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Author: Y. Richard Kim Publisher: ISBN: Category : Pavements Languages : en Pages : 158
Book Description
When FWD tests are performed on broken or cracked pavements (of which information is crucial in making rehabilitation and overlay decisions), the multi-layered elastic theory-based backcalulation programs assume that the effect of these discontinuities in a cracked layer on deflection basins would be accounted for by the reduction of the elastic modulus for that layer. However, it has been concluded and confirmed by researchers and practitioners that the backcalculation algorithms based on the multi-layered elastic theory produce large variation in the algorithms based on the multi-layered elastic theory produce large variation in the 'effective' moduli of the cracked layers. Studies have also shown that significant errors in the backcalculated pavement moduli can accrue from performing a static analysis of what is inherently a dynamic test. Unfortunately, dynamic analysis usually involves complex calculations and requires significant computation time, thus making it impracticable for routine applications. This study presents a methology based on deflection basin parameters.
Author: Y. Richard Kim Publisher: ISBN: Category : Pavements Languages : en Pages : 158
Book Description
When FWD tests are performed on broken or cracked pavements (of which information is crucial in making rehabilitation and overlay decisions), the multi-layered elastic theory-based backcalulation programs assume that the effect of these discontinuities in a cracked layer on deflection basins would be accounted for by the reduction of the elastic modulus for that layer. However, it has been concluded and confirmed by researchers and practitioners that the backcalculation algorithms based on the multi-layered elastic theory produce large variation in the algorithms based on the multi-layered elastic theory produce large variation in the 'effective' moduli of the cracked layers. Studies have also shown that significant errors in the backcalculated pavement moduli can accrue from performing a static analysis of what is inherently a dynamic test. Unfortunately, dynamic analysis usually involves complex calculations and requires significant computation time, thus making it impracticable for routine applications. This study presents a methology based on deflection basin parameters.
Author: Richard N. Stubstad Publisher: ISBN: Category : Pavements Languages : en Pages : 70
Book Description
Good materials and construction practices are vital to producing high quality and long lasting pavements. Quality control and assurance techniques can provide the owner of the roadway the means to ensure that these desired ends are achieved. The objective of this research study is to determine whether the Falling Weight Deflectometer (FWD) can effectively be used to assist in the QC/QA process during pavement construction. The Long Term Pavement Performance (LTPP) study provided the data needed to accomplish this research. LTPP began, in about 1988, as the Strategic Highway Research Program (SHRP), and it included a subset of newly constructed or rehabilitated pavements called the Specific Pavement Studies (SPS). Some of these were targeted at pavement maintenance and rehabilitation, while others were for new construction. New construction was subdivided into three LTPP experiments, one for asphalt concrete (AC) surfaced pavements (SPS-1), one for Portland Cement Concrete (PCC) surfaced pavements (SPS-2), and one for both AC and PCC pavements under the influence of light traffic loads (SPS-8). In each case, several thickness and material designs were developed in an experimental design matrix. These SPS experimental design matrices were constructed under a variety of climatic conditions and material sources in several states. During construction of the SPS-1, -2 and -8 projects, a large number of field and laboratory tests were performed on each structural layer. These tests included densities, moisture contents, layer thickness measurements and others, along with FWD tests conducted at each layer interface. This report shows that the FWD data is of reasonable quality and certainly of sufficient quantity to carry out the research. The traditional test results, although not as extensive as FWD data, were also reasonable and appeared to cover most of the wide variety of pavement designs and construction locations represented by the LTPP/SPS database. Sixteen SPS-1, SPS-2 and SPS-8 test sites (each site represents between 2 and 12 test sections) were utilized for analyses during this research project. These sites represent a wide variety of materials, climates, and construction dates.
Author: Shiraz D. Tayabji Publisher: ASTM International ISBN: 0803128584 Category : Materials Languages : en Pages : 534
Book Description
As with the previous two symposia, the 32 papers from the June/July, 1999, Seattle symposium present advances in the nondestructive testing of pavements using conventional falling weight deflectometer techniques and other promising techniques such as ground penetrating radar, rolling weight deflecto
Author: Kurt D. Smith Publisher: ISBN: Category : Pavements Languages : en Pages :
Book Description
The need to accurately characterize the structural condition of existing pavements has increased with the recent development, release, and ongoing implementation of the Mechanistic-Empirical Pavement Design Guide (MEPDG). A number of different material inputs are required in the procedure, and it is important to adequately characterize and define them. The analysis of deflection data collected by the falling weight deflectometer (FWD) provides a quick and reliable way to characterize the properties of the paving layers, as well as to assess the load-carrying capacity of existing pavement structures. With the release of the new MEPDG, there is a pressing need to identify and evaluate the way that FWD testing is integrated into the new design procedure. Moreover, as highway agencies continue to implement the MEPDG, they need best practices guidance on how to effectively test existing pavement structures and interpret the results as part of a mechanistic-empirical pavement evaluation and rehabilitation process.
Author: Nick Thom Publisher: Emerald Group Publishing ISBN: 1835497101 Category : Technology & Engineering Languages : en Pages : 448
Book Description
Principles of Pavement Engineering, Third edition is an essential reference on fundamental principles of pavement engineering, showing how to design, construct, evaluate and maintain pavements of all types.
Author: Y. Richard Kim
Author: Y. Richard Kim
Author: Paulo Pereira
Author: Richard N. Stubstad
Author: Bing Xu
Author: 
Author: 
Author: Shiraz D. Tayabji
Author: Kurt D. Smith
Author: Nick Thom
Author: National Research Council (U.S.). Transportation Research Board