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1

Concrete Overlay as a Rehabilitation Option for Distressed Asphalt Pavements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ultra-thin Whitetopping (UTW) involves placing a very thin concrete overlay 50 mm to 100 mm thick (2”-4”) on the milled surface of a distressed asphalt pavement. To investigate the performance of UTW placed over a flexible pavement subjected to slow and heavy moving wheel loads, whitetopping mixes were placed over a milled pavement surface in the Accelerated Pavement Testing (APT) facility of the Indiana Department of Transportation (INDOT) Research Division in West Lafayette Indiana in t...

2002-01-01

2

Evaluation of MDOT's Distress Thresholds for Maintained Pavement Projects.  

Science.gov (United States)

As an alternative to traditional contracting, pavement warranty has been adopted in Mississippi since 2000, aimed to enhance pavement performance and protect the investment in pavement construction. Currently, a manual distress survey method and the assoc...

A. El Gendy F. Wang Y. Qi

2012-01-01

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

Evaluation of Pavement Surface Friction Treatments  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The implementation of a pavement preservation program involves a learning curve with not only a determination to succeed, but also the courage to fail. Also, successful implementation of pavement preservation program requires knowledge of the performance of preservation surface treatments over time, which is critical to the select of candidate projects and the development of performance models for pavement management analysis. In addition, preservation surface treatments, such as chip seal, f...

2012-01-01

5

Pavement Monitoring and Evaluation Issues.  

Science.gov (United States)

Contents: Use of Seismic Pavement Analyzer in Pavement Evaluation; Nature and Detection of Void-Induced Pavement Failures; Evaluation of New Ground-Penetrating Radar Technology to Quantify Pavement Structures; Algorithms for Pavement Distress Classificati...

1995-01-01

6

Propagation Mechanisms for Surface Initiated Crackingin Composite Pavements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 presenc...

2009-01-01

7

Concrete Pavement Overlays over Existing Asphalt Pavement Structures, Project Summary.  

Science.gov (United States)

Whitetopping is a pavement system of portland cement concrete (PCC) placed on hot mix asphalt concrete (HMAC) pavement. Whitetopping is used to address distresses in asphalt pavement such as rutting and shoving. Three types of whitetopping pavements are c...

2007-01-01

8

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2013-01-01

9

Treatment Guidelines for Pavement Preservation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This project presents pavement treatment practice guidelines and a distress identification manual for the purpose of improving the INDOT pavement preservation practices. The treatment guidelines consist of 10 treatment types for asphalt pavements and composite pavements and 8 treatment types for Portland cement concrete pavement (PCCP). The treatment guidelines include treatment descriptions, benefits, applicable pavement conditions, treatment materials, and treatment procedures. The guidelin...

2010-01-01

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

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

2012-01-01

12

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

13

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

14

Pavement Condition Rating System: Review of PCR Methodolgy.  

Science.gov (United States)

This report describes the Pavement Condition Rating method which was developed for the State of Ohio Highway Network. The method is based upon visual inspection of pavement distresses. Although the relationship between pavement distresses and performance ...

C. L. Saraf

1998-01-01

15

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

16

Simulation of pavement surface runoff using the depth-averaged shallow water equations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Water on the pavement significantly affects traffic safety. Climate change will lead to a higher number of heavy rainstorms in Germany and the risk to have large amounts of water on the pavement will even increase. Therefore, it is important to have a tool which enables highway engineers to analyse existing and designed road sections concerning their drainage capability. In this work, a model is developed, which allows an integral simulation of pavement surface runoff. This includes features ...

Wolff, Anne

2013-01-01

17

A study of the effects of adding ice retardant additives to pavement surface course materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The formation of ice and snow on pavement surfaces is a recurring problem, creating hazardous driving conditions, restricting public mobility as well as having adverse economic effects. Current winter operations primarily consist of the correctly timed application of de-icing chemicals to the pavement surface to prevent hazardous conditions occurring.

Wright, Michael

2013-01-01

18

Long Life Pavements; Firmes de larga duracion  

Energy Technology Data Exchange (ETDEWEB)

The existence of long-life pavements is not new; they have been built in Europe and the United States for decades. In fact, the concept arises from the observation of in-service roads; it was verified how particular pavements, initially designed for a 20-year service life, did not seem to have reduced the bearing capacity along the time, and its maintenance necessities had been exclusively focused on the wearing course. The base idea of long-life pavements is the existence of a fatigue threshold below which the damage produced by each load application is, in practice, zero or below the healing potential of the asphalt mix. The use practice of long-life pavements design considers a pavements constituted by three asphalt layers, each one with a very specific role: a wearing course that provides with the surface characteristics, an intermediate course that provides with most of the structural capacity and a base course that provides with the fatigue resistance. Furthermore, one of the particularities is the design against specific distress mechanisms. Maintenance strategy also presents specific particularities for long-life pavements. It is essentially focused on the detection of surface deterioration, and the appropriate and timely repair, before the damage extends beyond the wearing course, putting into risk the structural integrity of the pavement. Nowadays, this new way to conceive the design, the construction and the maintenance of road pavements, constitutes one of the main challenges for pavement engineering worldwide. (Author) 5 refs.

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

2009-07-01

19

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

20

Automatic Pavement Crack Detection Using Texture and Shape Descriptors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2010-01-01

 
 
 
 
21

Pavement Management System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2007-01-01

22

PHYSIOLOGICAL INFORMATION FOR PAVEMENT HEALTH MONITORING BASED ON SURFACE RIDE QUALITY  

Science.gov (United States)

Pavement ride quality testing has traditionally been based on subjective questionnaire ratings. The questionnaire survey has ability to directly measure the sense of road users' ride quality. However, it is difficult to quantify the evaluation results based on the questionnaire due to its lack of objectivity. This study examines pavement health monitoring method using physiological information such as heart rate variability (HRV) for detecting mental stress of road users toward pavement ride quality. First, a results of a driving simulator experiment shows that potential mental stress caused by road roughness can be observed in high-frequency oscillations in 0.15-0.4Hz of HRV processed by continuous wavelet transform. Then, the high-frequency oscillations of HRV is summarized as an index related to the mental stress that makes objective ride quality evaluation possible. Finally, this study indicates that the index contributes to improve the accuracy of pavement health monitoring based on surface ride quality.

Tomiyama, Kazuya; Kawamura, Akira; Takahashi, Kiyoshi; Ishida, Tateki

23

Pavement cracking measurements using 3D laser-scan images  

Science.gov (United States)

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.

Ouyang, W.; Xu, B.

2013-10-01

24

Distress and rehabilitation method of airport concrete pavements. Kuko concrete hoso no henjo to hoshu hokyo hoho  

Energy Technology Data Exchange (ETDEWEB)

This paper summarizes methods to evaluate deformation of airport concrete pavements and introduces major repair methods. Airports carry out periodical investigations from daily checks to full scale investigations. Especially the road condition investigations performed every three years make evaluations using an index called a pavement rehabilitation index (PRI) that quantifies the conditions based on crack lengths/areas, joint damage lengths, and steps. (Airports in the U.S.A. use not only these three items, but 15 items of damage conditions to calculate the PCI.) Repair methods are determined according to these values. As a pavement structural evaluation method, a non-destructive evaluation method is proposed that uses a ball-dropping bend measurement. Elasticity coefficients, road bed bearing capacity, and existence of clearance are estimated from the bend measurement. Types of pavement damages are as various as blow-up, crack, patching, pop-out, etc. Based on the evaluation results, the necessity of repair and construction methods are determined, such as filler injection, patching, re-concreting, and overlay. 6 refs., 6 figs., 2 tabs.

Hachiya, Y. (Port and Harbour Research Institute, Kanagawa (Japan))

1993-07-01

25

Application of a three-surface kinematic hardening model to the repeated loading of thinly surfaced pavements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Little effort has been made to apply the Critical State Soil Mechanics concept to the prediction of pavement response. The aim of this research is to apply soil mechanics principles, particularly the kinematic hardening concept, to the prediction of the response of lightly trafficked pavements to repeated loading. For this purpose, the finite element critical state program CRISP is used. A comparison is made between the predictions given by the three-surface kinematic hardening (3-SKH) mo...

Hau, Kah Wai

2003-01-01

26

An Adaptive Frequency Domain Finite Element Model for Surface Wave Testing of Pavements  

Science.gov (United States)

The proposed adaptive frequency domain finite element (FE) model makes it possible to simulate wave propagation in a pavement structure over a wide frequency range using a normal size computer. The geometry and mesh size are optimized and regenerated for each frequency using a simple script in a commercial FE software package. Results from the FE model agree well with normal mode dispersion curves for a 3-layer reference pavement model. The proposed approach is fast and computationally efficient and intended to be used as a forward model for iterative surface wave inversion.

Ryden, N.; Castaings, M.

2009-03-01

27

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...

28

Mobile acoustic system for the detection of surface-breaking cracks in pavement  

Science.gov (United States)

Monitoring the structural condition of road and airport pavement is an extremely critical task to ensure the safety and efficiency of teh transportation. The topic is relevant to both civil and military transportation infrastructure. The presence of damage in pavement, including surface cracking, depressions, swells, and wear, is inevitable due to the sever environmental and service loads that these structures must be subject to. Existing NDE techniques aimed at assessing the structural condition of pavement include Falling Weight Deflectometer, Ground Penetrating Radar, and acoustic methods based on surface waves. This paper presents improvements to the traditional surface-wave method for the detection of surface-breaking cracks in pavement. The advances include 1) the modeling of the problem as dipsersive waves propagating in a multilayer system, 2) the inclusion of post-processing algorithms based on the Wavelet Transform to improve the sensitivity and accuracy of the inspection, and 3) the use of non-contact, air-coupled acoustic detectors to enhance the mobility of the inspection unit. The crack detection procedure consists of first generating a dispersive wave with an impulse hammer, and then measuring the changes in velocity, amplitude and/or frequency content as the wave travels across the flaw with the aid of the Continuous Wavelet Transform. Multilayer wave propagation modeling provides a better understanding of the experimental results by predicting how the various frequencies interact with cracks of different depths. The results of field tests will be presented for both rigid (concrete-based) and flexible (bitumen-based) pavement with surface cracks.

Marzani, Alessandro; Rizzo, Piervincenzo; Lanza di Scalea, Francesco; Benzoni, Gianmario

2004-07-01

29

Modeling snow melting on heated pavement surfaces. Pt. 1: Model development  

Energy Technology Data Exchange (ETDEWEB)

Hydronic or electric heating of pavement surfaces has been used in the prevention of ice formation and snow deposition with the aim of improving transportation safety. This paper describes a numerical model of a heated pavement and the snow melting processes occurring on its surface. A set of boundary conditions have been defined, and models of heat and mass transfer developed, that allow treatment of various surface and weather conditions associated with storm events. Given heat fluxes and weather data, this model can predict the transient surface conditions and temperatures including the extent of snow cover. Model development is described in this paper and its application to a representative snow melting system illustrated. A companion paper presents a validation exercise using data collected from a full-scale bridge snow melting system during a real storm event. (author)

Liu, Xiaobing [Climatemaster Inc., 7300 SW 44th Street, Oklahoma City, OK 73179 (United States); Rees, Simon J. [Institute of Energy and Sustainable Development, De Montfort University, Queens Building, The Gateway, Leicester, LE1 9BH (United Kingdom); Spitler, Jeffrey D. [School of Mechanical and Aerospace Engineering, Oklahoma State University, 218 Engineering North, Stillwater, OK 74078 (United States)

2007-04-15

30

Pavement Drainage and Pavement Shoulder Joint Evaluation Numerical Analysis of Infiltration and Drainage in Pavement Systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The continuing loss of pavement performance observed in the U.S. transportation infrastructure system raises the issue of the subdrainage design. Experience with the Indiana highways indicates that the lack of adequa the sub-drainage is probably a major cause of pavement distress. In order to provide highway engineers with a methodology to analyze the water migration and drainage into pavement systems a new numerical model has been developed. The numerical scheme is a finite difference formul...

1993-01-01

31

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 experime...

Tienfuan Kerh; Yu-Min Wang; Yulern Lin

2005-01-01

32

Density Measurement Verification for Hot Mix Asphalt Concrete Pavement Construction.  

Science.gov (United States)

Oregon Department of Transportation (ODOT) requires a minimum density for the construction of dense-graded hot mix asphalt concrete (HMAC) pavements to ensure the likelihood that the pavement will not experience distresses that reduce the expected service...

S. Darra T. V. Scholz

2010-01-01

33

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

34

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

2012-01-01

35

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

36

Pavement Condition Rating System: Development and Implementation of a System for Evaluation of Maintenance Repair Needs and Priorities.  

Science.gov (United States)

This report volume presents the system for rating visible pavement distress. The system is called Pavement Condition Rating (PCR) and is based upon both severity and extent of distress. Standard definitions and photographs are presented to aid in the iden...

K. Majidzadeh M. S. Luther

1980-01-01

37

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

38

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

39

Shakedown analysis and design of flexible road pavements under moving surface loads  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Flexible road pavements often fail due to excessive rutting. as a result of cumulative vertical permanent deformation under repeated traffic loads. The currently used analytical approach to flexible pavement design evaluates the pavement life in terms of critical elastic strain at the top of the subgrade. Hence, the plastic pavement behaviour is not properly considered. Shakedown analysis can take into account the material plasticity and guarantee structure stability under repeated loads. It ...

Wang, Juan

2011-01-01

40

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.

João Virgílio Merighi

2008-01-01

 
 
 
 
41

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 ...

42

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

43

State-of-art of asphalt surfacings on long-spanned orthotropic steel deck in China:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reliable and durable asphalt surfacing systems still remain to be desired for the long-spanned orthotropic steel bridges as the nationally and internationally reports on distresses in deck pavement. Based on ten-year research works, this paper has presented a brief review and discussion of the Chinese practices and experiences of deck pavement on long-spanned steel bridges, including issues of typical surfacing materials and their properties, main distresses in asphalt surfacing, and the basi...

Chen, X.; Liu, X.; Qian, Z.; Lei, Z.

2012-01-01

44

Upgrading the INDOT Pavement Friction Testing Program  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study investigated many important issues associate with pavement surface friction testing, in particular using the smooth tire. This study utilized 3-D FEM program to investigate the fundamental friction phenomenon in light of energy dissipation during friction process. It was demonstrated that the pavement friction depends on many factors such as test tire, test speed, surrounding conditions, pavement surface texture, and pavement type. A great amount of friction data has been collected...

2004-01-01

45

Quality assessment of the pavement structure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pavement surface as part of road is due to provide as safe, comfortable and economical drive to its user, as possible. Beside aforementioned, the quality level of pavement structure must be high enough to provide an adequate pavement life time. In order to ensure this demands, I prepared the Schedule of providing quality to pavement structures, which is the basic topic of this assignment. The Schedule refers to asphalt mixtures that are installed in asphalt surfacing and asphalt base course o...

2007-01-01

46

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

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.

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

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

50

Water Quality Performance of Three Side-by-Side Permeable Pavement Surface Materials: Three Year Update  

Science.gov (United States)

Communities are increasingly installing structural low impact development (LID) practices to mange stormwater and reduce pollutant loads associated with stormwater runoff. Permeable pavement is a LID practice that has limited research on working-scale, side-by-side performance o...

51

Permeable Pavement  

Science.gov (United States)

Students investigate how different riparian ground covers, such as grass or pavement, affect river flooding. They learn about permeable and impermeable materials through the measurement how much water is absorbed by several different household materials in a model river. Students use what they learn to make recommendations for engineers developing permeable pavement. Also, they consider several different limitations for design in the context of a small community.

Integrated Teaching And Learning Program

52

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2013-01-01

53

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

54

Recycling of Portland Cement Concrete Pavement, Johnson County.  

Science.gov (United States)

In recent years there has been increasing interest in recycling construction materials. Surface courses of bituminous pavements are currently being actively recycled all over Kansas. The recycling of portland cement concrete pavements (PCCP) can help alle...

J. B. Wojakowski G. A. Fager M. A. Catron

1995-01-01

55

New Method for Pavement Rutting Prediction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In recent years, pavement rutting rate has increased significantly due to constant traffic intensity increment. These solicitations affect the bituminous layers that can quickly attain their permanent deformation limit resistance. This phenomenon can lead to a pavement depression, located in the tyre-road contact surface. The purpose of this paper is to present a methodology to estimate the rutting of bituminous pavements and to predict the rutting risk considerin...

2006-01-01

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

A model for the pavement temperature prediction at specified depth  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

2013-01-01

58

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

59

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)

2003-10-01

60

A Study of Load Responses towards the Pavement Edge  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 fact that pavement edge damages r...

2002-01-01

 
 
 
 
61

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)

2003-01-01

62

Low temperature influence in the predicted of pavement overlay  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2003-01-01

63

Low-temperature influence in the predicted of pavement overlay  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2003-01-01

64

Modeling Deflection Basin Using Neurofuzzy in Backcaluculating Flexible Pavement Layer Moduli  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2002-01-01

65

Monitoring the condition of roads pavement surfaces: proposal of methodology using hyperspectral images / Monitoramento das condições das superfícies de pavimentos rodoviários: proposta de metodologia utilizando imagens hiperespectrais  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese No atual sistema de concessões rodoviária do Brasil ambos, concessionárias e agências reguladoras têm a missão de melhorar a qualidade dos pavimentos rodoviários no País. Tal situação requer a pesquisa e a identificação de novas ferramentas que facilitem o levantamento das condições dos pavimentos r [...] odoviários num tempo e custos menores que os métodos usuais. Recentemente, se verificou um grande aumento da disponibilidade de imagens de sensoriamento remoto com alta resolução espacial, seguindo uma tendência do mercado de novos satélites de sensoriamento remoto, e de sensores aerotransportados. De forma similar, imagens multi e hiperespectrais estão disponíveis tanto comercialmente quanto para a pesquisa científica. O artigo apresenta uma nova metodologia para a identificação das condições do asfalto em superfícies pavimentadas e uma classificação dos tipos de defeitos identificáveis a partir de imagens hiperespectrais adquiridas por sensores aerotransportados. O objetivo do artigo é o de mostrar que índices das condições das superfícies dos pavimentos asfaltados gerados via imagens hiperespectrais podem ser comparados com os indicadores vigentes, utilizados pela agência reguladora nacional. Abstract in english With the current system of concession roads in Brazil, both concessionaires and regulatory agents have been charged with improving the quality of the pavement on Brazilian highways. This situation requires the search for new tools that can facilitate the survey of pavement conditions in less time an [...] d at a lower cost than traditional methods. Recently, an increasing number of high-resolution spatial images have become available on the world market following the development of new remote sensing satellites and airborne sensors. Similarly, multispectral images and even hyperspectral images are now available commercially and for scientific research. The paper presents a new methodology for the identification of asphalted pavement surfaces condition and the classification of the main types of asphalt defects using hyperspectral images from airborne digital sensors. The objective of this study was to generate indexes of pavement conditions from images that can be compared with the indicators of pavement surface conditions already used by national regulatory agencies.

Resende, Marcos Ribeiro; Bernucci, Liedi Legi Bariani; Quintanilha, José Alberto.

66

Combination Treatments for Pavement Preservation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The benefits of several common preservation treatments will be discussed. The application and special considerations for the combination of treatments including cape seals, stress absorbing membrane interlayers, fog seals over chip seals, and surface treatments over crack treatments will all be discussed. These tailored combination treatments can provide a durable and cost-effective method for improving the pavement condition.

2013-01-01

67

Evaluation of Bituminous Pavement with Polypropylene Fiber.  

Science.gov (United States)

This study was conducted to evaluate the performance of a hot mix asphalt overlay modified with polypropylene fiber. In 1986, a continuously reinforced concrete pavement on Interstate 69 in Meridian, MS, was overlaid with hot mix asphalt binder and surfac...

M. Seshadri

1996-01-01

68

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. ...

69

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2008-01-01

70

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2007-01-01

71

Full Scale Tests for the Assessment of Wear of Pavement Surfaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

72

Pavement Management and Rehabilitation of Portland Cement Concrete Pavements.  

Science.gov (United States)

The 11 papers in this report deal with the following areas: economic analyses and dynamic programming in resurfacing project selection; implementation of an urban pavement management system; pavement performance modeling for pavement management; illustrat...

C. V. Zegeer K. R. Agent R. L. Rizenbergs P. C. Curtayne T. Scullion

1981-01-01

73

Image Preprocessing Methods to Identify Micro-cracks of Road Pavement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. Curre...

2013-01-01

74

Social Distress  

Science.gov (United States)

... 13 What can be done for social distress? Social distress is common with terminal illnesses. Not everyone ... be hard on yourself for not feeling very social. ? Allow yourself to be angry. Tell others about ...

75

A Study of Load Responses towards the Pavement Edge  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2002-01-01

76

Indiana Pavement Preservation Program  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2010-01-01

77

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.

2013-06-17

78

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

79

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.

80

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

 
 
 
 
81

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.

82

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

83

RIGID PAVEMENT PUMPING: (1) SUBBASE EROSION AND (2) ECONOMIC MODELING (SUBDRAINAGE, REHABILITATION, RIGID PAVEMENTS)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pumping of rigid pavements is a major contributor to rigid pavement failure. Fines can be removed through pore water pressure buildup in the subbase or through surface erosion of subbase and shoulder materials. A number of studies have been conducted since the 1940s, and a number of remedies have been implemented, viz., granular, stabilized, open-graded, and lean concrete subbases. The effectiveness of these measures varied. Stabilized layers, although reducing pumping, do not eliminate pumpi...

1985-01-01

84

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 layer...

Netterberg, F.; Beer, M.

2012-01-01

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

Traffic Load Forecasting for Pavement Design.  

Science.gov (United States)

A primary determinant of a pavement's actual service life is the traffic loading applied to the pavement. Consequently, an important consideration in pavement structural design is a forecast of the traffic loading expected to be applied to the pavement st...

A. J. Vlatas G. B. Dresser

1991-01-01

87

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...

88

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

89

Density Profiling of Asphalt Pavements.  

Science.gov (United States)

Asphalt pavement density measurements were made using a conventional nuclear density gauge and a new electrical resistivity device called the Pavement Quality Indicator. Five sets of density tests were made at each of nine sites during, or immediately fol...

S. Shuler

2005-01-01

90

DRAINAGE AND FLEXIBLE PAVEMENT PERFORMANCE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2012-01-01

91

Calculating condition of pavement structure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2012-01-01

92

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  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 proba [...] bilístico. 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. Abstract in english 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 respon [...] se 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.

Silva, José Guilherme Santos da; Roehl, João Luís Pascal.

93

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.

94

Pervious Pavements: Installation, Operations and Strength. Part 1: Pervious Concrete.  

Science.gov (United States)

Pervious pavement systems are now being recognized as a best management practice by the Environmental Protection Agency and the state of Florida. The pervious concrete system is designed to have enhanced pore sizes in the surface layer compared to convent...

E. Stuart I. Uju M. Chopra M. Hardin M. Wanielista

2011-01-01

95

Asphalt pavement temperature prediction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 fro...

Minhoto, Manuel; Pais, Jorge; Pereira, Paulo

2006-01-01

96

Asphalt pavement temperature prediction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 J. C.; Pais, Jorge C.; Pereira, Paulo A. A.

2006-01-01

97

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2008-01-01

98

Reconstruction of a pavement geothermal deicing system  

Energy Technology Data Exchange (ETDEWEB)

In 1948, US 97 in Klamath Falls, Oregon was routed over Esplanade Street to Main Street and through the downtown area. In order to widen the bridge across the US Bureau of Reclamation A Canal and to have the road cross under the Southern Pacific Railroad main north-south line, a new bridge and roadway were constructed at the beginning of this urban route. Because the approach and stop where this roadway intersected Alameda Ave (now Hwy 50 -- Eastside Bypass) caused problems with traffic getting traction in the winter on an adverse 8% grade, a geothermal experiment in pavement de-icing was incorporated into the project. A grid system within the pavement was connected to a nearby geothermal well using a downhole heat exchanger (DHE). The 419-foot well provided heat to a 50-50 ethylene glycol-water solution that ran through the grid system at about 50 gpm. This energy could provide a relatively snow free pavement at an outside temperature of {minus}10 F and snowfall up to 3 inches per hour, at a heat requirement of 41 Btu/hr/ft{sup 2}. Over time, the well temperature dropped from 143 to 98 F at the surface. The bridge and surface pavement, geothermal well, and associated equipment were modified. This paper describes the modifications.

Lund, J.W. [Geo-Heat Center, Klamath Falls, OR (United States)

1999-03-01

99

Modelling of the interaction component's of recycled hot mix asphalt and research its use in the road pavement construction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of the dissertation is to provide a science-based model of the interaction dynamics among the components and the results of this interaction, which shall help to design and to produce high quality hot-mix asphalt mixtures with granules of recycled asphalt pavement of Lithuanian roads. The main objectives of the dissertation: – To conduct the research, to collect, systemized and analyzed scientific works discussing the factors of asphalt pavement distresses and their influence on...

Muc?inis, Darjus?as

2012-01-01

100

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

 
 
 
 
101

Subsurface defect detection in first layer of pavement structure and reinforced civil engineering structure by FRP bonding using active infrared thermography  

Science.gov (United States)

In many countries road network ages while road traffic and maintenance costs increase. Nowadays, thousand and thousand kilometers of roads are each year submitted to surface distress survey. They generally lean on pavement surface imaging measurement techniques, mainly in the visible spectrum, coupled with visual inspection or image processing detection of emergent distresses. Nevertheless, optimisation of maintenance works and costs requires an early detection of defects within the pavement structure when they still are hidden from surface. Accordingly, alternative measurement techniques for pavement monitoring are currently under investigation (seismic methods, step frequency radar). On the other hand, strengthening or retrofitting of reinforced concrete structures by externally bonded Fiber Reinforced Polymer (FRP) systems is now a commonly accepted and widespread technique. However, the use of bonding techniques always implies following rigorous installing procedures. To ensure the durability and long-term performance of the FRP reinforcements, conformance checking through an in situ auscultation of the bonded FRP systems is then highly suitable. The quality-control program should involve a set of adequate inspections and tests. Visual inspection and acoustic sounding (hammer tap) are commonly used to detect delaminations (disbonds) but are unable to provide sufficient information about the depth (in case of multilayered composite) and width of debonded areas. Consequently, rapid and efficient inspection methods are also required. Among the non destructive methods under study, active infrared thermography was investigated both for pavement and civil engineering structures through experiments in laboratory and numerical simulations, because of its ability to be also used on field. Pulse Thermography (PT), Pulse Phase Thermography (PPT) and Principal Component Thermography (PCT) approaches have been tested onto pavement samples and CFRP bonding on concrete samples in laboratory. In parallel numerical simulations have been used to generate a set of time sequence of thermal maps for simulated samples with and without subsurface defect. Using this set of experimental and simulated data different approaches (thermal contrast, FFT analysis, polynomial interpolation, singular value decomposition…) for defect location have been studied and compared. Defect depth retrieval was also studied on such data using different thermal model coupled to a direct or an inverse approach. Trials were conducted both with an uncooled and cooled infrared camera with different measurement performances. Results obtained will be discussed and analysed in the paper we plan to present. Finally, combining numerical simulations and experiments allows us discussing on the sensitivity influence of the infrared camera used to detect subsurface defects.

Dumoulin, Jean; Ibos, Laurent

2010-05-01

102

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...

103

Mechanistic-Empirical Pavement Design Guide Implementation.  

Science.gov (United States)

The recently introduced Mechanistic-Empirical Pavement Design Guide (MEPDG) and associated computer software provides a state-of-practice mechanistic-empirical highway pavement design methodology. The MEPDG methodology is based on pavement responses compu...

N. R. Stires R. L. Baus

2010-01-01

104

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

105

New disclosures at pavement and maintenance treatment design on existent roads  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2007-01-01

106

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

107

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2013-01-01

108

Cloud Impacts on Pavement Temperature in Energy Balance Models  

Science.gov (United States)

Forecast systems provide decision support for end-users ranging from the solar energy industry to municipalities concerned with road safety. Pavement temperature is an important variable when considering vehicle response to various weather conditions. A complex, yet direct relationship exists between tire and pavement temperatures. Literature has shown that as tire temperature increases, friction decreases which affects vehicle performance. Many forecast systems suffer from inaccurate radiation forecasts resulting in part from the inability to model different types of clouds and their influence on radiation. This research focused on forecast improvement by determining how cloud type impacts the amount of shortwave radiation reaching the surface and subsequent pavement temperatures. The study region was the Great Plains where surface solar radiation data were obtained from the High Plains Regional Climate Center's Automated Weather Data Network stations. Road pavement temperature data were obtained from the Meteorological Assimilation Data Ingest System. Cloud properties and radiative transfer quantities were obtained from the Clouds and Earth's Radiant Energy System mission via Aqua and Terra Moderate Resolution Imaging Spectroradiometer satellite products. An additional cloud data set was incorporated from the Naval Research Laboratory Cloud Classification algorithm. Statistical analyses using a modified nearest neighbor approach were first performed relating shortwave radiation variability with road pavement temperature fluctuations. Then statistical associations were determined between the shortwave radiation and cloud property data sets. Preliminary results suggest that substantial pavement forecasting improvement is possible with the inclusion of cloud-specific information. Future model sensitivity testing seeks to quantify the magnitude of forecast improvement.

Walker, C. L.

2013-12-01

109

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

110

Urban evaporation rates for water-permeable pavements.  

Science.gov (United States)

In urban areas the natural water balance is disturbed. Infiltration and evaporation are reduced, resulting in a high surface runoff and a typical city climate, which can lead to floods and damages. Water-permeable pavements have a high infiltration rate that reduces surface runoff by increasing the groundwater recharge. The high water retention capacity of the street body of up to 51 l/m(2) and its connection via pores to the surface lead to higher evaporation rates than impermeable surfaces. A comparison of these two kinds of pavements shows a 16% increase in evaporation levels of water-permeable pavements. Furthermore, the evaporation from impermeable pavements is linked directly to rain events due to fast-drying surfaces. Water-permeable pavements show a more evenly distributed evaporation after a rain event. Cooling effects by evaporative heat loss can improve the city climate even several days after rain events. On a large scale use, uncomfortable weather like sultriness or dry heat can be prevented and the urban water balance can be attenuated towards the natural. PMID:20818060

Starke, P; Göbel, P; Coldewey, W G

2010-01-01

111

Experimental studies of the dilution of vehicle exhaust pollutants by environment-protecting pervious pavement.  

Science.gov (United States)

This study determines whether environment-protecting pervious pavement can dilute pollutants immediately after emissions from vehicle. The turbulence-driven dry-deposition process is too slow to be considered in this aspect. The pavement used is the JW pavement (according to its inventors name), a high-load-bearing water-permeable pavement with patents in over 100 countries, which has already been used for more than 8 years in Taiwan and is well suited to replacing conventional road pavement, making the potential implementation of the study results feasible. The design of this study included two sets of experiments. Variation of the air pollutant concentrations within a fenced area over the JW pavement with one vehicle discharging emissions into was monitored and compared with results over a non-JW pavement. The ambient wind speed was low during the first experiment, and the results obtained were highly credible. It was found that the JW pavement diluted vehicle pollutant emissions near the ground surface by 40%-87% within 5 min of emission; whereas the data at 2 m height suggested that about 58%-97% of pollutants were trapped underneath the pavement 20 min after emission. Those quantitative estimations may be off by +/- 10%, if errors in emissions and measurements were considered. SO2 and CO2 underwent the most significant reduction. Very likely, pollutants were forced to move underneath due to the special design of the pavement. During the second experiment, ambient wind speeds were high and the results obtained had less credibility, but they did not disprove the pollutant dilution capacity of the JW pavement. In order to track the fate of pollutants, parts of the pavement were removed to reveal a micro version of wetland underneath, which could possibly hold the responsibility of absorbing and decomposing pollutants to forms harmless to the environment and human health. PMID:22393814

Liu, Chung-Ming; Chen, Jui-Wen; Tsai, Jen-Hui; Lin, Wei-Shian; Yen, M-T; Chen, Ting-Hao

2012-01-01

112

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

113

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

2009-01-01

114

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

1976-01-01

115

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...

116

Consideration of pavement roughness effects on vehicle-pavement interaction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 si...

2001-01-01

117

Pavement Management Information System (PMIS).  

Science.gov (United States)

The report describes the Pavement Management Information System (PMIS) developed for the Mississippi State Highway Department. The purpose of PMIS is to determine road network status for assigning rehabilitation needs. Both Project level and Network level...

K. P. George

1990-01-01

118

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...

119

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

120

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

 
 
 
 
121

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

122

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

123

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

124

Pavement Structure Evaluation of Alaskan Highways.  

Science.gov (United States)

A three year study was implemented to review the construction and performance of pavement structures in Alaska. One hundred twenty uniform pavement sections were chosen and characterized by fatigue (alligator) cracking, thermal cracking, roughness of ride...

R. McHattie B. Connor D. Esch

1980-01-01

125

High Performance Concrete Pavement in Indiana  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2011-01-01

126

Generation mechanisms of tire-pavement noise  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2012-01-01

127

Pavement thickness evaluation using ground penetrating radar  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2006-01-01

128

Recycling of Asphalt Pavements with Asphalt Rubber  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pavement recycling has been an important rehabilitation technique to deal with reclaimed materials from old pavements which are usually sent to landfills. The application of this technique contributes to: i) the accomplishment of the requirements defined by the European legislation for the amount of material sent to landfills; ii) the reduction in the use of new raw materials used to produce pavement layers. The reduction of materials to be used in pavement rehabilitation has also been possib...

2008-01-01

129

Recycling of asphalt pavements with asphalt rubber  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pavement recycling has been an important rehabilitation technique to deal with reclaimed materials from old pavements which are usually sent to landfills. The application of this technique contributes to: i) the accomplishment of the requirements defined by the European legislation for the amount of material sent to landfills; ii) the reduction in the use of new raw materials used to produce pavement layers. The reduction of materials to be used in pavement rehabilitation has also been possib...

2008-01-01

130

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

131

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

132

Evaluation of a Hot Mix Asphalt Perpetual Pavement.  

Science.gov (United States)

In 2003, WisDOT constructed two perpetual pavement test sections on the entrance ramp to I-94 from the Kenosha Safety and Weigh Station Facility in Southeastern WI. Test section 1 (TS1) HMA layers were constructed as follows: 2-in surface layer (PG 76-28,...

B. Bischoff I. Battaglia J. Ryan S. Reichelt

2010-01-01

133

Making "Magic" Sidewalks of Pervious Pavement  

Science.gov (United States)

Students use everyday building materialsâsand, pea gravel, cement and waterâto 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),

134

Impact of pavement conditions on crash severity.  

Science.gov (United States)

Pavement condition has been known as a key factor related to ride quality, but it is less clear how exactly pavement conditions are related to traffic crashes. The researchers used Geographic Information System (GIS) to link Texas Department of Transportation (TxDOT) Crash Record Information System (CRIS) data and Pavement Management Information System (PMIS) data, which provided an opportunity to examine the impact of pavement conditions on traffic crashes in depth. The study analyzed the correlation between several key pavement condition ratings or scores and crash severity based on a large number of crashes in Texas between 2008 and 2009. The results in general suggested that poor pavement condition scores and ratings were associated with proportionally more severe crashes, but very poor pavement conditions were actually associated with less severe crashes. Very good pavement conditions might induce speeding behaviors and therefore could have caused more severe crashes, especially on non-freeway arterials and during favorable driving conditions. In addition, the results showed that the effects of pavement conditions on crash severity were more evident for passenger vehicles than for commercial vehicles. These results provide insights on how pavement conditions may have contributed to crashes, which may be valuable for safety improvement during pavement design and maintenance. Readers should notice that, although the study found statistically significant effects of pavement variables on crash severity, the effects were rather minor in reality as suggested by frequency analyses. PMID:23892046

Li, Yingfeng; Liu, Chunxiao; Ding, Liang

2013-10-01

135

Pervious Pavements: Installation, Operations and Strength. Part 4: FlexiPave (Recycled Rubber Tires) System.  

Science.gov (United States)

Pervious pavement systems are now being recognized as a best management practice by the Environmental Protection Agency and the state of Florida. The pervious concrete system is designed to have enhanced pore sizes in the surface layer compared to convent...

E. Stuart I. Uju M. Chopra M. Hardin M. Wanielista

2011-01-01

136

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

137

Desert Pavement Process and Form: Modes and Scales of Landscape Stability and Instability in Arid Regions  

Science.gov (United States)

Desert pavements are recognized in arid landscapes around the world, developing via diminution of constructional/depositional landform relief and creating a 1-2 stone thick armor over a "stone free" layer. Surface exposure dating demonstrates that clasts forming the desert pavements are maintained at the land surface over hundreds of thousands of years, as aeolian fines are deposited on the land surface, transported into the underlying parent material and incorporated into accretionary soil horizons (e.g., the stone free or vesicular [Av] horizon). This surface armor provides long-term stability over extensive regions of the landscape. Over shorter time periods and at the landform-element scale, dynamic surficial processes (i.e., weathering, runoff) continue to modify the pavement form. Clast size reduction in comparison to underlying parent material, along with armoring and packing of clasts in pavements contribute to their persistence, and studies of crack orientations in pavement clasts indicate physical weathering and diminution of particle size are driven by diurnal solar insolation. Over geologic time, cracks form and propagate from tensile stresses related to temporal and spatial gradients in temperature that evolve and rotate in alignment with the sun's rays. Observed multimodal nature of crack orientations appear related to seasonally varying, latitude-dependent temperature fields resulting from solar angle and weather conditions. Surface properties and their underlying soil profiles vary across pavement surfaces, forming a landscape mosaic and controlling surface hydrology, ecosystem function and the ultimate life-cycle of arid landscapes. In areas of well-developed pavements, surface infiltration and soluble salt concentrations indicate that saturated hydraulic conductivity of Av horizons decline on progressively older alluvial fan surfaces. Field observations and measurements from well-developed desert pavement surfaces landforms also yield significantly lower infiltration rates, enhanced rates of overland flow characterized by high water:sediment ratios and reduced production of desert ecosystems. Consequently, regionally extensive pavement and significantly decreased infiltration over geologic time have resulted in widespread overland flow, elaborate drainage networks on alluvial and eolian-mantled bedrock landscapes, and channel incision and regional dissection of the pavement-mantled landforms. However, these once stable landscapes become progressively unstable with time, serving as sediment source areas for younger alluvial deposits (i.e., geologic life-cycle). Thus, regional dissection (instability) of these desert landscapes can be influenced by the intrinsic properties of pavement-mantled landscapes and not necessarily to external forces of climate change and tectonics.

Wells, Stephen G.; McFadden, Leslie D.; McDonald, Eric V.; Eppes, Martha C.; Young, Michael H.; Wood, Yvonne A.

2014-05-01

138

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)

2014-01-01

139

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

140

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

1994-01-01

 
 
 
 
141

Recycling of portland cement concrete pavement, Johnson County. Final report, 1986-1995  

Energy Technology Data Exchange (ETDEWEB)

In recent years there has been increasing interest in recycling construction materials. Surface courses of bituminous pavements are currently being actively recycled all over Kansas. The recycling of portland cement concrete pavements (PCCP) can help alleviate any material disposal problems during construction, especially in urban areas and reduce the consumption or importation of virgin aggregate into aggregate poor areas. Two test sections using the coarser fraction from the original crushed portland cement concrete pavement were placed on K-7 in 1985. One section incorporated a recycled base and standard PCCP construction, another section was designed as a recycled base and recycled PCCP. Two other sections were control sections constructed with regular aggregate.

Wojakowski, J.B.; Fager, G.A.; Catron, M.A.

1995-08-01

142

Development of Pavement Temperature Contours for India  

Science.gov (United States)

The stress-strain response of the bituminous pavements is highly sensitive to temperature. To systematically analyze the pavement performance, it is necessary that one understands the variation of pavement temperature spatially and temporally during the life time of a pavement. In this investigation, historic air temperature data for 37 locations across India was collected. Using this database, pavement temperature data was predicted by an appropriate air temperature-pavement temperature model. High and low temperature pavement temperature contours were generated for the first time for India. It was seen that the locations spanning from Srinagar to Madhya Pradesh and Rajasthan to Orissa were extremely critical. The minimum temperature in these locations was - 10° C and the maximum temperature was around 68° C. Clearly such information is necessary when making choice of binder grade and bituminous layer thickness.

Nivitha, M. R.; Krishnan, J. M.

2014-06-01

143

The use of reflective and permeable pavements as a potential practice for heat island mitigation and stormwater management  

International Nuclear Information System (INIS)

To help address the built environmental issues of both heat island and stormwater runoff, strategies that make pavements cooler and permeable have been investigated through measurements and modeling of a set of pavement test sections. The investigation included the hydraulic and thermal performance of the pavements. The permeability results showed that permeable interlocking concrete pavers have the highest permeability (or infiltration rate, ?0.5 cm s?1). The two permeable asphalt pavements showed the lowest permeability, but still had an infiltration rate of ?0.1 cm s?1, which is adequate to drain rainwater without generating surface runoff during most typical rain events in central California. An increase in albedo can significantly reduce the daytime high surface temperature in summer. Permeable pavements under wet conditions could give lower surface temperatures than impermeable pavements. The cooling effect highly depends on the availability of moisture near the surface layer and the evaporation rate. The peak cooling effect of watering for the test sections was approximately 15–35?°C on the pavement surface temperature in the early afternoon during summer in central California. The evaporative cooling effect on the pavement surface temperature at 4:00 pm on the third day (25 h after watering) was still 2–7?°C lower compared to that on the second day, without considering the higher air temperature on the third day. A separate and related simulation study performed by UCPRC showed that full depth permeable pavements, if designed properly, can carry both light-duty traffic and certain heavy-duty vehicles while retaining the runoff volume captured from an average California storm event. These preliminarily results indicated the technical feasibility of combined reflective and permeable pavements for addressing the built environment issues related to both heat island mitigation and stormwater runoff management. (letter)

2013-01-01

144

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

145

The effect of loading conditions on pavement responses calculated using a linear-elastic model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In most structural pavement design methods, strains and stresses in the layers are calculated with multi-layer programs based on the Burmister model using the linear elastic theory. Burmister defined loads as a constant pressure applied on a circular surface. New technology for measuring tire-pavement contact stresses has shown that the assumptions used in the multi-layer models do not correspond to reality. This study evaluates the relative influence of different parameters, ...

Perret, J.

2002-01-01

146

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

2000-01-01

147

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

148

A study of ageing and degradation of asphalt pavements on low volume roads  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An important objective with this research work has been to get more knowledge about mix design and maintenance of low volume roads with asphalt pavements in Norway. A literature review on bitumen, filler, rheology and ageing has been carried out. This has been focused on bitumen and filler because of their importance in the asphalt mixture. Bitumen as the binder in the asphalt pavement, and filler because of its relatively large surface area compared to the rest of the aggregates. Filler will...

Lerfald, Bjørn Ove

2000-01-01

149

Validation of theoretical models through measured pavement response  

DEFF Research Database (Denmark)

Most models for structural evaluation of pavements are of the analytical-empirical type. An analytical model, derived from solid mechanics, is used to calculate stresses or strains at critical positions, and these stresses or strains are then used with empirical relationships to predict pavement performance. The analytical models are based on a number of simplifications with respect to reality and must be verified experimentally.Different pressure gauges were installed in a sand, assumed to be a semi-infinite halfspace. The surface of the sand was loaded by a Falling Weight Deflectometer (FWD) at different lateral positions with respect to the gauges. An integration of the stresses measured at the plane of the gauges showed that the total load recorded by the gauges was close to the loade imposed by the FWD, cofirming the reliability of the gauges. The theoretical stress calculated using continuum mechanics was quite different from the measured stress, the peak theoretical value being only half of the measured value.On an instrumented pavement structure in the Danish Road Testing Machine, deflections were measured at the surface of the pavement under FWD loading. Different analytical models were then used to derive the elastic parameters of the pavement layeres, that would produce deflections matching the measured deflections. Stresses and strains were then calculated at the position of the gauges and compared to the measured values. It was found that all analytical models would predict the tensile strain at the bottom of the asphalt layer reasonably well, but that the vertical strain at the top of the subgrade could only be predicted with some degree of accuracy if the subgrade was treated as a non-linear elastic material.

Ullidtz, Per

1999-01-01

150

Effective Pavement Marking Practices for Sealcoat and Hot-Mix Asphalt Pavements.  

Science.gov (United States)

This report describes the tasks of research conducted to identify effective pavement marking practices for seal coat and hot-mix asphalt (HMAC) pavements in Texas. The researchers reviewed literature, determined current Texas Department of Transportation ...

T. J. Gates H. G. Hawkins E. R. Rose

2003-01-01

151

Damage and healing evaluation of Mn/Road pavements using stress wave testing  

Science.gov (United States)

In order to accurately assess the fatigue life of asphalt concrete pavements, an in-situ field evaluation method must be used so that factors which cannot be accounted for in the lab are considered. Surface wave testing is employed in this research to nondestructively monitor sensitive structural changes in the asphalt surface layer of pavements in the field. Microcrack damage growth and healing are investigated on pavement test sections at the Minnesota Road Research Facility (Mn/Road) by way of surface wave testing. One of the mechanisms which cannot be simulated accurately in the lab is healing of asphalt concrete during rest periods. Healing of the asphalt pavement test sections at Mn/Road following a 24 hour rest period was quantified using wavespeed measurements. These measurements show that a significant amount of healing is occurring and can be detected using stress wave testing. Several signal processing methods are used to evaluate the microcrack damage growth and healing in the asphalt pavement sections. The 'apparent' modulus is computed from the velocity of wave propagation and used to quantify damage in the pavements. Attenuation of the stress waves is also calculated for damage assessment. It is discovered that attenuation parameters in the frequency domain are more sensitive than wavespeed calculations in the time domain, but contain significantly more variability.

Katzke, Evan; Kim, Y. R.

1998-03-01

152

Performance model for unbound grnular materials pavements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recently, there has been growing interest on the behaviour of unbound granular material in road base layers. Researchers have studied that the design of a new pavement and prediction of service life need proper characterization of unbound granular materials, which is one of the requirements for a new mechanistic design method in flexible pavement. Adequate knowledge of the strength and deformation characteristics of unbound layer in pavements is a prerequisite for proper thickness design, res...

Yideti, Tatek Fekadu

2012-01-01

153

DESIGN OF PAVEMENTS REINFORCED WITH GEOGRID  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2009-01-01

154

Dynamic contracting mechanism for pavement maintenance management:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Technological advances, financial possibilities and changes of demands have increasingly affected the pavement maintenance environment for outsourcing in recent years. This induces complexity in the contracting methods of pavement maintenance activities. Despite the fact that current contracting practices on pavement maintenance activities are not sufficient to deal with changes providing the improved level of services. Therefore road agencies are needed to enable appropriate contracting meth...

Demirel, H. C.; Ridder, H. A. J.

2013-01-01

155

Removable Urban Pavements: An innovative, sustainable technology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Vehicle dynamic response due to pavement roughness  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ro...

2011-01-01

157

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

158

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

159

Mathematical failure-theory (MFT methodology in pavement management system for rehabilitation and repair methods selection  

Directory of Open Access Journals (Sweden)

Full Text Available Pavement rehabilitation and repair methods selection is one of the key issues many road organizations and researchers have occupied. Not only road management cost but also road user’s cost and cost for inhabitants and community should be included in the life cycle cost in order to help infrastructure investment judgment. Thus in estimating life cycle cost, Pavement rehabilitation and repair methods selection is essential even if technological capabilities of evaluation are not sufficient. In order for Pavement Management Systems (PMS to be effective, they must be based on a reliable, statistically sound means for the rehabilitation and repair methods that are present on the system. To make sensible life cycle cost decisions in design and rehabilitation, pavement engineers must be able to account for distress phenomena and repair methods. This paper will present a Mathematical Failure-Theory (MFT methodology for incorporating statistical and probabilistically Factors into life cycle cost analysis and PMS. This approach gives the engineer the ability to statistically and probability consider different rehabilitation and repair method and statistically and probability factors in computing the life cycle costs for rehabilitation and repair methods selection.

Fereidoon Moghadas Nejad

2009-04-01

160

Compaction of asphalt pavement. Final report  

Energy Technology Data Exchange (ETDEWEB)

This synthesis will be of interest to construction and materials engineers, paving contractors, equipment manufacturers, and others who are involved in assessing the performance of asphalt pavements. Information is presented on various issues related to compaction of asphalt pavements. Compaction is one of the most important factors affecting the performance of asphalt pavements. The report of the Transportation Research Board describes the theory, methods, equipment, and specifications related to the compaction of asphalt pavements. A brief history of, the importance of, and factors affecting compaction are also discussed. Construction influences, density measurements, and trends are also considered.

Hughes, C.S.

1989-10-01

 
 
 
 
161

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

162

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

163

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 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

2001-01-01

164

Enhancing pavements for thermal applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Renewable energy combined with energy efficiency can offer a viable and influential solution to minimise the harmful consequences of both fossil fuel depletion and increases in the cost of power generation. However, in most cases renewable energy technologies require high initial investments that may deter potential users. Pavement Energy Systems (PES) potentially offer a low-cost solution to sustainable and clean energy generation by utilising the thermo-physical properties and design featur...

2012-01-01

165

The Road Traffic Noise Reduction on the Drainage Pavement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The drainage pavement or porous asphalt has open structure of its gradation. Therefore, the porous asphalt can reduce noise level from road traffic, as well as drains water from the road surface. These behaviors lead to the porous asphalt contribution on road traffic noise reduction and environment. This paper provides an artificial simulation on the road traffic noise reduction when the porous asphalt is applied an urban expressway. The simulation using and adapting ASJ RTN-2008 Model approa...

2013-01-01

166

Effects of impervious pavements on reducing runoff in an arid urban catchment  

Science.gov (United States)

The progressive urbanization of US arid and semi-arid southwestern territories has transformed undeveloped aridlands into dynamic, radially expanding metropolitan centers. As these mature, infill development further reduces undeveloped area, inversely coupling surface imperviousness to infiltration rates, with a subsequent increase in runoff generation. Intensified runoff carries undesirable environmental consequences, magnifying urban flooding events and concentrations, transport, and propagation of contaminants. Pervious pavements offer one potential solution for decreased urban infiltration. At present, the application potential of pervious pavements as an effective urban infiltration management tool exceeds its exploitation. While entirely eliminating urban Total Impervious Area is not a feasible solution, pervious pavements significantly reduce Effective Impervious Area at costs competitive with traditional Best Management Practices. Previous research into pervious pavements has largely consisted of laboratory prototypes or small-scale field experiments, with a heavy bias towards parking lots. In this study we explore the effectiveness of pervious pavements in increasing infiltration, thus decreasing runoff volume during summer monsoonal and winter convective rainfall events in an 8 ha residential catchment in Scottsdale, Arizona. Analysis focuses on the interaction dynamics between surface area of pervious pavement application and its net effect on runoff response at the catchment level. Hydrological response was modeled using MAHLERAN (Model for Assessing Hillslope-Landscape Erosion, Runoff and Nutrients), a spatially explicit, event-based model, parameterized at a spatial resolution of 0.25 sq m. Data for model parameterization was obtained from analysis of aerial imagery and field-based monitoring of surface properties. The model was tested against measurements of flow at the catchment outlet for multiple rainfall events with total event rainfall ranging from 5 mm to 25 mm. Model testing shows total event discharge simulated well, although low Nash-Sutcliffe coefficients for events indicate a poor fit between the shape and timing of the modeled and monitored hydrograph, which we attribute to poor characterization of friction factors in urban catchments. Scenario-based model analysis tested catchment response to substitution of pervious for conventional pavement by percent and pavement-function scenarios. Results are consistent with previous findings in that short duration-high intensity storms trigger threshold infiltration capacity, past which pervious pavement damping of runoff volume levels off, approaching conventional levels. However at the modeled catchment scale, this initial damping represents a significant reduction in volume, peak flow velocity, and contaminant loading potential. Urban surface drainage networks concentrate and channel flow along roads: the capacity of pervious pavements to simultaneously increase infiltration directly at location of greatest runoff and mitigate inflow effects from remote points has compelling potential as a hydrologic and urban systems engineering tool.

Epshtein, O.; Turnbull, L.; Earl, S.

2011-12-01

167

Dust accretion under stone pavements: A complementary environmental archive in arid environments  

Science.gov (United States)

Stone pavements are widespread surface covers in arid environments. They form predominantly by the trapping of aeolian dust, which trickles below the surficial clast layer, where it forms a continuous layer of fine-grained material with a prominent foamy structure: the vesicular horizon (Av). Successive accretion of dust leads to a thickening of the aeolian mantle and detaches clasts from bedrock. Since this process is dependent on environmental conditions, stone pavement-covered accretionary sections can be used as palaeoenvironmental archive. In the eastern Mojave Desert, correlation of six sediment sections on a 560 ka old basalt flow yield a standard section, comprising at least three distinct units of pulsed aeolian sediment input, interrupted by phases of stone pavement formation, their burial and subsequent pedogenetic alteration. Formation and subsequent burial of stone pavements requires lateral re-formation processes. Two such processes - clast drag by unconcentrated overland flow and clast creep by air release from the soil - are presented, along with their environmental boundary conditions. The different sedimentary units under stone pavements in the eastern Mojave Desert must be interpreted in the light of both, the prominent climatic changes during the Pleistocene/Holocene and the young drainage system in this region. Accretionary dust sections under stone pavements receive their sediment predominantly from modern playas. However, they typically start trapping sediment and thus environmental information when the lake level drops and the lacustrine archive deceases. Hence, they appear to be complementary archives with a the potential to fill the stratigraphic gaps in lacustrine records.

Dietze, Michael; Fuchs, Markus; Kleber, Arno

2014-05-01

168

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

169

Analysis and design optimization of flexible pavement  

Energy Technology Data Exchange (ETDEWEB)

A project-level optimization approach was developed to minimize total pavement cost within an analysis period. Using this approach, the designer is able to select the optimum initial pavement thickness, overlay thickness, and overlay timing. The model in this approach is capable of predicting both pavement performance and condition in terms of roughness, fatigue cracking, and rutting. The developed model combines the American Association of State Highway and Transportation Officials (AASHTO) design procedure and the mechanistic multilayer elastic solution. The Optimization for Pavement Analysis (OPA) computer program was developed using the prescribed approach. The OPA program incorporates the AASHTO equations, the multilayer elastic system ELSYM5 model, and the nonlinear dynamic programming optimization technique. The program is PC-based and can run in either a Windows 3.1 or a Windows 95 environment. Using the OPA program, a typical pavement section was analyzed under different traffic volumes and material properties. The optimum design strategy that produces the minimum total pavement cost in each case was determined. The initial construction cost, overlay cost, highway user cost, and total pavement cost were also calculated. The methodology developed during this research should lead to more cost-effective pavements for agencies adopting the recommended analysis methods.

Mamlouk, M.S.; Zaniewski, J.P.; He, W.

2000-04-01

170

Predicting Financial Distress and the Performance of Distressed Stocks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we consider the measurement and pricing of distress risk.We present a model of corporate failure in which accounting and market-based measures forecast the likelihood of future financial distress. Our best model is more accurate than leading alternative measures of corporate failure risk.We use our measure of financial distress to examine the performance of distressed stocks from 1981 to 2008. We find that distressed stocks have high stock return volatility and high market beta...

2011-01-01

171

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.

172

In place recycling of granular bases of asphalt pavements  

Directory of Open Access Journals (Sweden)

Full Text Available This work presents the results of a study intended the obtaining and introduction of the auxiliary elements to assure the road pavements technological control of rehabilitation which involves the recycling in place of granular bases. This verification was made using two techniques, the CBR in place verification, through the use of DCP (Dynamic Cone Penetrometer, and the granulometric framing, through the curve of Talbot, for recycled materials. The investigations were accomplished starting from practical applications in roads which involved, in an experimental way, the pavements rehabilitation through the base course recycling, incorporating the surface layer. Through the data processing obtained in the tests, it was possible the elaboration of the technical specification proposal of the granular bases recycling.

Taís Sachet

2008-04-01

173

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

Science.gov (United States)

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 11.2?m 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.

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

2008-01-01

174

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

175

Using Precast Concrete Panels for Pavement Construction in Indiana  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2004-01-01

176

Definition of in situ pavement instrumentation for data collection to develop a pavement performance model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

After the implementation of the AASHTO Road Test many researches have been carried out regarding material and pavement performance, both in laboratory and in situ. Many methods for pavement evaluation and design were obtained based on empirical or empirical-mechanistic approaches. Nowadays these methods are used in pavement analysis and design supported by a set of shift factors which consider the variables not included in their definition.

2008-01-01

177

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 st...

2007-01-01

178

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

179

Nonwoven Geotextile Interlayers for Separating Cementitious Pavement Layers: German Practice and U.S. Field Trails.  

Science.gov (United States)

Pavement engineering is traditionally a conservative field, but successful pavement engineers will constantly seek out proven innovative concepts with potential to improve pavement performance while reducing costs. Many pavement structures in the United S...

R. O. Rasmussen S. I. Garber

2009-01-01

180

Western States Drainable PCC Pavement Workshop. Held in Sacramento, California on July 21-22, 1993. Summary Report.  

Science.gov (United States)

Contents: Overview of Pavement Drainage Systems; Performance of Drainable PCC Pavements in Washington State; Arizona Experience With Concrete Pavements; Drainable PCC Pavements in Oregon; A Performance Evaluation of PCC Pavements Constructed on Permeable ...

R. Baumgardner L. Pierce G. Way L. Moore K. Smith S. Bemanian M. Farrar J. Stites G. Wells W. Nokes W. Frank J. Woodstrom

1993-01-01

 
 
 
 
181

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

182

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

183

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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-...

2007-01-01

184

Degradation Modeling of Polyurea Pavement Markings.  

Science.gov (United States)

Polyurea is a long life pavement marking material used for assets requiring long periods of uninterrupted accessibility. Knowing the performance characteristics of such markings is critical to asset management planning focused on maximizing marking materi...

J. D. Needham

2011-01-01

185

Airfield Pavement Condition Survey, Usns Adak, Alaska.  

Science.gov (United States)

The results of a condition survey of the airfield pavements at the U. S. Naval Station, Adak, Alaska are presented. The survey established statistically-based condition numbers (weighted defect densities) which were direct indicators of the condition of t...

D. J. Lambiotte R. B. Brownie

1971-01-01

186

Maintenance Methods for Continuously Reinforced Concrete Pavements.  

Science.gov (United States)

In late 1974, test maintenance sections were constructed on a section of I-65 south of Indianapolis, Indiana. The road was stratified into 'similar' sections of pavement using deflection, cracking, and breakup as selection criteria. Various types of measu...

S. J. Virkler

1978-01-01

187

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

188

Pervious Pavement System Evaluation- Abstract 1  

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...

189

Flexible Pavement Drainage Monitoring, Performance, and Stability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The current study is a continuation of the study FHWA/IN/JTRP project HPR-2078, “Locating the Drainage Layer for Flexible Pavements”. In this previous study, three test sections were constructed in a new pavement on a by-pass around Fort Wayne, Indiana. These test sections were instrumental to record temperatures, moisture, frost penetration, rainfall and subdrainage system overflow. Collected data and Finite Element Method (FEM) analysis indicate the subdrainage systems are performing...

1999-01-01

190

Adult respiratory distress syndrome  

International Nuclear Information System (INIS)

Our present-day knowledge concerning the clinico-chemical and radiological findings in adult respiratory distress syndrome are described. Three typical case histories have been selected to illustrate this condition; they were due to multiple trauma or sepsis. It is stressed that radiology is in a key position for making the diagnosis and for observing the course of the illness. (orig)

1986-01-01

191

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

1978-01-01

192

Guide for Curing of Portland Cement Concrete Pavements, Volume 1.  

Science.gov (United States)

This document provides guidance on details of concrete curing practice as they pertain to construction of portland cement concrete pavements. The guide is organized around the major events in curing pavements: curing immediately after placement (initial c...

2005-01-01

193

Seasonal Instrumentation of SHRP Pavements; the University of Toledo.  

Science.gov (United States)

Seasonal Monitoring Program (SMP) instrumentation was installed in five sections at the Ohio Test Pavement in Delaware County, Ohio using Strategic Highway Research Program (SHRP) protocols developed for the Long-Term Pavement Performance (LTPP) group of ...

A. G. Heydinger B. W. Randolph

1998-01-01

194

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 ...

195

Full scale accelerated testing of bituminous road pavement mixtures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The in-service behaviour of a standard Irish Dense Base Coarse Macadam mixture (DBC) was evaluated by using the material to overlay a road section, which was based upon a weak pavement structure. The response of the layer under a fully laden dual axle truck was examined using a series of pressure cells and asphalt strain gauges that were embedded in the test section. The section was traversed repeatedly until a network of fatigue cracks was observed on the road surface. The transverse horizon...

2001-01-01

196

Instrumentation, analysis and modeling of flexible pavement subdrainage  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

1996-01-01

197

Calculation method for permanent deformation of unbound pavement materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

198

Nonlinear Responses of a Two Dimensional Vehicle-pavement System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2013-01-01

199

Mixed linear modeling techniques for enhancing pavement performance predictions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The use of appropriate advanced modeling techniques for predicting the performance of pavements that have received rehabilitation treatments may reap substantial benefits to a Pavement Management System (PMS). If the modeling technique is appropriately chosen on the basis of practicality, precision, the intended use of the model, and the nature of the pavement data, its applicability to PMS can be enhanced greatly. Pavement rehabilitation data typically constitutes of repeated measurements th...

2012-01-01

200

Locating the Drainage Layer for Bituminous Pavements in Indiana  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. \tThis research study involves the evaluation of...

1996-01-01

 
 
 
 
201

Benefits of including hot mix recycled materials in pavement design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pavement recycling is becoming more acceptable among the available techniques for pavement maintenance/rehabilitation. It is based on sustainable development, by reusing materials reclaimed from the pavements and reducing the disposal of asphalt materials. Based on the results obtained from laboratory tests carried out on two bituminous mixtures, one of which including 50% of recycled asphalt, some simulations were made for the design of a pavement where those mixtures would be used as a bitu...

2005-01-01

202

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

203

Pavement Design for Curved Road Sections: Fatigue Performance of Interfaces and Longitudinal Top-down Cracking in Multilayered Pavements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper focuses on damage processes other than the main one observed and studied in pavement design. Previous research has targeted the experimental fatigue performance of tack coats. The French Pavement Design method has been chosen herein to illustrate how interface fatigue performance can lead to improved design, especially when pavements are subjected to repeated horizontal loadings. In a curved pavement section, longitudinal top-down cracking is observed, and this damage process may a...

2009-01-01

204

Materials Application Rates for Dense-Graded Asphalt Surface Treatments Using High Float Emulsion.  

Science.gov (United States)

Asphalt surface treatment (AST) pavements using high float emulsions and dense-graded aggregates have been used for more than 20 years in Alaska. However, the normally positive economics of these pavements have sometimes been offset by problems during or ...

R. L. McHattie

2005-01-01

205

Financial Distress Prediction Using Distress Score as a Predictor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Financial distress can be the reflection of corporation's management condition. Consequently the distress score
of corporations should be considered as a new predictor variable in predicting the financial distress.
The analysis of ROC curve, among the models employed to compare the effectiveness of different statistical
models, is often used in the fields of psychology and bio-physics in order to summarize the discriminatory of a
diagnostic...

Maryam Sheikhi; Mirfeiz Fallah Shams; Zeinab Sheikhi

2011-01-01

206

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2011-01-01

207

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

208

Breaking/cracking and seating concrete pavements. Final report  

Energy Technology Data Exchange (ETDEWEB)

This synthesis will be of interest to pavement designers, maintenance engineers, and others interested in reducing reflection cracking of asphalt overlays on portland cement concrete (PCC) pavement. Information is presented on the technique of breaking or cracking of the concrete pavement into small segments before overlaying with asphalt concrete. Asphalt concrete overlays on existing PCC pavements are subject to reflection cracking induced by thermal movements of PCC pavement. The report of the Transportation Research Board discusses the technique of breaking/cracking and seating of the existing PCC before an overlay as a means to reduce or eliminate reflection cracking.

Thompson, M.R.

1989-03-01

209

Targeting distress in rheumatic diseases  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Psychological distress is highly prevalent in patients with rheumatic diseases. It is associated with a variety of negative outcomes, including pain, fatigue, disability, and maladaptive cognitive behavioural coping strategies. In this thesis, psychological distress was studied both as an outcome measure and as a therapeutic target in the context of multidisciplinary rehabilitation. The longitudinal role of coping in psychological distress was systematically reviewed, a questionnaire to asses...

Vriezekolk, J. E.

2011-01-01

210

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2006-01-01

211

Financial Distress Prediction Using Distress Score as a Predictor  

Directory of Open Access Journals (Sweden)

Full Text Available Financial distress can be the reflection of corporation's management condition. Consequently the distress scoreof corporations should be considered as a new predictor variable in predicting the financial distress.The analysis of ROC curve, among the models employed to compare the effectiveness of different statisticalmodels, is often used in the fields of psychology and bio-physics in order to summarize the discriminatory of adiagnostic test and also to compare the performance of different models for binary outcomes. Therefore,concerning the topic of this research and the use of ROC curves in predicting the financial distress ofcorporations, we use logit models to study the financial distress of the manufacturing corporations in TehranStock Exchange. We also compare the accuracy of the prediction method with financial distress score variable tothe method without this variable.Concerning the accuracy of prediction and classification, the results of this research show that the accuracy ofprediction can be enhanced by using the distressed score, gained from DEA, as a new predictor variable inpredicting the financial distress.

Maryam Sheikhi

2011-12-01

212

Airfield Pavement Evaluation - Usnaf El Centro, California.  

Science.gov (United States)

The evaluation of the pavement at the U. S. Naval Air Facility, El Centro, California, is presented with the allowable gross load capacities of the runways, taxiways, and parking aprons for single, dual, single-tandem, and dual-tandem wheel assembly aircr...

R. J. Lowe W. H. Chamberlin

1966-01-01

213

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...

214

Airfield Pavement Evaluation, Usnalf Crows Landing, California.  

Science.gov (United States)

The evaluation of the pavement at the U. S. Naval Auxiliary Landing Field, Crows Landing, California is presented with the allowable gross load capacities of the runways, taxiways, and parking apron for single, dual, and dual-tandem wheel assembly aircraf...

D. J. Lambiotte J. A. Garcia

1969-01-01

215

Numerical integration approach to the problem of simulating damage in an asphalt pavement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A road develops permanent deformation or fatigue damage because of the stress and strain induced in its structure by surface loading and environmental change. Dynamic tyre forces generated by the vibration of moving heavy vehicles excited by the road surface profile are strongly influenced by vehicle speed and dynamic properties. A mechanistic-empirical approach is implemented here to simulate the deterioration of a pavement, taking account of dynamic excitation of the axles. This paper highl...

2011-01-01

216

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 (?PAH(8)) 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. PMID:22289152

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

2012-06-01

217

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

218

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

Science.gov (United States)

... crashes on similar roads. AAA Foundationfor Traffic Safety Pavement edge drop-off “ Pavement edge drop-off crashes are over twice as ... What to do if you drive off the pavement edge • • IF THERE ARE NO OBSTACLES DIRECTLY IN ...

219

Surface properties-vehicle interaction  

Energy Technology Data Exchange (ETDEWEB)

The 10 papers in the report deal with the following areas: South Dakota profilometer; development of a data-acquisition method for noncontact pavement macrotexture measurement; traction of an aircraft tire on grooved and porous asphaltic concrete; holes in the pavement-an assessment of their influence on safety; effect of pavement type and condition on the fuel consumption of vehicles; traction loss of a suspended tire on a sinusoidal road; effect of vehicle and driver characteristics on the psychological evaluation of road roughness; correlation of subjective panel ratings of pavement ride quality with profilometer-derived measures of pavement roughness; microprocessor-based noncontact distance measuring control system; and, representation of pavement-surface topography in predicting runoff depths and hydroplaning potential.

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

1984-01-01

220

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

 
 
 
 
221

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

222

Application of CalME incremental-recursive method to the evaluation of the structural condition as asphalt pavements  

International Nuclear Information System (INIS)

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.

2011-01-01

223

Runoff and infiltration characteristics of pavement structures--review of an extensive monitoring program.  

Science.gov (United States)

The stormwater runoff and infiltration performance of permeable pavements has been systematically evaluated within an intensive monitoring program. The primary objective of the investigation was to generate a broad database, which enables the development of an advanced simulation module for urban drainage modelling. Over 160 field and lab scale experiments have been completed and analyzed for surface runoff and infiltration characteristics. The test series include several pavement types under various boundary conditions such as diverse precipitation impacts, varying surface slope and layer construction as well as different stages of surface clogging and several base and subgrade layer characteristics. The results represent a reliable and comprehensive database that allows profound conclusions and substantial recommendations. PMID:18048986

Illgen, M; Harting, K; Schmitt, T G; Welker, A

2007-01-01

224

Durability and Retro-Reflectivity of Pavement Markings (Synthesis Study)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Waterborne paints are used to paint pavement markings (edgelines and centerlines) to provide guidance for motorists. The painted markings need to be repainted periodically as their retro-reflectivity deteriorates. The Indiana Department of Transportation (INDOT) repaints pavement markings at least annually. INDOT engineers would like to determine the feasibility of extending the time intervals of repainting pavement markings on at least some types of roadways. The purpose of this synthesis st...

2008-01-01

225

Non-linear dynamic analysis of flexible and rigid pavements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

1993-01-01

226

The Role of Asphalt Rejuvenators in Pavement Preservation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

2013-01-01

227

Life Cycle Cost Analysis for INDOT Pavement Design Procedures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2005-01-01

228

Urban infrastructure and economic development: Experimental evidence from street pavement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We design an infrastructure experiment in Mexico to evaluate the impact of street pavement on housing values and household outcomes. We find that the provision of street pavement raises housing values by 16% and land values by 54%, according to professional appraisals. Using homeowner valuations, we estimate the impact of pavement on housing values to be 25%. At the household level, street paving increased the use of collateral-based credit and average loan size. Additionally, among household...

2010-01-01

229

Benefits and Assessment of Annual Budget Requirements for Pavement Preservation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This research identifies methods and best practices that can be used by the Indiana Department of Transportation (INDOT) in performing various strategies for pavement preservation. It also identifies various methods of calculating benefits of pavement preservation and a methodology for allocation of funds for pavement preservation, which are the two main objectives of this research. In order to achieve these objectives, several tasks were performed: literature review, data collection through ...

2011-01-01

230

Evaluation of Road Pavement Density Using Ground Penetrating Radar  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 f...

Rsa, Raja Abdullah; Shafri, H. Zulhaidi M.; Mardeni, R.; Sabira Khatun; Muniandy, R.

2009-01-01

231

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.

232

Global Cooling: Policies to Cool the World and Offset Global Warming from CO2 Using Reflective Roofs and Pavements  

Energy Technology Data Exchange (ETDEWEB)

Increasing the solar reflectance of the urban surface reduce its solar heat gain, lowers its temperatures, and decreases its outflow of thermal infrared radiation into the atmosphere. This process of 'negative radiative forcing' can help counter the effects of global warming. In addition, cool roofs reduce cooling-energy use in air conditioned buildings and increase comfort in unconditioned buildings; and cool roofs and cool pavements mitigate summer urban heat islands, improving outdoor air quality and comfort. Installing cool roofs and cool pavements in cities worldwide is a compelling win-win-win activity that can be undertaken immediately, outside of international negotiations to cap CO{sub 2} emissions. We propose an international campaign to use solar reflective materials when roofs and pavements are built or resurfaced in temperate and tropical regions.

Akbari, Hashem; Levinson, Ronnen; Rosenfeld, Arthur; Elliot, Matthew

2009-08-28

233

Migration of contaminants associated with pavement construction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to achieve the goals of 'Sustainable Development', alternative (secondary) materials are being increasingly used as bulk-fill aggregate within pavement construction as substitutes for traditional aggregates. This finds an end-use for stockpiles of industrial by-products (and hence the allowing the land on which they stand to be reclaimed for other uses) and protects finite, natural resources which they replace from over-extraction.

2004-01-01

234

Effectiveness of transverse grooves in rigid pavement  

Science.gov (United States)

Transverse grooves were installed at 11 intersection approaches on worn rigid pavement to reduce a high rate of wet road accidents. In most cases, accident reductions were experienced only at intersections with multiple negative operational characteristics, including higher approach speeds, limited sight distances, and frequent vehicle stopping for turns or stop signs. Intersections with no more than one negative characteristic generally did not benefit from grooving.

Gurney, G. F.; Bryden, J. E.

1982-10-01

235

Hypertension Awareness and Psychological Distress  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

236

In Search of Distress Risk  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper explores the determinants of corporate failure and the pricing of financially distressed stocks whose failure probability, estimated from a dynamic logit model using accounting and market variables, is high. Since 1981, financially distressed stocks have delivered anomalously low returns. They have lower returns but much higher standard deviations, market betas, and loadings on value and small-cap risk factors than stocks with low failure risk. These patterns are more pronounced fo...

2008-01-01

237

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

238

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

239

Effects of Automobile Tire Loads on Thin Flexible Pavements.  

Science.gov (United States)

The report includes the results of an analytical study of the effects of automobile tire loads on thin asphalt pavements over flexible bases. Two different ways of calculating the tire contact pressure were used and the strains induced in the pavement str...

F. L. Roberts R. Urruela M. P. J. Olsen

1987-01-01

240

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...

 
 
 
 
241

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...

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 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...

244

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...

245

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...

246

Inclusion of LCCA in Alaska Flexible Pavement Design Software Manual.  

Science.gov (United States)

Life cycle cost analysis is a key part for selecting materials and techniques that optimize the service life of a pavement in terms of cost and performance. While the Alaska Flexible Pavement Design software has been in use since 2004, there is no compute...

B. McHattie J. Liu M. Lee

2012-01-01

247

Asphalt mixture moisture sensitivity evaluation using surface energy parameters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Asphalt mixture is mainly used for the construction of roads throughout the world. Large amounts of capital are spent for construction and maintenance of roads. Water is one of the major contributors towards the damage of the road structure. It is considered as the worst enemy of a pavement structure by directly causing a distress or indirectly magnifying a distress and hence damaging the road structure. Asphalt mixture loses its strength in the presence of water either through loss of cohesi...

Ahmad, Naveed

2011-01-01

248

Pavement snow melting in Klamath Falls - rehabilitation of the ODOT Well  

Energy Technology Data Exchange (ETDEWEB)

This paper discusses the use of geothermal energy in pavement de-icing in Klamath Falls, Oregon. Due to a change in traffic routing in 1948, U.S. Highway 97 was routed with a new bridge and roadway through downtown Klamath Falls with an adverse 8 percent grade. Problems with traffic in winter led to the incorporation of a geothermal experiment in de-icing into the Oregon Department of Transportation (ODOT) construction project. The geothermal well was originally artesian, but the static water level has dropped over the years of usage, and the water temperatures at various depths have also dropped. Changes in city environmental regulations in 1985 have called for the elimination of all surface and sewer discharge from geothermal wells. Modifications to the existing pavement de-icing system which would bring it into compliance with the city ordinances are discussed in this paper.

Thurston, R.E. [Oregon Dept. of Transportation, Milwaukee, OR (United States); Culver, G.; Lund, J.W.

1995-02-01

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 composition and sources.

2012-03-01

250

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...

251

Clogging evaluation of open graded friction course pavements tested under rainfall and heavy vehicle simulators.  

Science.gov (United States)

In this study a new procedure is developed to obtain core samples from field sections to assess clogging mechanisms of open graded friction course (OGFC) pavements using X-ray computed tomography (CT) imaging. The approach compared X-ray computed tomography (CT) images taken before and after: (1) rainfall simulations without trafficking to investigate particle-related clogging and (2) full-scale accelerated pavement rutting tests (APT) to investigate deformation related clogging of OGFC layers. Rainfall simulations were performed with runoff water of known total suspended solids (TSS) and particle size distributions (PSDs). Full-scale accelerated rutting tests were performed under controlled temperature and loads. Both investigations were performed for three different OGFC pavements with different layer thicknesses and mix types. The clogging of rutting test sections were also evaluated by comparing the surface permeability measurements performed before and after APT testing. The results of X-ray CT image processing revealed a significant reduction in air-void content of core samples after APT rutting tests. The highest air-void reduction was concentrated at the bottom of the OGFC layers. Permeability measurements also showed a 40%-90% reduction in permeability after APT trafficking. X-ray CT image processing of core samples tested under simulated rainfall showed that air void content reduction is concentrated in the lower part (2-6 mm from the bottom) of the OGFC layers as a result of particle accumulation. Small changes in air void contents were observed in the upper part of the OGFC layers (10-15 mm) while these reductions in air void contents were not significant to cause surface overflow and hence it is expected that the tested OGFC pavements will have sufficient permeability to infiltrate water during most average storm events. PMID:23920417

Coleri, Erdem; Kayhanian, Masoud; Harvey, John T; Yang, Kai; Boone, John M

2013-11-15

252

CAUSES OF RESPIRATORY DISTRESS IN CHILDREN  

Digital Repository Infrastructure Vision for European Research (DRIVER)

"nThere is a lack of large, prospective epidemiologic studies concerning acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) in pediatric population. To determine the different causes of respiratory distress in children, we prepared a retrospective study and included the whole 567 children with respiratory distress referred to 17-Shahrivar Hospital, Rasht, Guilan. Using their medical files, data including age, sex, and causes of respiratory distress were collected. SPS...

Karambin, M. M.; Hashemian, H.

2008-01-01

253

Accounting for distress in bank mergers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The inability of most bank merger studies to control for hidden bailouts may lead to biased results. In this study, we employ a unique data set of approximately 1,000 mergers to analyze the determinants of bank mergers. We use data on the regulatory intervention history to distinguish between distressed and non-distressed mergers. We find that, among merging banks, distressed banks had the worst profiles and acquirers perform somewhat better than targets. However, both distressed and non-dist...

Koetter, Michael; Bos, Jaap W. B.; Heid, Frank; Kool, Clemens J. M.; Kolari, James W.; Porath, Daniel

2005-01-01

254

Psychological Distress among Young Norwegian Health Professionals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2013-01-01

255

"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

256

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

257

Horseshoe lung without respiratory distress.  

Science.gov (United States)

A case of horseshoe lung associated with scimitar syndrome is reported. The patient, a six year old boy, had no respiratory distress. Plain chest film showed hypoplasia of the right lung and scimitar vein. Angiography demonstrated that right inferior pulmonary arteries crossed the midline and reached to the left lung base. PMID:2251009

Takeda, K; Kato, N; Nakagawa, T; Aoki, K; Matsuda, A

1990-01-01

258

Experimental and theoretical investigation of three dimensional strain occurring near the surface in asphalt concrete layers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several pavement failures have been observed to be initiated at or near the surface of the hot-mix asphalt layers and some of them propagate downward through the surface layer (top-down cracking). These modes of failure are affected by heavy vehicular loading configuration, pavement structure and their interaction at the tire-pavement contact. This paper documents an experimental investigation of surface strain induced under the entire tire by using specific instruments based on fiber optic s...

2012-01-01

259

Diabetes distress among type 2 diabetic patients  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Diabetes mellitus is being increasingly recognized as a serious global health problem and is frequently associated with co-morbid distress, contributing double burden for the individual and the society. Aim: This study documents the proportion of diabetes distress and factors associated with it. Methods: A cross-sectional study was conducted from January to June 2012. Data were collected through interview and record review of 165 adults with type 2 diabetes. Results: The proportion of diabetes distress among the study population was 48.5%, which includes 22.4% high distress and 26.1% moderate distress. The remainder had little or no distress. The Mean ± SD of total diabetes distress score was2.17 ± 0.75. The Mean ± SD for each domain score such as emotional burden, physician-related distress, regimen-related distress and interpersonal distress was (3.49 ± 1.52, (1.13 ± 0.32, (2.12 ± 0.85, (1.40± 0.65 respectively. Emotional burden was considered as the most important domain in measuring diabetes distress. The influence of age (p<0.001, occupation (p<0.05, smoking (p<0.005, BMI (p<0.001, duration since detection of diabetes mellitus (p<0.001, glycaemic status (p<0.001 treatment modalities (P<0.001, diabetic complications (p<0.001 on level of diabetes distress was statistically significant. There was a strong, positive correlation between the two variables (r=0.64, p<0.001; diabetes distress score with duration of diabetes mellitus. There was a medium, positive correlation between the two variables [r=0.43, p<0.001]; diabetes distress score with glycaemic status (HbA1c level .Conclusion: This study identified diabetes distress as a significant health problem among adult type 2 diabetes mellitus patients. This should be taken into consideration for effective management of patient.

Islam MR

2013-08-01

260

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

2005-06-07

 
 
 
 
261

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

262

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

263

Airfield Pavement Condition Survey, Usnalf Charlestown, Rhode Island.  

Science.gov (United States)

The results of a condition survey of the airfield pavements at the USNALF Charlestown, Rhode Island, are presented. The survey established statistically-based condition numbers (weighted defect densities) which were direct indicators of the condition of t...

D. J. Lambiotte L. J. Woloszynski

1971-01-01

264

Airfield Pavement Condition Survey, Usnas Willow Grove, Pennsylvania.  

Science.gov (United States)

The results of a condition survey of the airfield pavements at the U. S. Naval Air Station, Willow Grove, Pennsylvania are presented. The survey established statistically-based condition numbers (weighted defect densities) which were direct indicators of ...

D. J. Lambiotte L. J. Woloszynski

1971-01-01

265

Airfield Pavement Condition Survey, Usnas Point Mugu, California.  

Science.gov (United States)

The results of a condition survey of the airfield pavements at the U. S. Naval Air Station, Point Mugu, California are presented. The survey established statistically-based condition numbers (weighted defect densities) which were direct indicators of the ...

D. J. Lambiotte R. B. Brownie

1971-01-01

266

Airfield Pavement Condition Survey, USNAS Chase Field, Texas.  

Science.gov (United States)

The results of a condition survey of the airfield pavements at the U. S. Naval Air Station, Chase Field, Texas are presented. The survey established statistically-based condition numbers (weighted defect densities) which were direct indicators of the cond...

D. J. Lambiotte R. B. Brownie

1971-01-01

267

Airfield Pavement Condition Survey, Usnas Quonset Point, Rhode Island.  

Science.gov (United States)

The results of a condition survey of the airfield pavements at the U. S. Naval Air Station, Quonset Point, Rhode Island, are presented. The survey established statistically-based condition numbers (weighted defect densities) which were direct indicators o...

D. J. Lambiotte L. J. Woloszynski

1971-01-01

268

Airfield Pavement Condition Survey, USNAS New Orleans, Louisiana.  

Science.gov (United States)

The results of a condition survey of the airfield pavements at the U. S. Naval Air Station, New Orleans, Louisiana are presented. The survey established statistically-based condition numbers (weighted defect densities) which were direct indicators of the ...

D. J. Lambiotte R. B. Brownie

1971-01-01

269

Some Operational Characteristics of In-Pavement Lighting Fixtures.  

Science.gov (United States)

The report contains the results of technical tests performed on several types of in-pavement lighting fixtures to determine their operational characteristics. This testing was conducted in the laboratory, on a special test pad or with operational field in...

C. B. Phillips

1965-01-01

270

Literature Review - Elastic Constants for Airport Pavement Materials.  

Science.gov (United States)

A literature review was made to support an ongoing study to develop a method for evaluating airport pavements based on the layered elastic theory and using constants as determined from vibratory test results. The review covered the definitions and relatio...

J. L. Green

1978-01-01

271

Finite Element Evaluation of Pervious Concrete Pavement for Roadway Shoulders.  

Science.gov (United States)

Pervious concrete has provided an effective solution for storm runoff for parking lots, sidewalks, bike trails, and other applications. It should be readily adaptable for use on roadway shoulders. Being a relatively new material for use in pavement for ro...

A. Alam L. Haselbach W. Cofer

2011-01-01

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

Description and Evaluation of the Alaska Pavement Rating Procedure.  

Science.gov (United States)

This report describes and examines pavement condition rating methods used on Alaska's roadways since 1978. The methods were intended to provide the specific performance data necessary to optimize construction/maintenance planning and the allocation of ava...

R. L. McHattie

1982-01-01

274

Airfield Pavement Condition Survey, USNALF Crows Landing, California.  

Science.gov (United States)

The results of a condition survey of the airfield pavements at the USNALF Crows Landing, California are presented. The survey established statistically-based condition numbers (weighted defect densities) which were direct indicators of the condition of th...

H. Tomita L. J. Woloszynski

1972-01-01

275

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

276

Evaluation of the load associated cracking in flexible pavements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The overlay of a cracked pavement is subject to reflective cracking due the existing crack potential. In a cracked pavement, this cracking potential, due to traffic loads and temperature gradient, can be evaluated by means of crack activity. Traffic loads cause vertical and horizontal activity between the two edges of the cracks. These activities are caused by rocking of blocks between the cracks as well as by the shape of the deflection basin, combined with the size of the blocks. The temper...

2002-01-01

277

ASPHALT PAVEMENT DAMAGES, CAUSES AND MEASUREMENTS FOR REHABILITATION  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In modern road construction growing traffic and its traffic loads reflects in accelerated rehabilitation of existing and in constructing of new roads. Accordingly the field of a detailed analysis of existing pavement structures has developed. This also contributed to the great technological advances in this field. Asphalt pavement are every day exposed to the number types of loads therefore the knowledge of the composition of materials, dimensioning and process of implementation are essential...

2012-01-01

278

Constructibility aspects of ultra thin continuously reinforced concrete pavement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ultra Thin Continuously Reinforced Concrete Pavement (UTCRCP) is a new rehabilitation technique for roads which was originally imported from overseas and redesigned for South Africa conditions. Initial development involved accelerated pavement testing (APT) with the Heavy Vehicle Simulator (HVS) on experimental sections at the Heidelberg Traffic Control Centre. The success of these short experimental sections shifted the emphasis to constructability issues and associated design issues on a la...

2009-01-01

279

Analysis of dynamic loading behaviour for pavement on soft soil  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The increasing need for regional development has led engineers to find safe ways to construct the infrastructure of transportation on soft soils. Soft soil is not able to sustain external loads without having large deformations. The geotechnical properties of soft soil which is known for its low bearing capacity, high water content, high compressibility and long term settlement as well. In pavement engineering, either highway or runway as an infrastructure, a pavement encompasses three imp...

Widodo, Slamet

2014-01-01

280

Development of Mechanistic-Empirical Flexible Pavement Design in Iran  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2009-01-01

 
 
 
 
281

Technical-economical evaluation of pavement recycling alternatives  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pavement recycling is becoming an increasingly important alternative worldwide for maintenance of highways, once sustainability and environmental issues have continued to receive more attention. The reference point is that of considering the use of road materials in a closed cycle, in which a natural material, previously used in road construction, should not be rejected in the following life-cycle. The objective of this paper is that of analysing flexible pavement recycling alternatives techn...

2006-01-01

282

Investigation of asphalt concrete pavement quality of Lithuanian highways  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Planning of road building and repair sectors requires evaluation of the actual state of the road pavement. The available methods of evaluation of the condition and construction of pavement have serious shortcomings: some of them are lacking precision and reliability, others are too sophisticated. For this reason they are not very helpful in practice. Based on analysis of previous works and on the experimental results, a sufficiently accurate and simple method for evaluation of the state of as...

Petkevic?ius, Evaldas; Petkevic?ius, Rolandas; Babickas, Rimantas

2006-01-01

283

Application of surplus and waste materials in roads pavement making  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nowadays there are a lot of problems about surpluses and debris made by humans all around the world. Lots of these surpluses seriously harm our natural environment. Reuse of this kind of materials in other processes like building constructions or pavement help our natural environment in every aspect. Asphalt concrete is the main part of pavements in most parts of the world with an increasing rate of production in need of more ways and roads. In this paper we will provide...

Mousavi, S. M.; Fazli, A. H.; Rouzmehr, F.

2011-01-01

284

The adult respiratory distress syndrome.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The adult respiratory distress syndrome (ARDS) represents a common denominator of acute lung injury leading to alveolar flooding, decreased lung compliance, and altered gas transport. In the absence of specific etiology and therapy, the management of ARDS remains largely supportive. Ubiquitous use of intermittent positive-pressure ventilation with positive end-expiratory pressure (PEEP) improves arterial oxygenation but with some risk of pulmonary barotrauma and decreased cardiac output. The ...

Biondi, J. W.; Hines, R. L.; Barash, P. G.; Baker, C. C.; Matthay, M. A.; Matthay, R. A.

1986-01-01

285

Insular Lateralization in Tinnitus Distress  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tinnitus affects 15% of the population. Of these 1-2% are severely disabled by it. The role of the autonomic system in tinnitus is hardly being investigated. The aim of this study is to investigate the relationship between tinnitus distress and lateralization of the anterior insula, known to be involved in interoceptive awareness and (para)sympathetic changes. For this, Tinnitus Questionnaire scores are correlated to Heart Rate Variability markers, and related to neural activity in left and r...

Loo, Elsa; Congedo, Marco; Vanneste, Sven; Heyning, Paul; Ridder, Dirk

2011-01-01

286

Pavement macrotexture estimation using principal component analysis of tire/road noise  

Science.gov (United States)

An investigation on the prediction of macrotexture Mean Texture Depth (MTD) of pavement from a moving vehicle is conducted. The MTD was predicted by using the tire/road noise measured from a microphone mounted underneath a moving vehicle. Principal Component Analysis (PCA) is used to filter noise from microphone data prioer to estimating its energy over an optimally selected bandwidth. Energy obtained using this method is named PCA energy, hence the developed method for MTD estimation is termed as PCA Energy Method. The acoustic energy is assumed to have positive linear correlation with MTD of pavement. Moreover, PCA was used to differentiate important information about the road surface from noisy data while vehicle is moving, yielding a set of principal component vectors representing the conditions of each road section. This principal component vector was used to compute the PCA energy that is to be used for MTD prediction. The frequency band most relative to pavement macrotexture was determined to be 140 to 700 Hz through theoretical and statistical research. Then, a MTD prediction model was built based on a Taylor series expansion with two variables, PCA energy and the driving speed of the vehicle. The model parameters were obtained from an engineered track (interstate highway) with known MTD, and then applied to urban roads for the feasibility test. The accuracy of the model is 83.61% for the engineered track, which is 10% higher than the previous energy-based methods without PCA treatment. Moreover, applicability of the model is increased by the extended MTD prediction range between 0.2 and 3 mm compared to that of the engineered track having 0.4 to 1.5 mm. In addition, the MTD could be predicted every 7.8 meters and with good repeatability in the urban road test, which proves the feasibility of the proposed approach. Therefore, the PCA Energy Method is a reliable, efficient, and cost effective way to predict MTD for engineering applications as an important index for pavement friction prediction and pavement segregation identification.

Zhang, Yiying; McDaniel, J. Gregory; Wang, Ming L.

2014-04-01

287

Design of Continuously Reinforced Concrete Pavements Using Glass Fiber Reinforced Polymer Rebars.  

Science.gov (United States)

This report investigates the effects on stress development in pavement and on critical design factors from substituting glass fiber reinforced polymer (GFRP) reinforcement for conventional steel reinforcement in continuously reinforced concrete pavements ...

J. H. Choi R. H. Chen

2005-01-01

288

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

289

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

290

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

291

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...

2009-04-01

292

Impact of Airport Pavement Deicing Products on Aircraft and Airfield Infrastructure. A Synthesis of Airport Practice.  

Science.gov (United States)

Airfield pavement deicing and anti-icing are essential activities to maintain safe winter operations of the aviation industry. Airfield pavement deicing products (PDPs) traditionally consisting of urea or glycols have become less popular owing to their ad...

X. Shi

2008-01-01

293

Evaluation of the Dynaflect for the Non-Destructive Testing of Portland Cement Concrete Pavements.  

Science.gov (United States)

The report presents the results obtained from portland cement concrete pavement testing with the Dynaflect, an apparatus developed for the deflection testing of pavements under a dynamic load. Essentially the device was tested to determine if deflection m...

G. M. Pace

1967-01-01

294

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 ...

295

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...

296

Effects of Heavy-Vehicle Characteristics on Pavement Response and Performance.  

Science.gov (United States)

This report will be of special interest to pavement-design and pavement-management engineers, as well as the transportation planners and transportation-agency chief administrative officers responsible for funding the transportation network, allocating cos...

T. D. Gillespie S. M. Karamihas M. W. Sayers M. A. Nasim W. Hansen N. Ehsan D. Cebon

1993-01-01

297

Respiratory Distress Syndrome and its Complications  

Directory of Open Access Journals (Sweden)

Full Text Available Respiratory distress syndrome in premature babies is one of the most common and most important health problems in newborns. Respiratory distress syndrome of newborn is a syndrome in premature infants caused by developmental insufficiency of surfactant production and structural immaturity in the lungs. Respiratory distress syndrome begins shortly after birth and is manifest by tachypnea, tachycardia, chest wall retractions, expiratory grunting, nasal flaring and cyanosis during breathing efforts. Respiratory distress syndrome or complications caused by respiratory distress syndrome are the most important causes of mortality and morbidity in premature infants. This article briefly reviews respiratory distress syndrome and its complications. [Archives Medical Review Journal 2013; 22(4.000: 615-630

Eren Kale Cekinmez

2013-08-01

298

Exploring the moral distress of registered nurses.  

Science.gov (United States)

Registered nurses (RNs) employed in an urban medical center in the USA identified moral distress as a practice concern. This study describes RNs' moral distress and the frequency of morally distressing events. Data were collected using the Moral Distress Scale and an open-ended questionnaire. The instruments were distributed to direct-care-providing RNs; 100 responses were returned. Morally distressing events included: working with staffing levels perceived as 'unsafe', following families' wishes for patient care even though the nurse disagreed with the plan, and continuing life support for patients owing to family wishes despite patients' poor prognoses. One high frequency distressing event was carrying out orders for unnecessary tests and treatments. Qualitative data analysis revealed that the nurses sought support and information from nurse managers, chaplaincy services and colleagues. The RNs requested further information on biomedical ethics, suggested ethics rounds, and requested a non-punitive environment surrounding the initiation of ethics committee consultations. PMID:17459818

Zuzelo, Patti Rager

2007-05-01

299

Water quality and quantity assessment of pervious pavements performance in experimental car park areas.  

Science.gov (United States)

Pervious pavements have become one of the most used sustainable urban drainage system (SUDS) techniques in car parks. This research paper presents the results of monitoring water quality from several experimental car park areas designed and constructed in Spain with bays made of interlocking concrete block pavement, porous asphalt, polymer-modified porous concrete and reinforced grass with plastic and concrete cells. Moreover, two different sub-base materials were used (limestone aggregates and basic oxygen furnace slag). This study therefore encompasses the majority of the materials used as permeable surfaces and sub-base layers all over the world. Effluent from the test bays was monitored for dissolved oxygen, pH, electric conductivity, total suspended solids, turbidity and total petroleum hydrocarbons in order to analyze the behaviour shown by each combination of surface and sub-base materials. In addition, permeability tests were undertaken in all car parks using the 'Laboratorio Caminos Santander' permeameter and the Cantabrian Portable Infiltrometer. All results are presented together with the influence of surface and sub-base materials on water quality indicators using bivariate correlation statistical analysis at a confidence level of 95%. The polymer-modified porous concrete surface course in combination with limestone aggregate sub-base presented the best performance. PMID:24718346

Sañudo-Fontaneda, Luis A; Charlesworth, Susanne M; Castro-Fresno, Daniel; Andres-Valeri, Valerio C A; Rodriguez-Hernandez, Jorge

2014-01-01

300

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

 
 
 
 
301

Influence of the properties of flexible road pavement structure on the service indices of wearing courses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of the dissertation is based on the properties of flexible road pavement structures to develop a mathematical models for predicting the performance of wearing courses used in the pavements of the main roads. The main tasks of the dissertation are as follows: to analyze the main factors influencing the service indices of asphalt concrete pavements and to determine their reasons; to investigate the quality of materials and mixtures used in pavement structural layers of the main roads; t...

2014-01-01

302

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2011-01-01

303

Respiratory Distress Syndrome and its Complications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Respiratory distress syndrome in premature babies is one of the most common and most important health problems in newborns. Respiratory distress syndrome of newborn is a syndrome in premature infants caused by developmental insufficiency of surfactant production and structural immaturity in the lungs. Respiratory distress syndrome begins shortly after birth and is manifest by tachypnea, tachycardia, chest wall retractions, expiratory grunting, nasal flaring and cyanosis during breathing effor...

Eren Kale Cekinmez; Hacer Yapicioglu Yildizdas; Ferda Ozlu

2013-01-01

304

DISTRESS AND JOB PERFORMANCE OF INDUSTRIAL WORKERS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

305

Analysis of Instrumentation Selection and Placement to Monitor the Hydrologic Performance of Permeable Pavement Systems and Bioinfiltration Areas at the Edison Environmental Center in New Jersey  

Science.gov (United States)

In 2009, the U.S. Environmental Protection Agency constructed a 0.4-ha (1-ac) parking lot surfaced with three different permeable pavement types (interlocking concrete pavers, porous concrete, and porous asphalt) and six bioinfiltration areas with three different drainage area to...

306

Longitudinal Joint Systems in Slip-Formed Rigid Pavements. Volume I. - Literature Survey and Field Inspection.  

Science.gov (United States)

Most construction equipment for rigid pavements has been designed to place ribbons of concrete, called paving lanes, either 24 or 25 feet wide. Pavements of widths greater than 25 feet normally require the pavement be placed in parallel lanes with a const...

E. J. Barenberg R. E. Smith

1979-01-01

307

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

Science.gov (United States)

...2009-04-01 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 âPavement Management Guide.â2 2...

2009-04-01

308

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 âPavement Management Guide.â 1 1...

2010-04-01

309

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 âPavement Management Guide.â 1 1...

2010-04-01

310

Bearing capacity evaluation of rubblized concrete pavements  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents the findings of a research work performed on a real scale concrete pavement project where Rubblizing technology was used for its structural rehabilitation. Rubblizing may be defined as a fracture technique in which a concrete pavement slab is transformed in a granular base with a very high Modulus. This technique, fractures the concrete slab in angular pieces by using a concentrated dynamic load of low amplitude and high frequency. The research work was based on field study on the rehabilitation of 5 km motorway. The structural evaluations where made, before, during and after one year construction. Measurements and site evaluation where made by using DCP, Light Weight Deflectometer and FWD (on top of asphalt layer and excavating inside pits. The structural capacity of the Rubblized layer was evaluated through theoretical analysis. Because of the anisotropic properties of the Rubblized layer the results are presented using AASHTO structural layer coefficient. The structural layer coefficients recommended are between the range of 0.25 and 0.30 for concrete slabs with thickness grater than 220 mm.El trabajo presenta los resultados de un estudio a escala real de la capacidad estructural de un firme de hormigón rehabilitado utilizando la técnica de Rubblizing. La técnica de Rubblizing ha sido traducida como el pulverizado del firme de hormigón pero, es más bien un efecto combinado de trituración y fracturación de la losa de hormigón en todo su espesor para convertir esta en una base granular de alto módulo. Esta tecnica fractura la losa de hormigón en trozos angulares y entrelazados empleando una carga dinámica concentrada, de baja amplitud y alta frecuencia. La investigación se basó en el estudio de la rehabilitación de 5 km de autopista. Los estudios de la capacidad estructural fueron realizados durante, al término y un año después de la construcción. Para las mediciones y evaluaciones de terreno se utilizó, el DCP, Deflectómetro de Impacto Liviano, FWD (sobre carpeta asfáltica y excavando calicatas bajo el material triturado. La capacidad estructural del material triturado se realizó a través de un análisis teórico. Debido al las características anisotrópicas del material triturado, los resultados son presentados utilizando el coeficiente estructural AASHTO. Los resultados del estudio permiten recomendar un rango para el coeficiente estructural del pavimento sometido al proceso de Rubblizing el cual para espesores de losa superior a 22 cm está entre 0,25 a 0,30.

González, M.

2009-03-01

311

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.

2012-05-01

312

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

313

Stormwater quality performance of a macro-pervious pavement car park installation equipped with channel drain based oil and silt retention devices.  

Science.gov (United States)

This paper reports the results of a two year field monitoring exercise intended to investigate the pollution abatement capabilities of a novel system which offers an alternative to the, now well established, pervious pavement system as a source control device for stormwater management. The aim of this study was to determine the effectiveness of a live installation of a macro-pervious pavement system (MPPS) (operated as a visitors' car park at a prison in Central Scotland) in retaining and treating a range of pollutants which originate from automobile use or become concentrated on the parking surface from the wider environment. The MPPS is a sub-class of pervious pavement system where the vast majority of the surface is impermeable. It directs stormwater into a pervious sub surface storage/attenuation zone through a series of distinct infiltration points fast enough to prevent flooding during the design storm. In the particular system studied here the infiltration points consist of a network of oil/silt separation devices with extensive further pollutant retention/degradation provided during the passage of stormwater through the sub surface zone. Approximately 12 months after the car park was completed a sampling regime was instigated in which grab samples were collected at intervals from each of the three sub catchments whilst, simultaneously, samples were collected directly from the, pollutant retaining, infiltration devices. Through investigation of samples collected at the upstream end of the system, the retention of significant amounts of hydrocarbons and heavy metals in the initial collection devices has been illustrated and the analysis of effluent samples collected at the outlet points indicate that the system is capable of producing effluent which is of a standard comparable to that expected from a traditional pervious pavement system and is acceptable for direct release into a surface water receptor. The system offers the opportunity to accrue the benefits of a pervious pavement when the use of traditional paving surfaces is the preferred option. PMID:23954068

Newman, Alan Paul; Aitken, Douglas; Antizar-Ladislao, Blanca

2013-12-15

314

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

315

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 pavement sealants degrade stream invertebrate communities.

2010-05-01

316

Environmental Impact Assessment of Road Asphalt Pavements  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with a versatile, synthetic, simple and user-friendly method based on Life Cycle Assessment studies which summarizes multifaceted, often competing, environmental, technical and economic aspects in road construction. In many cases just economic criteria are applied in call for tenders, because the calculation of the environmental impact of road construction is difficult. In fact, it can be referred to many available options and both the economic and the environmental suitabilities have to be considered, in order to achieve globally sustainable results about road infrastructure work. In this research, the weighted sum model of multicriteria analysis is identified as the tool to evaluate global impact of road works, to compare solutions and to choose the best one. The advantages of the proposed approach are that the local contest and the stakeholders’ objective are represented by adopting variable parameters and weights, in order to apply the method to several contexts. A case study explains potential environmental implications of using this new Road Environmental Impact Assessment to calculate effect related to the production of asphalt pavement, considering the production system for aggregates from cradle to gate, the materials transportation to road site and the works to have the road done.

Laura Moretti

2013-10-01

317

Pavement system with rubber tire chips in subgrade  

Energy Technology Data Exchange (ETDEWEB)

A pavement design method was developed in which shredded rubber tire chips mixed with sand were used as a material for pavement subgrade. Rubber tire chips are highly compressible and produce both elastic and plastic deformations under the application of loads. Sand was added to fill the void between the tire chips and make the mixture a strong material. The design method considered the vertical compressive strain produced by the design life traffic load 18k (80 KN) repetitions. The equivalent thicknesses of the layers above the subgrade corresponding to this vertical compressive strain were determined using contour charts. From this equivalent thickness, the thicknesses for asphalt pavement, base, and sub-base were determined by Odemark`s method. 3 refs., 1 tab., 3 figs.

Ashtakala, B.; Hoque, A.K.M.M. [Concordia Univ., Montreal, PQ (Canada). Dept. of Civil Engineering

1995-12-31

318

Modified asphalt for pavements; Hosoyo kaishitsu asufuaruto ni tsuite  

Energy Technology Data Exchange (ETDEWEB)

Modified asphalt has been used widely in such applications as countermeasure against rutting, countermeasure against wear caused by tire chains in snowy and cold areas, or bridge deck pavement. Features of various kinds of modified asphalt, standards, and standard properties are introduced. Modified asphalt containing natural asphalt is used for steel plate deck pavement. Semi-blown asphalt is used when emphasis must be given to the countermeasure for flowing resistance of asphalt pavement. Features and standards of asphalt containing rubber, thermoplastic elastomer, and thermoplastic resin are described. Asphalt containing heat-setting resin shows excellent characteristics, which other types of modified asphalt do not possess, in the laboratory resistance test for fatigue, flowing, and wear. Change in the history of modified asphalt in Japan from the initial stage to the present are explained and shown in a table together with time and phenomena, and the change in the production of modified asphalt is shown. 15 refs., 5 figs., 5 tabs.

Tsukagoshi, T. [Nippon Oil Co. Ltd., Yokohama (Japan)

1997-10-01

319

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

320

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

 
 
 
 
321

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

322

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 (TiO2) 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 TiO2 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 TiO2 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

323

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

324

Fatigue properties of rubber modified pavements. Final report  

Energy Technology Data Exchange (ETDEWEB)

This report presents results of a study to determine the fatigue behavior of rubber modified pavements in Alaska in comparison with conventional asphalt concrete pavements. Laboratory studies were conducted on field specimens using the flexural fatigue test in the controlled-displacement mode. Tests were performed at 72 deg F and 40 deg F. Tested materials include (1) conventional HMA with AC 2.5 and AC 5; (2) PlusRide RUMAC with AC 5; (3) asphalt-rubber concrete with AC 2.5 (wet Process); and (4) rubberized asphalt-rubber concrete with AC 2.5 (wet/dry process).

Raad, L.; Saboundjian, S.; Yuan, X.

1995-05-01

325

Performance of waste tyre rubber on model flexible pavement  

Directory of Open Access Journals (Sweden)

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

326

Interlocking Paving Stones Pavement as a Solution to Marshy Roads  

Directory of Open Access Journals (Sweden)

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

327

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 estimat...

Constantia Achilleos; Diofantos Hadjimitsis; Kyriacos Neocleous; Kypros Pilakoutas; Neophytou, Pavlos O.; Stelios Kallis

2011-01-01

328

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

329

An elastoplastic model based on the shakedown concept for flexible pavements unbound granular materials  

Science.gov (United States)

Nowadays, the problem of rutting of flexible pavements linked to permanent deformations occurring in the unbound layers is taken into account only by mechanistic empirical formulas. Finite element modelling of realistic boundary value problems with incremental rheological models will lead to unrealistic calculation time for large cycle numbers. The objective of the authors is to present a simplified model which can be used to model the flexible pavements rutting with the finite elements framework. This method is based on the shakedown theory developed by Zarka which is usually associated to materials like steels. It has been adapted for granular materials by introducing a yield surface taking into account the mean stress influence on the mechanical behaviour and a dependency of the hardening modulus with the stress state. The Drucker-Prager yield surface has been used with a non-associated flow rule. Comparisons with repeated load triaxial tests carried out on a subgrade soil have been done. These comparisons underline the capabilities of the model to take into account the cyclic behaviour of unbound materials for roads. Finally, a discussion, dealing with the use of the simplified method within a finite element modelling of a full-scale experiment, is presented.

Habiballah, Taha; Chazallon, Cyrille

2005-05-01

330

Pathology Case Study: Respiratory Distress  

Science.gov (United States)

This cardiovascular pathology case study, provided by the University of Pittsburgh Department of Pathology, is an excellent resource for students and instructors in the health science fields. A 72-year-old female experiencing respiratory distress is the focus of this case. The patientâÂÂs history, gross description, and microscopic description of test results are provided to aid readers in understanding the patientâÂÂs diagnosis. The official final diagnosis is accompanied by a discussion of the contributing doctorâÂÂs findings and a list of references. This is an excellent resource for students in the health sciences to familiarize themselves with using patient history and laboratory results to diagnose patientâÂÂs conditions.

Ariyanayagam-Baksh, Shashi

2009-05-07

331

Monitoring pavement response and performance using in-situ instrumentation  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper is to present the effectiveness of in-situ instrumentation on diagnosing the pavement layer conditions under full-scale accelerated traffic loading. The test section is an in-service pavement (US281) in Jacksboro, Texas. Multi-Depth Deflectometers (MDDs) are used to measure both permanent deformations and transient deflections, caused by accelerated traffic loading and Falling Weight Deflectometers (MDDs) are used to measure both permanent deformations and transient deflections, caused by accelerated traffic loading and Falling Weight Deflectometer (FWD) tests. Four different FWD loads of 25, 40, 52, and 67 kN were applied in close proximity to the MDDs at various traffic loading intervals to determine pavement conditions. It was found that the majority of rutting occurred in the newly recycled asphalt mix. The aged ({gt}40 years) underlying base and subgrade layers contributed less than 30% to overall rutting. Only the top recycled Asphalt layer underwent notable deterioration due to traffic loading. Up to 1.5 million axle repetitions, the test pad responded to FWD load almost linearly, not only over the whole pavement system but also within individual layers. However, under higher FWD loads, the percentage of total deflection contributed by the subgrade increased.

Chen, D.H.; Bilyeu, J.; Hugo, F.

1999-07-01

332

Prediction of subgrade moisture conditions for purposes of pavement design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this paper is to summarize the procedures for determining moisture conditions in subgrade soils and make recommendations regarding the practical applications to pavement design. By using data from different moisture studies some moisture models were tested to demonstrate their capability of predicting ultimate moisture contents.

Correia, A. Gomes

1996-01-01

333

Evaluating Pavement Cracks with Bidimensional Empirical Mode Decomposition  

Directory of Open Access Journals (Sweden)

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

334

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...

335

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...

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

1999-06-02

337

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.

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

338

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

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.

340

The spiritual distress assessment tool: an instrument to assess spiritual distress in hospitalised elderly persons  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Although spirituality is usually considered a positive resource for coping with illness, spiritual distress may have a negative influence on health outcomes. Tools are needed to identify spiritual distress in clinical practice and subsequently address identified needs. This study describes the first steps in the development of a clinically acceptable instrument to assess spiritual distress in hospitalized elderly patients. Methods A three-ste...

Monod Stefanie M; Rochat Etienne; Büla Christophe J; Jobin Guy; Martin Estelle; Spencer Brenda

2010-01-01

 
 
 
 
341

Interpersonal relationships and emotional distress in adolescence  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 assessing qualities in important interpersonal relationships in their lives and emotional distress. Girls reported more p...

Kenny, Rachel; Dooley, Barbara A.; Fitzgerald, Amanda

2013-01-01

342

[Radiologic features of respiratory distress syndrome].  

Science.gov (United States)

An analysis of roentgenograms of 50 patients with a respiratory distress-syndrome has shown that roentgenosemiotics of this complication discloses alterations of permeability of pulmonary and bronchial capillaries, drainage of liquid from the interstice and alveoli, hemodynamics in the microcirculation link of the lesser circulation circle. A classification of the respiratory distress-syndrome is proposed which includes 3 stages and a period of involution of the process. PMID:2638798

Beliakov, N A; Bobylev, N V; Obolenski?, S V; Trofimova, T N

1989-12-01

343

Downside Risk Efficiency Under Market Distress  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In moments of financial distress downside risk measures like lower partial moments are more appropriate than the standard variance to characterize risk. The goal of this paper is to study how to choose optimal portfolios in these periods. In order to do this we extend the definition of lower partial moments to this environment, derive the corresponding mean-risk dominance set and define the concept of stochastic dominance under distress. The paper shows the close connection between the mean-r...

Gonzalo, Jesu?s; Olmo, Jose?

2009-01-01

344

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2005-01-01

345

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

346

Distress, demoralization and psychopathology: Diagnostic boundaries  

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: English Abstract in english Background and Objectives: The objectives of the manuscript are: (a) to review the understanding of demoralization and its assessment; (b) to describe its clinical progression; (c) to explain the differences between demoralization and other form of psychological distress; (d) to propose a set of cri [...] teria for future research on demoralization. Methods: A MEDLINE search using the keywords distress, subjective incompetence, depression, demoralization, helplessness, hopelessness and psychopathology was conducted. This was supplemented by a manual search of the literature. Results: Demoralization can be distinguished from passing or transient distress, non-specific distress, sub-threshold depression or anxiety, and certain mental disorders. Demoralization can be a risk factor for the manifestation of psychopathology, the prodromal phase of a mental disorder, or a trigger for exacerbation or recurrence of psychiatric distress symptoms. The domains of distress and demoralization are described and research diagnostic criteria for demoralization are presented. Conclusions: The scales discussed in this article differ in their time frames and have not yet been applied to the same population at the same time. The role of demoralization as a risk factor for mental disorders is just beginning to be understood. The domains and the diagnostic criteria for demoralization presented in this article need to be confirmed by epidemiological and empirical studies. Future research should continue to clarify its role in the pathogenesis of both mental disorders and physical illnesses and identify appropriate interventions for its arrest or prevention.

Figueiredo, John M. de.

347

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

348

Maintenance costs of road pavement and motor vehicles on the route Vilnius - Kaunas - Klaip?da  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The article describes the impact of axle loads of vehicles on the road pavement. Pavement deterioration intensity and the charge imposed on vehicles the axle load of which exceeds the set norm are analyzed on the road under investigation according to the results of weighing axle loads of vehicles as well as appropriate calculation methodologies. The work presents regressive equations according to which maintenance costs of vehicles can be predicted taking the condition of pavement into consid...

Mis?kinis, Dainius; Lingaitis, Vytautas

2006-01-01

349

Maintenance costs of road pavement and motor vehicles on the route Vilnius – Kaunas – Klaip?da  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The article describes the impact of axle loads of vehicles on the road pavement. Pavement deterioration intensity and the charge imposed on vehicles the axle load of which exceeds the set norm are analyzed on the road under investigation according to the results of weighing axle loads of vehicles as well as appropriate calculation methodologies. The work presents regressive equations according to which maintenance costs of vehicles can be predicted taking the condition of pavement into consid...

2006-01-01

350

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2010-01-01

351

Review of glass fibre grid use for pavement reinforcement and APT experiments at IFSTTAR  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reinforcement using an interlayer system has been demonstrated for more than four decades as a multi-purpose solution to improve performance, to extend service life and thus to reduce maintenance costs of road pavements. Among a large number of existing interlayer systems, glass fibre grids have shown effective use in pavement reinforcement with a hot mix asphalt overlay. Recently they have received increasing attention from the pavement community. However, as for other types of interlayer sy...

2013-01-01

352

Investigating the Feasibility of Integrating Pavement Friction and Texture Depth Data in Modeling for INDOT PMS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Under INDOT’s current friction testing program, the friction is measured annually on interstates but only once every three years on non-interstate roadways. The state’s Pavement Management System, however, would require current data if friction were to be included in the PMS. During routine pavement condition monitoring for the PMS, texture data is collected annually. This study explored the feasibility of using this pavement texture data to estimate the friction during those years when f...

2012-01-01

353

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2000-01-01

354

The influence of construction quality control data variability on pavements evolution  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Predicting pavement evolution is a fundamental component in pavement maintenance and rehabilitation management work. However, it is very complex to carry out due to several drawbacks, namely a common use of inadequate quality control procedures or a lack of reproducibility of quality control data. This paper describes the main conclusions of a study on the influence of construction quality control data on pavement evolution. It was possible to develop a methodology for this purpose based on s...

Freitas, Elisabete F.; Pereira, Paulo A. A.; Santos, Lui?s Picado

2005-01-01

355

Fracture testing and evaluation of asphalt pavement joints in quasi static tension mode  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Asphalt joints are inevitable parts of every pavement. They are constructed for different reasons. Although much attention is dedicated to the construction joints (hot with hot pavement), a scientific approach for cold joints (cold with hot pavement) with respect to large patch constructions is still missing. This report tries to evaluate existing construction techniques and to suggest new testing methods of tests. Although, indirect tensile tests IDT and direct tension tests DTT are familiar...

2012-01-01

356

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...

357

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

358

An application of smart dust for pavement condition monitoring  

Science.gov (United States)

Pavement maintenance is vital for travel safety; detecting road weather conditions using a wireless sensing network poses many challenges due to the harsh environment. This paper presents some preliminary results of an ongoing effort of applying "Smart Dust" sensor network for monitoring pavement temperature and moisture condition to detect icy road condition. Careful considerations yield effective solutions to various hardware and software development issues including the selection of sensors and antenna, design of casing, interfacing motes with alien sensors and programming of motes. A series of experiments is carried out to study traffic interference to packet delivery performance of a small-scale sensor network in a pseudo-field environment. In addition, several overnight tests are conducted to study the performance of motes operated under a power efficient condition. The results are analyzed and challenges are identified in this smart sensing application. The aforementioned research activities would benefit robust real-world implementations of off-the-shelf sensor network products.

Ferzli, Nadim A.; Ivey, Richard A.; King, Timothy; Sandburg, Colby J.; Pei, Jin-Song; Zaman, Musharraf M.; Refai, Hazem H.; Lin, Hung, Jr.; Landrum, Aaron; Victor, Rory

2006-04-01

359

Pavement roughness monitoring method using fiber optic vibration sensors  

Science.gov (United States)

Fiber optic sensor system, which is not corrosible semi-permanent, no influence by electromagnetic waves, and able to multiplex, can be expect to take an important part to assess the safety and residual estimate the life span of the highway pavement structure. In this research, as in situ monitoring of roughness of pavement, we propose the vibration monitoring method using fiber optic sensors. We designed and produced prototype fiber optic vibration sensor packages. Laboratory impact tests with the sensors were performed. The sensors showed very good responsibility to the impact and nice damping shape like other ordinary accelerometers. Actual road tests with the prototype vibration sensor were also performed. The ambient vibration by the vehicles was used for the experiment.

Kim, Ki-Soo; Baek, Yong; Yoo, In Kyoon

2010-03-01

360

Vehicle classes for pavement design and capacity analysis  

Energy Technology Data Exchange (ETDEWEB)

Transportation engineers working in Colorado were aware of a lack of published data at both the local and national level for vehicle classes on urban streets. Such vehicle class breakdowns are necessary for calculating equivalent daily loaded axle (EDLA) values for pavement design and conducting capacity analyses. A technical committee was formed to collect and analyze weekday vehicle class data on urban streets of various types. The major vehicle classes are passenger cars (70-75%), pickups (15-20%), single unit trucks (5-7%); tractor-trailers, buses, and recreational vehicles account for less than 1%. Using these data, a microcomputer spread sheet was set up to calculate EDLA values for pavement design for a range of design year volumes. This vehicle class data is also very useful in highway capacity calculations.

Kubala, J.; Asce, M.; Lalani, N.; O' Connell, R.; Petersen, C.

1986-11-01

 
 
 
 
361

Full scale demonstration of air-purifying pavement.  

Science.gov (United States)

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? 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, NO? 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. PMID:23731840

Ballari, M M; Brouwers, H J H

2013-06-15

362

Concrete Pavement Crack and Seat Performance Overlay Design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

1995-01-01

363

Combined permeable pavement and ground source heat pump systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The PhD thesis focuses on the performance assessment of permeable pavement systems incorporating ground source heat pumps (GSHP). The relatively high variability of temperature in these systems allows for the survival of pathogenic organisms within the sub?base. Salmonella sp, Escherichia coli, Enterococci and total heterotrophic bacteria were analysed in order to assess potential risk to health. Supplementary carbon dioxide monitoring indicated relatively high microbial activity on the geo...

2010-01-01

364

Performance of waste tyre rubber on model flexible pavement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2009-01-01

365

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

366

Pavement wear and airborne dust pollution in Norway  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 and regulate...

2008-01-01

367

Pavement wear and airborne dust pollution in Norway  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2008-01-01

368

Use of Recycled Aggregate and Fly Ash in Concrete Pavement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

369

Design Methodologies of Asphalt Pavement Used in China and Mozambique  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

370

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

Science.gov (United States)

...Determining the Color of Retroreflective Sign Materials and Pavement Marking Materials Appendix to Subpart F of Part 655 Highways...Determining the Color of Retroreflective Sign Materials and Pavement Marking Materials 1. Although the...

2010-04-01

371

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

372

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

373

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

2013-06-15

374

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.

2011-10-01

375

The Effects of Desert Pavements (Gravel Mulch) on Soil Micro-Hydrology  

Science.gov (United States)

The effect of desert pavements (gravel mulch) on near surface soil micro-hydrology has been inadequately studied. Micro-hydrology in arid ecosystems occurs due to a daily non rainfall atmospheric water cycle, consisting of an input phase (dew, fog, vapour adsorption) and an evaporation phase. A winter comparative study between a bare soil (control) and gravel mulch using the automated microlysimeter approach was conducted in Stellenbosch, South Africa in 2008. Results showed that dew deposition and direct water vapour adsorption were significantly higher into bare soil compared to gravel mulch. In contrast, however, soil moisture from rain persists for a longer time under gravel mulch compared to bare soil. This result suggests that the greatest impact of gravel mulch on soil micro-hydrology is towards conserving moisture and could explain why the treatment is used in dry-land agriculture in Mediterranean regions.

Kaseke, K. F.; Mills, A. J.; Henschel, J.; Seely, M. K.; Esler, K.; Brown, R.

2012-05-01

376

In-situ determination of moisture in road pavement by nuclear methods  

International Nuclear Information System (INIS)

The use of neutron moisture probes to determine moisture in compacted pavement layers has been studied on samples representative of those used by the New South Wales Department of Main Roads for roadway construction. The aim of this work was to measure the average moisture content of the upper layer (15-20 cm thick) with minimum interference from moisture in underlying layers. Sub-surface probes using high (?-Be) and low (?-Li) energy neutron sources were examined; conventional ?-Be sources in specially designed compact probes should result in an error due to base moisture and density variations of less than 0.4 wt % moisture. As this error is probably less than those due to sampling and geometry variations in the field, such a probe should be sufficiently accurate for DMR requirements. If less sensitivity to base moisture is required, the ?-Li source will reduce this sensitivity by a factor of about 1.4

1981-01-01

377

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

378

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2008-01-01

379

Recommendations for the repair, the lining or the strengthening of concrete slabs or pavements with bonded cement-based material overlays  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The recommendations presented in this publication are inspired by the State of the Art Report edited by the RILEM technical committee TC 193 RLS Bonded cement-based material overlays for the repair, the lining or the strengthening of slabs and pavements. The objective is to lay out all the practical aspects to be considered in the design of concrete overlays: bonded concrete overlay process, assessment of the existing structure, surface preparation, overlay materials, design methods, construc...

Courard, Luc; Bissonnette, Benoi?t; Beushausen, Hans; Fowler, David; Trevino, Manuel; Alex, Vaysburd; Johan, Silfwerbrand

2013-01-01

380

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

 
 
 
 
381

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

382

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

383

Active zone impact on deformation state of non-rigid pavement  

Science.gov (United States)

The paper deals with the design of non-rigid pavement, with emphasis on the effect of active zone on its deformation state. The concepts of determination of active zone are described. The results of numerical modelling of pavement laying on elastic subgrade are presented in the paper

Mandula, Ján

2014-06-01

384

Benchmarking the structural condition of flexible pavements with deflection bowl parameters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The falling weight deflectometer (FWD) is used worldwide as an established, valuable, nondestructive road testing device for pavement structural analyses. The FWD is used mostly for rehabilitation project level design investigations and for pavement management system (PMS) monitoring on a network basis. In project level investigations, design charts based on both empirical relations and mechanistic or theoretically based approaches are often used

Horak, Emile

2008-01-01

385

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...

386

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...

387

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

388

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...

389

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.

2013-06-17

390

Numerical simulation on the thermal response of heat-conducting asphalt pavements  

International Nuclear Information System (INIS)

Using asphalt pavements as a solar collector is a subject of current interest all over the world because the sun provides a cheap and abundant source of clean and renewable energy, which can be captured by black asphalt pavements. A heat-conducting device is designed to absorb energy from the sun. In order to validate what parameters are critical in the asphalt collector, a finite element model is developed to predict the thermal response of the heat-conducting device compared to the conventional asphalt mixture. Some factors that may affect the asphalt pavement collector are considered, including the coefficient of heat conductivity of the asphalt pavement, the distance between pipes with the medium, water, and the pipe's diameter. Ultimately, the finite element model can provide pavement engineers with an efficient computational tool that can be a guide to the conductive asphalt solar collector's experiment in the laboratory.

2010-05-01

391

Reduction in mental distress among substance users receiving inpatient treatment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Substance users being admitted to inpatient treatment experience a high level of mental distress. In this study we explored changes in mental distress during treatment. Methods Mental distress, as measured by the HSCL-10, was registered at admission and at discharge among 164 substance users in inpatient treatment in Northern Norway. Predictors of reduction in mental distress were examined utilizing hierarchical regression analysis. Re...

Hoxmark Ellen; Benum Vår; Friborg Oddgeir; Wynn Rolf

2010-01-01

392

Emotional distress in doctors: sources, effects and help sought.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

All doctors in a London Teaching Hospital were sent a self-administered, anonymous questionnaire, to study past episodes of emotional distress. We inquired about frequency of past and current emotional distress, sources of distress, effects on work and home life, type of help sought and perceived outcome of that help. Of 320 doctors, 210 (66%) responded. One hundred and forty-one (68%) reported previous episodes of moderate or severe emotional distress. Logistic regression revealed that distr...

1992-01-01

393

Breakup Distress and Loss of Intimacy in University Students  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Breakup distress and reasons for breakup including affiliation, intimacy, sexuality and autonomy reasons were stud-ied in 119 university students who had experienced a recent breakup of a romantic relationship. The sample was di-vided into high and low breakup distress groups based on a median score on the Breakup Distress Scale. The groups were then compared on their responses on the Breakup Reasons Scale. Only the intimacy subscale differentiated the high versus low breakup distress groups....

Tiffany Field; Miguel Diego; Martha Pelaez; Osvelia Deeds; Jeannette Delgado

2010-01-01

394

Use of High-Volume Reclaimed Asphalt Pavement (RAP) for Asphalt Pavement Rehabilitation Due to Increased Highway Truck Traffic from Freight Transportation.  

Science.gov (United States)

A recent rise in asphalt binder prices has led state agencies and contractors to use higher quantities of Reclaimed Asphalt Pavement (RAP). Besides being economic, sustainable, and environmentally friendly, RAP can be replaced for a portion of aggregates ...

H. Musty M. Hossain N. Sabahfer

2012-01-01

395

Evaluation of Rehabilitation Techniques for Flexible and Rigid Pavements in Nevada. Part 1. Cost-Effective Rehabilitation of Portland Cement Concrete Pavement in Nevada.  

Science.gov (United States)

The purpose of this study, was to evaluate the feasibility of several rehabilitation strategies for Portland Cement Concrete (PCC) pavement. Recommendations were made for future crack and seat, rubblization, and reconstruction projects based on a review o...

S. Bemanian

1999-01-01

396

The Contribution of Social Roles to Psychological Distress in Businesswomen.  

Science.gov (United States)

A study examined the relationship between the quality and number of domestic and work roles in businesswomen and psychological distress. The study attempted to answer the question: As the number of roles increases does distress increase? The study also considered what aspects of the roles elevate or diminish psychological distress. Following an…

Abrams, Leslie R.; Jones, Russell W.

397

Disordered Eating and Psychological Distress among Adults  

Science.gov (United States)

The majority of our knowledge about eating disorders derives from adolescent and young adult samples; knowledge regarding disordered eating in middle and later adulthood is limited. We examined the associations among known predictors of eating disorders for younger adults in an age-diverse sample and within the context of psychological distress.…

Patrick, Julie Hicks; Stahl, Sarah T.; Sundaram, Murali

2011-01-01

398

Happiness and Death Distress: Two Separate Factors  

Science.gov (United States)

The aim of the present study was to explore the relationship between happiness and death distress (death anxiety, death depression, and death obsession) in 275 volunteer Kuwaiti undergraduates. They responded to the Oxford Happiness Inventory, the Death Anxiety Scale, the Arabic Scale of Death Anxiety, the Death Depression Scale-Revised, and the…

Abdel-Khalek, Ahmed M.

2005-01-01

399

Spiritual distress: integrative review of literature  

Directory of Open Access Journals (Sweden)

Full Text Available This study aims to identify concepts and clinical indicators that evidence spiritual distress in patients. Integrative review was the method adopted for the development of the study. In the initial stage, 82 studies were found in the following databases PUBMED, COCHRANE, CINAHL, LILACS and North American Nursing Diagnosis Association Conference Proceedings and 18 were selected. The descriptors used were spirituality and nursing diagnosis in addition to the term spiritual distress. Literature review (38.9% and articles with level of evidence IV (27.8% were the predominant types of study. The analysis of the articles revealed that the identified concepts of spiritual distress presented common and related elements to the human being subjective and individual response to life experiences, which harm the human spiritual dimension. Defining spiritual distress is a complex task since it depends on the perspective of those evaluating it, limiting in this way, its generalization. However, knowledge regarding the constructs that guide the understanding of human spirituality can base the nursing care in its spiritual dimension, thus providing theoretical support for the diagnosis.

Cristina Maria Galvão

2008-07-01

400

Spiritual distress: integrative review of literature  

Directory of Open Access Journals (Sweden)

Full Text Available This study aims to identify concepts and clinical indicators that evidence spiritual distress in patients. Integrative review was the method adopted for the development of the study. In the initial stage, 82 studies were found in the following databases PUBMED, COCHRANE, CINAHL, LILACS and North American Nursing Diagnosis Association Conference Proceedings and 18 were selected. The descriptors used were spirituality and nursing diagnosis in addition to the term spiritual distress. Literature review (38.9% and articles with level of evidence IV (27.8% were the predominant types of study. The analysis of the articles revealed that the identified concepts of spiritual distress presented common and related elements to the human being subjective and individual response to life experiences, which harm the human spiritual dimension. Defining spiritual distress is a complex task since it depends on the perspective of those evaluating it, limiting in this way, its generalization. However, knowledge regarding the constructs that guide the understanding of human spirituality can base the nursing care in its spiritual dimension, thus providing theoretical support for the diagnosis.

Erika Cássia Lopes Chaves

2008-08-01

 
 
 
 
401

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

402

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

403

The spiritual distress assessment tool: an instrument to assess spiritual distress in hospitalised elderly persons  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Although spirituality is usually considered a positive resource for coping with illness, spiritual distress may have a negative influence on health outcomes. Tools are needed to identify spiritual distress in clinical practice and subsequently address identified needs. This study describes the first steps in the development of a clinically acceptable instrument to assess spiritual distress in hospitalized elderly patients. Methods A three-step process was used to develop the Spiritual Distress Assessment Tool (SDAT: 1 Conceptualisation by a multidisciplinary group of a model (Spiritual Needs Model to define the different dimensions characterizing a patient's spirituality and their corresponding needs; 2 Operationalisation of the Spiritual Needs Model within geriatric hospital care leading to a set of questions (SDAT investigating needs related to each of the defined dimensions; 3 Qualitative assessment of the instrument's acceptability and face validity in hospital chaplains. Results Four dimensions of spirituality (Meaning, Transcendence, Values, and Psychosocial Identity and their corresponding needs were defined. A formalised assessment procedure to both identify and subsequently score unmet spiritual needs and spiritual distress was developed. Face validity and acceptability in clinical practice were confirmed by chaplains involved in the focus groups. Conclusions The SDAT appears to be a clinically acceptable instrument to assess spiritual distress in elderly hospitalised persons. Studies are ongoing to investigate the psychometric properties of the instrument and to assess its potential to serve as a basis for integrating the spiritual dimension in the patient's plan of care.

Martin Estelle

2010-12-01

404

Repairs with polymer concrete. [Repair of bridge decks and pavements  

Energy Technology Data Exchange (ETDEWEB)

The practicality of using polymer concrete PC to repair portland cement concrete PCC bridge decks and pavements has been demonstrated. PC repairs will cure rapidly over a wide range of temperatures (0/sup 0/ to 38/sup 0/C), develop high strength in a few hours, and bond well to PCC. The use of PC as a thin, permeable, skid-resistant overlay has to date shown outstanding wear characteristics. The practicality of placement is not yet conclusive, but the material promises many advantages.

Fontana, J.J.; Reams, W.

1981-01-01

405

A method for assessing the physical recovery of Antarctic desert pavements following human-induced disturbances: a case study in the Ross Sea region of Antarctica.  

Science.gov (United States)

With increasing visitor numbers an understanding of the impacts of human activities in Antarctic terrestrial environments has become important. The objective of this study was to develop a means for assessing recovery of the ground surface desert pavement following physical disturbance. A set of 11 criteria were identified to assess desert pavement recovery. Assessed criteria were: embeddedness of surface clasts; impressions of removed clasts; degree of clast surface weathering; % overturned clasts; salt on underside of clasts; development of salt coatings; armouring per m(2); colour contrast; evidence of subsidence/melt out; accumulation of salt on cut surfaces; and evidence of patterned ground development. Recovery criteria were assigned a severity/extent rating on a scale from zero to four, zero being highly disturbed, and four being undisturbed. A relative % recovery for each criteria was calculated for each site by comparison with a nearby undisturbed control area, and an overall Mean Recovery Index (MRI) was assigned to each pavement surface. To test the method, 54 sites in the Ross Sea region of Antarctica were investigated including areas disturbed by: bulldozer scraping for road-fill, contouring for infrastructure, geotechnical investigations, and experimental treading trial sites. Disturbances had occurred at timescales ranging from one week to 50 years prior to assessment. The extent of desert pavement recovery at the sites investigated in this study was higher than anticipated. Fifty of the 54 sites investigated were in an intermediate, or higher, stage of desert pavement recovery, 30 sites were in an advanced stage of recovery, and four sites were indistinguishable from adjacent control sites (MRI = 100%). It was found that active surfaces, such as the gravel beach deposits at the Greenpeace World Park Base site at Cape Evans, the aeolian sand deposits at Bull Pass, and the alluvial fan deposits of the Loop Moraine field campsite, recovered relatively quickly, whereas less active sites, such as the bulldozed tracks at Marble Point, and Williams Field to McMurdo Station pipeline site on Ross Island, showed only intermediate recovery 20-30 years after disturbance. The slabby grano-diorite surface material at the former Vanda Station site, meant that the impacts that had occurred were hard to detect following decommissioning of the station and site remediation. Desert pavements disturbed by randomly dispersed footprints, temporary field campsites at the Loop Moraine and VXE6 Pond in the Wright Valley, recovered to be undetectable (MRI = 100%) within five years, whereas track formation from repeated trampling, particularly the concentration of larger clasts along the margin of a confined track, persisted for over 15 years (MRI = 82%). The recovery assessment method developed in this study has environmental management applications and potential to advance our ability to predict the recovery of desert pavement following human impacts from activities in Antarctica. PMID:23000478

O'Neill, Tanya A; Balks, Megan R; López-Martínez, Jerónimo; McWhirter, Judi L

2012-12-15

406

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

407

A System for Road Pavement Composite Material Deformation  

Directory of Open Access Journals (Sweden)

Full Text Available

For a comprehensive experimental evaluation of the material quality, forecast of the properties and parameter change of the bituminous material was made at the time under the impact of external factors, they are subjected to the necessary tests. In the article the automated set Tomsk-Asphalt-Test for determining the elastic modulus of the specimens made of bituminous materials was used in road pavements, maximally close to natural conditions of operation of highways of the Siberian region inRussiaare described. The automated set contains: electromechanical, climate, electronic, PC and software subsystem. The operation principle is a short-time deformation of the asphalt specimens; measurement of physical values: the stress, strain, variation of the size line and temperature of the asphalt pavement material test specimen, converting the measured values into electrical signals, their program processing and visualization. The control of testing and viewing results of measurements is carried out in accordance with the menu software subsystem. The results of calculations: the maximum values of vertical load the difference between the maximum horizontal deformation value and the value measured last after specimen of asphalt material loading for each test cycle, the sum of the differences of the horizontal deformation values of the two sensors and modulus of elasticity.

2012-12-01

408

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

409

Permeable pavement and stormwater management systems: a review.  

Science.gov (United States)

Uncontrolled stormwater runoff not only creates drainage problems and flash floods but also presents a considerable threat to water quality and the environment. These problems can, to a large extent, be reduced by a type of stormwater management approach employing permeable pavement systems (PPS) in urban, industrial and commercial areas, where frequent problems are caused by intense undrained stormwater. PPS could be an efficient solution for sustainable drainage systems, and control water security as well as renewable energy in certain cases. Considerable research has been conducted on the function of PPS and their improvement to ensure sustainable drainage systems and water quality. This paper presents a review of the use of permeable pavement for different purposes. The paper focuses on drainage systems and stormwater runoff quality from roads, driveways, rooftops and parking lots. PPS are very effective for stormwater management and water reuse. Moreover, geotextiles provide additional facilities to reduce the pollutants from infiltrate runoff into the ground, creating a suitable environment for the biodegradation process. Furthermore, recently, ground source heat pumps and PPS have been found to be an excellent combination for sustainable renewable energy. In addition, this study has identified several gaps in the present state of knowledge on PPS and indicates some research needs for future consideration. PMID:24527626

Imran, H M; Akib, Shatirah; Karim, Mohamed Rehan

2013-01-01

410

The Global Maritime Distress and Safety System  

Science.gov (United States)

The Global Maritime Distress and Safety System (GMDSS) is discussed with respect to its initial planning, the communication network, and other details, including the fully automated Maritime Safety Information service and the implementation of the whole system. GMDSS is the result of international cooperation over a period of about 10 years and provides the maritime community with an integrated distress and safety communication system which significantly enhances the safety of life and property in the harsh environment of the sea. Probably the most essential element of the GMDSS is the provision of an adequate communication network which will permit ships in need of assistance to notify responsible authorities, discuss the help they need, and allow the search and rescue activities to be coordinated by the most appropriate center.

Kent, Peter E.

1990-08-01

411

Acute respiratory distress syndrome with miliary tuberculosis.  

Science.gov (United States)

A 71-year-old man was admitted to the hospital complaining of productive cough and weight loss. Physical examination showed fine bilateral basal crackles. Laboratory findings showed elevated liver enzymes. Tuberculin skin test and sputum smear for acid-fast bacilli were negative. On the fifth day of admission, he deteriorated and developed severe respiratory distress. A chest radiograph demonstrated worsening pulmonary infiltrates. He was electively intubated and was put on a mechanical ventilator. The chest CT scan revealed diffuse bilateral pulmonary nodules and airspace disease. Based upon the clinical suspicion of acute respiratory distress syndrome associated with miliary tuberculosis (TB), empiric treatment with antituberculosis and systemic steroids was started. He was extubated after 6 days. The diagnosis of miliary TB was confirmed by a thoracoscopic lung biopsy. He was discharged with a near normal chest radiograph and was followed up as an outpatient. PMID:22273654

Khadawardi, Hadeel A; Gari, Abdul-Ghafoor A

2012-01-01

412

Pharmacological interventions in acute respiratory distress syndrome  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pharmacological interventions are commonly considered in acute respiratory distress syndrome (ARDS) patients. Inhaled nitric oxide (iNO) and neuromuscular blockers (NMBs) are used in patients with severe hypoxemia. No outcome benefit has been observed with the systematic use of iNO. However, a sometimes important improvement in oxygenation can occur shortly after starting administration. Therefore, its ease of use and its good tolerance justify iNO optionally combined with almitirne as a resc...

Roch, Antoine; Hraiech, Sami; Dizier, Ste?phanie; Papazian, Laurent

2013-01-01

413

An Unusual Cause of Recurrent Respiratory Distress  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A one and a half years old boy presented with recurrent episodes of respiratory distress, accompanied by dry non spasmodic cough and characterized by appearance of a continuous stridor showing no positional variation. The child was symptomatic since early infancy. Parents also complained of inability to gain weight as compared to other siblings.  There was no history of foreign body ingestion or complaints of asthma or tuberculosis in the family. General physical examination revealed tachypn...

Joshi Neha

2010-01-01

414

Progressive respiratory distress due to neck mass  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present report describes the case of an 80-year-old woman who presented at the emergency department with progressive respiratory distress caused by a massive anterior neck mass with tracheal deviation and compression. A CT scan showed diffuse enlargement of the thyroid gland. The patient underwent a left-sided hemithyroidectomy. Pathology unexpectedly revealed a primary thyroid lymphoma. Treatment with prednisone and vincristine was initiated to reduce tumour size and preserve the airway,...

La Parra, Raquel F. D.; Kroeze, Jan; Die, Jos; Mulder, Dries; Zanten, Arthur; Tjan, David H.

2009-01-01

415

Marital functioning, chronic pain, and psychological distress  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study examined whether marital functioning variables related uniquely to psychological distress and diagnoses of depressive disorder independent of pain severity and physical disability. Participants were 110 chronic musculoskeletal pain patients. Hierarchical regression results showed that marital variables (i.e. marital satisfaction, negative spouse responses to pain) contributed significantly to depressive and anxiety symptoms over and above the effects of pain severity and physical d...

Cano, Annmarie; Gillis, Mazy; Heinz, Wanda; Geisser, Michael; Foran, Heather

2004-01-01

416

Acute Respiratory Distress Syndrome in Children  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are an important challenge for pediatric intensive care units. These disorders are characterized by a significant inflammatory response to a local (pulmonary) or remote (systemic) insult resulting in injury to alveolar epithelial and endothelial barriers of the lung, acute inflammation and protein rich pulmonary edema. The reported rates in children vary from 8.5 to 16 cases/1000 pediatric intensive care unit (PICU) admiss...

Dincer Yildizdas; Ozden Ozgur Horoz; Ali Ertug Arslankoylu; Muge Sagiroglu

2009-01-01

417

Acute Respiratory Distress Due to Methane Inhalation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Inhalation of toxic gases can lead to pneumonitis. It has been known that methane gas intoxication causes loss of consciousness or asphyxia. There is, however, a paucity of information about acute pulmonary toxicity from methane gas inhalation. A 21-year-old man was presented with respiratory distress after an accidental exposure to methane gas for one minute. He came in with a drowsy mentality and hypoxemia. Mechanical ventilation was applied immediately. The patient's symptoms and chest rad...

Jo, Jun Yeon; Kwon, Yong Sik; Lee, Jin Wook; Park, Jae Seok; Rho, Byung Hak; Choi, Won-il

2013-01-01

418

The Genetic Susceptibility to Respiratory Distress Syndrome  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Previous studies to identify a genetic component to respiratory distress syndrome (RDS) have shown conflicting results. Our objectives were to evaluate and quantify the genetic contribution to RDS using data that comprehensively includes known environmental factors in a large sample of premature twins. Data from a retrospective chart review of twins born at ?32 weeks gestational age were obtained from 2 neonatal units. Mixed effects logistic regression (MELR) analysis was used to assess the...

Levit, Orly; Jiang, Yuan; Bizzarro, Matthew J.; Hussain, Naveed; Buhimschi, Catalin S.; Gruen, Jeffrey R.; Zhang, Heping; Bhandari, Vineet

2009-01-01

419

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

420

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

 
 
 
 
421

The Effect of Varying the Modulus and Thickness of Asphaltic Concrete Surfacing Materials.  

Science.gov (United States)

This report is a theoretical study of the effects of varying the modulus and thickness of asphalt concrete surfacing materials. Three typical flexible pavement design problems at two levels of hot mix asphaltic concrete (HMAC) elastic modulus are analyzed...

D. Y. Lu F. H. Scrivner

1974-01-01

422

Theoretical analysis of piezoelectric energy harvesting from traffic induced deformation of pavements  

Science.gov (United States)

The problem of energy harvesting using piezoelectric transducers for pavement system applications is formulated with a focus on moving vehicle excitations. The pavement behavior is described by an infinite Bernoulli-Euler beam subjected to a moving line load and resting on a Winkler foundation. A closed-form dynamic response of the pavement is determined by a Fourier transform and the residue theorem. The voltage and power outputs of the piezoelectric harvester embedded in the pavements are then obtained by the direct piezoelectric effect. A comprehensive parametric study is conducted to show the effect of damping, the Winkler modulus, and the velocity of moving vehicles on the voltage and power output of the piezoelectric harvester. It is found that the output increases sharply when the velocity of the vehicle is close to the so-called critical velocity.

Xiang, H. J.; Wang, J. J.; Shi, Z. F.; Zhang, Z. W.

2013-09-01

423

Theoretical analysis of piezoelectric energy harvesting from traffic induced deformation of pavements  

International Nuclear Information System (INIS)

The problem of energy harvesting using piezoelectric transducers for pavement system applications is formulated with a focus on moving vehicle excitations. The pavement behavior is described by an infinite Bernoulli–Euler beam subjected to a moving line load and resting on a Winkler foundation. A closed-form dynamic response of the pavement is determined by a Fourier transform and the residue theorem. The voltage and power outputs of the piezoelectric harvester embedded in the pavements are then obtained by the direct piezoelectric effect. A comprehensive parametric study is conducted to show the effect of damping, the Winkler modulus, and the velocity of moving vehicles on the voltage and power output of the piezoelectric harvester. It is found that the output increases sharply when the velocity of the vehicle is close to the so-called critical velocity. (paper)

2013-09-01

424

Pavement Marking Warranty Specifications. A Synthesis of Highway Practice. NCHRP Synthesis 408.  

Science.gov (United States)

This synthesis study updates information on the use of pavement marking warranties by U.S. state departments of transportation (DOTs) and Canadian provincial/territorial transportation agencies. It also reviews road construction warranty experience in Eur...

M. J. Markow

2010-01-01

425

Pilot Implementation of New Test Procedures for Curing in Concrete Pavements.  

Science.gov (United States)

Curing of concrete has substantial effects on the performance of Portland cement concrete (PCC) pavement. Curing effectiveness depends on the quality of the curing materials, time of curing compound application in relation to evaporation, and the amount a...

C. Suh J. H. Yeon M. Won

2009-01-01

426

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

427

Pavement Settlement Issues and Hydro-Geochemical Water Testing Results for the Cumberland Gap Tunnel.  

Science.gov (United States)

Both Ground Penetrating Radar (GPR) surveys and Hydro-Geochemical Water Testing (HGWT) have been performed at the Cumberland Gap Tunnel to determine why the reinforced concrete pavement has settled in various areas throughout both tunnels. To date, approx...

B. Rister C. Graves J. Dinger

2010-01-01

428

Assessment of Clogging Dynamics in Permeable Pavement Systems with Time Domain Reflectometers  

Science.gov (United States)

Infiltration is a primary functional mechanism in green infrastructure stormwater controls. This study used time domain reflectometers (TDRs) to measure spatial infiltration and assess clogging dynamics of permeable pavement systems in Edison, NJ, and Louisville, KY. In 2009, t...

429

Airfield Pavement Condition Survey, USNAS Whidbey Island and USNOLF Coupeville, Washington.  

Science.gov (United States)

The results of condition surveys of the airfield pavements at the U. S. Naval Air Station, Whidbey Island and U. S. Naval Outlying Field, Coupeville are presented. The surveys established statistically-based condition numbers (weighted defect densities) w...

D. J. Lambiotte L. J. Woloszynski

1971-01-01

430

Investigation of Subgrade Moisture Conditions in Connection with the Design of Flexible Pavement Structures.  

Science.gov (United States)

In the structural design of flexible pavements, the supporting power of subgrade soils should be evaluated on the basis of anticipated moisture conditions. It is, therefore, necessary to predict subgrade moisture conditions and to simulate these condition...

T. Y. Chu W. K. Humphries

1972-01-01

431

Evaluation of western and eastern shale oil residua as asphalt pavement recycling agents.  

Science.gov (United States)

The objective of this investigation was to perform a preliminary evaluation of the utility of residual materials prepared from Green River Formation (western) and New Albany Shale (eastern) shale oils as recycling agents for aged asphalt pavement. Four pe...

P. M. Harnsberger R. E. Robertson

1990-01-01

432

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

433

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 added to soil and granular materials and improve their various properties as compressive and tensile strengths. In present study, the result of previous researches are collected and presented, then, they are used to analyses the effect of using from waste materials in subgrade on highway pavement performance. By using analytical software and results of testing, tensile strain under asphalt layer and compressive strain on subgrade of pavement containing these materials are calculated and after that they are compared together. Next the allowable frequencies of loading for different pavement models are calculated by using existing formula. The results indicate that adding 1.5% of waste fiber to pavement subgrade increases the allowable frequency of loading to 15%.

Mohammad M. Khabiri

2011-07-01

434

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. ...

435

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)

2013-01-01

436

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...

437

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.

2010-06-01

438

Effects of Salt and Trace Minerals on Aggregates for Bituminous Pavements.  

Science.gov (United States)

This research on the effects of deicing salts and their trace minerals on bituminous highway wearing courses was prompted by several occurrences of early pavement deterioration on Indiana federal and state highways. Early deterioration of bituminous pavem...

T. R. West H. J. Park S. E. Grover

1999-01-01

439

Improving the Properties of Reclaimed Asphalt Pavement for Roadway Base Applications.  

Science.gov (United States)

The objective of this study was to improve Reclaimed Asphalt Pavements (RAP) strength in base course applications while reducing creep to an acceptable level using compaction techniques, fractionating, blending with high quality base course aggregate, and...

A. J. Petersen A. M. Bleakley A. M. Sajjadi B. S. Diouf E. H. Kalajian P. J. Cosentino R. E. Krajcik T. J. Misilo

2012-01-01

440