the larger permeameter cylinder diameter used in the ASTM method improved the reliability and reduced the variability of the measured permeability. PMID:23434738

Li, Hui; Kayhanian, Masoud; Harvey, John T

2013-03-30

159

Preliminary evaluation of the lifecycle costs and market barriers of reflective pavements  

Energy Technology Data Exchange (ETDEWEB)

The objective of this study is to evaluate the life cycle costs and market barriers associated with using reflective paving materials in streets and parking lots as a way to reduce the urban heat island effect. We calculated and compared the life cycle costs of conventional asphalt concrete (AC) pavements to those of other existing pavement technologies with higher reflectivity-portland cement concrete (PCC), porous pavements, resin pavements, AC pavements using light-colored chip seals, and AC pavements using light-colored asphalt emulsion additives. We found that for streets and parking lots, PCC can provide a cost-effective alternative to conventional AC when severely damaged pavements must be completely reconstructed. We also found that rehabilitating damaged AC streets and intersections with thin overlays of PCC (ultra-thin white topping) can often provide a cost-effective alternative to standard rehabilitation techniques using conventional AC. Chip sealing is a common maintenance treatment for low-volume streets which, when applied using light-colored chips, could provide a reflective pavement surface. If the incremental cost of using light-colored chips is low, this chip sealing method could also be cost-effective, but the incremental costs of light-colored chips are as of yet uncertain and expected to vary. Porous pavements were found to have higher life cycle costs than conventional AC in parking lots, but several cost-saving features of porous pavements fell outside the boundaries of this study. Resin pavements were found to be only slightly more expensive than conventional AC, but the uncertainties in the cost and performance data were large. The use of light-colored additives in asphalt emulsion seal coats for parking lot pavements was found to be significantly more expensive than conventional AC, reflecting its current niche market of decorative applications. We also proposed two additional approaches to increasing the reflectivity of conventional AC, which we call the chipping and aggregate methods, and calculated their potential life cycle costs. By analyzing the potential for increased pavement durability resulting from these conceptual approaches, we then estimated the incremental costs that would allow them to be cost-effective compared to conventional AC. For our example case of Los Angeles, we found that those allowable incremental costs range from less than dollar 1 to more than dollar 11 per square yard (dollar 1 to dollar 13 per square meter) depending on street type and the condition of the original pavement. Finally, we evaluated the main actors in the pavement market and the existing and potential market barriers associated with reflective pavements. Apart from situations where lifecycle costs are high compared to conventional AC, all reflective paving technologies face a cultural barrier based on the belief that black is better. For PCC, high first costs were found to be the most significant economic barrier, particularly where agencies are cons trained by first cost. Lack of developer standards was found to be a significant institutional barrier to PCC since developers are often not held accountable for the long-term maintenance of roads after initial construction, which creates a misplaced incentive to build low first-cost pavements. PCC also faces site-specific barriers such as poorly compacted base soils and proximity to areas of frequent utility cutting.

Ting, M.; Koomey, J.G.; Pomerantz, M.

2001-11-21

160

Superfícies estriadas no embasamento granítico e vestígio de pavimento de clastos neopaleozóicos na região de Salto, SP / Neopaleozoic striated surfaces in the granitic basement and clast pavement remains of Salto, SP  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Nas proximidades da Cerâmica Guaraú, localizada a sudoeste da cidade de Salto, Estado de São Paulo, dois afloramentos de granito, distantes algumas dezenas de metros um do outro, exibem superfícies estriadas neopaleozóicas. Essas superfícies estão em contato com diamictitos do Subgrupo Itararé. As e [...] strias correspondem a sulcos subparalelos com espaçamento e profundidade milimétrica, possuindo uma direção média de N48°W e mergulhos variando entre 12° e 42° para SE. As feições observadas e a sua associação com diamictitos indicam uma origem por abrasão glacial devido ao movimento de massas de gelo de sudeste para noroeste. A aproximadamente 1,8 km a este da cidade de Salto foi encontrado, no topo de afloramentos de granito, material inconsolidado contendo abundantes clastos de quartzito facetados e estriados. Esses clastos foram interpretados como vestígios de um pavimento de castos. Abstract in english Near Guaraú Ceramic, localized southwest of Salto city in the State of São Paulo, two granite outcrops, distant some tens of meters from each other, display Neopaleozoic striated surfaces. These surfaces are in contact with diamictites from the Itararé Subgroup. The striae correspond to sub parallel [...] grooves with millimetric spacing and depth, oriented about N48E and dipping 12° to 42° towards SE. Observed features and association with diamictites indicate an origin by glacial abrasion due to ice movement from southeast towards northwest. About 1.8 km east of Salto, unconsolidated material containing flat-iron-shaped and striated clasts was found on top of granite outcrops, interpreted as clast pavement remains.

Annabel, Pérez-Aguilar; Setembrino, Petri; Rafhael, Hypólito; Sibele, Ezaki; Paulo Alves de, Souza; Caetano, Juliani; Lena V.S., Monteiro; Francisco A., Moschini.

2009-03-01

161

Study of the Effect of Temperature Changes on the Elastic Modulus of Flexible Pavement Layers  

Directory of Open Access Journals (Sweden)

Full Text Available In general, the stiffness of flexible pavement is influenced by environmental changes, whereby temperature and rainfall affect the asphalt layer and non-asphalt layer, such as the subgrade, respectively. Normally, the effect of temperature on flexible pavement can be measured using two methods. The first is a destructive test whereby core samples are tested in a laboratory using a Universal Testing Machine (UTM. The second is a non-destructive in situ test using equipment such as a Falling Weight Deflectometer (FWD and Spectral Analysis of Surface Waves (SASW. This study was conducted to investigate the effect of temperature at different tensile levels on the Soekarno-Hatta and Purwakarta Cikampek roads in Bandung, West Java, Indonesia. It is observed that different tensile levels and testing methods result in various elastic modulus values of flexible pavement. The higher the temperature applied to the flexible pavement layer, the more the elastic modulus values decrease. In contrast, the lower the temperature imposed on the flexible pavement layer, the more the elastic modulus values increase. Different testing methods (FWD, UTM and SASW on the flexible pavement layer are also affected by temperature changes.

Mohd Raihan Taha

2013-02-01

162

Pervious Pavement System Evaluation-Paper  

Science.gov (United States)

The use of a pervious pavement can be effective as a low impact development stormwater control. The Urban Watershed Management Branch is evaluating interlocking concrete paver systems as a type of porous pavement. Although the pavers are impermeable, the spaces between the pave...

163

Road Asphalt Pavements Analyzed by Airborne Thermal Remote Sensing: Preliminary Results of the Venice Highway  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes a fast procedure for evaluating asphalt pavement surface defects using airborne emissivity data. To develop this procedure, we used airborne multispectral emissivity data covering an urban test area close to Venice (Italy.For this study, we first identify and select the roads’ asphalt pavements on Multispectral Infrared Visible Imaging Spectrometer (MIVIS imagery using a segmentation procedure. Next, since in asphalt pavements the surface defects are strictly related to the decrease of oily components that cause an increase of the abundance of surfacing limestone, the diagnostic absorption emissivity peak at 11.2μm of the limestone was used for retrieving from MIVIS emissivity data the areas exhibiting defects on asphalt pavements surface.The results showed that MIVIS emissivity allows establishing a threshold that points out those asphalt road sites on which a check for a maintenance intervention is required. Therefore, this technique can supply local government authorities an efficient, rapid and repeatable road mapping procedure providing the location of the asphalt pavements to be checked.

Rosa Cavalli

2008-02-01

164

Pavement Crack Detection Using Spectral Clustering Method  

Directory of Open Access Journals (Sweden)

Full Text Available Pavement crack detection plays an important role in pavement maintaining and management, nowadays, which could be performed through remote image analysis. Thus, edges of pavement crack should be extracted in advance; in general, traditional edge detection methods don’t consider phase information and the spatial relationship between the adjacent image areas to extract the edges. To overcome the deficiency of the traditional approaches, this paper proposes a pavement crack detection algorithm based on spectral clustering method. Firstly, a measure of similarity between pairs of pixels is taken into account through orientation energy. Then, spatial relationship is needed to find regions where similarity between pixels in a given region is high and similarity between pixels in different regions is low. After that, crack edge detection is completed with spectral clustering method. The presented method has been run on some real life images of pavement crack, experimental results display that the crack detection method of this paper could obtain ideal result.

Jin Huazhong

2015-01-01

165

Using Precast Concrete Panels for Pavement Construction in Indiana  

OpenAIRE

The closure of roadways for new pavement, overlays, or removal and replacement applications constantly causes traffic congestions. To minimize the effects of traffic congestions, the study is intended to assess the feasibility of using Precsat Concrete Pavement (PCP) method in INDOT pavement construction. The research investigated the state-of-the-art of the PCP methods lately developed in United States. The conventional concrete pavement methods such as Portland Cement Concrete Pavement (PCC...

Chang, Luh M.; Chen, Yu-tzu; Lee, Sangwook

2004-01-01

166

Application of the portable pavement seismic analyser (PSPA) for pavement analysis  

OpenAIRE

Paper presented at the 26th Annual Southern African Transport Conference 9 - 12 July 2007 "The challenges of implementing policy?", CSIR International Convention Centre, Pretoria, South Africa. ABSTRACT:The Portable Seismic Pavement Analyser (PSPA) is a non-destructive device used for the evaluation of the seismic stiffness of a pavement structure. The device can be used to obtain basic information on the condition of the pavement structure, including parameters such as the seismic stiffness ...

Steyn, Wynand J. Vdm; Sadzik, E.

2007-01-01

167

Thermal Stability Analysis under Embankment with Asphalt Pavement and Cement Pavement in Permafrost Regions  

OpenAIRE

The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The max...

Zhang Junwei; Li Jinping; Quan Xiaojuan

2013-01-01

168

Global warming potential of pavements  

Energy Technology Data Exchange (ETDEWEB)

Pavements comprise an essential and vast infrastructure system supporting our transportation network, yet their impact on the environment is largely unquantified. Previous life-cycle assessments have only included a limited number of the applicable life-cycle components in their analysis. This research expands the current view to include eight different components: materials extraction and production, transportation, onsite equipment, traffic delay, carbonation, lighting, albedo, and rolling resistance. Using global warming potential as the environmental indicator, ranges of potential impact for each component are calculated and compared based on the information uncovered in the existing research. The relative impacts between components are found to be orders of magnitude different in some cases. Context-related factors, such as traffic level and location, are also important elements affecting the impacts of a given component. A strategic method for lowering the global warming potential of a pavement is developed based on the concept that environmental performance is improved most effectively by focusing on components with high impact potentials. This system takes advantage of the fact that small changes in high-impact components will have more effect than large changes in low-impact components.

Santero, Nicholas J [Department of Civil and Environmental Engineering, 407 McLaughlin Hall, University of California, Berkeley, CA 94720-1712 (United States); Horvath, Arpad, E-mail: njsantero@cal.berkeley.ed, E-mail: horvath@ce.berkeley.ed [Department of Civil and Environmental Engineering, 215B McLaughlin Hall, University of California, Berkeley, CA 94720-1712 (United States)

2009-09-15

169

Global warming potential of pavements  

International Nuclear Information System (INIS)

Pavements comprise an essential and vast infrastructure system supporting our transportation network, yet their impact on the environment is largely unquantified. Previous life-cycle assessments have only included a limited number of the applicable life-cycle components in their analysis. This research expands the current view to include eight different components: materials extraction and production, transportation, onsite equipment, traffic delay, carbonation, lighting, albedo, and rolling resistance. Using global warming potential as the environmental indicator, ranges of potential impact for each component are calculated and compared based on the information uncovered in the existing research. The relative impacts between components are found to be orders of magnitude different in some cases. Context-related factors, such as traffic level and location, are also important elements affecting the impacts of a given component. A strategic method for lowering the global warming potential of a pavement is developed based on the concept that environmental performance is improved most effectively by focusing on components with high impact potentials. This system takes advantage of the fact that small changes in high-impact components will have more effect than large changes in low-impact components.

170

Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement  

Science.gov (United States)

Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, are a potential source of volatile PAHs to the atmosphere. An initial assessment of volatilization of PAHs from coal-tar-sealed pavement is presented here in which we measured summertime gas-phase PAH concentrations 0.03 m and 1.28 m above the pavement surface of seven sealed (six with coal-tar-based sealant and one with asphalt-based sealant) and three unsealed (two asphalt and one concrete) parking lots in central Texas. PAHs also were measured in parking lot dust. The geometric mean concentration of the sum of eight frequently detected PAHs (?PAH8) in the 0.03-m samples above sealed lots (1320 ng m-3) during the hottest part of the day was 20 times greater than that above unsealed lots (66.5 ng m-3). The geometric mean concentration in the 1.28-m samples above sealed lots (138 ng m-3) was five times greater than above unsealed lots (26.0 ng m-3). Estimated PAH flux from the sealed lots was 60 times greater than that from unsealed lots (geometric means of 88 and 1.4 ?g m-2 h-1, respectively). Although the data set presented here is small, the much higher estimated fluxes from sealed pavement than from unsealed pavement indicate that coal-tar-based sealants are emitting PAHs to urban air at high rates compared to other paved surfaces.

Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

2012-01-01

171

Modelación del envejecimiento de los pavimentos asfálticos con la metodología de la superficie de respuesta / Pavement Aging Model by Response Surface Modeling  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish En la presente investigación se realizó la modelación del envejecimiento de una carpeta asfáltica por medio de la Metodología de Superficie de Respuesta (MSR). Se elaboraron muestras cilíndricas tipo Marshall, que fueron colocadas en un horno bajo las condiciones de tiempo y temperatura establecidos [...] por las condiciones ambientales de la región geográfica donde se construyen pavimentos asfálticos con el AC-20 de la Refinería Ing. Antonio M. Amor, los cuales fueron codificados en la MSR, con esto se determinaron los modelos que predicen el cambio de la estabilidad Marshall (?L) y del flujo (?F), así como la volatilización del material (VM). Además, se extrajeron muestras cilíndricas de una carpeta asfáltica piloto para determinar el error de modelación, observando que el material volatilizado predicho por el modelo VM fue muy cercano al real, no así para los modelos de ?Ly ?F, posiblemente asociado a los factores ambientales que no fueron considerados al inicio de la investigación. Abstract in english In this work, surface course aging was modeled by Response Surface Methodology (RSM). The Marshall specimens were placed in a conventional oven for time and temperature conditions established on the basis of the environment factors of the region where the surface course is constructed by AC-20 from [...] the Ing. Antonio M. Amor refinery. Volatilized material (VM), load resistance increment (?L) and flow resistance increment (?F) models were developed by the RSM. Cylindrical specimens with real aging were extracted from the surface course pilot to evaluate the error of the models. The VM model was adequate, in contrast (?L) and (?F) models were almost adequate with an error of 20 %, that was associated with the other environmental factors, which were not considered at the beginning of the research.

L.E., Chávez-Valencia; C, Hernández-Barriga; A, Manzano-Ramírez.

2011-12-01

172

Validation Study of a Distress Screener  

OpenAIRE

Objectives A 3-item screening instrument called the Distress Screener was developed for early identification of distress among employees on sick leave. The Distress Screener consists of three items obtained from the distress subscale of the four-dimensional symptom questionnaire (4DSQ). This study assessed an optimal cut-off point and validated the Distress Screener by relating it to the 4DSQ and to medical diagnoses. Methods 171 sick-listed employees filled in the Distress Screener and the 4...

Braam, C.; Oostrom, S. H.; Terluin, B.; Vasse, R.; Vet, H. C. W.; Anema, J. R.

2009-01-01

173

Nonlinear Responses of a Two Dimensional Vehicle-pavement System  

Directory of Open Access Journals (Sweden)

Full Text Available The vehicle and pavement are usually investigated separately in vehicle dynamics and pavement dynamics. In this work, a new research scheme is proposed to link the vehicle and pavement model by tire loads and compute the nonlinear dynamic responses by analytical methods. A two-DOF nonlinear vehicle and a Bernoulli-Euler beam on a nonlinear elastic foundation with two simply supported ends compose the nonlinear vehicle-pavement system. The nonlinear tire loads are analytically gained using the averaging method. Then the nonlinear vibration equation of the pavement is obtained using Galerkin method and solved using the multiple scales method. The theoretical solutions are verified by numerical results and the effects of system parameters on pavement vibration are also studied. It is found that the pavement responses excited by tire loads attenuate quickly and small pavement mass, large foundation damping or foundation stiffness may decrease the pavement vibration.

Shaohua Li

2013-09-01

174

Modelling Flexible Pavement Response and Performance  

DEFF Research Database (Denmark)

This textbook is primarily concerned with models for predicting the future condition of flexible pavements, as a function of traffic loading, climate, materials, etc., using analytical-empirical methods.

Ullidtz, Per

1998-01-01

175

Distress or no distress, that's the question: A cutoff point for distress in a working population  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The objective of the present study is to establish an optimal cutoff point for distress measured with the corresponding scale of the 4DSQ, using the prediction of sickness absence as a criterion. The cutoff point should result in a measure that can be used as a credible selection instrument for sickness absence in occupational health practice and in future studies on distress and mental disorders. Methods Distress is measured using the Four Dimensional Symptom Questionnaire (4DSQ, a 50-item self-report questionnaire, in a working population with and without sickness absence due to distress. Sensitivity and specificity were compared for various potential cutoff points, and a receiver operating characteristics analysis was conducted. Results and conclusion A distress cutoff point of ?11 was defined. The choice was based on a challenging specificity and negative predictive value and indicates a distress level at which an employee is presumably at risk for subsequent sick leave on psychological grounds. The defined distress cutoff point is appropriate for use in occupational health practice and in studies of distress in working populations.

Schaufeli Wilmar B

2008-01-01

176

[Acute respiratory distress syndrome].  

Science.gov (United States)

Acute respiratory distress syndrome (ARDS) is a permeability pulmonary edema due to lung injury from various causes. In 2012, a new definition, taking into account the degree of hypoxemia and the level of positive end-expiratory pressure (PEEP), was published. In addition to progress in the support of organ failures in intensive care, mortality in patients suffering from ARDS has decreased significantly. This improved prognosis is also due to the advent of protective mechanical ventilation that has limited ventilator-induced lung injury (VILI). The treatment of ARDS consists on causative treatment and a strategy of protective ventilation associated with a PEEP level between 10 and 15 cm H20 and the use of prone position or inhaled nitric oxide in the severest cases. The role of extracorporeal membrane oxygenation as adjuvant therapy in ARDS remains unclear. PMID:23272466

Gaudry, Stéphane; Ricard, Jean-Damien; Dreyfuss, Didier

2012-11-01

177

A model for pavement temperature prediction  

OpenAIRE

A finite element model has been developed to calculate the temperature of a pavement located in the Northeast of Portugal. The goal of the case study presented in this paper is the validation of this model. Input data to the model are the hourly values for solar radiation and temperature, and mean daily values of wind speed obtained from a meteorological station. The thermal response of a multilayered pavement structure is modeled using a transient thermal analysis for four months...

Minhoto, Manuel; Pais, Jorge; Pereira, Paulo

2005-01-01

178

Technical and Economic Sustainability of Concrete Pavements  

OpenAIRE

Economic evaluation of road pavements is as important as their technical and structural design: often only initial construction costs are calculated to assess economic project sustainability. Instead, forgetting maintenance costs exposes society to unacceptable risks of expensive and incorrect decisions. Road pavements design and construction solutions affect maintenance works during service life, which not only entail economical and financial expenditures, but also damage service r...

Laura Moretti

2014-01-01

179

Pavement Crack Detection Using Computer Vision  

OpenAIRE

This thesis describes new methods for automatic crack detection in pavements. Cracks in pavements can be used as an early indication for the need of reparation. Automatic crack detection is preferable compared to manual inventory; the repeatability can be better, the inventory can be done at a higher speed and can be done without interruption of the traffic. The automatic and semi-automatic crack detection systems that exist today use Image Analysis methods. There are today powerful methods a...

Ha?kansson, Staffan

2005-01-01

180

Multiresolution texture analysis applied to road surface inspection  

Science.gov (United States)

Technological advances provide now the opportunity to automate the pavement distress assessment. This paper deals with an approach for achieving an automatic vision system for road surface classification. Road surfaces are composed of aggregates, which have a particular grain size distribution and a mortar matrix. From various physical properties and visual aspects, four road families are generated. We present here a tool using a pyramidal process with the assumption that regions or objects in an image rise up because of their uniform texture. Note that the aim is not to compute another statistical parameter but to include usual criteria in our method. In fact, the road surface classification uses a multiresolution cooccurrence matrix and a hierarchical process through an original intensity pyramid, where a father pixel takes the minimum gray level value of its directly linked children pixels. More precisely, only matrix diagonal is taken into account and analyzed along the pyramidal structure, which allows the classification to be made.

Paquis, Stephane; Legeay, Vincent; Konik, Hubert; Charrier, Jean

1999-03-01

181

Research on tensile strength characteristics of bridge deck pavement bonding layers  

Science.gov (United States)

As the development of the traffic in the world, the bridge deck pavement is playing a more and more important role in the whole traffic system. Big span bridge has become more and more especially cement concrete bridge, therefore the bridge deck pavement bonding layers are emphasized as an important part of bridge traffic system, which can mitigate travel impact to bridge and magnify stationary or traffic amenity. The quality and durability of deck pavement bonding layer has directly effect on traffic safety, comfort, durability and investment of bridge. It represents the first line of defence against the ingress of water, road de-icing salts and aggressive chemicals. In real project, many early age damage of bridge deck pavement has become serious disease that affecting the function of bridge. During the construction of the bridge deck, many types of asphalt binders were used, such as styrene-butadiene-styrene (SBS) modified asphalt, styrene-butadiene rubber (SBR) modified asphalt, neoprene latex asphalt, etc. In this paper UTM-25 was used to test the tensile strength of different bridge deck pavement bonding layers with the different treatment methods to inter-surface.

Wu, Shaopeng; Han, Jun

2010-03-01

182

Effects on evaporation rates from different water-permeable pavement designs.  

Science.gov (United States)

The urban water balance can be attenuated to the natural by water-permeable pavements (WPPs). Furthermore, WPPs have a 16% higher evaporation rate than impermeable pavements, which can lead to a better urban climate. Evaporation rates from pavements are influenced by the pavement surface and by the deeper layers. By a compared evaporation measurement between different WPP designs, the grain size distribution of the sub-base shows no influence on the evaporation rates in a significant way. On the contrary, a sub-base made of a twin-layer decreases the evaporation by 16% compared to a homogeneous sub-base. By a change in the colour of the paving stone, 19% higher evaporation rates could be achieved. A further comparison shows that the transpiration-effect of the grass in grass pavers increases the evaporation rates more than threefold to pervious concrete pavements. These high evapotranspiration rates can not be achieved with a pervious concrete paving stone. In spite of this, the broad field of application of the pervious concrete paving stone increases the importance in regard to the urban climate. PMID:22049757

Starke, P; Göbel, P; Coldewey, W G

2011-01-01

183

Investigation of antenna frequency impact on assessing voids of asphalt pavements using GPR  

Science.gov (United States)

Ground Penetrating Radar (GPR) is a Non Destructive Testing (NDT) technique that has been developed and improved upon over the past 30 years. The technique is frequently utilized in order to evaluate and assess pavement structures. GPR, for pavement evaluation purposes, can be described as a remote sensing system that emits a short pulse, of electromagnetic energy, into the pavement, with a central frequency varying from 10 MHz up to 2.5GHz. The two most commonly utilized setups are air-coupled and ground-coupled antenna systems. For air-coupled systems, the antennas are suspended above the pavement surface and can operate at normal traffic speeds (up to ~ 80 Km/h). The major drawback of the air-coupled antenna is that penetration depth is limited. On the other hand, for ground-coupled systems the antennas are in direct contact with the pavement surface, providing for better signal penetration into the pavement structure; however ground coupled systems can achieve only limited operational speeds. As a generalized rule, increasing the GPR central operating frequency, increases the investigation resolution, while decreasing the overall depth of investigation In the light of the above, air-coupled systems have become increasingly popular for the evaluation of the part of the pavement structure, especially for the asphalt layers, while ground-coupled systems are utilized mostly in order to gather information from the entire pavement structure (up to ~ 3 m depth). The majority of GPR pavement studies are carried out with air-coupled horn antennas, as they can be implemented at driving speeds without need for road closures. For instance, the 1 GHz air-coupled horn antenna is commonly used for the estimation of pavement layer thickness. However signals generated by horn antenna systems must have sufficient quality to allow the performance of automated signal processing and qualitative data analysis, especially when pavement data more sensitive to the analysis parameters, such voids or moisture, is concerned. The implementation of the horn antenna method is dependent upon, amongst others, the resolution of the antenna in use. The present research work investigates the application of the GPR sensor technique to assess voids within the asphalt layers, with a focus on the air-coupled antenna penetration depth and resolution. For this purpose the dielectric properties of asphalt layer materials were estimated and related voids contents were evaluated based on data collected by an air-coupled GPR system, operating at a 1 GHz and alternatively a 2 GHz central frequency. The collected data is analyzed comparatively for the two antennas. Comparison results indicate differences between the voids determined from the 1 GHz and 2GHz antennas. These differences are further analyzed and evaluated for pavement quality control purposes. The indication of a relationship between the measured voids is also evaluated, while ground truth data is used for the validation of the GPR data analysis results. The above is presented and discussed thoroughly with the aim to assist pavement quality assurance systems

Plati, C.; Georgouli, K.; Loizos, A.

2012-04-01

184

Friction evaluation of concrete paver blocks for airport pavement applications  

Science.gov (United States)

The development and use of concrete paver blocks is reviewed and some general specifications for application of this type of pavement surface at airport facilities are given. Two different shapes of interlocking concrete paver blocks installed in the track surface at NASA Langley's Aircraft Landing Dynamics Facility (ALDF) are described. Preliminary cornering performance results from testing of 40 x 14 radial-belted and bias-ply aircraft tires are reviewed. These tire tests are part of a larger, ongoing joint NASA/FAA/Industry Surface Traction and Radial Tire (START) Program involving several different tire sizes. Both dry and wet surface conditions were evaluated on the two concrete paver block test surfaces and a conventional, nongrooved Portland cement concrete surface. Future test plans involving evaluation of other concrete paver block designs at the ALDF are indicated.

Yager, Thomas J.

1992-01-01

185

Nondestructive testing of pavements and pavement bases. (a bibliography with abstracts). Report for 1964-Jan 78  

International Nuclear Information System (INIS)

Nondestructive methods for quality assurance of pavements and pavement bases are investigated in these Government-sponsored research reports. Vibration, nuclear activation, radiometry, and acoustic detection are among the various techniques employed. The updated bibliography contains 114 abstracts, 17 of which are new entries to the previous edition

186

Thermal stability analysis under embankment with asphalt pavement and cement pavement in permafrost regions.  

Science.gov (United States)

The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The maximum depth of temperature field under the embankment for concrete pavements and asphalt pavements was also studied by using the finite element method. The results of numerical analysis indicate that there were remarkable seasonal differences of the ground temperatures in superficial layer between asphalt pavement and concrete pavement. The maximum influencing depth of temperature field under the permafrost embankment for every pavement was under the depth of 8?m. The thawed cores under both embankments have close relation with the maximum thawed depth, the embankment height, and the service time. The effective measurements will be proposed to keep the thermal stabilities of highway embankment by the results. PMID:24027444

Junwei, Zhang; Jinping, Li; Xiaojuan, Quan

2013-01-01

187

Effective pollutant retention capacity of permeable pavements for infiltrated road runoffs determined by laboratory tests.  

Science.gov (United States)

The infiltration of urban runoff always implies an entrance of pollutants into the soil and ground water. Due to legal regulations in many communes there is no longer any permission needed for stormwater infiltration, if administrative regulations and the requirements of standards are observed. The results of a research project carried out under the heading "Development of an assessment procedure for permeable pavements" show, that the pollutant retention capacity of permeable pavements varies considerably, depending on the material and the specific reactive surface. The objective of the study was to work out recommendations of suitable permeable pavements for different types of urban runoff. Selected data about the quality of urban runoff was compiled into a runoff matrix, which was used for defining characteristic dilutions. In batch tests, the material of the infiltration devices is penetrated with the dilutions. A test installation in large scale is used to calibrate the sorption coefficients derived from the batch experiment. PMID:15790226

Fach, S; Geiger, W F

2005-01-01

188

POROUS PAVEMENT. PHASE I. DESIGN AND OPERATIONAL CRITERIA  

Science.gov (United States)

Design and operational criteria, utilization concepts, benefits and disadvantages, as well as other characteristics of porous pavements are presented in this report. Particular emphasis is placed on porous asphalt pavements, but the criteria and design approach are applicable to ...

189

The development and geometry of shape change in Arabidopsis thaliana cotyledon pavement cells  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The leaf epidermis is an important architectural control element that influences the growth properties of underlying tissues and the overall form of the organ. In dicots, interdigitated pavement cells are the building blocks of the tissue, and their morphogenesis includes the assembly of specialized cell walls that surround the apical, basal, and lateral (anticlinal cell surfaces. The microtubule and actin cytoskeletons are highly polarized along the cortex of the anticlinal wall; however, the relationships between these arrays and cell morphogenesis are unclear. Results We developed new quantitative tools to compare population-level growth statistics with time-lapse imaging of cotyledon pavement cells in an intact tissue. The analysis revealed alternating waves of lobe initiation and a phase of lateral isotropic expansion that persisted for days. During lateral isotropic diffuse growth, microtubule organization varied greatly between cell surfaces. Parallel microtubule bundles were distributed unevenly along the anticlinal surface, with subsets marking stable cortical domains at cell indentations and others clearly populating the cortex within convex cell protrusions. Conclusions Pavement cell morphogenesis is discontinuous, and includes punctuated phases of lobe initiation and lateral isotropic expansion. In the epidermis, lateral isotropic growth is independent of pavement cell size and shape. Cortical microtubules along the upper cell surface and stable cortical patches of anticlinal microtubules may coordinate the growth behaviors of orthogonal cell walls. This work illustrates the importance of directly linking protein localization data to the growth behavior of leaf epidermal cells.

Halsey Leah E

2011-02-01

190

ARDS (Acute Respiratory Distress Syndrome)  

Science.gov (United States)

... provide no benefit to COPD, ARDS outcomes Statin therapy does not prevent exacerbations of chronic obstructive pulmonary disease (COPD) or lower mortality from acute respiratory distress syndrome (ARDS), report two studies that rigorously ...

191

Hypertension Awareness and Psychological Distress  

OpenAIRE

There is conflicting evidence regarding the association of hypertension with psychological distress, such as anxiety and depressive symptoms. The association may be because of a direct effect of the raised blood pressure, adverse effects of treatment, or the consequences of labeling. In a representative study of 33 105 adults (aged 51.7 +/- 12.1 years; 45.8% men), we measured levels of psychological distress using the 12-item General Health Questionnaire and collected blood pressure, data on ...

Hamer, M.; Batty, G. D.; Stamatakis, E.; Kivimaki, M.

2010-01-01

192

Nonlinear Responses of a Two Dimensional Vehicle-pavement System  

OpenAIRE

The vehicle and pavement are usually investigated separately in vehicle dynamics and pavement dynamics. In this work, a new research scheme is proposed to link the vehicle and pavement model by tire loads and compute the nonlinear dynamic responses by analytical methods. A two-DOF nonlinear vehicle and a Bernoulli-Euler beam on a nonlinear elastic foundation with two simply supported ends compose the nonlinear vehicle-pavement system. The nonlinear tire loads are analytically gained using the...

Shaohua Li; Haoyu Li

2013-01-01

193

Locating the Drainage Layer for Bituminous Pavements in Indiana  

OpenAIRE

Pavement subsurface drainage and its effect on pavement performance has been a subject of interest since the 18th and 19th centuries. With no doubt the detrimental effects of heavy wheel loads on pavements with saturated base material is a significant factor. The consequence of subsurface water on pavement performance includes premature rutting, cracking, faulting, and increased roughness, all of which lead to a decrease in serviceability. This research study involves the evaluation of the...

Hassan, Hossam Farouk; White, Thomas D.

1996-01-01

194

Instrumentation, analysis and modeling of flexible pavement subdrainage  

OpenAIRE

Pavement subsurface drainage and its effect on pavement performance has been a subject of interest since the 18$\\sp{\\rm th}$ and 19$\\sp{\\rm th}$ centuries. With no doubt the detrimental effects of heavy wheel loads on pavements with saturated base material is a significant factor. The consequence of subsurface water on pavement performance includes premature rutting, cracking, faulting, and increased roughness, all of which lead to a decrease in serviceability.^ This research study involve...

Hassan, Hossam Farouk

1996-01-01

195

Calculation method for permanent deformation of unbound pavement materials  

OpenAIRE

An analytical-mechanistic method for the calculation of permanent deformations of pavements has been developed at the Technical Research Centre of Finland (VTT) over some years by the author. The calculation method is needed in the analytical design procedure of pavements. This research concentrated on the calculation method for permanent deformations in unbound pavement materials. The calculation method was generated based on the results of full-scale accelerated pavement tests along with th...

Korkiala-tanttu, Leena

2009-01-01

196

What is fetal distress?  

Science.gov (United States)

Fetal distress is a widely used but poorly defined term. This confusion of definition compounds the difficulty of making an accurate diagnosis and initiating appropriate treatment. The fetus reacts at the onset of asphyxia with a remarkable series of responses, primarily a complexly regulated redistribution of blood flow that serves to limit the deleterious effects of oxygen limitation in vital organs. This enables the fetus to survive asphyxia intact unless the insult is profound or prolonged. The most common asphyxial stresses imposed on the fetus during labor are insufficiency of uterine blood flow, or insufficiency of umbilical blood flow, and occasionally decrease in uterine arterial oxygenation. Each of these stresses produces characteristic fetal heart rate patterns: late decelerations, variable decelerations, or prolonged bradycardia. There is strong evidence that the presence of normal fetal heart rate variability represents normal central nervous system integrity, including adequate oxygenation. A decrease or loss of variability in the presence of these patterns is a sign that the physiologic compensations are overwhelmed as a result of the severity of asphyxia. Knowledge of the fetal responses to asphyxia, together with the known evolution of fetal heart rate patterns during asphyxia, should allow a more accurate definition of the onset of unacceptable asphyxia, and more rational management and timing of intervention. PMID:2193513

Parer, J T; Livingston, E G

1990-06-01

197

Acute respiratory distress syndrome  

Directory of Open Access Journals (Sweden)

Full Text Available Acute respiratory distress syndrome (ARDS is characterized by non-cardiogenic pulmonary oedema and respiratoy failure. In 1994, ARDS was defined by the American – European Consensus Conference (AECC and since then issues regarding the reliability and validity of this definition have emerged. The Berlin definition was developed by a panel of experts in a convention in 2011 with an initiative of European Society of Intensive Care Medicine endorsed by American Thoracic Society, mainly focussing on feasibility, reliability and validity and objective evaluation of performance. The definition proposed three exclusive categories of ARDS based on degree of hypoxaemia, namely, mild, moderate and severe. The updated and revised Berlin definition of ARDS may serve as model to create a more accurate, evidence based critical illness syndrome and to improve clinical care, research, health services planning and resource management. The article describes clinical, aetiological and physiological basis of ARDS and summarizes how its molecular pathogenesis leads to physiologic alterations of respiratory failure. It provides a physiologic basis for understanding and implementing modern strategies for the respiratory management of patients with ARDS.

M.H. Rao

2014-04-01

198

Surface properties-vehicle interaction  

Science.gov (United States)

Several topics related to the surface properties of aircraft runways are discussed. The South Dakota profilometer; development of a data acquisition method for noncontact pavement macrotexture measurement; the traction of an aircraft tire on grooved and porous asphaltic concrete; holes in the pavements; the effect of pavement type and condition on the fuel consumption of vehicles; the traction loss of a suspended tire on a sinusoidal road; the effect of vehicle and driver characteristics on the psychological evaluation of road roughness; the correlation of subjective panel ratings of pavement ride quality with profilometer-derived measures of pavement roughness; a microprocessor-based noncontact distance measuring control system, and, the representation of pavement surface topography in predicting runoff depths and hydroplaning potential are discussed.

Huft, D. L.; Her, I.; Agrawal, S. K.; Zimmer, R. A.; Bester, C. J.

199

Analysis of Asphalt Pavement under Nonuniform Tire-pavement Contact Stress using Finite Element Method  

OpenAIRE

Tire-pavement contact stress is traditionally assumed to be uniformly distributed over a circular contact area. In this study, the tire-pavement contact pressure has been modeled to be nonuniform. A new tire model is developed for the analysis based on the geometry of the tire footprint because the contact area between the tire and the pavement is not exactly rectangular or circular. The objective of this study is to develop a finite element model based on viscoplastic theory for simulating t...

Ariffin, A. K.; Ismail, A.; Nahi, M. H.

2011-01-01

200

Finite Deformation Analysis of Layered Asphalt Pavement  

Directory of Open Access Journals (Sweden)

Full Text Available Layered asphalt pavement structures are usually analyzed applying small deformation theory. In this study, finite deformation theory was employed to achieve more accurate results. The response of pavement structure under vertical and horizontal loads was investigated by three-dimensional finite element method. The calculating results, especially for deflection, on the basis of finite deformation theory are very different from that according to the small deformation theory. And the difference will increase while the stiffness of pavement structure decrease. With only vertical loads, asphalt layer is mainly under compressive stress in three directions. With horizontal loads and vertical loads, shear stress contributes to accumulated plastic deformation in the asphalt layer. Sliding between layers could occur due to the shear stress. Tensile strain can cause fatigue cracking in asphalt layer under low temperature. Due to a small modulus of resilience, there exists a large compressive strain and visible deflection in soil base.

Ming-Jian Li

2013-01-01

201

Noise characteristics of hot mix asphalt and Portland cement concrete pavements in United States  

Science.gov (United States)

In today's society, traffic noise is a serious problem that generally is considered an environmental pollution because it lowers the standard of living. Research in Europe and in the United States has indicated that it is possible to build pavement surfaces that will reduce the level of noise generated on roadways. In January of 2002 the National Center for Asphalt Technology initiated a research study with the objective to develop safe, quiet and durable asphalt pavement surfaces. As a part of that study over 300 pavement surfaces [both Portland Cement Concrete (PCCP) and Hot Mix Asphalt (HMA)] throughout the United States have been tested using a close-proximity noise trailer. The study has shown that in general PCCP surfaces have a higher noise level than HMA surfaces. But, it has also shown that by properly choosing the surface texture of the PCCP surface significant reductions in the noise level of a PCCP surface can be achieved. The study has shown that it is possible to construct low-noise HMA mixes and that in general the smaller the nominal maximum size for those mixes (regards whether they are dense graded, SMA or OFGC mixes) the lower the noise level.

Hanson, Douglas I.

2005-09-01

202

Platelet surface glycoproteins. Studies on resting and activated platelets and platelet membrane microparticles in normal subjects, and observations in patients during adult respiratory distress syndrome and cardiac surgery.  

OpenAIRE

The accurate definition of surface glycoprotein abnormalities in circulating platelets may provide better understanding of bleeding and thrombotic disorders. Platelet surface glycoproteins were measured on intact platelets in whole blood and platelet membrane microparticles were assayed in cell-free plasma using 125I-monoclonal antibodies. The glycoproteins (GP) studied were: GP Ib and GP IIb-IIIa, two of the major intrinsic plasma membrane glycoproteins; GMP-140, an alpha-granule membrane gl...

George, J. N.; Pickett, E. B.; Saucerman, S.; Mcever, R. P.; Kunicki, T. J.; Kieffer, N.; Newman, P. J.

1986-01-01

203

Modeling the Pavement Present Serviceability Index of Flexible Highway Pavements Using Data Mining  

OpenAIRE

The term present serviceability was adopted to represent the momentary ability of pavement to serve traffic and the performance of the pavement was represented by its serviceability history in conjunction with its load application history. Serviceability was found to be influenced by longitudinal and transverse profile as well as the extent of cracking and patching. The amount of weight to assign to each element in the determination of the over-all serviceability is a matter of subjective opi...

Serdal Terzi

2006-01-01

204

Mechanistic - empirical pavement design guide implementation and pavement preservation strategies with asphalt rubber  

OpenAIRE

Asphalt-Rubber (AR) mixtures, with their great fleld performance, have received great attention from many transportation agencies world-wide. Current pavement design procedures do not specifically address the unique engineering properties that these mixtures offer. For example, the Mechanistic-Empirical Pavement Design Guide (MEPDG) did not include asphalt-rubber mixes as part of its calibration and Implementation in the USA. This paper addresses some issues on asphalt rubber mixture...

Kaloush, Kamil; Way, George B.; Belshe, Mark; Rodezno, Maria Carolina

2011-01-01

205

13 CFR 301.3 - Economic distress levels.  

Science.gov (United States)

...2010-01-01 false Economic distress levels. 301.3 Section 301...Distress Criteria § 301.3 Economic distress levels. (a) Part 305 (Public...EDA will determine the economic distress levels pursuant to this...

2010-01-01

206

How Is Respiratory Distress Syndrome Treated?  

Science.gov (United States)

... Distress Syndrome Treated? Treatment for respiratory distress syndrome (RDS) usually begins as soon as an infant is ... delivery room. Most infants who show signs of RDS are quickly moved to a neonatal intensive care ...

207

47 CFR 80.1111 - Distress alerting.  

Science.gov (United States)

...Distress and Safety Communications § 80.1111...indicates that a mobile unit or person...for terrestrial radio-communication or a distress...carrying the mobile station or the...using voice or narrowband direct...

2010-10-01

208

Mindfulness and bodily distress.  

Science.gov (United States)

We have created a mindfulness approach to treat patients who experience multiple, persistent, and disabling physical symptoms that cannot be explained by a well-defined medical or surgical condition. Randomized controlled trials in this area are few, and research is hampered by the lack of clear definitions. Bodily distress syndrome (BDS) or bodily stress is an empirically defined definition unifying various conditions such as fibromyalgia, chronic fatigue syndrome, and somatization disorder. In the present PhD, we explored whether patients suffering from BDS may be committed to mental training in the form of mindfulness therapy, which is a mindfulness program specifically targeted patients suffering from BDS. The theoretical model for including mindfulness training in the treatment of BDS is based on identified neurobiological impairments in these patients and the neurobiological improvements that mindfulness training may offer. BDS is a major public health issue possibly associated with the pathology of the immuno-endocrine and autonomic nervous system. BDS patients are often stigmatized, and effective treatment is rarely delivered, which leaves these patients isolated, left by themselves, vulnerable to potentially harming medical and/or alternative treatments. Accordingly, there is a need for non-harming practical tools that patients can learn to master so that they can improve the ability to take responsibility for their own health and wellbeing. Mindfulness-Based Stress Reduction (MBSR) is a group program that employs mindfulness practice to alleviate suffering associated with physical, psychosomatic, and psychiatric disorders. Mindfulness-Based Cognitive Therapy (MBCT) is designed to prevent depressive relapse. Paper I and II present systematic literature reviews only of randomized controlled trials on MBSR and MBCT. The effect of MBSR has been explored on fibromyalgia in three studies, none of them showed convincing results, but gave some indications as to improvement. The reviews recommended MBSR as a useful method for improving mental health; however, lack of long-term follow-up and active control groups are limitations in most studies. MBCT was recommended as a tool for preventing depressive relapse in recovered, recurrently depressed patients, but the implication of MBSR and MBCT is problematic, especially due to the lack of well educated mindfulness teachers. We combined MBSR with cognitive behavioral therapy, CBT, specifically targeted BDS. Paper III provides original data from 119 patients enrolled in a randomized clinical trial, mindfulness therapy for BDS. The randomized controlled trial indicates that BDS patients are capable of and willing to engage in mindfulness therapy. This thesis showed that mindfulness therapy can safely and successfully engage BDS patients in mindfulness practice. Since individual CBT and psychiatric consultation have previously been found to have positive outcomes for BDS patients, we compared mindfulness therapy to an active control group entitled specialized treatment in which an individual treatment was planned in collaboration between the patient and an MD specialized in BDS, CBT, and psychiatry. Mindfulness therapy was comparable to specialized treatment in improving the quality of life and the symptoms of the patients with BDS at 15-month follow-up. For primary outcome physical health (PCS) at 15-month follow-up, different developments over time for the two treatment groups could not be established (F(3,2674) = 1.51, p = 0.21). However, in the mindfulness therapy group, PCS significant changed at the end of treatment and this change remained at 15-month follow-up, whereas no significantly change was seen in the specialized treatment group until at the 15-month follow-up. In the mindfulness therapy group, 26%; CI: 14-38 reported a marked improvement (> 1 SD) at the end of treatment compared with 10%; CI: 2-18 in the specialized treatment group. This amounts to a statistically significant difference between the groups (OR = 3.21; CI 1.05-9.78, p = 0.04). The results are i

Fjorback, Lone Overby

2012-11-01

209

Permeable pavement research ? Edison, New Jersey  

Science.gov (United States)

These are the slides for the New York City Concrete Promotional Council Pervious Concrete Seminar presentation. The basis for the project, the monitoring design and some preliminary monitoring data from the permeable pavement parking lot at the Edison Environmental Center are pre...

210

Assessment of flexible airfield pavements using Heavy Weight Deflectometers. Development of a FEM dynamical time-domain analysis for the backcalculation of structural properties.  

OpenAIRE

Evolved from the French “déflectomètre à boulet”, the Heavy Weight Deflectometer (HWD) is today viewed worldwide as the most appropriate device to assess the bearing capacity of airport pavements. Its principle consists in applying a transient impulsive load simulating the weight effect of an aircraft rolling wheel, onto a stationary load plate placed over the pavement, through a buffer system, and studying the surface deflections induced by this dynamic loading. The latter are continu...

Broutin, Michae?l

2010-01-01

211

Financial Distress Comparison Across Three Global Regions  

OpenAIRE

Globalization has precipitated movement of output and employment between regions. We examine factors related to corporate financial distress across three continents. Using a multidimensional definition of financial distress we test three hypotheses to explain financial distress using historical financial data. A null hypothesis of a single global model was rejected in favor of a fully relaxed model which created individual financial distress models for each region. This result suggests that d...

Platt, Harlan D.; Platt, Marjorie B.

2008-01-01

212

Psychological Distress among Young Norwegian Health Professionals  

OpenAIRE

High psychological distress has been shown to be a risk for acquisition of skills that are necessary when working in the health professions. In this study, we present longitudinal data on psychological distress among 169 young Norwegian health professionals. We measured distress at the end of their studies, and three years later on, when being professional nurses, physiotherapists and occupational therapists. Psychological distress was assessed by applying the 12-item version of the General H...

Per Nerdrum; Amy Østertun Geirdal

2013-01-01

213

Comparative study of nondestructive pavement testing, WES (Waterways Experiment Station) NDT (nondestructive tests) methodologies  

Science.gov (United States)

A demonstration of nondestructive airfield pavement evaluation procedures conducted by the US Army Engineer Waterways Experiment Station (WES) using both the WES 16-kip vibrator and a Dynatest falling weight deflectometer (FWD) is described. The nondestructive tests (NDT) were conducted at MacDill Air Force Base on five pavement test areas consisting of asphaltic concrete, portland cement concrete, and composite pavements. Two methods of data analysis were used. The dynamic stiffness modulus (DMS) method used dynamic deflection data from the WES 16-kip vibrator with a correlation analysis developed a number of years ago by WES. This method uses a correlation between the DSM (a load-deflection ratio) and the allowable load on a single wheel as derived from traditional test pit methods. The second analysis scheme used measured deflection basins at the pavement surface and layered elastic theory. Elastic moduli are computed by matching measured deflection basins with computed basins. Limiting stress/strain is then used to compute allowable aircraft loadings. This method was used with data from both the WES 16-kip vibrator and the FWD. Also demonstrated was a method of determining joint load transfer and of making appropriate adjustments to the allowable load to account for lack of load transfer.

Hall, J. W.; Alelxander, D. R.

1985-09-01

214

Utilize Cementitious High Carbon Fly Ash (CHCFA) to Stabilize Cold In-Place Recycled (CIR) Asphalt Pavement as Base Coarse  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to evaluate the performance of cementitious high carbon fly ash (CHCFA) stabilized recycled asphalt pavement as a base course material in a real world setting. Three test road cells were built at MnROAD facility in Minnesota. These cells have the same asphalt surface layers, subbases, and subgrades, but three different base courses: conventional crushed aggregates, untreated recycled pavement materials (RPM), and CHCFA stabilized RPM materials. During and after the construction of the three cells, laboratory and field tests were carried out to characterize the material properties. The test results were used in the mechanistic-empirical pavement design guide (MEPDG) to predict the pavement performance. Based on the performance prediction, the life cycle analyses of cost, energy consumption, and greenhouse gasses were performed. The leaching impacts of these three types of base materials were compared. The laboratory and field tests showed that fly ash stabilized RPM had higher modulus than crushed aggregate and RPM did. Based on the MEPDG performance prediction, the service life of the Cell 79 containing fly ash stabilized RPM, is 23.5 years, which is about twice the service life (11 years) of the Cell 77 with RPM base, and about three times the service life (7.5 years) of the Cell 78 with crushed aggregate base. The life cycle analysis indicated that the usage of the fly ash stabilized RPM as the base of the flexible pavement can significantly reduce the life cycle cost, the energy consumption, the greenhouse gases emission. Concentrations of many trace elements, particularly those with relatively low water quality standards, diminish over time as water flows through the pavement profile. For many elements, concentrations below US water drinking water quality standards are attained at the bottom of the pavement profile within 2-4 pore volumes of flow.

Wen, Haifang; Li, Xiaojun; Edil, Tuncer; O' Donnell, Jonathan; Danda, Swapna

2011-02-05

215

Perfectionism, Procrastination, and Psychological Distress  

Science.gov (United States)

Using a cross-panel design and data from 2 successive cohorts of college students ( N = 357), we examined the stability of maladaptive perfectionism, procrastination, and psychological distress across 3 time points within a college semester. Each construct was substantially stable over time, with procrastination being especially stable. We also…

Rice, Kenneth G.; Richardson, Clarissa M. E.; Clark, Dustin

2012-01-01

216

23 CFR 972.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...2010-04-01 false Federal lands pavement management system (PMS). 972.208...Systems § 972.208 Federal lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.”2 2...

2010-04-01

217

23 CFR 971.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...2010-04-01 false Federal lands pavement management system (PMS). 971.208...Systems § 971.208 Federal lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.” 1 1...

2010-04-01

218

23 CFR 970.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...2010-04-01 false Federal lands pavement management system (PMS). 970.208...Systems § 970.208 Federal lands pavement management system (PMS). In addition... (i) An inventory of the physical pavement features including the number of...

2010-04-01

219

23 CFR 973.208 - Indian lands pavement management system (PMS).  

Science.gov (United States)

...2010-04-01 false Indian lands pavement management system (PMS). 973.208...Systems § 973.208 Indian lands pavement management system (PMS). In addition...concepts described in the AASHTO's “Pavement Management Guide.” 1 1...

2010-04-01

220

23 CFR 973.208 - Indian lands pavement management system (PMS).  

Science.gov (United States)

...lands pavement management system (PMS...AASHTO's “Pavement Management Guide.” 1 1 “Pavement Management Guide...collection and maintenance of the inventory...information; (ii) A history of project...

2010-04-01

221

23 CFR 972.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...lands pavement management system (PMS...AASHTO's “Pavement Management Guide.”2 2 “Pavement Management Guide...collection and maintenance of the inventory...information; (ii) A history of project...

2010-04-01

222

23 CFR 971.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...lands pavement management system (PMS...AASHTO's “Pavement Management Guide.” 1 1 “Pavement Management Guide...collection and maintenance of the inventory...information; (ii) A history of project...

2010-04-01

223

Analysis of Asphalt Pavement under Nonuniform Tire-pavement Contact Stress using Finite Element Method  

Directory of Open Access Journals (Sweden)

Full Text Available Tire-pavement contact stress is traditionally assumed to be uniformly distributed over a circular contact area. In this study, the tire-pavement contact pressure has been modeled to be nonuniform. A new tire model is developed for the analysis based on the geometry of the tire footprint because the contact area between the tire and the pavement is not exactly rectangular or circular. The objective of this study is to develop a finite element model based on viscoplastic theory for simulating the laboratory testing of asphalt mixes in Hamburg Wheel Rut Tester (HWRT for rutting and to model in-situ pavement performance. The creep parameters C1, C2 and C2 are developed from the triaxial repeated load creep test at 50C and at frequency of 1 Hz. Viscoplastic model (creep model is adopted and a commercially available Finite Element (FE program, ANSYS, is used in this study, in order to predict the rutting for in-situ pavement under nonuniform contact pressure. In the simulation, the used element has an eight-node with a three degrees of freedom per node translations in the nodal x, y and z directions. Dual wheel system of a standard axle load of 80 kN is used in the 2D pavement in-situ performance analysis. Reasonable agreement has been obtained between the predicted rut depths and the measured one. Moreover, it is found that creep model parameter C1, strongly influences rutting than the parameter C3. Finally it can be concluded that creep model based on finite element method can be used as an effective tools to analyze rutting of asphalt pavements.

A.K. Ariffin

2011-01-01

224

Comparison Between 2-D and 3-D Stiffness Matrix Model Simulation of Sasw Inversion for Pavement Structure  

Directory of Open Access Journals (Sweden)

Full Text Available The Spectral Analysis of Surface Wave (SASW method is a non-destructive in situ seismic technique used to assess and evaluate the material stiffness (dynamic elastic modulus and thickness of pavement layers at low strains. These values can be used analytically to calculate load capacities in order to predict the performance of pavement system. The SASW method is based on the dispersion phenomena of Rayleigh waves in layered media. In order to get the actual shear wave velocities, 2-D and 3-D models are used in the simulation of the inversion process for best fitting between theoretical and empirical dispersion curves. The objective of this study is to simulate and compare the 2-D and 3-D model of SASW analysis in the construction of the theoretical dispersion curve for pavement structure evaluation. The result showed that the dispersion curve from the 3-D model was similar with the dispersion curve of the actual pavement profile compared to the 2-D model. The wave velocity profiles also showed that the 3-D model used in the SASW analysis is able to detect all the distinct layers of flexible pavement units.

Sri Atmaja P. Rosidi

2007-01-01

225

Life Cycle Cost Analysis for INDOT Pavement Design Procedures  

OpenAIRE

Given the aging of highway pavements, high traffic levels, and uncertainty of sustained preservation funding, there is a need for balanced decision-making tools such as LCCA to ensure long-term and cost-effective pavement investments. With driving forces such as ISTEA 1991, the NHS Act of 1995, and TEA-21, LCCA enables evaluation of overall long-term economic efficiency between competing alternative investments and consequently has important applications in pavement design and management. It ...

Lamptey, Geoffery; Ahmad, Muhammad Z.; Labi, Samuel; Sinha, Kumares C.

2005-01-01

226

The Role of Asphalt Rejuvenators in Pavement Preservation  

OpenAIRE

Efforts of the National Center for Pavement Preservation, the FHWA and various users groups such as AEMA, ARRA, and ISSA have brought agency managers’ attention to pavement preservation. Agencies are evaluating alternatives to provide a cost-effective pavement maintenance program. This presentation will focus on the history, composition, and effectiveness of rejuvenators as well as where and how to use them to provide a lower cost maintenance alternative to push out maintenance curves.

Brownridge, Jim

2013-01-01

227

Non-linear dynamic analysis of flexible and rigid pavements  

OpenAIRE

Closed form analysis is commonly used to analyze pavement structures. This type of analysis assumes linear elastic material properties and static loading conditions. In reality, pavement materials are not linear elastic materials. For example, asphalt mixtures are viscoelastic materials and cohesive soils are elastic-plastic materials. Also truck loads are moving loads. The difference between the closed form analysis assumptions and the actual pavement conditions leads to significant differen...

Zaghloul, Sameh Mohamed

1993-01-01

228

Fracture in high performance fibre reinforced concrete pavement materials  

OpenAIRE

An innovative pavement system known as Ultra Thin Continuously Reinforced Concrete Pavement (UTCRCP) was recently developed in South Africa. The technology is currently being implemented on some major routes in the country. The system consists of a high performance fibre reinforced concrete pavement slab with a nominal thickness of approximately 50 mm. The material has a significant post crack stress capacity compared to plain concrete. Current design methods for UTCRCP are bas...

Denneman, Erik

2011-01-01

229

An Airport Pavement Traffic Simulation Based on CPN  

OpenAIRE

According to the characteristics of airport pavement traffic, we discuss a method of building an airport pavement traffic model which is based on CPN theory and simulate a practical situation as well. The method overcomes the shortage of modelling with normal Petri Net theory, solves the difficult problems of airport pavement traffic such as complex traffic nets, frequent road changing, etc., refines the process of the model, and will be good for the model’s analysis and simulation.

Heng Hong-jun; Yang Jue

2014-01-01

230

Evaluating Functional and Structural Condition Based Maintenances of Airfield Pavements  

OpenAIRE

This study evaluates airfield pavements’ functional- and structural-condition to determine the most economical maintenance method. As a part of the analysis, Pavement Condition Index (PCI) for several runways, taxiways, and aprons has been determined by MicroPAVER. Structural evaluation of airport pavements has been performed by Falling Weight Deflectometer (FWD) test. Evaluation of Layer Moduli and Overlay Design (ELMOD) also determines the required overlay thickness based on the E-values,...

Tarefder R.; Ahmed M.U.; Rahman M.M.

2013-01-01

231

Pervious Concrete: New Era For Rural Road Pavement  

OpenAIRE

Pervious concrete is a relatively new concept for rural road pavement, with increase into the problems in rural areas related to the low ground water level, agricultural problem. Pervious concrete has introduced in rural road as a road pavement material. Pervious concrete as a paving material has seen renewed interest due to its ability to allow waterto flow through itself to recharge groundwater level and minimize storm water runoff. This introduction topervious concrete pavements reviews it...

Darshan S Shah, Prof Jayeshkumar Pitroda Prof J. J. Bhavsar

2013-01-01

232

Performance of Recycled Asphalt Pavement as Coarse Aggregate in Concrete  

OpenAIRE

Recycled asphalt pavement (RAP) is the reclaimed and reprocessed pavement material containing asphalt and aggregate. Most RAP is recycled back into pavements, and as a result there is a general lack of data pertaining to the mechanical properties for RAP in other possible applications such as Portland cement concrete. In the present study, some mechanical properties of Portland cement concrete containing RAP as coarse aggregate were investigated in the laboratory. Six concrete mixes of widely...

Okafor, Fidelis O.

2010-01-01

233

Smart Road Pavement Research HomePage  

Science.gov (United States)

Dubbed "the Smart Road" by Virginia's Department of Transportation, this full-scale facility for pavement research and evaluation of high-tech transportation systems uses computers, electronics, and satellites to create a realistic environment for collecting traffic and environmental data under controlled conditions, "and should advance the general understanding of the engineering behavior of pavement systems." This site, from the Virginia Tech Civil Engineering Materials Program, provides information from the researchers who have designed the Smart Road. The page contains a description of the project's current status, an explanation of objectives, construction photos, a detailed description of the instrumentation used, and data. Note, the research plan and testing links are still under construction. This site introduces an interesting project for highway and transportation engineers.

234

Incidence of respiratory distress syndrome  

International Nuclear Information System (INIS)

Objective: To determine the incidence of respiratory distress syndrome (RDS) in hospital born babies. Subjects and Methods: All live born infants delivered at the hospital and who fulfilled the diagnostic criteria of respiratory distress syndrome (RDS) were included in the study. Results: Ninety-four neonates developed RDS. Out of these, 88 (93.61%) were preterm and 06 (6.38%) were term infants. There was a male preponderance (65.95%). RDS was documented in 1.72% of total live births. 37.28% of preterm and 0.11% of term neonates born at the hospital. The incidence of RDS was 100% at 26 or less weeks of gestation, 57.14% at 32 weeks, and 3.70% at 36 weeks. The mortality with RDS was 41 (43.61%). Conclusion: RDS is the commonest cause of respiratory distress in the newborn, particularly, in preterm infants. It carries a high mortality rate and the incidence is more than that documented in the Western world. (author)

235

Lichen colonization of the Roman pavement at Baelo Claudia ( Cadiz, Spain): biodeterioration vs. bioprotection  

OpenAIRE

This paper describes the effect of lichen colonization on the first century A.D. pavement of the forum at Baelo Claudia, a Roman city located in southern Spain. Lichen colonization is scarce, covering only 13% of the total surface. The rest of the flagstones are mostly uncovered but show strong physico-chemical weathering. The flagstones colonized by lichens do not show weathering. The distribution of the species is influenced by environmental factors, confirming the role of lichens as bioind...

Arin?o, Xavier; Ortega Calvo, J. J.; Go?mez Bolea, A.; Sa?iz-jime?nez, Cesa?reo

1995-01-01

236

Desempeño de pavimentos estabilizado con asfalto espumado en una prueba de pavimentos a escala real y carga acelerada Performance of foamed bitumen pavements in accelerated testing facility  

Directory of Open Access Journals (Sweden)

Full Text Available Uno de los objetivos claves de la gestión de pavimentos es desarrollar e implementar una estrategia de construcción y mantenimiento rentables, con el fin de alcanzar niveles requeridos de servicio y desempeño. Una técnica rentable y sustentable para la rehabilitación de pavimentos es la de estabilización o reciclado con asfalto espumado (AE. Este artículo presenta un estudio sobre el desempeño de pavimentos estabilizados con asfalto espumado en el Canterbury Accelerated Pavement Testing Indoor Facility CAPTIF. CAPTIF es un laboratorio a escala real para pavimentos ubicado en Nueva Zelandia, que permite aplicar un gran número de cargas de tráfico en un breve período de tiempo. Seis secciones de pavimentos con distintos contenidos de asfalto y cemento fueron ensayadas en CAPTIF. Los resultados del experimento mostraron que las deflexiones disminuyen en las secciones con mayor contenido de asfalto espumado. Luego de aplicar más de un millón de ciclos de carga, las secciones estabilizadas sólo con cemento, sólo con asfalto y la sección sin estabilizar mostraron un deterioro significativo en forma de ahuellamiento. Por otro lado, las secciones que fueron estabilizadas con AE y cemento mostraron un buen desempeño, demostrando que el cemento y el AE juntos mejoran significativamente el desempeño del pavimento. Los resultados de ahuellamiento fueron empleados para desarrollar modelos y describir el deterioro estable y acelerado de los pavimentos en estudio, lo que puede ser utilizado para una mejor gestión de los pavimentos estabilizados con asfalto espumado.One of the key principal goals of pavement asset management is to develop and implement cost-effective pavement construction and maintenance strategies that achieve the required levels of service and performance. A sustainable, cost-effective technique for rehabilitating pavements is foamed bitumen stabilization. This paper presents a study on the performance of foamed bitumen pavements tested in the Canterbury Accelerated Pavement Testing indoor Facility (CAPTiF, for full scale testing of pavements. Six pavement sections were tested; the variables were bitumen and cement content; one control section with the untreated unbound material was tested. Results showed that surface deflections decreased at sections with higher bitumen contents. After the application of 5,710,000 Equivalent Standard Axles (ESAs, the sections stabilised with cement only, bitumen only, and the control section all showed large amounts of rutting. Conversely, little rutting was observed in the three sections stabilised with foamed bitumen and 1.0% cement, showing that cement and FB together significantly improve pavement performance. The rutting results were used to develop models to describe the stable and unstable performance of the tested pavements. The paper concludes by outlining some of the practical benefits of utilising this technology in pavement asset management.

Alvaro Gonzalez

2012-08-01

237

Measurements of the stiffness and thickness of the pavement asphalt layer using the enhanced resonance search method.  

Science.gov (United States)

Enhanced resonance search (ERS) is a nondestructive testing method that has been created to evaluate the quality of a pavement by means of a special instrument called the pavement integrity scanner (PiScanner). This technique can be used to assess the thickness of the road pavement structure and the profile of shear wave velocity by using the principle of surface wave and body wave propagation. In this study, the ERS technique was used to determine the actual thickness of the asphaltic pavement surface layer, while the shear wave velocities obtained were used to determine its dynamic elastic modulus. A total of fifteen locations were identified and the results were then compared with the specifications of the Malaysian PWD, MDD UKM, and IKRAM. It was found that the value of the elastic modulus of materials is between 3929 MPa and 17726 MPa. A comparison of the average thickness of the samples with the design thickness of MDD UKM showed a difference of 20 to 60%. Thickness of the asphalt surface layer followed the specifications of Malaysian PWD and MDD UKM, while some of the values of stiffness obtained are higher than the standard. PMID:25276854

Zakaria, Nur Mustakiza; Yusoff, Nur Izzi Md; Hardwiyono, Sentot; Nayan, Khairul Anuar Mohd; El-Shafie, Ahmed

2014-01-01

238

DISTRESS AND JOB PERFORMANCE OF INDUSTRIAL WORKERS  

OpenAIRE

The present study aims at the investigation of the relationship between distress and job performance of industrial workers. The sample consisted of 500 workers of public and private sectors. CMI Health Questionnaire and Performance Appraisal Scale (PAS) were used to measure the level of distress and quality of performance at job, respectively. Results showed that physical, menial and overall distress correlated significantly and negatively with workers ?performance as appraised Furthermore,...

Samanta, C. R.; Singh, Avneesh

1993-01-01

239

Permeable Pavement Research at the Edison Environmental Center  

Science.gov (United States)

There are few detailed studies of full-scale, replicated, actively-used permeable pavement systems. Practitioners need additional studies of permeable pavement systems in its intended application (parking lot, roadway, etc.) across a range of climatic events, daily usage conditio...

240

Permeable pavement demonstration at the Edison Environmental Center (Hartford, CT)  

Science.gov (United States)

In general, there is a lack of full-scale, outdoor, real-world porous pavement studies with system replicates. More studies of porous pavement operating in its intended use (parking lot, roadway, etc.) with climatic events, regular use, and maintenance effects, are necessary. The...

241

Permeable Pavement Demonstration at the Edison Environmental Center (Hartford)  

Science.gov (United States)

In general, there is a lack of full-scale, outdoor, real-world porous pavement studies with system replicates. More studies of porous pavement operating in its intended use (parking lot, roadway, etc.) with climatic events, regular use, and maintenance effects, are necessary. The...

242

Permeable pavement demonstration site at Edison Environmental Center (Presentation)  

Science.gov (United States)

There are few studies of full-scale, outdoor, replicated, working pervious pavement systems. More studies of pervious pavement operating in its intended use (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions, and maintenance regimes are necessa...

243

Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site  

Science.gov (United States)

There are few detailed studies of full-scale, replicated, actively-used pervious pavement systems. Practitioners need additional studies of pervious pavement systems in its intended application (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions...

244

Permeable pavement demonstration at the Edison Environmental Center  

Science.gov (United States)

There are few studies of full-scale, outdoor, replicated, functioning pervious pavement systems. More studies of pervious pavement operating in its intended use (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions, and maintenance regimes are nec...

245

Pavement thickness evaluation by GPR survey in Idaho  

Science.gov (United States)

In 1995 and 1996, the Idaho Transportation Department (ITD) conducted a series of ground-penetrating radar (GPR) surveys as a nondestructive testing (NDT) method to evaluate the thickness of asphalt and Portland cement concrete (AC/PCC) pavements in Idaho. GPR surveys employed both air-coupled and combination air and ground coupled systems with their associated equipment and software. A total of 30 miles of AC/PCC pavements were evaluated by GPR surveys. The results obtained were correlated with the site-specific ground-truth data from borings. Knowledge of pavement layer thickness is needed to predict pavement performance, establish load carrying capacities and develop maintenance and rehabilitation priorities. In addition, for new construction, it is important to ensure that the thickness of materials being placed by the contractor is acceptably close to specification. Core sampling and test pits are destructive to the pavement system, expensive, time consuming and intrusive to traffic. The objective of the ITD study was to evaluate, compare and assess the ability of these two GPR systems to accurately measure the thickness of multiple pavement layers, and document the data nondestructively. This paper reviews the findings of these surveys and provides statistically based data for both AC and PCC pavements. The overall study has shown that reasonably accurate, dependable determination of pavement thickness can be achieved by using GPR survey for conditions encountered in Idaho.

Sener, Joseph C.; Smith, Robert M.; Garz, Michael D.; Murgel, George A.; Hamilton, Robert W.; Haws, David R.

1998-03-01

246

Adjustment to Cancer: Anxiety and Distress (PDQ®)  

Science.gov (United States)

Expert-reviewed information summary about the difficult emotional responses many cancer patients experience. This summary focuses on normal adjustment issues, psychosocial distress, and adjustment disorders.

247

Pervious Concrete: New Era For Rural Road Pavement  

Directory of Open Access Journals (Sweden)

Full Text Available Pervious concrete is a relatively new concept for rural road pavement, with increase into the problems in rural areas related to the low ground water level, agricultural problem. Pervious concrete has introduced in rural road as a road pavement material. Pervious concrete as a paving material has seen renewed interest due to its ability to allow waterto flow through itself to recharge groundwater level and minimize storm water runoff. This introduction topervious concrete pavements reviews its applications and engineering properties, including environmentalbenefits, structural properties, and durability.In rural area cost consideration is the primary factor which must be kept in mind. So that in rural areas costly storm water management practices is not applicable. Pervious concrete pavement is unique and effective means to meet growing environmental demands. By capturing rainwater and allowing it to seep into the ground. This pavement technology createsmore efficient land use by eliminating the need for retention ponds, swell, and other costly stormwater management devices.

Darshan S. Shah 1 , Prof. Jayeshkumar Pitroda2Prof.J.J.Bhavsar

2013-08-01

248

Respiratory distress in the newborn.  

Science.gov (United States)

Respiratory distress presents as tachypnea, nasal flaring, retractions, and grunting and may progress to respiratory failure if not readily recognized and managed. Causes of respiratory distress vary and may not lie within the lung. A thorough history, physical examination, and radiographic and laboratory findings will aid in the differential diagnosis. Common causes include transient tachypnea of the newborn, neonatal pneumonia, respiratory distress syndrome (RDS), and meconium aspiration syndrome (MAS). Strong evidence reveals an inverse relationship between gestational age and respiratory morbidity. (1)(2)(9)(25)(26) Expert opinion recommends careful consideration about elective delivery without labor at less than 39 weeks’ gestation. Extensive evidence, including randomized control trials, cohort studies, and expert opinion, supports maternal group B streptococcus screening, intrapartum antibiotic prophylaxis, and appropriate followup of high-risk newborns according to guidelines established by the Centers for Disease Control and Prevention. (4)(29)(31)(32)(34) Following these best-practice strategies is effective in preventing neonatal pneumonia and its complications. (31)(32)(34). On the basis of strong evidence, including randomized control trials and Cochrane Reviews, administration of antenatal corticosteroids (5) and postnatal surfactant (6) decrease respiratory morbidity associated with RDS. Trends in perinatal management strategies to prevent MAS have changed. There is strong evidence that amnioinfusion, (49) oropharyngeal and nasopharyngeal suctioning at the perineum, (45) or intubation and endotracheal suctioning of vigorous infants (46)(47) do not decrease MAS or its complications. Some research and expert opinion supports endotracheal suctioning of nonvigorous meconium-stained infants (8) and induction of labor at 41 weeks’ gestation (7) to prevent MAS. PMID:25274969

Reuter, Suzanne; Moser, Chuanpit; Baack, Michelle

2014-10-01

249

Characterization of nanoparticles released during construction of photocatalytic pavements using engineered nanoparticles  

International Nuclear Information System (INIS)

With the increasing use of titanium dioxide (TiO2) nanoparticles in self-cleaning materials such as photocatalytic concrete pavements, the release of nanoparticles into the environment is inevitable. Nanoparticle concentration, particle size, surface area, elemental composition, and surface morphology are pertinent to determine the associated risks. In this study, the potential of exposure to synthetic nanoparticles released during construction activities for application of photocatalytic pavements was measured during laboratory-simulated construction activities of photocatalytic mortar overlays and in an actual field application of photocatalytic spray coat. A scanning mobility particle sizer system measured the size distribution of nanoparticles released during laboratory and field activities. Since incidental nanoparticles are released during construction activities, nanoparticle emissions were compared to those from similar activities without nano-TiO2. Nanoparticle counts and size distribution suggest that synthetic nanoparticles are released during application of photocatalytic pavements. In order to identify the nanoparticle source, nanoparticles were also collected for offline characterization using transmission electron microscopy. However, positive identification of synthetic nanoparticles was not possible due to difficulties in obtaining high-resolution images. As a result, further research is recommended to identify nanoparticle comporecommended to identify nanoparticle composition and sources.

250

Characterization of nanoparticles released during construction of photocatalytic pavements using engineered nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

With the increasing use of titanium dioxide (TiO{sub 2}) nanoparticles in self-cleaning materials such as photocatalytic concrete pavements, the release of nanoparticles into the environment is inevitable. Nanoparticle concentration, particle size, surface area, elemental composition, and surface morphology are pertinent to determine the associated risks. In this study, the potential of exposure to synthetic nanoparticles released during construction activities for application of photocatalytic pavements was measured during laboratory-simulated construction activities of photocatalytic mortar overlays and in an actual field application of photocatalytic spray coat. A scanning mobility particle sizer system measured the size distribution of nanoparticles released during laboratory and field activities. Since incidental nanoparticles are released during construction activities, nanoparticle emissions were compared to those from similar activities without nano-TiO{sub 2}. Nanoparticle counts and size distribution suggest that synthetic nanoparticles are released during application of photocatalytic pavements. In order to identify the nanoparticle source, nanoparticles were also collected for offline characterization using transmission electron microscopy. However, positive identification of synthetic nanoparticles was not possible due to difficulties in obtaining high-resolution images. As a result, further research is recommended to identify nanoparticle composition and sources.

Dylla, Heather; Hassan, Marwa M., E-mail: marwa@lsu.edu [Louisiana State University, Department of Construction Management and Industrial Engineering (United States)

2012-03-15

251

Permeable Pavement Research ? Edison, NJ  

Science.gov (United States)

This presentation gives the rationale behind NRMRL?s decision to construct and test a permeable surface parking lot the Edison Environmental Center. It also describes the monitoring program and gives preliminary results. The presentation is being given at the request of the New...

252

47 CFR 80.312 - Priority of distress transmissions.  

Science.gov (United States)

... false Priority of distress transmissions. 80.312 Section 80.312...80.312 Priority of distress transmissions. The distress call has absolute priority over all other transmissions. All stations which hear it...

2010-10-01

253

46 CFR 25.25-19 - Visual distress signals.  

Science.gov (United States)

...2010-10-01 2010-10-01 false Visual distress signals. 25.25-19 ...Lifesaving Equipment § 25.25-19 Visual distress signals. Each uninspected passenger vessel must meet the visual distress signal requirements of...

2010-10-01

254

33 CFR 175.130 - Visual distress signals accepted.  

Science.gov (United States)

... 2010-07-01 2010-07-01 false Visual distress signals accepted. 175.130 Section... BOATING SAFETY EQUIPMENT REQUIREMENTS Visual Distress Signals § 175.130 Visual distress signals accepted. (a) Any...

2010-07-01

255

Full scale tests on grid reinforced flexible pavements on the French fatigue carrousel  

OpenAIRE

Grids are increasingly used. They have proved their efficiency, but there is presently no widely accepted design method to predict the long term life of grid reinforced pavements. This paper describes a full scale experiment carried out on the large pavement fatigue carrousel of IFSTTAR, to test simultaneously 3 pavement sections with different types of grids, in comparison with an unreinforced pavement structure. The tests are carried out on typical French low traffic pavement structures. Re...

Hornych, Pierre; Kerzreho, Jean Pierre; Chabot, Armelle; Trichet, Ste?phane; Sohm, Juliette; Joutang, Jean-luc; Bastard, Nicolas

2012-01-01

256

Psychological distress among young Norwegian health professionals  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, we present longitudinal data on psychological distress among 169 young Norwegian health professionals. Psychological distress was measured at the end of their studies, and three years later on, when being professional nurses, physiotherapists and occupational therapists. Psychological distress was assessed by applying the 12-item version of the General Health Questionnaire (GHQ 12. Twenty-seven percent of the nursing students scored higher than the GHQ 12 case score at the end of the study, but as nurses, they became significantly less distressed three years later (13 percent. The other two professions showed relatively small and non-significant reductions in psychological distress during the first three years as a professional. Hierarchical multiple analyses showed that the level of psychological distress when finishing the study, the young professionals’ experience of personal support from colleagues, the experience of work-home conflicts and the experience of methodological coping at work were significant predictors of psychological distress three years after working as young health professionals. These four predictors explained together 29 percent in the variance in GHQ 12 three years after graduation. Belonging to any of the three professions did not contribute to the explained variance in psychological distress three years after graduation.

Per Nerdrum

2014-03-01

257

Moral distress: recognizing it to retain nurses.  

Science.gov (United States)

Faced with the challenges in today's acute care environment, 15% of the nurses in one study reported resigning a position due to experiencing moral distress. Moral distress is the physical or emotional suffering that is experienced when constraints (internal or external) prevent one from following the course of action that one believes is right. With more responsibility than authority, nurses often lack the autonomy to do what they feel should be done. Nurses often seem unaware of moral distress experience in themselves. Feelings labeled as stress, burnout, emotional exhaustion, and job dissatisfaction may actually be symptomatic of moral distress. An organizational commitment to addressing the issue of moral distress could reap benefits with greater employee job satisfaction, decreased turnover, and ultimately improved patient care. PMID:17847657

Pendry, Patricia S

2007-01-01

258

An Innovative Strategy for Maintenance of Highway Pavement  

Directory of Open Access Journals (Sweden)

Full Text Available Highway pavement are deteriorating fast due to lack of timely maintenance, leading to higher vehicle operating costs, increasing number of accidents etc. Thus, timely maintenance of the highway pavement is essential. Because, once pavements start to deteriorate; they deteriorate rapidly beyond the point where maintenance is effective. Thus, there is an urgent need to develop a strategy for maintenance of pavement in a huge highway network. In this study, an innovative strategy for maintenance of highway pavement is proposed. A two stage maintenance strategy is proposed. In stage I, it is proposed to determine priority of highway sections. In Stage II, priority of various maintenance activities to be carried out on various sections will be determined. Maintenance priority of the pavement is based on importance of the road sections, present road conditions, and future road conditions. The methodology proposed in this study is illustrated with the help of example of some hypothetical highway network consisting of 4 sections. Analysis results indicated that the proposed strategy is considered to be more rational, innovative & logical. Some strategies for maintenance of urban roads are also presented in this study. Therefore, it is expected that this study will be useful for maintenance of huge highway network in India and thus will be useful for preserving huge asset of pavement infrastructure.

Sandeep Choudhary, Dr. P. K. Agarwal

2013-05-01

259

Pattern recognition algorithms for density estimation of asphalt pavement during compaction: a simulation study  

Science.gov (United States)

This paper presents the application of artificial neural network (ANN) based pattern recognition to extract the density information of asphalt pavement from simulated ground penetrating radar (GPR) signals. This study is part of research efforts into the application of GPR to monitor asphalt pavement density during compaction. The main challenge is to eliminate the effect of roller-sprayed water on GPR signals during compaction and to extract density information accurately. A calibration of the excitation function was conducted to provide an accurate match between the simulated signal and the real signal. A modified electromagnetic mixing model was then used to calculate the dielectric constant of asphalt mixture with water. A large database of GPR responses was generated from pavement models having different air void contents and various surface moisture contents using finite-difference time-domain simulation. Feature extraction was performed to extract density-related features from the simulated GPR responses. Air void contents were divided into five classes representing different compaction statuses. An ANN-based pattern recognition system was trained using the extracted features as inputs and air void content classes as target outputs. Accuracy of the system was tested using test data set. Classification of air void contents using the developed algorithm is found to be highly accurate, which indicates effectiveness of this method to predict asphalt concrete density.

Shangguan, Pengcheng; Al-Qadi, Imad L.; Lahouar, Samer

2014-08-01

260

"Full-Scale Testing of Pavement Response"  

DEFF Research Database (Denmark)

Three pavement sections in southern Sweden were instrumented in late 1991. Each section have instruments for measuring the strain at the bottom of the asphalt layer, vertical stress and strains in the subgrade and temperatures at different depths. The purpose was to evaluate different theoretical methods for determining stresses, strains and deflections in pavement structurers.Falling Weight Deflectometer (FWD) test were done on the test sections, and stresses and strains were measured both under FWD loading and under a rolling wheel load. Different back-analysis procedures were used to derive layer moduli from FWD testing. The forward calculated stresses and strains were then compared to the measured values. The tests were done under different climatic conditions, the latest in November 1996, where almost all of the gauges were still functioning.Of the different methods used for back-analysing FWD data and for calculating the stresses and the strains, the simple method based on Odemark's transformations and Boussinesq's equations appeared to be as good as, or better than, the more sophisticated methods using layered elastic theory or the Finite Element Method.

Ullidtz, Per; Ekdahl, Peter

1998-01-01

261

Development of Improved Mechanistic Deterioration Models for Flexible Pavements  

DEFF Research Database (Denmark)

The paper describes a pilot study in Denmark with the main objective of developing improved mechanistic deterioration models for flexible pavements based on an accelerated full scale test on an instrumented pavement in the Danish Road Tessting Machine. The study was the first in "International Pavement Subgrade Performance Study" sponsored by the Federal Highway Administration (FHWA), USA. The paper describes in detail the data analysis and the resulting models for rutting, roughness, and a model for the plastic strain in the subgrade.The reader will get an understanding of the work needed to be done to be succesful in establishing mechanistic models based on Accelerated Load Testing (ALT) complemented by laboratory testing.

Ullidtz, Per; Ertman, Hans Larsen

1998-01-01

262

Development of Mechanistic-Empirical Flexible Pavement Design in Iran  

Directory of Open Access Journals (Sweden)

Full Text Available Recent advances in flexible pavement design have prompted agencies to move toward the development and use of Mechanistic-Empirical (M-E design procedures. Mechanistic-Empirical (M-E design combine the elements of mechanical modeling and performance observation in determining the required pavement thickness for a set of design condition. In this study, a Mechanistic-Empirical (M-E design procedures and algorithm based on KENLAYER software with regard to Iran climatic and traffic conditions is developed. This study also explores present relationships and diagrams based on effective variable on pavement design to facilitate design process.

M. Ameri

2009-01-01

263

YOUTH UNEMPLOYMENT AND PHYSICAL DISTRESS  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, an effort has been made to investigate the role of unemployment in the development of the physical distress in youth. A sample of 400 subjects (200 males and 200 females was drawn randomly from Shimla district of Himachal Pradesh. Comparison was done between unemployed and employed youth in both the gender groups i.e. males and females. A 2 x 2 ANOVA has yielded significant results that unemployed people had significantly perceived poor physical health profiles (eyes and ears, respiratory system, cardiovascular system, digestive tract, musculoskeletal system, skin, nervous system, genitourinary system, fatigability, frequency of illness, miscellaneous diseases, habits than employed people. Findings from this study suggest that the impetus for unemployment be it voluntary or involuntary, may significantly impact a person's physical health.

ANITA SHARMA

2013-02-01

264

STUDY ON PROPERTIES OF SKID RESISTANCE ON FREEZING PAVEMENTS AND QUANTITATIVE EVALUATION METHOD OF ANTIFREEZING EFFECTS  

Science.gov (United States)

Snow and ice control in winter roads trends to be controlled by the skid friction coefficients in North America and North European countries at present, but the measurements are not necessarily easy. We studied on a simplified measurement method based on the relationship between skid friction coefficients and the bare pavement ratio (BPR) in the laboratory tests and field tests. The factors of BPR, surface textures and antifreezing materials which affect the skid friction coefficient are reviewed by a multiple linear regression analysis and a spectrum analysis, considering different freezing surfaces. These studies indicate that conclusions induced by laboratory tests could be applied to roads in service.

Tanaka, Shunsuke; Takeichi, Kiyoshi; Masuyama, Yukiei; Takahashi, Naoto

265

Automatic Detection and Classification of Defect on road Pavement using Anisotropy Measure  

OpenAIRE

Automatic pavement cracking detection is a part of road maintenance and rehabilitation strategies. Cracks detec-tion is one of the main features used by road authorities to manage efficiently its networks. Road surface is made using aggregates which can have different sizes, organized randomly. Scanned pictures of theses surfaces appear has random distribution of a re-duced set of gray levels. Cracks or defaults can't be ex-tracted by a simple threshold. In this paper, we introduce a measure ...

Nguyen, Tien Sy; Avila, Manuel; Begot, Ste?phane

2009-01-01

266

Time series observations of marsh recovery and pavement persistence at three Metula spill sites after 30.5 years  

International Nuclear Information System (INIS)

In 1974, the oil tanker Metula ran aground in the Strait of Magellan, Chile and spilled about 50,000 tons of light Arabian crude and 2,000 tons of Bunker C fuel. No attempt was made to recover or treat the stranded oil and the coast was left to recover by natural attenuation. Field visits to the coastal sites affected by the spill were conducted 30 years after the incident. The survey in 2005 repeated observations and measurements made in 1998 in the heavily affected Punta Espora area that documented salt marsh recovery at 2 sites, and changes in asphalt pavement at a third site. The 1998 survey also indicated that tilling was responsible for a significant increase in the number of plants that recolonized the area. A comparison of the plant counts between 1998 and 2005 showed that the number of plants in tilled plots was reduced because of fewer larger plants. A comparison of oil distribution in the west marsh from 1998 to 2005 showed that recolonization was evident. A large 550 m-long asphalt pavement on a mixed sediment beach showed very little changes in pavement area in the aftermath of the spill. However, the upper edge of the pavement showed signs of erosion by backwash action of waves during high-tide. The presence of surface oil cover continues to dominate the physical character of the upper intertidal and supratidal zones. 11 refs., 6 tabs., 3 figs

267

On-site inspections of pavement damages evolution using GPR  

Science.gov (United States)

Ground-penetrating radar (GPR) is being increasingly used for pavements maintenance due to the wide range of applications spanning from physical to geometrical inspections, thereby allowing for a reliable diagnosis of the main causes of road structural damages. In this work, an off-ground GPR system was used to investigate a large-scale rural road network. Two sets of surveys were carried out in different time periods, with the main goals to i) localize the most critical sections; ii) monitor the evolution of previous damages and localize newborn deep faults, although not revealed at the pavement surface level; iii) analyze the causes of both evolution and emergence of faults by considering environmental and human factors. A 1-GHz GPR air-launched antenna was linked to an instrumented van for collecting data at traffic speed. Other support techniques (e.g. GPS data logger, odometer, HD video camera) were used for cross-checking,. Such centre frequency of investigation along with a 25-ns time window allow for a signal penetration of 900 mm, consistent with the deepest layer interfaces. The bottom of the array was 400 mm over the surface, with a minimum distance of 1200 mm from the van body. Scan length of maximum 10 km were provided for avoiding heavy computational loads. The rural road network was located in the District of Rieti, 100 km north from Rome, Italy, and mostly develops in a hilly and mountainous landscape. In most of the investigated roads, the carriageway consists in two lanes of 3.75 meters wide and two shoulders of 0.50 meters wide. A typical road section includes a HMA layer (65 mm average thickness), a base layer (100 mm average thickness), and a subbase layer (300 mm average thickness), as described by pavement design charts. The first set of surveys was carried out in two days at the beginning of spring in moderately dry conditions. Overall, 320-km-long inspections were performed in both travel directions, thereby showing a productivity of approximately 160 km/day at 40 km/h speed, on the average. After processing and first-checking, GPR profiles were divided into homogeneous sections according to the combination of different parameters (e.g. route analyzed, long distance conditions of regularity/irregularity in layers arrangement). In such context, a high consistency between surface damages, mismatches from the GPR scans, and boundary environmental conditions was demonstrated. In addition, deep mismatches were detected even for early-stage or unrevealed faults. The second set of surveys was carried out in autumn in high humidity conditions, due to recent rainfalls. 160 km of relevant routes from the same road network were investigated. Results showed a high consistency with those collected during the first-stage of surveys. Minor changes were found in those sections with low traffic loads (e.g. farther away from the biggest town of Rieti), whereas major mismatches were detected in wetlands (e.g. close to rivers), work zones, and nearby those sections already deeply damaged in the past. This work benefited from networking activities carried out within the EU funded COST Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar'.

Tosti, Fabio; D'Amico, Fabrizio; Calvi, Alessandro; Benedetto, Andrea

2014-05-01

268

23 CFR Appendix to Subpart F of... - Alternate Method of Determining the Color of Retroreflective Sign Materials and Pavement Marking...  

Science.gov (United States)

...of Retroreflective Sign Materials and Pavement Marking Materials Appendix to Subpart...of Retroreflective Sign Materials and Pavement Marking Materials 1. Although...Specification Limits for Retroreflective Pavement Marking Material With CIE 2°...

2010-04-01

269

The impact of light-colored pavements on active layer dynamics revealed by Ground-Penetrating Radar monitoring  

DEFF Research Database (Denmark)

Ground-penetrating radar (GPR) has been used to study the variations in the depth of the frost table throughout a complete thaw-freeze season in Kangerlussuaq Airport, western Greenland. In autumn 2000, three test areas were painted white on the parking area of the airport in order to reduce further development of depressions in the asphalt pavement. One of these areas has been used in the GPR investigations to compare the variations of the frost table underneath a normal dark asphalt surface to that below a more reflective surface. The GPR results have shown a clear correlation between the use of the reflective surface and a reduced depth to frost table. In late summer the difference in the depths to the frost table is approximately 0.9 m. The results should promote the interest in the development and use of light colored pavement materials in order to reduce the effect of a warming climate on arctic infrastructures.

JØrgensen, Anders Stuhr; Ingeman-Nielsen, Thomas

2008-01-01

270

Moral distress in medical education and training.  

Science.gov (United States)

Moral distress is the experience of cognitive-emotional dissonance that arises when one feels compelled to act contrary to one's moral requirements. Moral distress is common, but under-recognized in medical education and training, and this relative inattention may undermine educators' efforts to promote empathy, ethical practice, and professionalism. Moral distress should be recognized as a feature of the clinical landscape, and addressed in conjunction with the related concerns of negative role modeling and the goals and efficacy of medical ethics curricula. PMID:24146350

Berger, Jeffrey T

2014-02-01

271

Data Analysis Report : Preliminary Test Pavement Danish Road Testing Machine  

DEFF Research Database (Denmark)

Main conclusions: 1) The Asphalt Strain Gauges (ASG), the Soil Deformation Transducers (SDT) and the Soil Pressure Cells (SPC) performed well during the experiment, but the SPCs need frequent in situ calibration. A different installation procedure for the SPCs should be considered. Due to the variability of the soil more instruments (than two) are needed for each response value to be determined. 2) Strains measured using the emu coils did not have a satisfactory degree of accuracy. Laboratory tests showed the Kulite pressure cells to be dependent upon loading history and soil stiffness. For this reason the cells were not used in the RTM experiment. The volumetric moisture content recorded by the VITEL moisture probes did not appear to be reliable. 3) Linear elastic theory did not give a satisfactory agreement with measured stresses and strains. The measured vertical strains could be several times larger than the theoretical values. Elsym5 seems to produce incorrect deflections in some cases. 4) Satisfactory agreement between measured and theoretical stresses and strains could be obtained using the Finite Element Method and appropriate non-linear relationships for the moduli of the unbound materials. 5) The variation of stresses and strains with distance from the load was found to be in very good agreement with Boussinesgs equations, with the exception of the horizontal stress. The relationship between the depth used with Boussinesq's equations the the actual depth needs further study. 6) The subgrade showed thixotropyc behavior with strains increasing with the number of load repetitions and decreasing after a rest period. This behavior was only observed under the wheel load, not under the FWD. 7) Existing design criteria for subgrades appear to be reasonable when used with strains calculated using linear elastic theory and moduli determined from FWD tests, but ar much too conservative if used with measured strains. 8) Plastic strain in the subgrade, surface rutting and roughness could all be related to the measured resilient strain at the top of the subgrade, with damage being proportional to the load raised to a power between 6.23 and 6.67. These relationships can be used to calculate the pavement condition after a given number of loads or to determine the permissible number of loads for a given terminal condition of the pavement. For surface rutting and roughness the contribution from the individual layers could not be established.

Ullidtz, Per; Zhang, Wei

1997-01-01

272

Permeable Pavement Demonstration at the Edison Environmental Center - Poster  

Science.gov (United States)

Poster for the SAB Review detailing the porous pavement parking lot project. The poster describes the design of the parking lot, the research components that were incorporated into the design, and the monitoring plan....

273

Fatigue resistance of bituminous layers incorporating reclaimed asphalt pavement  

OpenAIRE

This paper presents the results of an investigation into the fatigue performance of a 20mm Binder Course Asphalt Pavement Mix incorporating Recycled Asphalt Pavement (RAP). For the study, a series of binder course mixes were designed containing varying percentages of RAP. A mix made only from virgin material, was selected as the control mix for the investigation. A Circular Wheel Tracker (CWT) was developed in order to simulate the dynamic loading conditions of a rolling wheel and to st...

Tabakovic, Amir; Gibney, Amanda; Gilchrist, M. D.; Mcnally, Ciaran

2006-01-01

274

The applicability of published pavement deterioration models for national roads  

OpenAIRE

The growing interest in pavement management systems (PMSs), both in South Mrica and internationally, has been in response to a shift in importance from the construction of new roads to the maintenance of the existing paved network coupled with increasingly restrictive road funding. In order to develop a balanced expenditure programme for the national roads of South Africa there is a need to predict the rate of deterioration of a pavement and the nature of the changes in its ...

Kannemeyer, Louw

1993-01-01

275

Pavement condition description using a deduct point approach.  

OpenAIRE

The method to describe pavement condition, as documented in the existing TRH22 document, has specific shortcomings when several defects of slight degree, or when only major defects e.g. potholes exist on a road segment. Following the testing of several alternative techniques, a deduct-point method was implemented and calibrated to calculate different condition and need indices in the Pavement Management System of the Western Cape Provincial Government. This paper describes the backgr...

Zyl, G. D.; Gryp, A.

2013-01-01

276

Evaluation of Common Maintenance Methods for Flexible Pavements  

OpenAIRE

Problem statement: With the increasing use and awareness of pavement management systems and the growing emphasis on asset management of pavement infrastructure, it is important to strengthen the maintenance components of these systems and particularly the preventive maintenance component. Iraqi Roads don?t receive an effective and proper maintenance during their service life until they reach the state of major failure that requires rehabilitation. Roads in Iraq are being lost. Appr...

Ibraheem, Asma T.; Gani, Suda M.

2011-01-01

277

Development of Mechanistic-Empirical Flexible Pavement Design in Iran  

OpenAIRE

Recent advances in flexible pavement design have prompted agencies to move toward the development and use of Mechanistic-Empirical (M-E) design procedures. Mechanistic-Empirical (M-E) design combine the elements of mechanical modeling and performance observation in determining the required pavement thickness for a set of design condition. In this study, a Mechanistic-Empirical (M-E) design procedures and algorithm based on KENLAYER software with regard to Iran climatic and traffic conditions ...

Ameri, M.; Khavandi, A.

2009-01-01

278

Construction of a recycled Portland cement concrete pavement  

Science.gov (United States)

Connecticut's first experience with Portland cement concrete recycling is described. The test location was on I-84 in Waterbury, a major expressway which required extensive realignment and widening. The primary concern was to obtain the technical expertise to design and place a recycled pavement. Secondary factors also investigated were the analysis of environmental, economic and energy factors relative to the option of recycling or new construction of a portland cement concrete pavement.

Lane, K. R.

1980-09-01

279

A Detailed Study of Cbr Method for Flexible Pavement Design  

OpenAIRE

As per IRC recommendation, California Bearing Ratio (CBR) value of subgrade is used for design of flexible pavements. California Bearing Ratio (CBR) value is an important soil parameter for design of flexible pavements and runway of air fields. It can also be used for determination of sub grade reaction of soil by using correlation. It is one of the most important engineering properties of soil for design of sub grade of roads. CBR value of soil may depends on many factors lik...

Er. Devendra Kumar Choudhary; Joshi, Dr Y. P.

2014-01-01

280

Latex improvement of recycled asphalt pavement  

Science.gov (United States)

The performance of a single unmodified milled recycled asphalt concrete was compared to milled asphalt concrete modified by addition of three types of rubber latex. Latex was added at 2, 3, 5, and 8 percent latex by weight of asphalt in the asphalt concrete. Lattices used were a styrene butadiene (SBR), a natural rubber (NR), an acrylonitrile butadiene (NBR), and four varieties of out of specification SBR lattices. Marshall tests, while indecisive, showed a modest improvement in properties of SBR and NR added material at 3 and 5 percent latex. Addition of NBR latex caused deterioration in Marshall stability and flow over that of control. Repeated load tests were run using the indirect tensile test, analyzed by the VESYS program, which computes life of pavements. Repeated load tests showed improvement in asphalt concrete life when 3 and 5 percent SBR was added. Improvement was also shown by the out of specification SBR.

Drennon, C.

1982-08-01

281

Brain Aneurysm: Dealing with Emotional Distress  

Science.gov (United States)

... this family crisis. During and immediately after the aneurysm, the family of the survivor experiences a broad ... positive outcome for both you and the brain aneurysm survivor. There are many forms of emotional distress. ...

282

Cortico-limbic morphology separates tinnitus from tinnitus distress  

Directory of Open Access Journals (Sweden)

Full Text Available Tinnitus is a common auditory disorder characterized by a chronic ringing or buzzing “in the ear.” Despite the auditory-perceptual nature of this disorder, a growing number of studies have reported neuroanatomical differences in tinnitus patients outside the auditory-perceptual system. Some have used this evidence to characterize chronic tinnitus as dysregulation of the auditory system, either resulting from inefficient inhibitory control or through the formation of aversive associations with tinnitus. It remains unclear, however, whether these “non-auditory” anatomical markers of tinnitus are related to the tinnitus signal itself, or merely to negative emotional reactions to tinnitus (i.e., tinnitus distress. In the current study, we used anatomical MRI to identify neural markers of tinnitus, and measured their relationship to a variety of tinnitus characteristics and other factors often linked to tinnitus, such as hearing loss, depression, anxiety, and noise sensitivity. In a new cohort of participants, we confirmed that people with chronic tinnitus exhibit reduced grey matter in ventromedial prefrontal cortex (vmPFC compared to controls matched for age and hearing loss. This effect was driven by reduced cortical surface area, and was not related to tinnitus distress, symptoms of depression or anxiety, noise sensitivity, or other factors. Instead, tinnitus distress was positively correlated with cortical thickness in the anterior insula in tinnitus patients, while symptoms of anxiety and depression were negatively correlated with cortical thickness in subcallosal anterior cingulate cortex (scACC across all groups. Tinnitus patients also exhibited increased gyrification of dorsomedial prefrontal cortex (dmPFC, which was more severe in those patients with constant (vs. intermittent tinnitus. Our data suggest that the neural systems associated with chronic tinnitus are different from those involved in aversive or distressed reactions to tinnitus.

AmberMLeaver

2012-04-01

283

Millimeter-wave nondestructive evaluation of pavement conditions  

Science.gov (United States)

The United States is suffering from an aging civil infrastructure crisis. Key to recovery are rapid inspection technologies like that being investigated by the VOTERS project (Versatile Onboard Traffic Embedded Roaming Sensors), which aims to outfit ordinary road vehicles with compact low-cost hardware that enables them to rapidly assess and report the condition of roadways and bridge decks free of driver interaction. A key piece of hardware, and the focus of this paper, is a 24 GHz millimeter-wave radar system that measures the reflectivity of pavement surfaces. To account for the variability of real-world driving, such as changes in height, angle, speed, and temperature, a sensor fusion approach is used that corrects MWR measurements based on data from four additional sensors. The corrected MWR measurements are expected to be useful for various characterization applications, including: material type; deterioration such as cracks and potholes; and surface coverage conditions such as dry, wet, oil, water, and ice. Success at each of these applications is an important step towards achieving the VOTERS objective, however, this paper focuses on surface coverage, as whatever covers the driving surface will be most apparent to the MWR sensor and if not accounted for could significantly limit the accuracy of other applications. Contributions of the paper include findings from static lab tests, which validate the approach and show the effects of height and angle. Further contributions come from lab and in-field dynamic tests, which show the effects of speed and demonstrate that the MWR approach is accurate under city driving conditions.

Vines-Cavanau, David; Busuioc, Dan; Birken, Ralf; Wang, Ming

2012-04-01

284

Effects of rejuvenator seal and fog seal on performance of open-graded friction course pavement  

Directory of Open Access Journals (Sweden)

Full Text Available An open-graded friction course (OGFC is a special-purpose surface layer of hot-mix asphalt (HMA pavement that is increasingly being used around the world. Owing to its numerous benefits, OGFC is being regularly used as a final riding surface on interstate and high-traffic expressways by different highway agencies in the United States. However, some OGFC sections have experienced premature failure due to ravelling only after 6-8 years of service life. To maintain an effective, longer service life and enhanced performance of OGFC, preventive maintenance has been considered essential. There are several approaches to maintaining OGFC, one of which is the application of a fog seal and rejuvenator seal. A fog seal can reduce ravelling and extend the service life of OGFC while a rejuvenator seal can revitalise the existing aged asphalt binder in the top OGFC layer. This research focuses on optimising the fog and rejuvenator seal application rates by evaluating their effectiveness in terms of surface friction and durability. Three types of seal material were evaluated: Pavegaard (PG and Pavepreserve (PP asphalt rejuvenators and a cationic slow-setting asphalt emulsion (CSS-1H as a fog seal. Improvement in abrasion resistance of OGFC pavement was observed on application of fog and rejuvenator seals but surface friction was reduced to some extent. Hamburg test clearly shows a trend that the medium application rate of 0.10 gallon/square yard is better in enhancing resistance to rutting/moisture susceptibility of OGFC.

Nadeem A. Qureshi

2013-05-01

285

Passive pavement-mounted acoustical linguistic drive alert system and method  

Science.gov (United States)

Systems and methods are described for passive pavement-mounted acoustical alert of the occupants of a vehicle. A method of notifying a vehicle occupant includes providing a driving medium upon which a vehicle is to be driven; and texturing a portion of the driving medium such that the textured portion interacts with the vehicle to produce audible signals, the textured portion pattern such that a linguistic message is encoded into the audible signals. The systems and methods provide advantages because information can be conveyed to the occupants of the vehicle based on the location of the vehicle relative to the textured surface.

Kisner, Roger A. (Knoxville, TN); Anderson, Richard L. (Oak Ridge, TN); Carnal, Charles L. (Cookeville, TN); Hylton, James O. (Clinton, TN); Stevens, Samuel S. (Harriman, TN)

2001-01-01

286

Evaluation of Three Porous Pavement Systems in a Newly Constructed Parking Lot  

Science.gov (United States)

This project examines porous pavement systems in a newly constructed parking lot next to Building 205 at the Edison Environmental Center. Porous pavement systems are one means of promoting environmental sustainability through stormwater runoff reduction. This project examines t...

287

POROUS PAVEMENT PHASE I DESIGN AND OPERATIONAL CRITERIA (EPA/600/2-80/135)  

Science.gov (United States)

Design and operational criteria, utilization concepts, benefits and disadvantages, as well as other characteristics of porous pavements are presented in this report. Particular emphasis is placed on porous asphalt pavements, but the criteria and design approach are applicable to ...

288

Over the Edge and Back: What to Do If You Drive Off the Pavement Edge  

Science.gov (United States)

AAA Foundation for Traffic Safety Over the Edge and Back What to do if you drive off ... fatal relative to other crashes on similar roads. AAA Foundationfor Traffic Safety Pavement edge drop-off “ Pavement ...

289

23 CFR 972.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...Federal lands pavement management system (PMS). 972.208 Section 972.208 Highways...Federal lands pavement management system (PMS). In addition to the requirements provided in § 972.204, the PMS must meet the following...

2010-04-01

290

23 CFR 973.208 - Indian lands pavement management system (PMS).  

Science.gov (United States)

...Indian lands pavement management system (PMS). 973.208 Section 973.208 Highways...Indian lands pavement management system (PMS). In addition to the requirements provided in § 973.204, the PMS must meet the following requirements:...

2010-04-01

291

23 CFR 971.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...Federal lands pavement management system (PMS). 971.208 Section 971.208 Highways...Federal lands pavement management system (PMS). In addition to the requirements provided in § 971.204, the PMS must meet the following...

2010-04-01

292

23 CFR 970.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...Federal lands pavement management system (PMS). 970.208 Section 970.208 Highways...Federal lands pavement management system (PMS). In addition to the requirements provided in § 970.204, the PMS must meet the following requirements:...

2010-04-01

293

23 CFR 972.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...and Wildlife Service Management Systems § 972.208 Federal lands pavement management system (PMS). ...b) The PMS may be based on the concepts described...AASHTO's “Pavement Management Guide.”2 2 ...Identifies alternative strategies to improve...

2010-04-01

294

23 CFR 973.208 - Indian lands pavement management system (PMS).  

Science.gov (United States)

...Bureau of Indian Affairs Management Systems § 973.208 Indian lands pavement management system (PMS). ...and tribal PMSs may be based on the concepts described...AASHTO's “Pavement Management Guide.” 1 1 ...Identifies alternative strategies to improve...

2010-04-01

295

23 CFR 971.208 - Federal lands pavement management system (PMS).  

Science.gov (United States)

...Forest Highway Program Management Systems § 971.208 Federal lands pavement management system (PMS). ...b) The PMS may be based on the concepts described...AASHTO's “Pavement Management Guide.” 1 1 ...Identifies alternative strategies to improve...

2010-04-01

296

78 FR 26847 - Including Specific Pavement Types in Federal-aid Highway Traffic Noise Analyses  

Science.gov (United States)

...rely on data from three pavement types: dense-graded asphaltic concrete (DGAC), open-graded asphaltic concrete (OGAC), and Portland cement concrete (PCC). Prediction of...on the ``average'' pavement type, calculated as...

2013-05-08

297

Distress vs. Non-Distress Approach and the Personal Space of Masculine, Feminine, and Androgynous Subjects.  

Science.gov (United States)

Examined was the relationship between personal space and sex roles. Feminine females (N=25), androgynous females (N=25) and masculine males (N=25) viewed a film of male and female approaching stimulus persons in distress and non-distress conditions. Subjects marked the Comfortable Interpersonal Distance Scale at the point where they would prefer…

Glisson, Pamela A.; Thomas, Georgelle

298

Comparison between noise reducing pavement and noise barriers. : From a cost and technical perspective.  

OpenAIRE

Noise reducing pavement has a porous structure that improves drainage and reduces traffic noise but these propitious qualities causes’ problems such as rapid wear and pore clogging. This means that the pavement must be repaved and cleaned more frequently than a conventional pavement such as ABS 16. Criticism of the noise reducing pavement has been raised and has to do with the high operating and maintenance costs, this result in more invests in noise barriers instead. The purpose with this ...

Cardenas, Pablo; Wall, Peter

2013-01-01

299

Implementation of the AASHTO pavement design procedures into MULTI-PAVE.  

OpenAIRE

This thesis implements the empirical pavement design procedures for flexible as well as rigid pavement by American Association of State Highways and Transportation Officials (AASHTO) into two MATLAB modules of MULTI-PAVE. MULTI-PAVE was developed as a teaching tool that performs pavement thickness design for multiple design procedures using a common input file and a common output format. The AASHTO components were developed in accordance with the 1993 AASHTO Pavement Design Guide, and verifie...

Bekele, Abiy

2011-01-01

300

Comparison of isotropic and cross-anisotropic analysis of pavement structures  

OpenAIRE

In most existing pavement design methods, pavements are analyzed using linear elastic multilayer theory, with the assumption that isotropic conditions are present in the structural layers of the pavement section. There are however numerous researchers that disagree with this assumption and their research have proven that there are inherent and induced cross-anisotropic material behaviors in the structural layers of a pavement section. The problem facing the South African Mechanistic Design Me...

Steyn, Wynand J. Vdm; Maina, James; Repsold, Anton

2013-01-01

301

PAH volatilization following application of coal-tar-based pavement sealant  

Science.gov (United States)

Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (?PAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 ?g m-2 h-1 and decreased rapidly during the 45 days after application to 160 ?g m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ?PAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ?PAH8 lost to the atmosphere on the basis of air sampling (2–3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ?PAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (~1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

2012-01-01

302

Evaluation of Road Pavement Density Using Ground Penetrating Radar  

Directory of Open Access Journals (Sweden)

Full Text Available This study describes an analysis of Ground Penetrating Radar (GPR measurements at frequency range of 1.7-2.6 GHz to get a relationship between attenuation and density for nine road pavements slabs with different densities. There are about four different frequencies had been tested. The method is simple, fast, non-destructive and accurate way to determine the density of road pavement. Density is a one of the important parameter in order to determine the compressive strength of road pavement for road user safety. In laboratory, the measurement system consists of a signal generator (250 kHz-3 GHz as a source, spectrum analyzer (100 Hz-8 GHz, directional coupler with adapter and horn antenna. The first part of the measurement system setup is to determine the amplitude of transmitted wave (received signal strength. A few of received signal strength and attenuation for nine road pavement slab samples were taken at four different frequencies. An instantaneous method for measuring the density of road pavement was developed by using microwave reflection technique and free space method. The MATLAB software is used to analyze the measurement data and also for the graphs comparisons. At the end of this study, it is found that density plays an important factor in causing a major in the recorded signal strength as well as the differences of attenuation of the GPR signal.

RSA Raja Abdullah

2009-01-01

303

Asphalt Pavement Material Improvement: A Review  

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Full Text Available The recycling of solid industrial wastes (SIW such as waste rubber tires and plastics will not only solve the global environmental problem of these SIW but also act as very promising modifiers for the improvement of engineering characteristics of the asphalt pavement material. The present work was concerned with assisting the interested readers to be familiarized with the paving material asphalt-modifiers obtained from SIW by providing historical perspective on its first invention and development. The paper has also provided highlights on common processes of asphalt mixture production. It was also worth mentioning that there are two asphalt production technologies: the warm mix asphalt (WMA and hot mix asphalt (HMA technologies, and the various advantages of using each one. Additionally, the paper has provided the reader with an overview of a number of case studies which were conducted by scientists and researchers for serious attempting to reach development and capturing significant properties of incorporating SIWs in civil engineering represented by scarp tires in form of crumb rubber (CR, plastics (polymers in their different forms.

Mohamed Sulyman

2014-10-01

304

Measurement of pavement macrotexture through digital image processing - doi: 10.4025/actascitechnol.v35i1.12808  

Directory of Open Access Journals (Sweden)

Full Text Available The texture data of roads and airport pavement are extremely important for reducing accidents, mainly in cases of wet surface. The texture measurement is essential to evaluate the driving quality, however the conventional processes (field tests are expensive and cause traffic interruption.   The aim of the present study was to develop a practical procedure to measure the asphalt pavement macrotexture using image processing and to compare it with sand patch tests. The parameter selected to quantify the surface pavement condition was the image information content calculated by a FFT (Fast Fourier Transform through modification in the light intensity among neighboring pixels, this modification is called spatial frequency. Seeking to contribute with traditional methods, the proposed procedure causes low interruption in traffic, being also fast, accurate, with good reproducibility, and low cost. In comparison with sand patch test, the image processing technique proved to be efficient, and suitable to be used to identify areas with texture problem, reducing the possibility of accidents.  

Reginaldo Tudéia dos Santos

2013-01-01

305

Evaluating Functional and Structural Condition Based Maintenances of Airfield Pavements  

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Full Text Available This study evaluates airfield pavements’ functional- and structural-condition to determine the most economical maintenance method. As a part of the analysis, Pavement Condition Index (PCI for several runways, taxiways, and aprons has been determined by MicroPAVER. Structural evaluation of airport pavements has been performed by Falling Weight Deflectometer (FWD test. Evaluation of Layer Moduli and Overlay Design (ELMOD also determines the required overlay thickness based on the E-values, i.e. FWD data analysis. Damage analysis determines the time of repeated overlay application. In addition, functional parameters have been included to determine the time of functional maintenance. Maintenance and rehabilitation alternatives have been selected to develop different program strategies. Life Cycle Cost Analysis (LCCA has been performed to determine the maintenance cost. Structural condition based maintenance cost is compared to functional condition based maintenance cost. Comparison shows that structural condition based approach yields cheaper maintenance strategies than functional condition based maintenance approach.

Tarefder R.

2013-01-01

306

Geo synthetic-reinforced Pavement systems; Sistemas de pavimentos reforzados con geosinteticos  

Energy Technology Data Exchange (ETDEWEB)

Geo synthetics have been used as reinforcement inclusions to improve pavement performance. while there are clear field evidence of the benefit of using geo synthetic reinforcements, the specific conditions or mechanisms that govern the reinforcement of pavements are, at best, unclear and have remained largely unmeasured. Significant research has been recently conducted with the objectives of: (i) determining the relevant properties of geo synthetics that contribute to the enhanced performance of pavement systems, (ii) developing appropriate analytical, laboratory and field methods capable of quantifying the pavement performance, and (iii) enabling the prediction of pavement performance as a function of the properties of the various types of geo synthetics. (Author)

Zornberg, J. G.

2014-02-01

307

Artificial intelligence modeling to evaluate field performance of photocatalytic asphalt pavement for ambient air purification.  

Science.gov (United States)

In recent years, the application of titanium dioxide (TiO?) as a photocatalyst in asphalt pavement has received considerable attention for purifying ambient air from traffic-emitted pollutants via photocatalytic processes. In order to control the increasing deterioration of ambient air quality, urgent and proper risk assessment tools are deemed necessary. However, in practice, monitoring all process parameters for various operating conditions is difficult due to the complex and non-linear nature of air pollution-based problems. Therefore, the development of models to predict air pollutant concentrations is very useful because it can provide early warnings to the population and also reduce the number of measuring sites. This study used artificial neural network (ANN) and neuro-fuzzy (NF) models to predict NOx concentration in the air as a function of traffic count (Tr) and climatic conditions including humidity (H), temperature (T), solar radiation (S), and wind speed (W) before and after the application of TiO? on the pavement surface. These models are useful for modeling because of their ability to be trained using historical data and because of their capability for modeling highly non-linear relationships. To build these models, data were collected from a field study where an aqueous nano TiO? solution was sprayed on a 0.2-mile of asphalt pavement in Baton Rouge, LA. Results of this study showed that the NF model provided a better fitting to NOx measurements than the ANN model in the training, validation, and test steps. Results of a parametric study indicated that traffic level, relative humidity, and solar radiation had the most influence on photocatalytic efficiency. PMID:24699867

Asadi, Somayeh; Hassan, Marwa; Nadiri, Ataallah; Dylla, Heather

2014-07-01

308

Avian respiratory distress: etiology, diagnosis, and treatment.  

Science.gov (United States)

Respiratory distress is usually a life-threatening emergency in any species and this is particularly important in avian species because of their unique anatomy and physiology. In the emergency room, observation of breathing patterns, respiratory sounds, and a brief physical examination are the most important tools for the diagnosis and treatment of respiratory distress in avian patients. These tools will help the clinician localize the lesion. This discussion focuses on the 5 anatomic divisions of the respiratory system and provides clinically important anatomic and physiologic principles and diagnosis and treatment protocols for the common diseases occurring in each part. PMID:21601813

Orosz, Susan E; Lichtenberger, Marla

2011-05-01

309

Acute respiratory distress in a silversmith  

OpenAIRE

A 25-year-old young male patient presented in casualty department with severe respiratory distress on the fourth day from onset of symptoms. The patient was nonsmoker and had no antecedent medical or drug history. Prior to admission, patient had dry cough and bilateral pleuritic chest pain for the last three days. He was in severe respiratory distress with use of accessory muscles of respiration. On examination, he had heart rate of 120 beats/min, blood pressure (BP) of 150/80, respiratory ra...

Parikh, Jignesh Mukeshkumar; Dhareshwar, Shashank; Sharma, Anand; Karanth, Raghuveer; Ramkumar, V. S.; Ramaiah, Indira

2014-01-01

310

Performance of an enhanced pervious pavement system loaded with large volumes of hydrocarbons.  

Science.gov (United States)

Five litres of lubricating oil and two 8.5 litre batches of diesel were deposited on each of two hydraulically isolated experimental enhanced pervious pavement parking bays. The 50 mm aggregate subbases of the two bays were of either recycled concrete or crushed limestone. The bays were constructed in such a way that a near-surface gravity separator was created by the arranging of the outlet pipes such that a permanent pool of water was maintained in the system and water could only enter from below the level of any floating oil. Dissolved/dispersed hydrocarbons were measured at acceptable concentrations when monitoring was carried out over a period of approximately 5 months. The maximum concentration was 7.2 mg/l and of all the samples collected only 3% exceeded the 5 mg/l limit applied in the UK for a class 1 interceptor, and the majority of samples had hydrocarbon concentrations of less than 2 mg/l. Much more significant is the fact that no free product was discharged from either system up to the time the experiment was dismantled 2 years from the first oil application despite the fact that sufficient hydrocarbon had been added to each pavement to produce a film on a water surface of over 500 hectares. PMID:25225930

Newman, Alan P; Puehmeier, Tim; Shuttleworth, Andy; Pratt, Christopher J

2014-01-01

311

An algorithm for pavement crack detection based on multiscale space  

Science.gov (United States)

Conventional human-visual and manual field pavement crack detection method and approaches are very costly, time-consuming, dangerous, labor-intensive and subjective. They possess various drawbacks such as having a high degree of variability of the measure results, being unable to provide meaningful quantitative information and almost always leading to inconsistencies in crack details over space and across evaluation, and with long-periodic measurement. With the development of the public transportation and the growth of the Material Flow System, the conventional method can far from meet the demands of it, thereby, the automatic pavement state data gathering and data analyzing system come to the focus of the vocation's attention, and developments in computer technology, digital image acquisition, image processing and multi-sensors technology made the system possible, but the complexity of the image processing always made the data processing and data analyzing come to the bottle-neck of the whole system. According to the above description, a robust and high-efficient parallel pavement crack detection algorithm based on Multi-Scale Space is proposed in this paper. The proposed method is based on the facts that: (1) the crack pixels in pavement images are darker than their surroundings and continuous; (2) the threshold values of gray-level pavement images are strongly related with the mean value and standard deviation of the pixel-grey intensities. The Multi-Scale Space method is used to improve the data processing speed and minimize the effectiveness caused by image noise. Experiment results demonstrate that the advantages are remarkable: (1) it can correctly discover tiny cracks, even from very noise pavement image; (2) the efficiency and accuracy of the proposed algorithm are superior; (3) its application-dependent nature can simplify the design of the entire system.

Liu, Xiang-long; Li, Qing-quan

2006-10-01

312

Evaluation of Common Maintenance Methods for Flexible Pavements  

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Full Text Available Problem statement: With the increasing use and awareness of pavement management systems and the growing emphasis on asset management of pavement infrastructure, it is important to strengthen the maintenance components of these systems and particularly the preventive maintenance component. Iraqi Roads don?t receive an effective and proper maintenance during their service life until they reach the state of major failure that requires rehabilitation. Roads in Iraq are being lost. Approach: In this study, a study of the status of maintenance methods for road pavements in Iraq with special reference to flexible pavements is presented. For this purpose, open and closed questionnaires were executed in Baghdad to investigate the status of road pavement maintenance in Iraq. Road maintenance offices as (Ministry of construction and Housing, State Corporation for Roads and Bridges, Amanat Baghdad, Project office, were included in the questionnaire to arrive at the level of maintenance and techniques followed to maintain paved road in Iraq. Results: The interviews carried out reveal that maintenance in Iraq has secondary importance, apparently with no special budget allocated for such important works. In addition the maintenance methods and techniques followed do not comply the developments and modern techniques. Conclusion/Recommendations: Poor and miss-management of maintenance works and activities leading to delays and accumulation of failure in the highway network that require unusual expenditures to repair and maintain the accumulated damages. Also shortages in resources allocated for maintenance works and this leads to the diversion of significant portion of the allocated fund for maintenance works toward purchasing of new, or additional equipment to be used for the construction of new roads. It is strongly recommended to design a planning system for management pavement maintenance of road network in Iraq and develop a particular failure criterion for roads in Iraq.

Asma T. Ibraheem

2011-01-01

313

13 CFR 301.3 - Economic distress levels.  

Science.gov (United States)

...distress criteria: (i) An unemployment rate that is, for the most recent...greater than the national average unemployment rate; (ii) Per capita income...distress levels based upon the unemployment rate or per capita income...

2010-01-01

314

13 CFR 301.3 - Economic distress levels.  

Science.gov (United States)

...2010-01-01 2010-01-01 false Economic distress levels. 301.3 Section 301.3 Business Credit and Assistance ECONOMIC DEVELOPMENT ADMINISTRATION, DEPARTMENT...PROPOSAL AND APPLICATION REQUIREMENTS Economic Distress Criteria § 301.3...

2010-01-01

315

Pavement Image Segmentation Based on FCM Algorithm Using Neighborhood Information  

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Full Text Available Standard FCM algorithm takes the pixel gray-scale information into account only, while ignoring the spatial location of pixels, so the standard FCM algorithm is sensitive to noise. This paper present a pavement image segmentation algorithm based on FCM algorithm using neighborhood information. The presented algorithm introduces neighborhood information into membership function to improve the standard FCM algorithm. It can eliminate noise effectively and retain the boundary information. The experiments by synthetic images and real pavement images show that the presented algorithm in this paper performs more robust to noise than the standard FCM algorithm and retain the boundary information effectively.

Guofeng Qin

2012-11-01

316

Interlocking Paving Stones Pavement as a Solution to Marshy Roads  

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Full Text Available This study is focused on the use of interlocking paving stones pavement for marshy roads and high groundwater table terrain. The permeable interlocking paving type of stones was used to combat intrusion of underground/saline water for the road of case study (Akin-Adesola Street, Victoria Island, Lagos. Hydrogeologic data, i.e., groundwater level information for marshy roads terrain including the area of case study was obtained in form of investigation hole/borehole data. Different scientific tests and researches put together show the effectiveness and durability of the modified exfiltration system type of permeable pavement for high ground water table terrain.

Oluwapelumi O. Ojuri

2012-04-01

317

Performance of waste tyre rubber on model flexible pavement  

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Full Text Available This paper investigates the performance of flexible pavement on expansive soil subgrade using gravel/flyash as subbase course with waste tyre rubber as a reinforcing material. It was observed that from the laboratory test results of direct shear and CBR, the gravel subbase shows better performance as compared to flyash subbase with different percentages of waste tyre rubber as reinforcing material. Cyclic load tests are also carried out in the laboratory by placing a circular metal plate on the model flexible pavements. It is observed that the maximum load carrying capacity associated with less value of rebound deflection is obtained for gravel reinforced subbase compared to flyash reinforced subbase.

D. S. V. Prasad

2009-08-01

318

Functionality enhancement of industrialized optical fiber sensors and system developed for full-scale pavement monitoring.  

Science.gov (United States)

Pavements always play a predominant role in transportation. Health monitoring of pavements is becoming more and more significant, as frequently suffering from cracks, rutting, and slippage renders them prematurely out of service. Effective and reliable sensing elements are thus in high demand to make prognosis on the mechanical properties and occurrence of damage to pavements. Therefore, in this paper, various types of functionality enhancement of industrialized optical fiber sensors for pavement monitoring are developed, with the corresponding operational principles clarified in theory and the performance double checked by basic experiments. Furthermore, a self-healing optical fiber sensing network system is adopted to accomplish full-scale monitoring of pavements. The application of optical fiber sensors assembly and self-healing network system in pavement has been carried out to validate the feasibility. It has been proved that the research in this article provides a valuable method and meaningful guidance for the integrity monitoring of civil structures, especially pavements. PMID:24854060

Wang, Huaping; Liu, Wanqiu; He, Jianping; Xing, Xiaoying; Cao, Dandan; Gao, Xipeng; Hao, Xiaowei; Cheng, Hongwei; Zhou, Zhi

2014-01-01

319

Functionality Enhancement of Industrialized Optical Fiber Sensors and System Developed for Full-Scale Pavement Monitoring  

Directory of Open Access Journals (Sweden)

Full Text Available Pavements always play a predominant role in transportation. Health monitoring of pavements is becoming more and more significant, as frequently suffering from cracks, rutting, and slippage renders them prematurely out of service. Effective and reliable sensing elements are thus in high demand to make prognosis on the mechanical properties and occurrence of damage to pavements. Therefore, in this paper, various types of functionality enhancement of industrialized optical fiber sensors for pavement monitoring are developed, with the corresponding operational principles clarified in theory and the performance double checked by basic experiments. Furthermore, a self-healing optical fiber sensing network system is adopted to accomplish full-scale monitoring of pavements. The application of optical fiber sensors assembly and self-healing network system in pavement has been carried out to validate the feasibility. It has been proved that the research in this article provides a valuable method and meaningful guidance for the integrity monitoring of civil structures, especially pavements.

Huaping Wang

2014-05-01

320

Groove depth requirements for tine-textured rigid pavement 5: Durability of tine texturing on PCC pavements  

Science.gov (United States)

The required depth for grooves on new tine textured concrete pavements in order to assure an adequate skid resistance over their entire design life is discussed. Measurements of texture depth and skid resistance, with both ribbed and smooth tires were made on 0 to 5 year-old New York pavements. Initial groove depth needs of 3/16 in. minimum were calculated from two values estimated from the study data: the minimum depth (0.050 in.) to assure adequate skid resistance with a minimally legal treaded tire, and the mean groove wear rate (0.013 in./million vehicle passes). Groove depth measurements on new concrete pavements and bridge decks indicated 21 an 14 percent compliance, respectively, with the proposed new standard of 3/16 in. minimum, and 60 and 44 percent compliance with the current standard of 2/16 in. minimum.

Grady, J. E.; Chamberlin, W. P.

1981-06-01

321

Development of a distress inventory for cancer: preliminary results.  

OpenAIRE

CONTEXT: Advances in cancer treatment have led to cure and prolongation of patients? lives; however associated psychosocial problems, including distress, can detrimentally affect patients? compliance with treatment and ultimately, their outcome. Symptom distress has been well addressed in many studies; however, psychological distress has only been quantified by using depression or anxiety scales/checklists or quality of life scales containing a distress sub scale/component or by...

Thomas B; Mohan V; Thomas I; Pandey M

2002-01-01

322

Evaluación de pavimentos y decisiones de conservación con base en sistemas de inferencia difusos / Pavement Evaluation and Maintenance Decisions Based on Fuzzy Inference Systems  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish Las decisiones de conservación y la vida remanente de pavimentos en servicio, dependen en buena parte de la condición estructural que exhiben durante su operación. Con el ánimo de proveer una metodología que permita caracterizar el pavimento de manera rápida, con los niveles de detalle que se deseen [...] , en este trabajo se plantean tres sistemas basados en la lógica difusa, para inferir la condición de rigidez y deterioro, así como las decisiones de conservación. Para esos fines, se utilizaron datos de auscultación no destructiva registrados en sistemas de pavimento de tres y cuatro capas, incluyendo estructuras tradicionales y estructuras invertidas (con capa de sub-base rigidizada). Las bases de datos incluyen información sobre magnitud y severidad de daños estructurales y parámetros e indicadores de rigidez, derivados de pruebas de deflexión por impacto. Los sistemas desarrollados, permitieron integrar directamente en la caracterización estructural de los pavimentos, tanto el conocimiento y criterios de expertos, como las variables de carácter subjetivo y cualitativo, que se utilizan comúnmente para describir los niveles de severidad del deterioro. Asimismo, permitieron expresar los resultados mediante palabras o adjetivos cuantificadores del lenguaje, facilitando su interpretación y comprensión. En virtud de los resultados alcanzados, resulta razonable concluir que los sistemas propuestos pueden utilizarse con confianza para evaluaciones rápidas y toma de decisiones a nivel global o detallado en corredores viales. Abstract in english The remaining service life and maintenance decisions of existing pavements are highly dependent on stiffness and deterioration conditions throughout their operation. A non-conventional fuzzy logic based methodology is proposed in this work to address the stiffness-deterioration condition and conserv [...] ation decisions, by means of three Fuzzy Inference Systems. Analysis were conducted using a database gathered from field tests performed on three and four layer pavement systems, that included traditional layer structuring and pavements having a subbase stiffer than their granular base. Information about layer thicknesses, magnitude and severity of structural distresses, and parameters and indicators derived from deflection testing by impulse load devices were used. The developed systems, allowed representing expert knowledge and linguistic variables of subjective and qualitative nature, commonly used to describe the severity levels of deterioration; thus they can be involved into structural characterization of pavements. Results were also expressed linguistically, to facilitate their interpretation and understanding. Based on the high quality of results obtained, it seems reasonable to conclude that the proposed systems could be used confidently for assessing and making decisions about pavement conservation, with low computational cost.

Gloria Inés, Beltrán-Calvo; Miguel Pedro, Romo-Organista.

2014-09-01

323

Terrorism, the Media, and Distress in Youth  

Science.gov (United States)

Following the 1995 bombing of the Alfred P. Murrah Federal Building in Oklahoma City, the authors examined emotional distress among youth who were not physically present at the disaster site. This research continued even two years after the bombing as the trial of Timothy McVeigh was beginning. The authors found an association between…

Pfefferbaum, Rose L.; Gurwitch, Robin H.; Robertson, Madeline J.; Brandt, Edward N., Jr.; Pfefferbaum, Betty

2003-01-01

324

Interpersonal Relationships and Emotional Distress in Adolescence  

Science.gov (United States)

The aim of this study was to examine positive and negative qualities in adolescents' interpersonal relationships and their relative importance in predicting emotional distress. Participants were 260 students from three schools in the Dublin area (119 girls; 141 boys), aged 12-18 years (M = 15.32, SD = 1.91). Students completed questionnaires…

Kenny, Rachel; Dooley, Barbara; Fitzgerald, Amanda

2013-01-01

325

Discrimination Distress among Chinese American Adolescents  

Science.gov (United States)

This paper addresses contradictions between common perceptions of Asian Americans as a "model minority" and growing evidence of discrimination and its negative psychological implications for this group. The current study examined Chinese American early adolescents' distress from experiences of discrimination, its relationship with mental health…

Grossman, Jennifer M.; Liang, Belle

2008-01-01

326

Managing ethical distress in nursing practice.  

Science.gov (United States)

In this monthly column, Aysha Mendes explores the many aspects of psychology interwoven into nursing practice. This month, she explores the causes of ethical distress in nursing, the effect it can have on nurses and what can be done to manage it. PMID:25492438

Mendes, Aysha

2014-12-11

327

Distress respiratorio agudo en el embarazo Acute respiratory distress syndrome in pregnancy  

OpenAIRE

Aunque la ocurrencia de Síndrome de distress respiratorio agudo/daño pulmonar agudo (SDRA/DPA) durante el embarazo es infrecuente, su letalidad es elevada y ha sido reportado como un factor importante en la mortalidad materna. Las investigaciones realizadas al respecto han sido escasas en la literatura nacional e internacional. Nuestra experiencia en la atención a la paciente materna crítica por más de 20 años demuestra que el distress en el embarazo constituye una entidad sindrómica d...

Alfredo Sánchez Valdivia; Alfredo Sánchez Padrón

2006-01-01

328

Riding Quality Model for Asphalt Pavement Monitoring Using Phase Array Type L-band Synthetic Aperture Radar (PALSAR  

Directory of Open Access Journals (Sweden)

Full Text Available There are difficulties associated with near-real time or frequent pavement monitoring, because it is time consuming and costly. This study aimed to develop a binary logit model for the evaluation of highway riding quality, which could be used to monitor pavement conditions. The model was applied to investigate the influence of backscattering values of Phase Array type L-band Synthetic Aperture Radar (PALSAR. Training data obtained during 3–7 May 2007 was used in the development process, together with actual international roughness index (IRI values collected along a highway in Ayutthaya province, Thailand. The analysis showed that an increase in the backscattering value in the HH or the VV polarization indicated the poor condition of the pavement surface and, of the two, the HH polarization is more suitable for developing riding quality evaluation. The model developed was applied to analyze highway number 3467, to demonstrate its capability. It was found that the assessment accuracy of the prediction of the highway level of service was 97.00%. This is a preliminary study of the proposed technique and more intensive investigation must be carried out using ALOS/PALSAR images in various seasons.

Kamiya Yoshikazu

2010-11-01

329

Experimental and Numerical Studies of the Effects of Water Sprinkling on Urban Pavement on Heat Island Mitigation  

Science.gov (United States)

One of the main causes of 'heat island phenomeno' is thought to be the artificial covers of the ground surface with asphalt or concrete which reduce greatly inherent cooling effect of water evaporation from soil surface. In this study, as a candidate method of mitigating the heat island the effects of the 'water sprinkling' on the pavements are discussed from field experiments and numerical studies. Three field experiments of water sprinkling on the asphalt/concrete pavements were performed in hot summer days in 2004-2006. For detecting the change in temperatures, the authors developed and used a 3-D measurements system which consists of two vertical planes with 6m high and 16m wide, and has network arrays of 102 thermistors distributed spatially in the planes. The temperatures measured in and around the water sprinkled area indicated that the ground surface temperature decreased 5 to 15 degrees uniformly in the water sprinkled area compared with those in the un-sprinkled area, while the relative decrease of atmospheric temperature was approximately up to 1 degree. The subsurface temperature at a depth of 14cm under the pavement decreased significantly and kept lower than that at the same depth in un-sprinkled area over the next morning. A numerical model was developed and applied to interpret the experimental results. It deals with the heat balance of radiation, sensible/latent heat transfer at the ground surface and heat conduction through the artificial and natural soil layer under ground. temperature and vapor conditions changes at and near ground surface were modeled by using the bulk formula.Good agreements between the calculated time-temperature profiles and the experimental ones were obtained by assuming adequate physical parameters and meteorological conditions. The model could be improved in order to evaluate the changes of temperature and vapor contents in atmosphere near the ground surface caused by aerodynamic turbulent diffusion.

Yoshioka, M.; Tosaka, H.; Nakagawa, K.

2007-12-01

330

Modeling Recycling Asphalt Pavement Processing Technologies in Asphalt Mixing Plants  

Directory of Open Access Journals (Sweden)

Full Text Available The article presents reclaimed asphalt pavement (RAP processing technologies and equipment models used in the asphalt mixing plant (AMP. The schematic model indicating all possible ways to process RAP in AMP is shown. The model calculating the needed temperature of mineral materials used for heating RAP is given and an example of such calculation is provided.Article in Lithuanian

Simonas Tamali?nas

2011-04-01

331

Modeling Recycling Asphalt Pavement Processing Technologies in Asphalt Mixing Plants  

OpenAIRE

The article presents reclaimed asphalt pavement (RAP) processing technologies and equipment models used in the asphalt mixing plant (AMP). The schematic model indicating all possible ways to process RAP in AMP is shown. The model calculating the needed temperature of mineral materials used for heating RAP is given and an example of such calculation is provided.Article in Lithuanian

Simonas Tamali?nas; Henrikas Sivilevi?ius

2011-01-01

332

Evaluating Pavement Cracks with Bidimensional Empirical Mode Decomposition  

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Full Text Available Crack evaluation is essential for effective classification of pavement cracks. Digital images of pavement cracks have been analyzed using techniques such as fuzzy set theory and neural networks. Bidimensional empirical mode decomposition (BEMD, a new image analysis method recently developed, can potentially be used for pavement crack evaluation. BEMD is an extension of the empirical mode decomposition (EMD, which can decompose nonlinear and nonstationary signals into basis functions called intrinsic mode functions (IMFs. IMFs are monocomponent functions that have well-defined instantaneous frequencies. EMD is a sifting process that is nonparametric and data driven; it does not depend on an a priori basis set. It is able to remove noise from signals without complicated convolution processes. BEMD decomposes an image into two-dimensional IMFs. The present paper explores pavement crack detection using BEMD together with the Sobel edge detector. A number of images are filtered with BEMD to remove noise, and the residual image analyzed with the Sobel edge detector for crack detection. The results are compared with results from the Canny edge detector, which uses a Gaussian filter for image smoothing before performing edge detection. The objective is to qualitatively explore how well BEMD is able to smooth an image for more effective edge detection with the Sobel method.

Nii Attoh-Okine

2008-05-01

333

DEVELOPMENT OF A HYDROPHOBIC SUBSTANCE TO MITIGATE PAVEMENT ICE ADHESION  

Science.gov (United States)

The specific problem to which this report is addressed is the development of a hydrophobic substance to mitigate the adhesion of ice to pavement as an alternative to deicing chemicals. The factors involved in evaluating this concept are the following: Economics; safety; environme...

334

Nitrogen Transformations in Three Types of Permeable Pavement  

Science.gov (United States)

In 2009, USEPA constructed a 0.4-ha (1-ac) parking lot at the Edison Environmental Center in Edison, NJ, that incorporated three different permeable pavement types - permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA). The driving lanes...

335

A Detailed Study of Cbr Method for Flexible Pavement Design  

Directory of Open Access Journals (Sweden)

Full Text Available As per IRC recommendation, California Bearing Ratio (CBR value of subgrade is used for design of flexible pavements. California Bearing Ratio (CBR value is an important soil parameter for design of flexible pavements and runway of air fields. It can also be used for determination of sub grade reaction of soil by using correlation. It is one of the most important engineering properties of soil for design of sub grade of roads. CBR value of soil may depends on many factors like maximum dry density (MDD, optimum moisture content (OMC, liquid limit (LL, plastic limit (PL, plasticity index (PI, type of soil, permeability of soil etc. Besides, soaked or unsoaked condition of soil also affects the value. These tests can easily be performed in the laboratory. the estimation of the CBR could be done on the basis of these tests which are quick to perform, less time consuming and cheap, then it will be easy to get the information about the strength of subgrade over the length of roads, By considering this aspect, a number of investigators in the past made their investigations in this field and designed different pavements by determining the CBR value on the basis of results of low cost, less time consuming and easy to perform tests. In this study, attempts have been made to seek the values of CBR of different soil samples and correlate their CBR values for the design purpose of flexible pavement as per guidelines of IRC: SP: 37-2001.

Er. Devendra Kumar Choudhary

2014-06-01

336

Long-term salt marsh recovery and pavement persistence at Metula' spill sites  

International Nuclear Information System (INIS)

Three coastal sites oiled from the 1974 'Metula' oil spill in the Strait of Magellan were revisited in May 1998 to document oiling conditions 23.5 years after the spill. The sites revisited are in the Punta Espora area. Two are salt marshes and the third, an inter-tidal asphalt pavement. It was found that the marshes were still oil covered and bare of vegetation in most sections, although the tilling conducted in 1993 resulted in substantial increases in the number of plants that were able to recolonize. Application of fertilizer without tilling of the surface of the oil had no effect. By 1998 the oil, although still present, was weathered to a rubbery consistency. The large, 550 m. long asphalt pavement that had formed on the mixed-sediment beach remained, and showed relatively little change. Chemical analysis of the asphalt indicated extremely high degradation, including even some of the highly biodegradation-resistant biomarker compounds. The experimental treatment plots that were tilled in 1993 showed the highest level of weathered oil, and the highest degree of plant recolonization, suggesting that recolonization of the marshes could have been accelerated had tilling been conducted on these sites soon after the spill. 15 refs., 5 tabs., 6 figs

337

ROP GTPase-mediated auxin signaling regulates pavement cell interdigitation in Arabidopsis thaliana.  

Science.gov (United States)

In multicellular plant organs, cell shape formation depends on molecular switches to transduce developmental or environmental signals and to coordinate cell-to-cell communication. Plants have a specific subfamily of the Rho GTPase family, usually called Rho of Plants (ROP), which serve as a critical signal transducer involved in many cellular processes. In the last decade, important advances in the ROP-mediated regulation of plant cell morphogenesis have been made by using Arabidopsis thaliana leaf and cotyledon pavement cells. Especially, the auxin-ROP signaling networks have been demonstrated to control interdigitated growth of pavement cells to form jigsaw-puzzle shapes. Here, we review findings related to the discovery of this novel auxin-signaling mechanism at the cell surface. This signaling pathway is to a large extent independent of the well-known Transport Inhibitor Response (TIR)-Auxin Signaling F-Box (AFB) pathway, and instead requires Auxin Binding Protein 1 (ABP1) interaction with the plasma membrane-localized, transmembrane kinase (TMK) receptor-like kinase to regulate ROP proteins. Once activated, ROP influences cytoskeletal organization and inhibits endocytosis of the auxin transporter PIN1. The present review focuses on ROP signaling and its self-organizing feature allowing ROP proteins to serve as a bustling signal decoder and integrator for plant cell morphogenesis. Deshu Lin. PMID:25168157

Lin, Deshu; Ren, Huibo; Fu, Ying

2015-01-01

338

Stabilization of Black Cotton Soil With Sand and Cement as a Subgrade for Pavement  

Directory of Open Access Journals (Sweden)

Full Text Available Expansive soil (Black cotton soil is very weak and does not have enough stability for any type of construction work. In pavement, subgrade layer is the bottommost layer underlying the base course or surface course. To make the subgrade soil stable, by improving its engineering properties is very essential. In the present work, stabilization of subgrade soil by using sand and cement (varying percentage of sand and constant percentage of cement by weight of soil is used to enhance the strength of subgrade soil. The purpose of this study is to determine the optimum dose of the stabilizer, which improves the strength of soil (CBR less than or equal to 2% to more than 7% which is suitable for pavement structure. To evaluate the strength of soil, various test have been performed such as sieve analysis, liquid limit, Plastic limit, Standard proctor test and CBR test in the laboratory. The result shows that the use of sand and cement in combination, increases the California Bearing Ratio values (CBR i.e. the strength of soil to a great extent.

Mrs. Neetu B. Ramteke *1 ,

2014-06-01

339

Desempeño de pavimentos estabilizado con asfalto espumado en una prueba de pavimentos a escala real y carga acelerada / Performance of foamed bitumen pavements in accelerated testing facility  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Uno de los objetivos claves de la gestión de pavimentos es desarrollar e implementar una estrategia de construcción y mantenimiento rentables, con el fin de alcanzar niveles requeridos de servicio y desempeño. Una técnica rentable y sustentable para la rehabilitación de pavimentos es la de estabiliz [...] ación o reciclado con asfalto espumado (AE). Este artículo presenta un estudio sobre el desempeño de pavimentos estabilizados con asfalto espumado en el Canterbury Accelerated Pavement Testing Indoor Facility CAPTIF. CAPTIF es un laboratorio a escala real para pavimentos ubicado en Nueva Zelandia, que permite aplicar un gran número de cargas de tráfico en un breve período de tiempo. Seis secciones de pavimentos con distintos contenidos de asfalto y cemento fueron ensayadas en CAPTIF. Los resultados del experimento mostraron que las deflexiones disminuyen en las secciones con mayor contenido de asfalto espumado. Luego de aplicar más de un millón de ciclos de carga, las secciones estabilizadas sólo con cemento, sólo con asfalto y la sección sin estabilizar mostraron un deterioro significativo en forma de ahuellamiento. Por otro lado, las secciones que fueron estabilizadas con AE y cemento mostraron un buen desempeño, demostrando que el cemento y el AE juntos mejoran significativamente el desempeño del pavimento. Los resultados de ahuellamiento fueron empleados para desarrollar modelos y describir el deterioro estable y acelerado de los pavimentos en estudio, lo que puede ser utilizado para una mejor gestión de los pavimentos estabilizados con asfalto espumado. Abstract in english One of the key principal goals of pavement asset management is to develop and implement cost-effective pavement construction and maintenance strategies that achieve the required levels of service and performance. A sustainable, cost-effective technique for rehabilitating pavements is foamed bitumen [...] stabilization. This paper presents a study on the performance of foamed bitumen pavements tested in the Canterbury Accelerated Pavement Testing indoor Facility (CAPTiF), for full scale testing of pavements. Six pavement sections were tested; the variables were bitumen and cement content; one control section with the untreated unbound material was tested. Results showed that surface deflections decreased at sections with higher bitumen contents. After the application of 5,710,000 Equivalent Standard Axles (ESAs), the sections stabilised with cement only, bitumen only, and the control section all showed large amounts of rutting. Conversely, little rutting was observed in the three sections stabilised with foamed bitumen and 1.0% cement, showing that cement and FB together significantly improve pavement performance. The rutting results were used to develop models to describe the stable and unstable performance of the tested pavements. The paper concludes by outlining some of the practical benefits of utilising this technology in pavement asset management.

Alvaro, Gonzalez; Misko, Cubrinovski; Bryan, Pidwerbesky; David, Alabaster.

2012-08-01

340

Application of CalME incremental-recursive method to the evaluation of the structural condition as asphalt pavements; Aplicacion del metodo recursivo-incremental CalME a la evaluacion del estado estructural de los pavimentos bituminosas  

Energy Technology Data Exchange (ETDEWEB)

CalME procedure represents one of the most advanced tools for the design, of flexible pavements world-wide. It is an incremental-recursive method, which means that pavements service life must be divided into many time intervals where both structural integrity and environmental conditions can be regarded as constants. It also means that the damage calculated at the end of each interval must be considered as initial condition for the next one. The goal of this type of models is the prediction of the evolution of the different distress mechanisms. The advantages of incremental-recursive procedures versus classical analytical design are shown in this paper. Advantages are shown not only in terms of design, but also as a tool in order to support structural evaluation. In particular, the potential of asphalt fatigue model incorporated in CalME is presented. this model is initially calibrated in the laboratory, and it is then re-calibrated based on the actual performance observed from field deflection testing. The model provides a reliable prediction of the future evolution of the damage of the asphalt mixture. Fatigue model validation has been conducted based on the performance from several flexible sections evaluated in CEDEX full-scale pavements test track. (Author) 14 refs.

Mateos Moreno, A.; Perez Ayuso, J.; Cadavid Jauregui, B.; Marron Fernandez, J. O.

2011-07-01

341

Mechanistic modelling of weak interlayers in flexible and semi-flexible road pavements: Part 2  

Directory of Open Access Journals (Sweden)

Full Text Available This paper (Part 2 of a two-part set of papers discusses models and illustrates the adverse effects of weak layers, interlayers, laminations and/or weak interfaces in flexible and semi-flexible pavements, also incorporating lightly cemented layers. The modelling is based on mechanistic analyses for pavement design and evaluation. In Part 1, the effects of these relatively weak layers, interlayers, laminations and/or weak interfaces were discussed. It was shown that methodologies are available to detect and investigate the existence of these weak layers in cemented pavement layers. In Part 2, several cases of the above conditions for different road pavement types are discussed, with field examples. Mechanistic analyses were done on a typical hot mix asphalt (HMA, several cases of a cemented base pavement and a granular base pavement, with and without these weak layers and interface conditions to demonstrate their adverse effects. The analyses focus on the strain energy of distortion (SED as a pavement response parameter to indicate the potential for structural damage expected within the pavement structure or layer. Generally, the higher the SED, the higher the potential damage in the pavement layer. SED shows some potential for quantifying the relative effects of these weak layers, interlayers, laminations and/or weak interfaces within flexible and semi-flexible pavements.

M de Beer

2012-04-01

342

An assessment of the skid resistance effect on traffic safety under wet-pavement conditions.  

Science.gov (United States)

Pavement-tire friction provides the grip that is required for maintaining vehicle control and for stopping in emergency situations. Statistically significant negative correlations of skid resistance values and wet-pavement accident rates have been found in previous research. Skid resistance measured with SCRIM and crash data from over 1750km of two-lane rural roads in the Spanish National Road System were analyzed to determine the influence of pavement conditions on safety and to assess the effects of improving pavement friction on safety. Both wet- and dry-pavement crash rates presented a decreasing trend as skid resistance values increased. Thresholds in SCRIM coefficient values associated with significant decreases in wet-pavement crash rates were determined. Pavement friction improvement schemes were found to yield significant reductions in wet-pavement crash rates averaging 68%. The results confirm the importance of maintaining adequate levels of pavement friction to safeguard traffic safety as well as the potential of pavement friction improvement schemes to achieve significant crash reductions. PMID:19540980

Pardillo Mayora, José M; Jurado Piña, Rafael

2009-07-01

343

Mechanistic modelling of weak interlayers in flexible and semi-flexible road pavements: Part 2  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english This paper (Part 2 of a two-part set of papers) discusses models and illustrates the adverse effects of weak layers, interlayers, laminations and/or weak interfaces in flexible and semi-flexible pavements, also incorporating lightly cemented layers. The modelling is based on mechanistic analyses for [...] pavement design and evaluation. In Part 1, the effects of these relatively weak layers, interlayers, laminations and/or weak interfaces were discussed. It was shown that methodologies are available to detect and investigate the existence of these weak layers in cemented pavement layers. In Part 2, several cases of the above conditions for different road pavement types are discussed, with field examples. Mechanistic analyses were done on a typical hot mix asphalt (HMA), several cases of a cemented base pavement and a granular base pavement, with and without these weak layers and interface conditions to demonstrate their adverse effects. The analyses focus on the strain energy of distortion (SED) as a pavement response parameter to indicate the potential for structural damage expected within the pavement structure or layer. Generally, the higher the SED, the higher the potential damage in the pavement layer. SED shows some potential for quantifying the relative effects of these weak layers, interlayers, laminations and/or weak interfaces within flexible and semi-flexible pavements.

M, de Beer; J W, Maina; F, Netterberg.

2012-04-01

344

Moral distress and moral conflict in clinical ethics.  

Science.gov (United States)

Much research is currently being conducted on health care practitioners' experiences of moral distress, especially the experience of nurses. What moral distress is, however, is not always clearly delineated and there is some debate as to how it should be defined. This article aims to help to clarify moral distress. My methodology consists primarily of a conceptual analysis, with especial focus on Andrew Jameton's influential description of moral distress. I will identify and aim to resolve two sources of confusion about moral distress: (1) the compound nature of a narrow definition of distress which stipulates a particular cause, i.e. moral constraint, and (2) the distinction drawn between moral dilemma (or, more accurately, moral conflict) and moral distress, which implies that the two are mutually exclusive. In light of these concerns, I argue that the definition of moral distress should be revised so that moral constraint should not be a necessary condition of moral distress, and that moral conflict should be included as a potential cause of distress. Ultimately, I claim that moral distress should be understood as a specific psychological response to morally challenging situations such as those of moral constraint or moral conflict, or both. PMID:24602097

Fourie, Carina

2015-02-01

345

Psychological distress among women with newly diagnosed breast cancer  

DEFF Research Database (Denmark)

PURPOSE: Psychological distress is common in the cancer continuum. Our objectives were to determine the prevalence of distress and to investigate the related problems and the characteristics of women with breast cancer who experienced psychological distress at the time of diagnosis. METHODS: We used cross-sectional data from a questionnaire study. Women with newly diagnosed breast cancer were consecutively invited to respond before breast surgery. Between October 2008 and October 2009, a total of 357 responded out of 426 (84%) invited. Among these, 343 patients completed the 'distress thermometer' to measure psychological distress and the accompanying 'problem list' to identify related problems. Logistic regression models with 95% confidence intervals were used to estimate the associations between psychological distress, age, social support and domains on the problem list. RESULTS: With a cut-off of 3 on the distress thermometer, 77% of women with breast cancer reported distress, whereas when the cut-off was 7, 43% were distressed. The mean distress score was 5.4 (SD, 3.1). The most frequently reported problems were worry (77%) and nervousness (71%). Distress was significantly associated with the total score and three domains on the problem list. Younger women (

Mertz, Birgitte; Bistrup, Pernille Envold

2012-01-01

346

Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates  

International Nuclear Information System (INIS)

Non-point-source pollution is a major source of ecological impairment in urban stream systems. Recent work suggests that coal-tar pavement sealants, used extensively to protect parking areas, may be contributing a large portion of the polycyclic aromatic hydrocarbon (PAH) loading seen in urban stream sediments. The hypothesis that dried coal-tar pavement sealant flake could alter the macroinvertebrate communities native to streams in Austin, TX was tested using a controlled outdoor laboratory type approach. The treatment groups were: control, low, medium, and high with total PAH concentrations (TPAH = sum of 16 EPA priority pollutant PAHs) of 0.1, 7.5, 18.4, and 300 mg/kg respectively. The low, medium, and high treatments were created via the addition of dried coal-tar pavement sealant to a sterile soil. At the start of the 24-day exposure, sediment from a minimally impacted local reference site containing a community of live sediment-dwelling benthic macroinvertebrates was added to each replicate. An exposure-dependent response was found for several stream health measures and for several individual taxa. There were community differences in abundance (P = 0.0004) and richness (P < 0.0001) between treatments in addition to specific taxa responses, displaying a clear negative relationship with the amount of coal-tar sealant flake. These results support the hypothesis that coal-tar pavement sealants contain bioavailable PAHs that may harm aquatic environments. - Coal-tar may harm aquatic environments. - Coal-tar pavement sealants degrade stream invertebrate communities.

347

Study on the influence of asphalt concrete pavement physical – mechanical and other incices on the transport – operation properties of the main Lithuanian highways  

OpenAIRE

The main aim of this thesis paper is to determine the influence of physical and mechanical indices of asphalt concrete pavement on the operational properties of Lithuanian highway pavement as well as on the functional lifetime of road pavement. The analysis of pavement condition of Lithuanian highways is presented. The classification regarding the damage and deformation of material used for the construction of asphalt concrete pavement and of road pavement structure is provided. The causes of...

Baltrus?aitis, Andrius

2005-01-01

348

Influence of Three Permeable Pavement Surfaces on Nitrogen Treatment  

Science.gov (United States)

Nitrogen is a stressor of concern in many nutrient sensitive watersheds often associated with algal blooms and resulting fish kills. Communities are increasingly installing green infrastructure stormwater control measures (SCMs) to reduce pollutant loads associated with stormwat...

349

Acute respiratory distress caused by massive thymolipoma.  

Science.gov (United States)

The authors present the case of a 40-year-old female with a massive anterior mediastinal tumor who presented with acute respiratory distress. She required emergent intubation and ventilatory support for respiratory compromise caused by lung compression. Preoperative computed tomographic scan results suggested a mediastinal lipomatous mass. Resection of the tumor resulted in immediate improvement in her pulmonary status. Because thymolipomas can attain enormous dimensions and compress adjacent structures, they should be resected at the time of diagnosis. PMID:15586609

Halkos, Michael E; Symbas, John D; Symbas, Panagiotis N

2004-11-01

350

Acute Respiratory Distress Syndrome in Lemierre's Syndrome  

OpenAIRE

Lemierre's syndrome is an infectious disease defined by the presence of septic thrombophlebitis with associated embolic phenomenon, most commonly to the lungs. Here we present two cases from a single institution of acute respiratory distress syndrome (ARDS) developing as a result of Lemierre's syndrome in previously healthy young adult men. ARDS can occur as a consequence of pulmonary septic emboli and sepsis, both of which are well-described consequences of Lemierre's syndrome. We describe i...

Hein, Paul N.; Soghikian, Maida V.; Bhangoo, Munveer S.

2014-01-01

351

Adaptive Road Crack Detection System by Pavement Classification  

OpenAIRE

This paper presents a road distress detection system involving the phases needed to properly deal with fully automatic road distress assessment. A vehicle equipped with line scan cameras, laser illumination and acquisition HW-SW is used to storage the digital images that will be further processed to identify road cracks. Pre-processing is firstly carried out to both smooth the texture and enhance the linear features. Non-crack features detection is then applied to mask areas of the images wit...

Alejandro Amírola; Pedro Yarza; Pedro Aliseda; Manuel Ocaña; Ignacio Parra; Sotelo, Miguel A.; Llorca, David F.; Miguel Gavilán; Oscar Marcos; David Balcones

2011-01-01

352

Researches and Evaluation of Climate Influence on the Structural Strength of Road Asphalt Pavement  

OpenAIRE

This final master thesis performs asphalt pavement structural behavior of the Lithuanian climate conditions, taking into account the temperature and moisture, as one of the most important climatic factors that influence the road asphalt pavement structural strength. The Falling Weight Deflectometer (FWD) measurement methods used in other countries are presented. The temperature and moisture changes in the day are analysed, evaluating their impact on pavement design. The strength of asphalt pa...

Paliukaite?, Migle?

2010-01-01

353

Finite element modeling and analysis of accelerated pavement testing devices and rutting phenomenon  

OpenAIRE

The Indiana Department of Transportation/Purdue University accelerated pavement testing facilities (APT and PURWheel) have been utilized in conducting the National Pooled Funds Study (PFS) No. 176, “Validation of SHRP Asphalt Mixture Specifications Using Accelerated Pavement Testing”. Benefit of using the Accelerated Pavement Tester is that early rutting performance could be obtained for Superpave mixtures. ^ In conjunction with the testing, finite element models have been developed for...

Hua, Jianfeng

2000-01-01

354

Non-Destructive Estimation of Pavement Thickness, Structural Number and Subgrade Resilience along INDOT Highways  

OpenAIRE

Nondestructive testing has become an integral part for evaluation and rehabilitation strategies of pavements in recent years. Pavement evaluation employing the Falling Weight Deflectometer (FWD) and the Ground Penetrating Radar (GPR) can provide valuable information about pavement performance characteristics and be a very useful tool for project prioritization purposes and estimation of construction budget at the network level. FWD deflection testing is an accurate tool for determining paveme...

Noureldin, Samy; Zhu, Karen; Harris, Dwayne Authur; Li, Shuo

2005-01-01

355

Socio-economic aspects of the Byzantine mosaic pavements of Phoenicia and northern Palestine  

OpenAIRE

?The present thesis analyzes the Byzantine mosaic pavements of Phoenicia and Northern Palcatine from a socio-economic perspective, primarily by examining the laying of pavements including technical aspects and bedding, the quality of decoration, the distribution of pavements in time and space, as well as inscriptions which provide names of donors and artists as well as dates. The approach adopted represents a novel alternative and complement to typical interpretations of mosaic floor dec...

Merrony, Mark W.; Dr Claudine Dauphin, Dr Julian Raby

2002-01-01

356

[Extracorporeal membrane oxygenation by acute respiratory distress syndrome].  

Science.gov (United States)

After various observational studies demonstrated a benefit of extracorporeal membrane oxygenation (ECMO) in the therapy of severe acute respiratory distress syndrome (ARDS), ECMO now represents an important contribution for ARDS therapy using clinical algorithms despite a lack of positive controlled studies. In specialized centers patients with severe ARDS and imminent hypoxia despite intensive conventional therapy, are treated with ECMO using blood pumps and artificial membrane lungs (oxygenators) for extracorporeal lung assist. The development of new surface modifications, optimized oxygenators and miniaturized blood pumps should increase hemocompatibility and lead to simplified treatment as well as less complications. New oxygenators with significantly decreased blood resistance allow the clinical application of pumpless arteriovenous extracorporeal lung assist (ECLA). After these new developments indications for ECMO could be extended from use not only as ultimate ratio but to less severe ARDS to enable lung protective, less invasive mechanical ventilation. PMID:14991195

Kopp, R; Henzler, D; Dembinski, R; Kuhlen, R

2004-02-01

357

Psychological and physical distress of cancer patients during radiotherapy  

CERN Document Server

Purpose: patients undergoing radiotherapy have physical and psychological symptoms related to the underlying disease and the treatment. In order to give the best possible support to the patients, more knowledge about the amount and the changing of distress in the course of radiotherapy is of essentially importance. Methods: The distress was measured in a consecutive sample of cancer patients (n=82) undergoing radiotherapy. Each patient was given the EORTC-QLQ-C30, the HADS and a special questionnaire which ascertain radiotherapy-specific items before starting the radiotherapy, at the onset of radiotherapy, in the third week of radiotherapy and 3 weeks after the end of radiotherapy. Results: within the first week of treatment the psychological distress of the patients is increasing; 98.8 % of the patients are 'moderate distressed', 46 % 'severe distressed'. General physical symptoms seem not to be affected by the radiotherapy, there is no changing. The distress caused by the organization of the radiotherapy is...

König, A

2001-01-01

358

A demedicalized view of maternal distress: conceptualization and instrument development.  

Science.gov (United States)

The goal of this article was to describe instrument development of a demedicalized, multidomain view of maternal distress, with psychological, relational, and situational manifestations. We developed a pilot instrument derived from our previous grounded theory conceptualization of maternal distress and administered it to a purposive sample of 100 low-income single mothers. Analyses testing the relationship between maternal distress and depressive symptoms, guilt, child rearing stress, and community needs variables suggested that the maternal distress inventory had convergent, discriminant, and concurrent validity. Not only was maternal distress distinct from depressive symptomology and generalized child rearing stress, it appeared to be more meaningfully associated with "real world" outcomes of interest to psychological service providers than purely psychological measures of the distress. PMID:22984879

Arditti, Joyce A; Grzywacz, Jospeh G; Gallimore, Sara Wang

2013-11-01

359

Sources of anticipatory distress among breast surgery patients.  

Science.gov (United States)

Surgical consultation concerning the possibility of breast cancer is a distressing experience, and having to take the next step of breast surgery even more so for many women. However, the sources of variability in such presurgical distress are not well understood. Sixty-one women (mean age = 51) were recruited immediately following surgical consultation in which a recommendation of breast surgery (excisional biopsy/lumpectomy) was made. Patients completed measures of distress, worry about cancer and surgery, trait anxiety, optimism and pessimism prior to surgery. Surprisingly, results revealed no effect of surgeon-provided information concerning preliminary diagnosis on patient distress. Rather, worry about what the surgeon might find concerning the breast mass during surgery, worry about having to go through the operative procedures, and patient optimism were the only factors that uniquely contributed to patient distress (p's foundation for future clinical interventions to reduce presurgery distress. PMID:12776384

Montgomery, Guy H; David, Daniel; Goldfarb, Alisan B; Silverstein, Jeffrey H; Weltz, Christina R; Birk, Jennifer S; Bovbjerg, Dana H

2003-04-01

360

Design Methodologies of Asphalt Pavement Used in China and Mozambique  

Directory of Open Access Journals (Sweden)

Full Text Available This study discusses and compares Asphalt Concrete (AC pavement design methodologies used in China and Mozambique (based on South African Transportation and Communication Commission (SATCC methodologies. The SATCC design methodologies use California Bearing Ratio (CBR and catalogues methods. The South African catalogues are basically used for roads with traffic less than 30 million ESAs. The design catalogues method give small thickness than CBR and Chinese methods. The Chinese and the South African design methods give nearly the same thickness; this study concludes that these methods can be used in both countries; China and Mozambique. The results also show that the strong point of Chinese method is verifying the tensile stress and allowable displacement on the pavement calculated from computer program APDS.

Jose Francisco Rufino Diogo

2007-01-01

361

Design Methodologies of Asphalt Pavement Used in China and Mozambique  

Science.gov (United States)

This study discusses and compares Asphalt Concrete (AC) pavement design methodologies used in China and Mozambique (based on South African Transportation and Communication Commission (SATCC) methodologies). The SATCC design methodologies use California Bearing Ratio (CBR) and catalogues methods. The South African catalogues are basically used for roads with traffic less than 30 million ESAs. The design catalogues method give small thickness than CBR and Chinese methods. The Chinese and the South African design methods give nearly the same thickness; this study concludes that these methods can be used in both countries; China and Mozambique. The results also show that the strong point of Chinese method is verifying the tensile stress and allowable displacement on the pavement calculated from computer program APDS.

Francisco Rufino Diogo, Jose; Shubber, Ammar Abbas Mohammed; Lin, Mu Han

362

Use of Recycled Aggregate and Fly Ash in Concrete Pavement  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Recycled materials aggregate from the demolished concrete structures and fly ash from burning coal shows the possible application as structural and non structural components in concrete structures. This research aims to evaluate the feasibility of using concrete containing recycled concrete aggregate and fly ash in concrete pavement. Approach: Two water cement ratio (0.45 and 0.55 the compressive strength, modulus of electricity and flexural strength for concrete with recycled aggregate and fly ash with 0, 25% replacing cement in mass were considered. Results: The material properties of recycled aggregate concrete with fly ash indicate comparable results with that of concrete with natural aggregate and without fly ash. Conclusion/Recommendations: The recycled materials could be used in concrete pavement and it will promote the sustainability of concrete.

Myle N. James

2011-01-01

363

Pavement wear and airborne dust pollution in Norway  

OpenAIRE

In several large cities in Norway the traffic volume is high. The use of studded tires and other friction enhancing measures during winter leads to significant pavement wear, which in turn leads to an increase in the amount of airborne particulate matter, often exceeding the limits set in the ambient air regulation. This represents a nuisance or health risk for people being exposed to the pollution. According to regulations set by the European Union particulate matter is measured an...

Snilsberg, Brynhild

2008-01-01

364

Road Performance of Fiber Reinforced Asphalt Concrete Bridge Deck Pavement  

OpenAIRE

As the problem of asphalt concrete bridge deck pavement is becoming more and more serious, how to improve its road performance has become the focus of the study. Considering fiber is widely used in road engineering, wheel tracking test, flexural test, immersion marshall test and freeze-thaw splitting test were carried out to study road performance of asphalt mixture with different fiber contents, analyzing the function mechanism of fiber reinforced asphalt ...

Xiu Liu; Zhaojie Sun; Decheng Feng; Yixiang Cao

2013-01-01

365

Modeling aggregate interlock load transfer at concrete pavement joints  

OpenAIRE

Please read the abstract in the section 00front of this document © 2003, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria Please cite as follows: Brink AC, 2003, Modelling aggregate interlock load transfer at concrete pavement jounts, PhD ...

Brink, Anna Catharina

2005-01-01

366

Frictional Resistance of Aggregates for Hot-Mix Asphalt Pavements  

OpenAIRE

In 1997 the Indiana Department of Transportation adopted the Superpave mixture design method and attendant specifications for hot-mix asphalt pavements. Prior to Superpave, the Indiana Department of Transportation aggregate frictional requirements were based on average daily traffic volumes and were divided into low, medium, and high volume categories. With the implementation of Superpave in Indiana, aggregate frictional requirements were reassigned to categories based on equivalent single ax...

O Brien, Joan Patricia; Haddock, John E.

2004-01-01

367

DYNAMIC JOINT LOAD TRANSFER EFFICIENCY OF RIGID PAVEMENT  

Directory of Open Access Journals (Sweden)

Full Text Available the mechanistic analysis presented in this paper is only the beginning of new approach for understanding the real joint load transfer capability on airport and highway concrete pavements. It gives up the two major assumptions those have been popularly adopted by hundreds of published papers: the load is transferred under a wheel with zero speed and with fixed position. The real load transfer in field is always under wheels with non-zero speed and with varied position at any moment. The objective of this study focuses on quantifying the dynamic effects of a moving wheel while it is crossing a joint on a pavement. The analysis is conducted using a model of two-slab system on Kelvin foundation under a moving wheel with variable speed v, different pavement damping Cs, foundation reaction modulus k and foundation damping Ck. The dynamic joint load transfer efficiency is temporarily and empirically defined by the peak strain ratio LTE(S on the two sides of a joint. The primary findings include: (1 The higher speed of a moving wheel leads to the higher LTE(S;(2 The larger the pavement damping Cs leads to the higher LTE(S;(3 The numerical ratio c(=LTE(Sdynamic/ LTE(Sstatic varies in the range 1 to 2 mainly depending on speed v and damping Cs;(4 The LTE(Sdynamic is not sensitive to foundation reaction modulus k and foundation damping Ck. Further researches are needed for appropriate applications of the new model in practice.

YU Xinhua

2011-02-01

368

Innovations in design and construction of granular pavements and railways  

OpenAIRE

This paper describes some of the work related with the International Technical Committee TC3 – Geotechnics of Pavements of ISSMGE. For brevity, some topics are selected to be described in some detail, while others are acknowledged for reference purposes. These topics cover: (1) Data Mining tools in transporttation geotechnics showing the capabilities to predict real-value from several attributes and also the possibility to develop a formal updating framework to reduce uncertainty a...

Correia, A. Gomes

2008-01-01

369

Cytokinin signaling regulates pavement cell morphogenesis in Arabidopsis  

OpenAIRE

The puzzle piece-shaped Arabidopsis leaf pavement cells (PCs) with interdigitated lobes and indents is a good model system to investigate the mechanisms that coordinate cell polarity and shape formation within a tissue. Auxin has been shown to coordinate the interdigitation by activating ROP GTPase-dependent signaling pathways. To identify additional components or mechanisms, we screened for mutants with abnormal PC morphogenesis and found that cytokinin signaling regulates the PC interdigita...

Li, Hongjiang; Xu, Tongda; Lin, Deshu; Wen, Mingzhang; Xie, Mingtang; Duclercq, Je?ro?me; Bielach, Agnieszka; Kim, Jungmook; Reddy, G. Venugopala; Zuo, Jianru; Benkova?, Eva; Friml, Jir?i?; Guo, Hongwei; Yang, Zhenbiao

2012-01-01

370

Performance of waste tyre rubber on model flexible pavement  

OpenAIRE

This paper investigates the performance of flexible pavement on expansive soil subgrade using gravel/flyash as subbase course with waste tyre rubber as a reinforcing material. It was observed that from the laboratory test results of direct shear and CBR, the gravel subbase shows better performance as compared to flyash subbase with different percentages of waste tyre rubber as reinforcing material. Cyclic load tests are also carried out in the laboratory by placing a circular metal plate on t...

Prasad, D. S. V.; Prasada Raju, G. V. R.

2009-01-01

371

Concrete Pavement Crack and Seat Performance Overlay Design  

OpenAIRE

The objective of this study is to develop guidelines and criteria for design and construction of overlays on cracked and seated concrete pavements. The main factors which are investigated in this study include number of the seated roller pass, weight of seating roller pass, weight of seating roller, thickness of overlay, fiber content and fiber layer location. Eleven test sections were constructed on I-65 and twenty two test sections were constructed on US-31. An extensive investigation was...

Huang, Haiming; White, Thomas D.

1995-01-01

372

Design Methodologies of Asphalt Pavement Used in China and Mozambique  

OpenAIRE

This study discusses and compares Asphalt Concrete (AC) pavement design methodologies used in China and Mozambique (based on South African Transportation and Communication Commission (SATCC) methodologies). The SATCC design methodologies use California Bearing Ratio (CBR) and catalogues methods. The South African catalogues are basically used for roads with traffic less than 30 million ESAs. The design catalogues method give small thickness than CBR and Chinese methods. The Chinese and the So...

Jose Francisco Rufino Diogo; Ammar Abbas Mohammed Shubber; Mu Han Lin

2007-01-01

373

Use of Recycled Aggregate and Fly Ash in Concrete Pavement  

OpenAIRE

Problem statement: Recycled materials aggregate from the demolished concrete structures and fly ash from burning coal shows the possible application as structural and non structural components in concrete structures. This research aims to evaluate the feasibility of using concrete containing recycled concrete aggregate and fly ash in concrete pavement. Approach: Two water cement ratio (0.45 and 0.55) the compressive strength, modulus of e...

James, Myle N.; Wonchang Choi; Taher Abu-Lebdeh

2011-01-01

374

Using recycled concrete as coarse aggregate in pavement concrete  

OpenAIRE

The main objective of this study was to evaluate the effects of using aggregate produced from recycled concrete as a replacement for natural (virgin) coarse aggregate in pavement mixtures. All mixtures containing the recycled concrete aggregate (RCA) were designed to meet the requirements of Indiana Department of Transportation (INDOT) specifications. The scope of the study included evaluation and comparison of several properties of RCA and natural aggregates, evaluation and analysis of the e...

Verian, Kho Pin

2012-01-01

375

Distress criterion influences prevalence rates of functional gastrointestinal disorders  

OpenAIRE

BackgroundFunctional gastrointestinal disorders (FGID) are defined by a combination of chronic or recurrent gastrointestinal symptoms. Prevalence rates of FGID are high. Symptoms are associated with distress, and sufferers show high stress levels. However, the current diagnostic criteria do not consider subjective distress elicited by the symptoms, thus potentially leading to overestimated prevalence rates. The aim of this study was to explore the reduction in prevalence rates when distress i...

Markert, Charlotte; Suarez-hitz, Kerstin; Ehlert, Ulrike; Nater, Urs M.

2014-01-01

376

Vulnerability, Distress, and Immune Response to Vaccination in Older Adults  

OpenAIRE

Psychological distress and biobehavioral vulnerability (e.g., arising from being older or sedentary) have independently predicted immune responses to influenza vaccination in older adults. Recent research examining basal inflammatory markers suggests that, rather than having additive effects, distress and vulnerability interact with each other. The present study tested the interactions between distress and age, sex, education, BMI, sleep quality, and physical activity over up to 8 years in ol...

Segerstrom, Suzanne C.; Hardy, Jaime K.; Evans, Daniel R.; Greenberg, Richard N.

2012-01-01

377

Full scale demonstration of air-purifying pavement  

International Nuclear Information System (INIS)

Highlights: ? The results of a demonstration project for photocatalytic pavement are shown. ? The photocatalytic performance was studied in a street as well as on lab scale. ? The outdoor monitoring was performed in different seasons and weather conditions. ? The NOx concentration was in average 19% lowered by the photocatalytic street. ? Under ideal weather conditions the NOx reduction reached up to 45%. -- Abstract: Experiments concerning a full-scale demonstration of air purifying pavement in Hengelo, The Netherlands, are reported. The full width of the street was provided with concrete pavement containing TiO2 over a length of 150 m (“DeNOx street”). Another part of the street, about 100 m, was paved with normal paving blocks (“Control street”). The outdoor monitoring was done during 26 days for a period exceeding one year, and measured parameters included traffic intensity, NO, NO2 and ozone concentrations, temperature, relative humidity, wind speed and direction, and the visible and UV light irradiance. Prior and parallel to these field measurements, the used blocks were also measured in the lab to assess their performance. The NOx concentration was, on average, 19% (considering the whole day) and 28% (considering only afternoons) lower than the obtained values in the Control street. Under ideal weather conditions (high radiation and low relative humidity) a NOx concentration decrease of 45% could be observed

378

Reliability-based performance simulation for optimized pavement maintenance  

International Nuclear Information System (INIS)

Roadway pavement maintenance is essential for driver safety and highway infrastructure efficiency. However, regular preventive maintenance and rehabilitation (M and R) activities are extremely costly. Unfortunately, the funds available for the M and R of highway pavement are often given lower priority compared to other national development policies, therefore, available funds must be allocated wisely. Maintenance strategies are typically implemented by optimizing only the cost whilst the reliability of facility performance is neglected. This study proposes a novel algorithm using multi-objective particle swarm optimization (MOPSO) technique to evaluate the cost-reliability tradeoff in a flexible maintenance strategy based on non-dominant solutions. Moreover, a probabilistic model for regression parameters is employed to assess reliability-based performance. A numerical example of a highway pavement project is illustrated to demonstrate the efficacy of the proposed MOPSO algorithms. The analytical results show that the proposed approach can help decision makers to optimize roadway maintenance plans. - Highlights: ?A novel algorithm using multi-objective particle swarm optimization technique. ? Evaluation of the cost-reliability tradeoff in a flexible maintenance strategy. ? A probabilistic model for regression parameters is employed to assess reliability-based performance. ? The proposed approach can help decision makers to optimize roadway maintenance plans.imize roadway maintenance plans.

379

Full scale demonstration of air-purifying pavement  

Energy Technology Data Exchange (ETDEWEB)

Highlights: ? The results of a demonstration project for photocatalytic pavement are shown. ? The photocatalytic performance was studied in a street as well as on lab scale. ? The outdoor monitoring was performed in different seasons and weather conditions. ? The NO{sub x} concentration was in average 19% lowered by the photocatalytic street. ? Under ideal weather conditions the NO{sub x} reduction reached up to 45%. -- Abstract: Experiments concerning a full-scale demonstration of air purifying pavement in Hengelo, The Netherlands, are reported. The full width of the street was provided with concrete pavement containing TiO{sub 2} over a length of 150 m (“DeNO{sub x} street”). Another part of the street, about 100 m, was paved with normal paving blocks (“Control street”). The outdoor monitoring was done during 26 days for a period exceeding one year, and measured parameters included traffic intensity, NO, NO{sub 2} and ozone concentrations, temperature, relative humidity, wind speed and direction, and the visible and UV light irradiance. Prior and parallel to these field measurements, the used blocks were also measured in the lab to assess their performance. The NO{sub x} concentration was, on average, 19% (considering the whole day) and 28% (considering only afternoons) lower than the obtained values in the Control street. Under ideal weather conditions (high radiation and low relative humidity) a NO{sub x} concentration decrease of 45% could be observed.

Ballari, M.M., E-mail: ballari@santafe-conicet.gov.ar [Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Brouwers, H.J.H., E-mail: jos.brouwers@tue.nl [Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2013-06-15

380

Reliability-based performance simulation for optimized pavement maintenance  

Energy Technology Data Exchange (ETDEWEB)

Roadway pavement maintenance is essential for driver safety and highway infrastructure efficiency. However, regular preventive maintenance and rehabilitation (M and R) activities are extremely costly. Unfortunately, the funds available for the M and R of highway pavement are often given lower priority compared to other national development policies, therefore, available funds must be allocated wisely. Maintenance strategies are typically implemented by optimizing only the cost whilst the reliability of facility performance is neglected. This study proposes a novel algorithm using multi-objective particle swarm optimization (MOPSO) technique to evaluate the cost-reliability tradeoff in a flexible maintenance strategy based on non-dominant solutions. Moreover, a probabilistic model for regression parameters is employed to assess reliability-based performance. A numerical example of a highway pavement project is illustrated to demonstrate the efficacy of the proposed MOPSO algorithms. The analytical results show that the proposed approach can help decision makers to optimize roadway maintenance plans. - Highlights: > A novel algorithm using multi-objective particle swarm optimization technique. > Evaluation of the cost-reliability tradeoff in a flexible maintenance strategy. > A probabilistic model for regression parameters is employed to assess reliability-based performance. > The proposed approach can help decision makers to optimize roadway maintenance plans.

Chou, Jui-Sheng, E-mail: jschou@mail.ntust.edu.tw [Department of Construction Engineering, National Taiwan University of Science and Technology (Taiwan Tech), 43 Sec. 4, Keelung Rd., Taipei 106, Taiwan (China); Le, Thanh-Son [Department of Construction Engineering, National Taiwan University of Science and Technology (Taiwan Tech), 43 Sec. 4, Keelung Rd., Taipei 106, Taiwan (China)

2011-10-15

381

EVALUATION OF TIRE RUBBER DISPOSAL IN CONCRETE FOR PAVEMENTS  

Directory of Open Access Journals (Sweden)

Full Text Available The production of waste by the tire industry has been a growing problem, indicating the need for its reuse. More than thirty million tires are discharged per year in Brazil, where regulation for the environment states that for each four new tires, five unusable ones must be adequately disposed by manufacturers and importers. Paving consumes an extremely large quantity of materials, which can be the source of rational application of waste and rejected materials. Research shows that tire rubber can be added to asphalt, which increases its durability and improves pavement quality and safety conditions by absorbing the rubber elastic properties, and also be used for architectural applications, among others. This study deals with the addition of rubber fibers from tire crushing in concrete for roadway pavements in order to provide proper indication about the alternative material disposal through an evaluation of the mechanical behavior of the modified concrete. Different concrete mixes were produced, within which, part of fine aggregates were substituted by tire rubber and mechanical experiment tests were performed, which show that, due to great resistance losses, the disposal of this alternative material in concrete should be considered for light traffic pavements, with the addition of rubber ranging up to 10% in mass.

Rosa Cristina Cecche Lintz

2009-12-01

382

Performance of Recycled Asphalt Pavement as Coarse Aggregate in Concrete  

Directory of Open Access Journals (Sweden)

Full Text Available Recycled asphalt pavement (RAP is the reclaimed and reprocessed pavement material containing asphalt and aggregate. Most RAP is recycled back into pavements, and as a result there is a general lack of data pertaining to the mechanical properties for RAP in other possible applications such as Portland cement concrete. In the present study, some mechanical properties of Portland cement concrete containing RAP as coarse aggregate were investigated in the laboratory. Six concrete mixes of widely differing water/cement ratios and mix proportions were made using RAP as coarse aggregate. The properties tested include the physical properties of the RAP aggregate, the compressive and flexural strengths of the concrete. These properties were compared with those of similar concretes made with natural gravel aggregate. Results of the tests suggest that the strength of concrete made from RAP is dependent on the bond strength of the ?asphalt-mortar? (asphalt binder-sand-filler matrix coatings on the aggregates and may not produce concrete with compressive strength above 25 MPa. However, for middle and low strength concrete, the material was found to compare favorably with natural gravel aggregate.

Fidelis O. OKAFOR

2010-12-01

383

Patología de pavimentos articulados Pathology of interlocking pavements  

Directory of Open Access Journals (Sweden)

Full Text Available Este artículo presenta los resultados de un proyecto de grado sobre patología de pavimentos articulados, el cual fue elaborado con el propósito de hacer una recolección de los deterioros típicos de los pavimentos articulados construidos con adoquines de concreto o de ladrillo; y de esta forma, elaborar un catálogo de deterioros para este tipo de estructuras que facilitará la identificación y cuantificación de los deterioros en una inspección visual. El segundo propósito de este proyecto, es la formulación para Colombia de una metodología que permita determinar el Índice de Condición de las estructuras de pavimentos articulados.This article presents the results of a thesis on pathology of interlocking pavements, which objective was to make a compilation of typical damages of interlocking pavements constructed with concrete or brick pavers and, in this way, to elaborate a catalogue of damages for this kind of structures which will make the identification and quantification of deteriorations possible in a visual inspection. The second purpose of this project is the formulation of a methodology which allows determining the Index of pavement conditions for Colombia.

Carlos Hernando Higuera Sandoval

2010-07-01

384

Patología de pavimentos articulados / Pathology of interlocking pavements  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Este artículo presenta los resultados de un proyecto de grado sobre patología de pavimentos articulados, el cual fue elaborado con el propósito de hacer una recolección de los deterioros típicos de los pavimentos articulados construidos con adoquines de concreto o de ladrillo; y de esta forma, elabo [...] rar un catálogo de deterioros para este tipo de estructuras que facilitará la identificación y cuantificación de los deterioros en una inspección visual. El segundo propósito de este proyecto, es la formulación para Colombia de una metodología que permita determinar el Índice de Condición de las estructuras de pavimentos articulados. Abstract in english This article presents the results of a thesis on pathology of interlocking pavements, which objective was to make a compilation of typical damages of interlocking pavements constructed with concrete or brick pavers and, in this way, to elaborate a catalogue of damages for this kind of structures whi [...] ch will make the identification and quantification of deteriorations possible in a visual inspection. The second purpose of this project is the formulation of a methodology which allows determining the Index of pavement conditions for Colombia.

Carlos Hernando, Higuera Sandoval; Óscar Fabián, Pacheco Merchán.

2010-07-01

385

Permeability measurement and scan imaging to assess clogging of pervious concrete pavements in parking lots.  

Science.gov (United States)

This paper describes a study that used permeability measurement along with physical and hydrological characteristics of 20 pervious concrete pavements in parking lots throughout California. The permeability was measured at five locations: the main entrance, an area with no traffic, and three separate measurements within a parking space at each parking lot. Hydrological and physical site characteristics such as traffic flow, erosion, vegetation cover, sediments accumulation, maintenance practice, presence of cracking, rainfall, and temperature data were also collected for each parking lot. These data were used to perform detailed statistical analysis to determine factors influencing changes in permeability and hence assessing possible cause of clogging. In addition, seven representative core samples were obtained from four different parking lots with permeability ranging from very low to very high. Porosity profiles produced from CT scanning were used to assess the possible nature and extent of clogging. Results showed that there is a large variation in permeability within each parking lot and between different parking lots. In general, the age of the parking lot is the predominant factor influencing the permeability. Statistical analysis revealed that fine sediment (particles less than 38 ?m) mass is also an important influencing factor. Other influencing factors with lower significance included number of days with a temperature greater than 30°C and the amount of vegetation next to the parking lot. The combined scanned image analysis and porosity profile of the cores showed that most clogging occurs near the surface of the pavement. While lower porosity generally appeared to be limited to the upper 25 mm, in some core samples evidence of lower porosity was found up to 100mm below the surface. PMID:22115516

Kayhanian, Masoud; Anderson, Dane; Harvey, John T; Jones, David; Muhunthan, Balasingam

2012-03-01

386

Accuracy of the Danish version of the 'distress thermometer'  

DEFF Research Database (Denmark)

Objective: Short screening instruments have been suggested to improve the detection of psychological symptoms. We examined the accuracy of the Danish version of the 'Distress Thermometer'. Methods: Between October 2008 and October 2009, 426 women with newly diagnosed primary breast cancer who were operated at the Breast Surgery Clinic of the Rigshospitalet, Copenhagen, were eligible for this study. Of these, 357 participated (84%) and 333 completed a questionnaire. The distress thermometer was evaluated against the 'hospital anxiety and depression scale' (HADS). We also examined the women's wish for referral for psychological support. Results: A cut-off score of 6 vs 7 (low:¿6, high:¿7) on the distress thermometer was optimal for confirming distress, with a sensitivity of 42%, a specificity of 93%, a positive predictive value (PPV) of 78% and a negative predictive value (NPV) of 73%. A cut-off score of 2 vs 3 was optimal for screening, with a sensitivity of 99%, a specificity of 36%, a PPV of 47% and a NPV of99%. Of those who were distressed using the cut-off score of 2 vs 3 on the distress thermometer, 17% (n = 41) wished to be referred for psychological support and 57% (n = 140) potentially wanted a later referral. Conclusion: The distress thermometer performed satisfactorily relative to the HADS in detecting distress in our study. A screening procedure in which application of the distress thermometer is a first step could be useful for identifying persons in need of support. Copyright © 2011 John Wiley & Sons, Ltd.

Bidstrup, Pernille Envold; Mertz, Birgitte

2012-01-01

387

Moral distress experienced by nurses: A quantitative literature review.  

Science.gov (United States)

Nurses are frequently confronted with ethical dilemmas in their nursing practice. As a consequence, nurses report experiencing moral distress. The aim of this review was to synthesize the available quantitative evidence in the literature on moral distress experienced by nurses. We appraised 19 articles published between January 1984 and December 2011. This review revealed that many nurses experience moral distress associated with difficult care situations and feel burnout, which can have an impact on their professional position. Further research is required to examine worksite strategies to support nurses in these situations and to develop coping strategies for dealing with moral distress. PMID:24091351

Oh, Younjae; Gastmans, Chris

2015-02-01

388

Development of a distress inventory for cancer: preliminary results.  

Directory of Open Access Journals (Sweden)

Full Text Available CONTEXT: Advances in cancer treatment have led to cure and prolongation of patients? lives; however associated psychosocial problems, including distress, can detrimentally affect patients? compliance with treatment and ultimately, their outcome. Symptom distress has been well addressed in many studies; however, psychological distress has only been quantified by using depression or anxiety scales/checklists or quality of life scales containing a distress sub scale/component or by the use of scales that are not psychological distress-specific. AIMS: The present study is an attempt to construct a psychological distress inventory for specific use with cancer patients. SETTINGS AND DESIGN: The standardisation sample consisted of 63 randomly selected patients with head and neck cancer who had undergone/ were undergoing curative treatment at the Regional Cancer Centre, Trivandrum. PATIENTS AND METHODS: The Distress Inventory for Cancer contained 57 positively and negatively toned items. An item analysis was conducted, followed by a factor analysis, thereby identifying the domains influencing distress. RESULTS: The final questionnaire contained 26 items subdivided into four domains viz. the personal, spiritual, physical, and the family domains, with each domain providing a sub score. The reliability coefficient (Cronbach?s alpha of the scale was found to be 0.85. CONCLUSIONS: These are the preliminary results of an ongoing study on global distress and tool development process. Reported here is the first step towards development of such tool.

Thomas B

2002-01-01

389

GPR used in combination with other NDT methods for assessing pavements in PPP projects  

Science.gov (United States)

In the recent decades, Public-Private Partnerships (PPP) has been adopted for highway infrastructure procurement in many countries. PPP projects typically take the form of a section of highway and connecting roadways which are to be construction and managed for a given concession period. Over the course of the highway concession period, the private agency takes over the pavement maintenance and rehabilitation duties. On this purpose, it is critical to find the most cost effective way to maintain the infrastructure in compliance with the agreed upon performance measures and a Pavement Management Systems (PMS) is critical to the success of this process. For the prosperous operation of a PMS it is necessary to have appropriate procedures for pavement monitoring and evaluation, which is important in many areas of pavement engineering. Non Destructive Testing (NDT) has played a major role in pavement condition monitoring, assessments and evaluation accomplishing continuous and quick collection of pavement data. The analysis of this data can lead to indicators related to trigger values (criteria) that define the pavement condition based on which the pavement "health" is perceived helping decide whether there is the need or not to intervene in the pavement. The accomplished perception appoints required management activities for preserving pavements in favor not only of the involved highway/road agencies but also of users' service. Amongst NDT methods Ground Penetrating Radar (GPR) seems to be a very powerful toll, as it provides a range of condition and construction pavement information. It can support effectively the implementation of PMS activities in the framework of pavement monitoring and evaluation. Given that, the present work aims to the development and adaptation of a protocol for the use of GPR in combination with other NDT methods, such as Falling Weight Deflectometer (FWD), for assessing pavements in PPP projects. It is based on the experience of Laboratory of Pavement Engineering of National Technical University of Athens (NTUA) gained through its research activities in various Greek PPP projects as well its involvement in several related European and International scientific actions. It is suggested that the implementation of such protocol could support the pavement management activities with respect to the needs of a PPP project. This is accomplished through the resulted advantages that include simplicity in application, economic benefits and familiarity that are very important factors towards the optimization of the resources and the utilization of the available information; both of them are required for the orderly operation of a PPP project. Acknowledgments: This work benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar."

Loizos, Andreas; Plati, Christina

2014-05-01

390

Analysis and Determination of Axle Load Spectra and Traffic Input for the Mechanistic-Empirical Pavement Design Guide  

OpenAIRE

The values of equivalent single axle loads (ESAL) have been used to represent the vehicle loads in pavement design. To improve the pavement design procedures, a new method, called the Mechanistic-Empirical Pavement Design Guide (MEPDG), has been developed to use the axle load spectra to represent the vehicle loads in pavement design. These spectra represent the percentage of the total axle applications within each load interval for single, tandem, tridem, and quad axles. Using axle load spect...

Jiang, Yi; Li, Shuo; Nantung, Tommy E.; Chen, Huaxin

2008-01-01

391

Development of an evaporation-optimized and water-permeable pavement  

Science.gov (United States)

During recent decades, urban areas have been threatened more frequently by flood events. Furthermore, the potential for damage from these events has increased on average. The construction of houses, streets and parking lots has caused this trend by sealing the ground surface, i.e. these water-impermeable areas reduce the natural infiltration and evaporation-rates, and in some cases it is even completely stopped. The consequence is the so called "urban water cycle". Water from precipitation cannot be stored anywhere and so there is an immediate and very high surface run-off effect. Especially after intense rain events, canalisations and sewage-treatment plants are overloaded and this leads to higher costs for water treatment and to environmental damage. A practical solution to this problem is the use of water-permeable pavements. Here higher infiltration rates lead to a groundwater recharge that is greater than that of natural soils. The consequences from using these surfaces are already noticeable in many places through increasing groundwater levels. These increases cause damage to buildings. A second difference from a natural-soil water-balance is a lower evapotranspiration rate. Up to now the evaporation rates for water-permeable pavements has not been established accurately. The aim of the applied research project at the University of Muenster, which is sponsored by the DBU (The German Federal Environmental Foundation), is to gain knowledge of urban evaporation rates and of water-permeable surfaces, especially water-permeable pavements. Water-permeable pavements consist of the paving stone surface and the two sub-base layers below. Pre-investigations show that evaporation can be influenced by the complete sub-base. Therefore, the first step was to investigate which materials are used for sub-base construction. All in all, 27 materials were collected from throughout Germany and these materials were then tested (in terms of physical and hydraulic attributes) in the soil-mechanics laboratory of the University of Muenster. For their street construction useability, and having regard to evaporation, a selection of appropriate materials were built into a test field. The test field consisted of seven hexagonal areas each about 10 m2 large, which are placed in a honeycomb manner. The evaporation measurements are carried out with a WERNER tunnel-evaporation gauge (TUV) which is able to detect the actual evaporation rate. Its functional principle also allows a direct comparison between the middle reference area and one outer area of the test field. Every measuring period lasts one week and after that the TUV is moved to between the next outer area and the reference area. So the TUV rotates over the whole test field and every measuring area is covered by a measurement. In addition, a Hellman rain-gauge near the test field enables the measurement of a direct precipitation-evaporation ratio. Since the start of the measurements in July 2008, the first results collected showed that measureable differences in evaporation rates could be detected after a few measuring periods, i.e. the differences are up to 32% between the reference area and one outer area. In July 2009, the six outer measuring areas of the test field will be replaced and, based on the actual results collected, the sub-base layers will be replaced by an evaporation-optimized sub-base. The new outer measuring areas will only differ in terms of a different paving-stone surface. These paving stones are actually under developement and under laboratory testing (i.e. permeability, porosity, capillary water and evaporationrates), and so they will be evaporation-opimized. The open-air test in the test field is to assure and compare the evaporation rates. As a final result, the evaporation-optimized and water-permeable pavement and the knowledge of its exact drainage ratio will allow city planners or architects to build water-permeable streets with due regard to the respective area-specific conditions. This new developed pavement is an approximation to the water balanc

Starke, P.; Göbel, P.; Coldewey, W. G.

2009-04-01

392

An analysis of pavement heat flux to optimize the water efficiency of a pavement-watering method  

OpenAIRE

Pavement-watering as a technique of cooling dense urban areas and reducing the urban heat island effect has been studied since the 1990's. The method is currently considered as a potential tool for and climate change adaptation against increasing heat wave intensity and frequency. However, although water consumption necessary to implement this technique is an important aspect for decision makers, optimization of possible watering methods has only rarely been conducted. We propose an analysis ...

Hendel, Martin; Colombert, Morgane; Diab, Youssef; Royon, Laurent

2014-01-01

393

Distress respiratorio agudo en el embarazo Acute respiratory distress syndrome in pregnancy  

Directory of Open Access Journals (Sweden)

Full Text Available Aunque la ocurrencia de Síndrome de distress respiratorio agudo/daño pulmonar agudo (SDRA/DPA durante el embarazo es infrecuente, su letalidad es elevada y ha sido reportado como un factor importante en la mortalidad materna. Las investigaciones realizadas al respecto han sido escasas en la literatura nacional e internacional. Nuestra experiencia en la atención a la paciente materna crítica por más de 20 años demuestra que el distress en el embarazo constituye una entidad sindrómica de alta incidencia en nuestra serie. Motivados en ello y considerando que resulta potencialmente prevenible y altamente letal decidimos realizar la presente revisión sobre un aspecto de la paciente materna grave, muy poco abordado y de gran interés si deseamos reducir los niveles de mortalidad materna.Although acute respiratory distress syndrome/acute lung damage in pregnancy are not common, its lethality index is high and it has been reported as an important factor in maternal mortality. Research works carried out on this topic are very few in both national and international literature. Our over 20 years of experience in the care of critically ill maternal patients revealed that respiratory distress in pregnancy is a highly incidental syndromic entity in our series. Encouraged by this topic and taking into account that it is potentially preventable but highly lethal, we decided to make the present literature review about a problem faced by critical maternal patient, which has been poorly addressed but has a great importance if the maternal mortality indexes are to be reduced.

Alfredo Sánchez Valdivia

2006-04-01

394

Large thymolipoma causing primarily respiratory distress.  

Science.gov (United States)

Thymolipoma, is an anterior mediastinal tumor that is benign in origin. It is often asymptomatic, but can enlarge significantly prior to diagnosis. It consists of thymic and fatty tissue and is surrounded by a capsule. Less than a hundred cases have been reported worldwide. Although rare, it should be considered in the differential diagnosis of mediastinal tumors. In this paper, we report the case of a 44-year-old woman presenting with a giant thymolipoma causing symptoms of severe respiratory distress. The patient underwent surgical resection, which is the main treatment, and remains free of disease. PMID:22919867

Abi Ghanem, Moussa; Habambo, Georges; Bahous, Joudy; Chouairy, Camil; Abu Khalil, Bassam

2012-01-01

395

A Statistical Analysis to Predict Financial Distress  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study is to apply the statistical inference to identify if a firm is likely to become financially distressed in the short term. To do this, we decided to collect data from the firms’ financial statements. The analyses performed were based on a group of 45 financial ratios observed from a sample of 86 firms operating in Argentina. First, we used the principal component analysis to turn the information in the 45 original ratios into two new global variables named as ?Risk and ?Return. In this way, we can easily represent and compare in a graph the firms’ risk and return variations. By the computation of these new variables it is possible to quickly financially categorize a certain firm based on the risk the company has with regard to the nature of its business and the risk involved in the amount of debt it has taken in comparison to the profits that were generated during the last two fiscal years. Second, we performed a logistic regression analysis to estimate the probability that a firm becomes financially distressed in the short term. The model finally selected managed to successfully identify 85% of the companies from the sample and it explains 65% of the total sample variability. The model is represented by the following variables: 1 Current Debt Ratio, 2 Total Cost of Debt, 3 Operating Profit Margin, and 4 ?ROE. The outcomes from this study are two tools that were developed based on the statistical inference from which we can quickly asses the financial status of a firm based on its risks and return’s variation as well as to estimate the probability that a firm becomes financially distressed in the short term. There are different ways of taking these tools into practice such as: 1 to control and follow up the financial performance of a company, 2 to support the decision of lending money to a company, 3 to support the decision of investing money or the decision of merging with a company, 4 to support market analysis from a financial perspective, and 5 to support actions or decisions related to the financial assessment of a company that declares itself to be financially distressed.

Nicolas Emanuel Monti

2010-09-01

396

Family competence in coping with unemployment distress  

OpenAIRE

The study presents results of research on family adaptation pattern in situation of unemployment distress. Theoretical basis is McMaster Model of Family Functioning, modified by P. Steinhauer. The method was Family Questionaire, by M. Cierpka (C i e r p k a, E r e v e r t, 1994) based on Family Assessment Measure III, by P. S t e i n h a u e r et al. (1984). Subjects was unemployed men (23) and women (22) and their families. The results suggest serious disfunctions in every fam...

S?wie?tochowski, Waldemar

2005-01-01

397

Surfactant treatment for acute respiratory distress syndrome  

OpenAIRE

OBJECTIVE—To determine prospectively the efficacy of surfactant in acute respiratory distress syndrome.?STUDY DESIGN—Twenty patients, 1 month to 16 years of age, diagnosed with an acute pulmonary disease with severe hypoxaemia (PaO2/FiO2 < 100) (13 with systemic or pulmonary disease and seven with cardiac disease) were treated with one to six doses of 50-200 mg/kg of porcine surfactant administered directly into the trachea. The surfactant was considered to be ef...

Lopez-herce, J.; Lucas, N.; Carrillo, A.; Bustinza, A.; Moral, R.

1999-01-01

398

Acute Respiratory Distress Syndrome in Lemierre's Syndrome.  

Science.gov (United States)

Lemierre's syndrome is an infectious disease defined by the presence of septic thrombophlebitis with associated embolic phenomenon, most commonly to the lungs. Here we present two cases from a single institution of acute respiratory distress syndrome (ARDS) developing as a result of Lemierre's syndrome in previously healthy young adult men. ARDS can occur as a consequence of pulmonary septic emboli and sepsis, both of which are well-described consequences of Lemierre's syndrome. We describe important diagnostic and management considerations in the care of patients with hypoxemic respiratory failure and Lemierre's syndrome. Essential components of management include prompt antibiotic therapy, lung-protective ventilation strategies, and supportive care. PMID:25143837

Hein, Paul N; Soghikian, Maida V; Bhangoo, Munveer S

2014-01-01

399

Acute respiratory distress caused by Neosartorya udagawae  

Directory of Open Access Journals (Sweden)

Full Text Available We describe the first reported case of acute respiratory distress syndrome (ARDS attributed to Neosartorya udagawae infection. This mold grew rapidly in cultures of multiple respiratory specimens from a previously healthy 43-year-old woman. Neosartorya spp. are a recently recognized cause of invasive disease in immunocompromised patients that can be mistaken for their sexual teleomorph, Aspergillus fumigatus. Because the cultures were sterile, phenotypic identification was not possible. DNA sequencing of ITS, calmodulin and ?-tubulin genes supported identification of Neosartorya udagawae. Our case is the first report of ARDS associated with Neosartorya sp. infection and defines a new clinical entity.

John J. Farrell

2014-10-01

400

Investigation of mechanical properties of pavement through electromagnetic techniques  

Science.gov (United States)

Ground-penetrating radar (GPR) is considered as one of the most flexible geophysical tools that can be effectively and efficiently used in many different applications. In the field of pavement engineering, GPR can cover a wide range of uses, spanning from physical to geometrical inspections of pavements. Traditionally, such inferred information are integrated with mechanical measurements from other traditional (e.g. plate bearing test) or non-destructive (e.g. falling weight deflectometer) techniques, thereby resulting, respectively, in time-consuming and low-significant measurements, or in a high use of technological resources. In this regard, the new challenge of retrieving mechanical properties of road pavements and materials from electromagnetic measurements could represent a further step towards a greater saving of economic resources. As far as concerns unpaved and bound layers it is well-known that strength and deformation properties are mostly affected, respectively, by inter-particle friction and cohesion of soil particles and aggregates, and by bitumen adhesion, whose variability is expressed by the Young modulus of elasticity. In that respect, by assuming a relationship between electromagnetic response (e.g. signal amplitudes) and bulk density of materials, a reasonable correlation between mechanical and electric properties of substructure is therefore expected. In such framework, a pulse GPR system with ground-coupled antennae, 600 MHz and 1600 MHz centre frequencies was used over a 4-m×30-m test site composed by a flexible pavement structure. The horizontal sampling resolution amounted to 2.4×10-2 m. A square regular grid mesh of 836 nodes with a 0.40-m spacing between the GPR acquisition tracks was surveyed. Accordingly, a light falling weight deflectometer (LFWD) was used for measuring the elastic modulus of pavement at each node. The setup of such instrument consisted of a 10-kg falling mass and a 100-mm loading plate so that the influence domain of the elasticity measure could be comparable to that of the radar signal. Good agreement were found between high Young modulus values and repaved zones, whereas damaged areas were characterized by lower values of E. Tomographic maps of amplitudes along the z axis were extracted up to a depth of z

Benedetto, Andrea; Tosti, Fabio; D'Amico, Fabrizio

2014-05-01

401

A philosophical taxonomy of ethically significant moral distress.  

Science.gov (United States)

Moral distress is one of the core topics of clinical ethics. Although there is a large and growing empirical literature on the psychological aspects of moral distress, scholars, and empirical investigators of moral distress have recently called for greater conceptual clarity. To meet this recognized need, we provide a philosophical taxonomy of the categories of what we call ethically significant moral distress: the judgment that one is not able, to differing degrees, to act on one's moral knowledge about what one ought to do. We begin by unpacking the philosophical components of Andrew Jameton's original formulation from his landmark 1984 work and identify two key respects in which that formulation remains unclear: the origins of moral knowledge and impediments to acting on that moral knowledge. We then selectively review subsequent literature that shows that there is more than one concept of moral distress and that explores the origin of the values implicated in moral distress and impediments to acting on those values. This review sets the stage for identifying the elements of a philosophical taxonomy of ethically significant moral distress. The taxonomy uses these elements to create six categories of ethically significant moral distress: challenges to, threats to, and violations of professional integrity; and challenges to, threats to, and violations of individual integrity. We close with suggestions about how the proposed philosophical taxonomy of ethically significant moral distress sheds light on the concepts of moral residue and crescendo effect of moral distress and how the proposed taxonomy might usefully guide prevention of and future qualitative and quantitative empirical research on ethically significant moral distress. PMID:25503608

Thomas, Tessy A; McCullough, Laurence B

2015-02-01

402

47 CFR 80.319 - Radiotelegraph distress call and message transmission procedure.  

Science.gov (United States)

...mobile station in distress. (b) The radiotelegraph distress transmissions must be sent by means of the international Morse code at a speed not exceeding 16 words per minute nor less than 8 words per minute. (c) The distress message,...

2010-10-01

403

Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site - Abstract  

Science.gov (United States)

The EPA?s Urban Watershed Management Branch (UWMB) is monitoring an instrumented, working, 110-space pervious pavement parking at EPA?s Edison Environmental Center (EEC). Permeable pavement systems are classified as stormwater best management practices (BMPs) which reduce runo...

404

Effects of reclaimed asphalt pavement on indirect tensile strength test of conditioned foamed asphalt mix  

International Nuclear Information System (INIS)

This paper presents the results of Indirect Tensile Strength (ITS) Test for samples prepared with reclaimed asphalt pavement (RAP). Samples were conditioned in water at 25°C for 24 hours prior to testing. Results show that recycled aggregate from reclaimed asphalt pavement performs as well as virgin aggregate.

405

Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site - presentation  

Science.gov (United States)

The EPA?s Urban Watershed Management Branch has been monitoring an instrumented 110-space pervious pavement parking lot. The lot is used by EPA personnel and visitors to the Edison Environmental Center. The design includes 28-space rows of three permeable pavement types: asphal...

406

Asphalt Pavement Aging and Temperature Dependent Properties Using Functionally Graded Viscoelastic Model  

Science.gov (United States)

Asphalt concrete pavements are inherently graded viscoelastic structures. Oxidative aging of asphalt binder and temperature cycling due to climatic conditions being the major cause of non-homogeneity. Current pavement analysis and simulation procedures dwell on the use of layered approach to account for these non-homogeneities. The conventional…

Dave, Eshan V.

2009-01-01

407

Permeable pavement monitoring at the EPA's Edison Environmental Center demonstration site  

Science.gov (United States)

There are few detailed studies of full-scale, replicated, actively-used pervious pavement systems. Practitioners need additional studies of pervious pavement systems in its intended application (parking lot, roadway, etc.) during a range of climatic events, daily usage conditions...

408

AN ASSESSMENT OF THE OPERATIONAL LIFE OF CONCRETE AIRFIELD PAVEMENTS ON THE BASIS OF RELIABILITY THEORY  

Directory of Open Access Journals (Sweden)

Full Text Available The mathematical model of development and accumulation of defects of air-field pavements obtained with the use of the principal dependences of relia-bility theory is proposed. This model is implemented in the method of assessment of an operational life of concrete airfield pavements.

Yu. M. Borisov

2010-02-01

409

Implementation of interactive Web-based training tools in pavement engineering  

OpenAIRE

Pavement Interactive, an online pavement community built on an open-source wiki platform, is a novel and possible approach to giving distance training to South African and southern African roads professionals in various aspects of road construction, maintenance and management.

Steyn, Wynand J. Vdm

2010-01-01

410

Refining the measurement of distress intolerance.  

Science.gov (United States)

Distress intolerance is an important transdiagnostic variable that has long been implicated in the development and maintenance of psychological disorders. Self-report measurement strategies for distress intolerance (DI) have emerged from several different models of psychopathology and these measures have been applied inconsistently in the literature in the absence of a clear gold standard. The absence of a consistent assessment strategy has limited the ability to compare across studies and samples, thus hampering the advancement of this research agenda. This study evaluated the latent factor structure of existing measures of DI to examine the degree to which they are capturing the same construct. Results of confirmatory factor analysis in three samples totaling 400 participants provided support for a single-factor latent structure. Individual items of these four scales were then correlated with this factor to identify those that best capture the core construct. Results provided consistent support for 10 items that demonstrated the strongest concordance with this factor. The use of these 10 items as a unifying measure in the study of DI and future directions for the evaluation of its utility are discussed. PMID:22697451

McHugh, R Kathryn; Otto, Michael W

2012-09-01

411

Technical development of cost-efficient installation of power distribution cables under pavements. Haiden chichuka ni okeru doboku kensetsu gorika gijutsu no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Various latest technical developments were surveyed for the cost-effective installation of power distribution cables under pavements, and their applicabilities were demonstrated with the evaluation of their cost-reduction effects. Cables in conventional vinyl protection tubes could be buried only 30cm under pavements, and in such case, the cost was reduced to 51% of those of conventional methods. As the results of soil tests, excavated soil over 80% was reusable through coarse screening. Underground radar technique to explore buried pipes from the surface was detectable several pipes buried 1.5-2.0m underground, although some problems in precision were found. The improvement of reinforced concrete man-hole structures to minimize the volume of excavated soil indicated the cost reduction of nearly 20%. The application of these techniques to the installation of cables was expected to ultimately halve the total civil engineering cost. 21 refs., 130 figs., 46 tabs.

Kokusho, Koji; Kataoka, Tetsuyuki; Tanaka, Yasuyuki; Yoshida, Yasuo; Ikemi, Motoyoshi; Suzuki, Koichi; Kitano, Koichi; Kobayashi, Seiichi; Kanazu, Tsutomu; Komada, Hiroya.

1987-12-01

412

Partnership Transitions and Mental Distress: Investigating Temporal Order  

Science.gov (United States)

The study uses 15 waves of the British Household Panel Survey and the General Health Questionnaire to investigate changes in mental distress over several years surrounding transitions both into and out of marital partnerships (marriages and cohabitations) using fixed effects models. Entering marital partnerships is associated with reduced distress

Blekesaune, Morten

2008-01-01

413

BEHAVIOR OF MODEL ASPHALT PAVEMENT CONTAINING A HYDRAULIC, GRADED IRON AND STEEL SLAG BASE-COURSE UNDER REPEATED PLATE-LOADING  

Science.gov (United States)

In this paper, the dynamic response of asphalt pave ment containing a hydraulic, graded iron and steel slag (hereafter called HMS) base-course under repeated plate-loading was investigated using a model asphalt pavement and the influence of hydraulicity on th e pavement behavior was discussed. The model pavement constructed was a 4-layer system consis ting of a dense-graded asphalt mix surface layer, a dense-graded asphalt mix binder-course, a HMS base-course and a Masado (heavily-weathered granitic sand) subgrade. A repeated plate-loading test was carri ed out so as to achieve a resilient state. It is shown that surface resilient deflection decreases as curing progresses and after 90 days, the deflection becomes almost half of the initial. Large horizontal tensile strains develop at the bottoms of binder- and base-course, which decrease significantly with curing. It is indicative that HMS base-course behaves like a stiffer plate resulting in a hard-to-deflect state due to the development of hydraulicity.

Yoshida, Nobuyuki; Sugisako, Yasunari

414

Optimal Maintenance Works for the Aborshada Road in the Western Region of Libya  

Science.gov (United States)

In this research, the condition of a road pavement was investigated for the Aborshada Road in the Gharian region of Libya to determine the optimal maintenance works. Previously, a simple engineering judgment was the only procedure followed by the Gharian municipal engineers for evaluating pavements and prioritizing maintenance. The surface condition of the Aborshada Road pavement was investigated using "the Pavement Condition Index (PCI)" visual technique. The pavement was inspected to survey the different distresses in each sample unit. Ninteen pavement distresses were classified according to the PCI standards (PCI for roads and parking lots became an ASTM standard in 2007 (D6433-07)). It was necessary to know the most common distresses of the Aborshada Road to provide assistance for the decision maker in his evaluation of the pavement and the optimum repair method to be selected. This study reveals the actual performance of the pavements and suggests the research required for dealing with the pavement maintenance problem in Libya, especially in the western region. The best maintenance alternative for Aborshada Road was Case No. 3 (Potholes, Long. & Trans. Cracking and Alligator Crack Maintenance). Also, the most common pavement distresses on the Aborshada Road were Distress Nos. 1, 3, 6, 7, 10 and 13 according to the ASTM - D6433-07 classification

Youssef, Medhat Abdelrahman; Elbasher, Abdelbary Altayb

2014-09-01

415

Psychological Distress and Pain Reporting in Australian Coal Miners  

Science.gov (United States)

Background Coal mining is of significant economic importance to the Australian economy. Despite this fact, the related workforce is subjected to a number of psychosocial risks and musculoskeletal injury, and various psychological disorders are common among this population group. Because only limited research has been conducted in this population group, we sought to examine the relationship between physical (pain) and psychological (distress) factors, as well as the effects of various demographic, lifestyle, and fatigue indicators on this relationship. Methods Coal miners (N = 231) participated in a survey of musculoskeletal pain and distress on-site during their work shifts. Participants also provided demographic information (job type, age, experience in the industry, and body mass index) and responded to questions about exercise and sleep quality (on- and off-shift) as well as physical and mental tiredness after work. Results A total of 177 workers (80.5%) reported experiencing pain in at least one region of their body. The majority of the sample population (61.9%) was classified as having low-level distress, 28.4% had scores indicating mild to moderate distress, and 9.6% had scores indicating high levels of distress. Both number of pain regions and job type (being an operator) significantly predicted distress. Higher distress score was also associated with greater absenteeism in workers who reported lower back pain. In addition, perceived sleep quality during work periods partially mediated the relationship between pain and distress. Conclusion The study findings support the existence of widespread musculoskeletal pain among the coal-mining workforce, and this pain is associated with increased psychological distress. Operators (truck drivers) and workers reporting poor sleep quality during work periods are most likely to report increased distress, which highlights the importance of supporting the mining workforce for sustained productivity. PMID:25516813

Carlisle, Kristy N.; Parker, Anthony W.

2014-01-01

416

Acute respiratory distress in a silversmith.  

Science.gov (United States)

A 25-year-old young male patient presented in casualty department with severe respiratory distress on the fourth day from onset of symptoms. The patient was nonsmoker and had no antecedent medical or drug history. Prior to admission, patient had dry cough and bilateral pleuritic chest pain for the last three days. He was in severe respiratory distress with use of accessory muscles of respiration. On examination, he had heart rate of 120 beats/min, blood pressure (BP) of 150/80, respiratory rate of 48-52/min and central cyanosis present. On systemic examination, reduced intensity of breath sounds with extensive rhonchi and crepitation was found in both lung fields, with other examination being within normal limits. On pulse oximetry, oxygen saturation was 28% on room air, which increased up to 36% with the help of 4 L oxygen via nasal prongs. PaO2/FiO2 ratio was 100. Chest X-ray analysis was suggestive of non-cardiac pulmonary edema in view of bilateral fluffy opacity without cardiomegaly. In view of 2/3 positive criteria, his provisional diagnosis was Acute Respiratory Distress Syndrome (ARDS). He required mechanical ventilatory support and was gradually weaned over a period of 10 days. The patient was treated with broad spectrum antibiotics and other supportive measures. On re-evaluation of history, we found that he was a goldsmith by occupation, smelting silver and gold for the past 8-10 years. On the day of onset of symptoms, while smelting silver he was exposed to golden yellow fumes for around 15 minutes, with the quantum of exposure more than any other day earlier. From previous experience and analysis of similar silver metals, he was able to tell us that the silver was adulterated with large amount of cadmium on that day than before. Serum level of cadmium was 2.9 ?g/L 6 days after initial exposure. At the time of discharge, he had residual opacities in the chest radiograph and resting oxygen saturation was 94% on room air. PMID:25006313

Parikh, Jignesh Mukeshkumar; Dhareshwar, Shashank; Sharma, Anand; Karanth, Raghuveer; Ramkumar, V S; Ramaiah, Indira

2014-01-01

417

Synthesis report: D-cracking in portland cement concrete pavements  

Science.gov (United States)

The mechanisms and testing procedures for D-cracking in portland cement concrete pavements are examined. Benefication procedures are also investigated. The three general responses to freezing in the aggregate/paste system include elastic accommodation, high internal pressure, and high external pressure. It is found that the critical aggregate parameters influencing D-cracking are degree of saturation, maximum particle size, permeability, porosity, and pore size distribution. Evaluation of present laboratory testing procedures indicated that the ASTM C666, VPI slow-cool, Mercury Porosimetry, and Iowa Pore Index Tests correlated the best with field performance of concrete with respect to D-cracking.

Thompson, S. R.; Olsen, M. P. J.; Dempsey, B. J.

1980-06-01

418

Distress respiratorio agudo en el embarazo / Acute respiratory distress syndrome in pregnancy  

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish Aunque la ocurrencia de Síndrome de distress respiratorio agudo/daño pulmonar agudo (SDRA/DPA) durante el embarazo es infrecuente, su letalidad es elevada y ha sido reportado como un factor importante en la mortalidad materna. Las investigaciones realizadas al respecto han sido escasas en la literat [...] ura nacional e internacional. Nuestra experiencia en la atención a la paciente materna crítica por más de 20 años demuestra que el distress en el embarazo constituye una entidad sindrómica de alta incidencia en nuestra serie. Motivados en ello y considerando que resulta potencialmente prevenible y altamente letal decidimos realizar la presente revisión sobre un aspecto de la paciente materna grave, muy poco abordado y de gran interés si deseamos reducir los niveles de mortalidad materna. Abstract in english Although acute respiratory distress syndrome/acute lung damage in pregnancy are not common, its lethality index is high and it has been reported as an important factor in maternal mortality. Research works carried out on this topic are very few in both national and international literature. Our over [...] 20 years of experience in the care of critically ill maternal patients revealed that respiratory distress in pregnancy is a highly incidental syndromic entity in our series. Encouraged by this topic and taking into account that it is potentially preventable but highly lethal, we decided to make the present literature review about a problem faced by critical maternal patient, which has been poorly addressed but has a great importance if the maternal mortality indexes are to be reduced.

Alfredo, Sánchez Valdivia; Alfredo, Sánchez Padrón.

2006-04-01

419

Hydrological consequences of soil surface type and condition  

OpenAIRE

Extensive semi-arid areas over mica schist in SE Spain have soils with a sandy loam texture, a poorly developed structure, a relatively high infiltrability and a quite high saturated hydraulic conductivity. Under non-tillage land use, a stony pavements armours the soil surface and is responsible for high infiltration, low runoff and almost negligible erosion. However, when this stony pavement is absent, and no plant cover is present, i.e. in tilled soils, this soil is very vuln...

Sole?-benet, Albert

2010-01-01

420

Surfactant alteration and replacement in acute respiratory distress syndrome  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract The acute respiratory distress syndrome (ARDS is a frequent, life-threatening disease in which a marked increase in alveolar surface tension has been repeatedly observed. It is caused by factors including a lack of surface-active compounds, changes in the phospholipid, fatty acid, neutral lipid, and surfactant apoprotein composition, imbalance of the extracellular surfactant subtype distribution, inhibition of surfactant function by plasma protein leakage, incorporation of surfactant phospholipids and apoproteins into polymerizing fibrin, and damage/inhibition of surfactant compounds by inflammatory mediators. There is now good evidence that these surfactant abnormalities promote alveolar instability and collapse and, consequently, loss of compliance and the profound gas exchange abnormalities seen in ARDS. An acute improvement of gas exchange properties together with a far-reaching restoration of surfactant properties was encountered in recently performed pilot studies. Here we summarize what is known about the kind and severity of surfactant changes occuring in ARDS, the contribution of these changes to lung failure, and the role of surfactant administration for therapy of ARDS.

Walmrath Dieter

2001-10-01

421

Thickness and air voids measurement on asphalt concrete pavements using ground-penetrating radar  

Science.gov (United States)

Layer thickness and air voids are important parameters in quality assurance of newly paved hot mix asphalt (HMA) pavements. A non-destructive testing (NDT) technique was used to collect layer thickness information. The thicknesses estimated by the technique were compared with core thicknesses. Ground penetrating radar (GPR) system with air coupled antennas was used for on-site pavement data collection. Two application softwares - RADAN and ROAD DOCTOR - were used to process the field data for estimating layer thicknesses and air voids along the scanned pavements. 150 mm diameter cores taken from random locations on the pavements were tested in the laboratory to determine layer thickness and air voids. Statistical analyses were conducted to compare thicknesses and generate a regression equation relating air voids and dielectric constant of the pavement material. No significant differences were found between thickness estimates from RADAN and ROAD DOCTOR softwares when compared to the core measurements. However, RADAN and ROAD DOCTOR results are marginally significantly different from each other. ROAD DOCTOR software was used to generate air voids for the pavements scanned. Laboratory results from cores were utilized to determine calibration factors for the air voids -- dielectric equation. A relationship between air voids and dielectric constant is presented. It is concluded that GPR system with air coupled antennas used alongside a reduced core testing has a potential for quality control of newly paved hot mixed asphalt pavements.

Dhakal, Sharad Raj

422

Estimation of carrying capacity of slag and gravel forest road pavements  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of the study was to estimate the carrying capacity of forest roads with slag and gravel pavements. Deformation module and elastic deflection were used as characteristic parameters of road carrying capacity. There were 9 tested sections divided into set groups. All investigated sections were measured using VSS plate (29 measurements and deflectometer (53 measurements. Averaged results of the measurements of specific pavements were introduced in the analysis. The present study proved that the carrying capacity of slag and gravel pavements defined according to mean module ME is insufficient. The largest (122.87 MPa mean deformation module was detained for gravel pavement. Two slag pavements with significant constructional differences had very similar values of deformation modules 98.26 and 94.84 MPa. Taking maximum deformation modules ME into consideration, slag, gravel and gravel-broken-stone pavements comply with the requirements for low traffic intensity (ME=130–200 MPa. Only two-ply gravel pavements (about 25 cm thick have the mean carrying capacity complying with the requirements of low traffic intensity.

Grzegorz Trzcinski

2006-06-01

423

Termômetro de Distress: validação de um instrumento breve para avaliação diagnóstica de pacientes oncológicos / Distress Thermometer: validation of a brief screening instrument to detect distress in oncology patients  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A literatura especializada disponibiliza instrumentos de medida de estresse de aplicação geral, os quais vêm sendo empregados em diferentes contextos ocupacionais e em saúde. Mas, desde 1997, a National Comprehensive Cancer Network (NCCN) recomenda a adoção de uma medida específica para pacientes on [...] cológicos. Considerando, portanto, o interesse clínico e científico de desenvolver futuros estudos de meta-análise em Oncologia, que incluam amostras brasileiras, realizaram-se a adaptação e a validação do Termômetro de Distress (TD). A eficácia de avaliação do TD foi verificada por meio da comparação com a Escala de Ansiedade e Depressão (HAD), um instrumento clinicamente estabelecido de avaliação de distress. Para tanto, avaliou-se uma amostra de 83 pacientes, que responderam ao TD e ao HAD. Os dados foram submetidos ao SPSS 15.0. Os resultados indicam uma sensibilidade de 82% e uma especificidade de 98%, o que indica que o TD é viável e eficiente para avaliar o distress psicológico. Abstract in english The specialized literature provides instruments measuring stress for general application. Those instruments have been employed in occupational and health contexts. But since 1997, the National Comprehensive Cancer Network (NCCN) recommends the adoption of a specific measuring instrument for the asse [...] ssment of cancer patients. Considering the existence of clinical and scientific interest to develop future meta-analysis studies in the field of Oncology, which will include Brazilian samples, the adaptation and validation of the Distress Thermometer (TD) was undertaken. The effectiveness of the TD in assessing distress was verified by comparison with the Anxiety and Depression Scale (HAD), a clinically established tool for evaluating distress. In order to that, a sample of 83 patients answered the TD and the HAD. The data were analyzed using SPSS 15.0. Results of the analysis indicated 82% for sensitivity and 98% for specificity. Using the TD appeared feasible and effective for psychological distress screening.

Cristiane Sant' Anna, Decat; Jacob Arie, Laros; Tereza Cristina Cavalcanti Ferreira de, Araujo.

2009-12-01

424

Termômetro de Distress: validação de um instrumento breve para avaliação diagnóstica de pacientes oncológicos Distress Thermometer: validation of a brief screening instrument to detect distress in oncology patients  

Directory of Open Access Journals (Sweden)

Full Text Available A literatura especializada disponibiliza instrumentos de medida de estresse de aplicação geral, os quais vêm sendo empregados em diferentes contextos ocupacionais e em saúde. Mas, desde 1997, a National Comprehensive Cancer Network (NCCN recomenda a adoção de uma medida específica para pacientes oncológicos. Considerando, portanto, o interesse clínico e científico de desenvolver futuros estudos de meta-análise em Oncologia, que incluam amostras brasileiras, realizaram-se a adaptação e a validação do Termômetro de Distress (TD. A eficácia de avaliação do TD foi verificada por meio da comparação com a Escala de Ansiedade e Depressão (HAD, um instrumento clinicamente estabelecido de avaliação de distress. Para tanto, avaliou-se uma amostra de 83 pacientes, que responderam ao TD e ao HAD. Os dados foram submetidos ao SPSS 15.0. Os resultados indicam uma sensibilidade de 82% e uma especificidade de 98%, o que indica que o TD é viável e eficiente para avaliar o distress psicológico.The specialized literature provides instruments measuring stress for general application. Those instruments have been employed in occupational and health contexts. But since 1997, the National Comprehensive Cancer Network (NCCN recommends the adoption of a specific measuring instrument for the assessment of cancer patients. Considering the existence of clinical and scientific interest to develop future meta-analysis studies in the field of Oncology, which will include Brazilian samples, the adaptation and validation of the Distress Thermometer (TD was undertaken. The effectiveness of the TD in assessing distress was verified by comparison with the Anxiety and Depression Scale (HAD, a clinically established tool for evaluating distress. In order to that, a sample of 83 patients answered the TD and the HAD. The data were analyzed using SPSS 15.0. Results of the analysis indicated 82% for sensitivity and 98% for specificity. Using the TD appeared feasible and effective for psychological distress screening.

Cristiane Sant'Anna Decat

2009-12-01

425

Resolution of opisthotonus in respiratory distress by aortopexy.  

Science.gov (United States)

We report a case of worsening respiratory distress associated with opisthotonus secondary to tracheomalacia, a rather unique pathophysiological phenomenon. A 2-month-old male baby was referred to our hospital for respiratory distress syndrome with a noticeable opisthotonus. Examination and investigation confirmed the presence of an aberrant innominate artery compressing the trachea. The infant underwent aortopexy and made a dramatic post-operative recovery. Of special note, the opisthotonus vanished soon after the operation. Opisthotonus is not always related to neurological impairment and may be a warning sign of mediastinal overcrowding in patients with respiratory distress syndrome secondary to vascular compression. PMID:23769450

Trozzi, M; Briganti, V; Conforti, A; Schiavino, A; Bottero, S

2013-08-01

426

Sustainable Drainage Practices in Spain, Specially Focused on Pervious Pavements  

Directory of Open Access Journals (Sweden)

Full Text Available The Spanish climate is full of contrasts, with torrential rains and long droughts; under these conditions, appropriate water management is essential. In Spain, until the end of the twentieth century, water management and legislative development lagged behind other more developed countries. Nowadays, great efforts are being made to reverse this situation and improve both water management and legislation in order to control the two main problems related to stormwater management in cities: floods and diffuse pollution. In this context, Sustainable Urban Drainage Systems (SUDS were developed as the main solution to these problems. The study of these techniques started in the 1970s in the USA, but they were not studied in Spain until 1993 when the University of Cantabria and CLABSA started to look into solutions for stormwater management. After 20 years of research and application, sustainable drainage in Spain is still behind other countries in spite of the efforts to change this situation, notably by the University of Cantabria with 10 years of experience in these techniques, mainly regarding pervious pavements, where more than 13 related research projects have been carried out. The future challenges focus on the application of pervious pavements for Urban Hydrological Rehabilitation.

Jorge Rodriguez-Hernandez

2013-01-01

427

Locating voids beneath pavement using pulsed electromagnetic waves  

Science.gov (United States)

The feasibility of using pulsed electromagnetic wave technology for locating and sizing voids beneath reinforced and nonreinforced portland cement concrete pavements is determined. The data processing techniques developed can be implemented to provide information for void depth and sizing to + or - 1/2 in. and spatial location within + or - 6 in. A very short pulse radar directly connected to a microcomputer was chosen as the equipment necessary to obtain measurements. This equipment has the required accuracy and reliability, and is a cost effective solution for the void locating problem. The radar provides a signal return from voids that has unique characteristics that can be examined to provide information regarding the location, depth, and shape of the void. The microcomputer provides a means of real time processing to extract the information from the radar signal return and record the results. Theoretical modeling of signal returns from voids led to suitable techniques for locating and sizing voids beneath the pavement. Analysis and application of these techniques to radar measurements verified the theoretical predictions that radar can be used to determine the location, size, and shape of actual voids.

Steinway, W. J.; Echard, J. D.; Luke, C. M.

1981-11-01

428

Finite Element Investigation of the Deterioration of Doweled Rigid Pavements  

CERN Document Server

The purpose of this study is to describe the failure of concrete around dowel bars in jointed rigid pavements, and the resulting effect on the pavement performance. In fact, under repetitive vehicle loading, concrete in contact with the dowel bar deteriorates, particularly at the joint face. The degradation of concrete around the dowel negatively affects the latter's performance in terms of transferring wheel loads through vertical shear action. In this context, a nonlinear 3D Finite Element analysis was performed using the commercial FE code Abaqus (v-6.11). The FE model was validated with classical analytical solutions of shear and moment along the dowel. A concrete damaged plasticity model was used for the PCC slab to model the degradation of concrete matrix around the dowels under incremental loading. Results obtained show, among other things, that the degradation of concrete matrix around the dowel was found to initiate at the face of the joint and propagate towards the interior of the dowel. Also, resul...

Ghauch, Ziad G

2011-01-01

429

Study of Sand Characteristics as Bearing and Filler in Joint of Inter-locking Concrete Block Pavement  

Directory of Open Access Journals (Sweden)

Full Text Available The use of interlocking concrete block pavement as a road surface has increased in the road constructionrecently. This study was conducted to envisage the problems occur particularly for the bedding and joint filling sand of the interlocking concrete block pavement. Moreover, the effect of the moisture on the bedding sandwas also studied. Two type of additives namely as palm oil fly ash (POFA and silica fume, which carry thepozzolanic behaviour, were mixed with joint filling sand in order to improve its quality. These materials areindustrial waste compound which can be easily found in Malaysia. Two types of permeability experiments,the constant and falling head tests were conducted to evaluate the permeability of the joint filling sands withthe percentage additives used of 2%, 4%, 6%, 8% and 10%. A physical model was developed to investigatethe degree of compaction and water absorption via sand in joints. Water absorption test was also conductedonto the model with the addition of additives of 0%, 5% and 10% with the joint filling sand for 5 and 10days. Study shown that the incorporation of additives reduced the permeability of joint filling sand withthe optimum values obtained for both POFA and silica fume mixtures both were at 2% respectively.

Rosli Hainin

2009-09-01

430

Proportioning of Steel Fibre Reinforced Concrete Mixes for Pavement Construction and Their Impact on Environment and Cost  

Directory of Open Access Journals (Sweden)

Full Text Available Steel fibre reinforced concrete (SFRC is a construction material investigated for more than 40 years including for pavement applications. A number of studies have demonstrated the technical merits of SFRC pavements over conventional concrete pavements; however little work has been carried out on the environmental and economical impact of SFRC during the pavement’s life cycle. Therefore, extended research was undertaken within the framework of the EU funded project “EcoLanes” to estimate the environmental and economical loadings of SFRC pavements. The innovative concept of the project is the use of recycled steel tyre-cord wire as concrete fibre reinforcement, which provides additional environmental benefits for tyre recycling over landfilling. Within the project framework a demonstration of a steel-fibre-reinforced roller-compacted concrete (SFR-RCC pavement was constructed in a rural area in Cyprus. In order to assess the economical and environmental picture of the demonstration pavement, life cycle cost analysis (LCCA and life cycle assessment (LCA studies were undertaken, which also compared the under study pavement design with four conventional alternatives. The main output of the studies is that SFR-RCC is more environmentally and economically sustainable than others. In addition, various concrete mix designs were investigated by considering parameters such as fibre type and dosage, cement type, and transportation distances to the construction site. Fibre dosage has been highlighted as a crucial factor compared with economical and environmental loadings in SFR-RCC pavement construction.

Stelios Kallis

2011-07-01

431

'Moral distress' - time to abandon a flawed nursing construct?  

Science.gov (United States)

Moral distress has been characterised in the nursing literature as a major problem affecting nurses in all healthcare systems. It has been portrayed as threatening the integrity of nurses and ultimately the quality of patient care. However, nursing discourse on moral distress is not without controversy. The notion itself is conceptually flawed and suffers from both theoretical and practical difficulties. Nursing research investigating moral distress is also problematic on account of being methodologically weak and disparate. Moreover, the ultimate purpose and significance of the research is unclear. In light of these considerations, it is contended that the notion of moral distress ought to be abandoned and that concerted attention be given to advancing inquiries that are more conducive to improving the quality and safety of moral decision-making, moral conduct and moral outcomes in nursing and healthcare domains. PMID:24311238

Johnstone, Megan-Jane; Hutchinson, Alison

2015-02-01

432

Lung tissue remodeling in the acute respiratory distress syndrome  

Directory of Open Access Journals (Sweden)

Full Text Available Acute respiratory distress syndrome (ARDS is characterized by diffuse alveolar damage, and evolves progressively with three phases: exsudative, fibroproliferative, and fibrotic. In the exudative phase, there are interstitial and alveolar edemas with hyaline membrane. The fibropro­liferative phase is characterized by exudate organization and fibroelastogenesis. There is proliferation of type II pneumocytes to cover the damaged epithelial surface, followed by differentiation into type I pneumocytes. The fibroproliferative phase starts early, and its severity is related to the patient?s prognosis. The alterations observed in the phenotype of the pulmonary parenchyma cells steer the tissue remodeling towards either progressive fibrosis or the restoration of normal alveolar architecture. The fibrotic phase is characterized by abnormal and excessive deposition of extracellular matrix proteins, mainly collagen. The dynamic control of collagen deposition and degradation is regulated by metalloproteinases and their tissular regulators. The deposition of proteoglycans in the extracellular matrix of ARDS patients needs better study. The regulation of extracellular matrix remodeling, in normal conditions or in several pulmonary diseases, such as ARDS, results from a complex mechanism that integrate the transcription of elements that destroy the matrix protein and produce activation/inhibition of several cellular types of lung tissue. This review article will analyze the ECM organization in ARDS, the different pulmonary parenchyma remodeling mechanisms, and the role of cytokines in the regulation of the different matrix components during the remodeling process.

Souza Alba Barros de

2003-01-01

433

Lung tissue remodeling in the acute respiratory distress syndrome  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Acute respiratory distress syndrome (ARDS) is characterized by diffuse alveolar damage, and evolves progressively with three phases: exsudative, fibroproliferative, and fibrotic. In the exudative phase, there are interstitial and alveolar edemas with hyaline membrane. The fibropro­liferative phase i [...] s characterized by exudate organization and fibroelastogenesis. There is proliferation of type II pneumocytes to cover the damaged epithelial surface, followed by differentiation into type I pneumocytes. The fibroproliferative phase starts early, and its severity is related to the patient’s prognosis. The alterations observed in the phenotype of the pulmonary parenchyma cells steer the tissue remodeling towards either progressive fibrosis or the restoration of normal alveolar architecture. The fibrotic phase is characterized by abnormal and excessive deposition of extracellular matrix proteins, mainly collagen. The dynamic control of collagen deposition and degradation is regulated by metalloproteinases and their tissular regulators. The deposition of proteoglycans in the extracellular matrix of ARDS patients needs better study. The regulation of extracellular matrix remodeling, in normal conditions or in several pulmonary diseases, such as ARDS, results from a complex mechanism that integrate the transcription of elements that destroy the matrix protein and produce activation/inhibition of several cellular types of lung tissue. This review article will analyze the ECM organization in ARDS, the different pulmonary parenchyma remodeling mechanisms, and the role of cytokines in the regulation of the different matrix components during the remodeling process.

Alba Barros de, Souza; Flavia Brandão dos, Santos; Elnara Marcia, Negri; Walter Araujo, Zin; Patricia Rieken Macedo, Rocco.

2003-08-01

434

Emotional and Physical Distress Relief Using a Novel Endorphinergic Formulation  

Directory of Open Access Journals (Sweden)

Full Text Available While the endogenous opioid system has generally been associated with regulation of pain, it also modulates the experience of distress and may play a central role in many psychiatric and neurodevelopmental disorders. Decades of preclinical research on the analgesic effects of endogenous opioids, i.e., endorphins, suggests that opioid receptors have plastic bimodal (inhibitory/excitatory properties that may explain conflicting findings in clinical research. An exploratory study with 60 healthy volunteer participants, using a cold pressor-induced pain paradigm, found evidence that a combination of a nutraceutical agent that enhances endorphin release (Endorphin Enhancer with one that switches opioid receptors from an excitatory to inhibitory mode (Opioid Receptor Switcher not only increases pain tolerance but also reduces emotional and physical distress. This discovery led to clinical application of a critically formulated endorphinergic treatment in 203 case studies over a two-year period. Findings revealed the remarkable clinical efficacy and safety of this treatment in the relief of chronic emotional and physical distress, including anxiety, anger, depression, cravings, and hyperalgesia, as well as enhancement of well-being, productivity, mental clarity, relationships, and an adaptive response to life’s stresses. These studies provide new insights into the role of endogenous opioid system imbalances in the development, treatment, and prevention of dysfunctional emotional and physical distress. We postulate that an Endorphinergic Distress Syndrome (EDS consists of abnormal endorphin levels together with opioid receptors predominately in their excitatory mode. EDS may account for many core distress symptoms associated with chronic anxiety, addictions, pain, as well as affective personality, autism spectrum, attention-deficit, and distress-related medical problems. Our research has led to new endorphinergic formulations, combining Endorphin Enhancers, such as caffeine, with Opioid Receptor Switchers, such as n-acetylcysteine, for the relief of emotional and physical distress. Our studies also provide a novel method to reverse the anxiogenic effects of caffeine and related hyperexcitatory substances.

Steven Crain

2013-09-01

435

Fibromyalgia: When Distress Becomes (Un)sympathetic Pain  

OpenAIRE

Fibromyalgia is a painful stress-related disorder. A key issue in fibromyalgia research is to investigate how distress could be converted into pain. The sympathetic nervous system is the main element of the stress response system. In animal models, physical trauma, infection, or distressing noise can induce abnormal connections between the sympathetic nervous system and the nociceptive system. Dorsal root ganglia sodium channels facilitate this type of sympathetic pain. Similar mechanisms may...

Manuel Martinez-Lavin

2012-01-01

436

Perceived Discrimination and Psychological Distress of Myanmar Refugees in Malaysia  

OpenAIRE

The purpose of this research is to explore the psychological distress and discrimination experienced by refugees from Myanmar in Malaysia. A narrative inquiry approach and an in depth interview were chosen to get in touch with the social world of the refugees. Bronfenbrenner’s (1979) ecological theory was used to examine the psychological distress of the participants in their social context. The findings revealed the social, economical and psychological discrimination experienced by these r...

Sew Kim Low; Jin Kuan Kok; Wan Ying Lee

2014-01-01

437

Does tinnitus distress depend on age of onset?  

OpenAIRE

Objectives: Tinnitus is the perception of a sound in the absence of any physical source of it. About 5 - 15% of the population report hearing such a tinnitus and about 1 - 2% suffer from their tinnitus leading to anxiety, sleep disorders or depression. It is currently not completely understood why some people feel distressed by their tinnitus, while others don’t. Several studies indicate that the amount of tinnitus distress is associated with many factors including comorbid anxiety, comorbi...

Schlee, Winfried; Kleinjung, Tobias; Hiller, Wolfgang; Goebel, Gerhard; Kolassa, Iris-tatjana; Langguth, Berthold

2011-01-01

438

Leachability of dissolved chromium in asphalt and concrete surfacing materials.  

Science.gov (United States)

Leachate metal pollutant concentrations produced from different asphalt and concrete pavement surfacing materials were measured under controlled laboratory conditions. The results showed that, in general, the concentrations of most metal pollutants were below the reporting limits. However, dissolved chromium was detected in leachate from concrete (but not asphalt) specimens and more strongly in the early-time leachate samples. As the leaching continued, the concentration of Cr decreased to below or close to the reporting limit. The source of the chromium in concrete pavement was found to be cement. The concentration of total Cr produced from leachate of different cement coming from different sources that was purchased from retail distributors ranged from 124 to 641mug/L. This result indicates that the potential leachability of dissolved Cr from concrete pavement materials can be reduced through source control. The results also showed that the leachability of dissolved Cr in hardened pavement materials was substantially reduced. For example, the concentration of dissolved Cr measured in actual highway runoff was found to be much lower than the Cr concentration produced from leachate of both open and dense graded concrete pavement specimens under controlled laboratory study. It was concluded that pavement materials are not the source of pollutants of concern in roadway runoff; rather most pollutants in roadway surface runoff are generated from other road-use or land-use sources, or from (wet or dry) atmospheric deposition. PMID:19604624

Kayhanian, Masoud; Vichare, Akshay; Green, Peter G; Harvey, John

2009-08-01

439

Schizotypy, psychotic-like experiences and distress: an interaction model.  

Science.gov (United States)

Psychotic-like experiences (PLEs) have been found to exist on a continuum in both general and clinical populations. Such experiences may characterize normal and abnormal variations in personality, as well as prodromal or high risk states for the development of psychotic disorders. High risk paradigms tend to emphasize distress and impairment associated with PLEs, yet the extent to which individuals find PLEs to be distressing likely depends on moderating factors. In particular, individuals high in trait schizotypy may differ in their appraisal and reaction to PLEs. The current study examines the relationship between schizotypy, PLEs, and distress associated with PLEs in a college sample. Participants (N=355) completed the Schizotypal Personality Questionnaire - Brief Version (SPQ-B), which assesses schizotypal traits, and the Prodromal Questionnaire - Brief Version (PQ-B), which assesses both PLEs and associated distress. Schizotypy was found to significantly moderate the association between PLEs and subjective distress. Individuals high in trait schizotypy reported more PLEs, yet less distress associated with PLEs, relative to individuals low in trait schizotypy. Implications for high-risk state assessment are discussed. PMID:22906952

Kline, Emily; Wilson, Camille; Ereshefsky, Sabrina; Nugent, Katie L; Pitts, Steven; Reeves, Gloria; Schiffman, Jason

2012-12-30

440

Prevalence and etiology of respiratory distress in newborns  

International Nuclear Information System (INIS)

Objective: To determine the prevalence and etiology of respiratory distress in the newborns delivered over the period of one year from 1st January 2008 to 31st Dec 2008. Study Design: A descriptive study Place and Duration of Study: The study was conducted in Armed Forces Hospital Sharurah Kingdom of Saudi Arabia over a period of one year from January 2008 to Dec 2008 Patients and methods: All live newborns delivered at Armed Forces Hospital Sharurah during the study period were included and observed for development of respiratory distress. Results: All newborns (n=659), delivered at this hospital over the period of 12 months, were observed for respiratory distress. The overall prevalence of respiratory distress (RD) was 4.24%. Prevalence was 19.7% in preterm and 2.3% in full term. Transient tachypnea of newborn(TTN) was found to be the commonest 35.7% cause of Respiratory Distress (RD) followed by Hyaline membrane disease (HMD) 25%, meconium aspiration syndrome (MAS) 17.9%, congenital pneumonia 7.1% and other congenital anomalies 14.3%. TTN was found to be common among both term and preterm babies, while hyaline membrane disease was seen among preterm, and meconium aspiration syndrome among term and post term babies. Conclusion: Respiratory distress is a common neonatal problem with significant morbidity and mortality. Majority of cases are due to TTN followed by hyaline membrane disease and meconium aspiration syndrome. (author)hor)

441

Asian elephants (Elephas maximus reassure others in distress  

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Full Text Available Contact directed by uninvolved bystanders toward others in distress, often termed consolation, is uncommon in the animal kingdom, thus far only demonstrated in the great apes, canines, and corvids. Whereas the typical agonistic context of such contact is relatively rare within natural elephant families, other causes of distress may trigger similar, other-regarding responses. In a study carried out at an elephant camp in Thailand, we found that elephants affiliated significantly more with other individuals through directed, physical contact and vocal communication following a distress event than in control periods. In addition, bystanders affiliated with each other, and matched the behavior and emotional state of the first distressed individual, suggesting emotional contagion. The initial distress responses were overwhelmingly directed toward ambiguous stimuli, thus making it difficult to determine if bystanders reacted to the distressed individual or showed a delayed response to the same stimulus. Nonetheless, the directionality of the contacts and their nature strongly suggest attention toward the emotional states of conspecifics. The elephants’ behavior is therefore best classified with similar consolation responses by apes, possibly based on convergent evolution of empathic capacities.

Joshua M. Plotnik

2014-02-01

442

Neuroleptic-induced acute respiratory distress syndrome  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese CONTEXTO: Apresentamos um caso de síndrome neuroléptica maligna e de síndrome do desconforto respiratório do adulto relacionada ao uso do neuroléptico. Discutimos a possível relação clínica e as alterações de creatinino-quinase, relaxamento muscular e função respiratória. RELATO DE CASO: Paciente de [...] 41 anos, homem, branco. Internado por otalgia e paralisia facial periférica à direita. A tomografia computadorizada de crânio mostrou uma área hiperdensa de 2 cm de diâmetro na região da artéria intercomunicante anterior. Os exames pré-operatórios revelaram: pH 7.4, PaCO2 40 torr, PaO2 80 torr (em ar ambiente), Hb 13.8 g/dl, nitrogênio uréico no plasma 3.2 mmol/l, e creatinina 90 mmol/l. A radiografia de tórax era normal. O paciente fez jejum de 12 horas previamente à cirurgia. Foram usados na anestesia: halotano, fentanil 0.5 mg e droperidol 25 mg (intravenosa). Após seis horas o paciente apresentava PaO2 65 torr (PCO2 normal) sob FiO2 de 50% (relação PaO2/FiO2 130) e permaneceu neste nível até o final da cirurgia. O achado intraoperatório foi de um aneurisma trombosado, que foi ressecado; o vaso foi clipado. Não havia vasoespasmo. Este caso ilustra que drogas neurolépticas podem causar síndrome maligna por neuroléptico e síndrome do desconforto respiratório do adulto em associação. Contudo, há possibilidade de que o neuroléptico ou o solvente da droga possam produzir síndrome do desconforto respiratório do adulto sem apresentar as manifestações de síndrome maligna por neuroléptico. Esta possibilidade é importante pois, nos pacientes com síndrome do desconforto respiratório do adulto que estejam recebendo neurolépticos, será necessário que se pense em sua substituição, especialmente se o paciente não apresentar outros fatores que possam explicar a síndrome do desconforto respiratório do adulto. Abstract in english CONTEXT: A case of neuroleptic malignant syndrome and acute respiratory distress syndrome is presented and discussed with emphasis on the role of muscle relaxation, creatine kinase, and respiratory function tests. CASE REPORT: A 41-year-old man presented right otalgia and peripheral facial paralysis [...] . A computed tomography scan of the skull showed a hyperdense area, 2 cm in diameter, in the pathway of the anterior intercommunicating cerebral artery. Preoperative examination revealed: pH 7.4, PaCO2 40 torr, PaO2 80 torr (room air), Hb 13.8 g/dl, blood urea nitrogen 3.2 mmol/l, and creatinine 90 mmol/l. The chest x-ray was normal. The patient had not eaten during the 12-hour period prior to anesthesia induction. Intravenous halothane, fentanyl 0.5 mg and droperidol 25 mg were used for anesthesia. After the first six hours, the PaO2 was 65 torr (normal PaCO2) with FiO2 50% (PaO2/FiO2 130), and remained at this level until the end of the operation 4 hours later, maintaining PaCO2 at 35 torr. A thrombosed aneurysm was detected and resected, and the ends of the artery were closed with clips. No vasospasm was present. This case illustrates that neuroleptic drugs can cause neuroleptic malignant syndrome associated with acute respiratory distress syndrome. Neuroleptic malignant syndrome is a disease that is difficult to diagnose. Acute respiratory distress syndrome is another manifestation of neuroleptic malignant syndrome that has not been recognized in previous reports: it may be produced by neuroleptic drugs independent of the manifestation of neuroleptic malignant syndrome. Some considerations regarding the cause and effect relationship between acute respiratory distress syndrome and neuroleptic drugs are discussed. Intensive care unit physicians should consider the possibility that patients receiving neuroleptic drugs could develop respiratory failure in the absence of other factors that might explain the syndrome.

Francisco Garcia, Soriano; Elcio dos Santos Oliveira, Vianna; Irineu Tadeu, Velasco.

443

Development of Knowledge-Based Expert System for Flexible Pavement Design  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, the knowledge-based expert system approach was used to design a programmer using shell expert system of KAPPA PC Version 2.4 that is object oriented and displaying higher graphic resolutions. The flexible pavement design based on the accumulation of knowledge from several experts, books and journals results in a modular approach. Normally, the process of flexible pavement design is done by experts. The process was computerized and apply artificial intelligent that is a new technology in providing a system that can design and give the suggestion for user to choices the best and economy of the thickness of pavement layers. The expert system was tested using several design calculation samples. From the test, the success is 100% for pavement design. The expert system has revealed satisfactorily findings in a faster layers design.

Deprizon

2009-01-01

444

Permeable Pavement Research at NRMRL?s Urban Watershed Research Facility (Poster 2)  

Science.gov (United States)

Assess pollutant removal efficiency of porous pavement systems with regard to parking lot runoff. Bench-scale study will examine: Discharge volume Flow rate Total suspended solids (TSS) of influent vs. effluent Use of a geotextile permeable filter fabric...

445

Stress Analysis and Determination of Effective k-value for Rigid Pavement  

Directory of Open Access Journals (Sweden)

Full Text Available EverFE is a user-friendly 3D finite-element analysis tool for simulating the response of jointed plain concrete pavement (JPCP systems to axle loads and environmental effects. EverFE is useful for both concrete pavement researchers and designers who must perform either complex nonlinear or simple linear stress analyses of JPCP.With help of this develop any type of model of rigid pavement considering practical condition thus getting more accurate and advance analysis for rigid pavement. It can also determine effective k-values for different combination of granular sub-base and dry lean concrete. A comparative study is done for two types of loading i.e. single and tandem axle. Edge and Corner stresses are also calculated for Class-AA of loading. Also calculate moment and shear force transfer by dowel bar by EverFE.

Kundan Meshram

2013-03-01

446

Integration and road tests of a self-sensing CNT concrete pavement system for traffic detection  

International Nuclear Information System (INIS)

In this paper, a self-sensing carbon nanotube (CNT) concrete pavement system for traffic detection is proposed and tested in a roadway. Pre-cast and cast-in-place self-sensing CNT concrete sensors were simultaneously integrated into a controlled pavement test section at the Minnesota Road Research Facility (MnROAD), USA. Road tests of the system were conducted by using an MnROAD five-axle semi-trailer tractor truck and a van, respectively, both in the winter and summer. Test results show that the proposed self-sensing pavement system can accurately detect the passing of different vehicles under different vehicular speeds and test environments. These findings indicate that the developed self-sensing CNT concrete pavement system can achieve real-time vehicle flow detection with a high detection rate and a low false-alarm rate. (paper)

447

Monitoring of the Permeable Pavement Demonstration Site at the Edison Environmental Center (Poster)  

Science.gov (United States)

This is a poster on the permeable pavement parking lot at the Edison Environmental Center. The monitoring scheme for the project is discussed in-depth with graphics explaining the instrumentation installed at the site. ...

448

Reinforcement of asphalt concrete pavement by segments of exhausted fiber used for sorption of oil spill  

Science.gov (United States)

The paper is aimed at construction of the experimental road pavement made of dispersed reinforced asphalt concrete. Electronic paramagnetic resonance, infrared spectroscopy and fluorescent bitumen studies were used to prove that disperse reinforcement of asphalt concrete mixtures with fibers of exhausted sorbents reduce the selective filtration of low polymeric fractions of petroleum bitumen and improve its properties in the adsorption layer. Sesquioxides are neutralized as catalysts aging asphalt binder. This leads to improvement in the elasticity of bitumen films at low temperatures and provide better crack resistance of coatings to reduce the intensity of the aging of asphalt binder, and, therefore, to increase the durability of road pavements. The experimental road pavement made of dispersed reinforced asphalt concrete operated during 4 years and demonstrated better transport- performance properties in comparison with the analogue pavements.

Lukashevich, V. N.; Efanov, I. N.

2015-01-01

449

The use of accelerometers in the pavement performance monitoring and analysis  

International Nuclear Information System (INIS)

This study investigated the use of sensor technology to enhance the management of highway infrastructure. With the help of monitoring data, it is possible to assess the current analytical pavement analysis method, which is based on multi-layered elastic analysis, and, thus enhance the pavement design practices in use. Pavement response was measured using different sensors, installed at various depths. Most promising sensors for the continuous monitoring purposes were the accelerometers. The drawback of these sensors is that the measured quantity is acceleration, which must be converted to the deflection via mathematical integration. In this paper some issues related to the manipulation of accelerometer data is presented and discussed, in addition of the discussion of the calculated and measured pavement response.

450

The Influence of Waste Carpet on the Structural Soil Characteristics in Pavement Granular Layer  

Directory of Open Access Journals (Sweden)

Full Text Available Solid waste materials can be left out of environment in different ways or can be used again. As an example of waste fiber materials is the fibers reselling from producing carpet which are made in Iran in largest quantity. These materials are add