Author: Brian K. Diefenderfer Publisher: ISBN: Category : Asphalt concrete Languages : en Pages : 0
Book Description
The results of dynamic modulus testing have become one of the primarily used performance criteria to evaluate the laboratory properties of asphalt mixtures. This test is commonly conducted to characterize asphalt mixtures mechanistically using an asphalt mixture performance tester as developed in NCHRP Project 9-29. The typical test specimen geometry consists of a cylinder having a 100-mm diameter and a 150-mm height. This geometry is practical for laboratory-prepared specimens produced using a gyratory compactor. However, the specimen scale is problematic when the test specimen is prepared from field cores and the investigator wishes to isolate the testing to a single asphalt mixture material/layer. This is because most asphalt mixture layers, especially surface and intermediate layers, are placed having a thickness less than 150 mm. This study investigated the use of small-scale cylindrical specimens as an alternative means to conduct dynamic modulus testing of asphalt mixtures. To validate the small-scale approach, the dynamic modulus from small-scale specimens was compared to the dynamic modulus from full-size specimens (100 × 150 mm) using asphalt mixtures having a nominal maximum aggregate size (NMAS) of 9.5, 12.5, 19.0, and 25.0 mm. Small-scale cylindrical specimens having a diameter and height of 38 × 135 mm, 50 × 135 mm, 38 × 110 mm, and 50 × 110 mm were studied. Based on the findings of the study, for 9.5- and 12.5-mm NMAS mixtures, any of the four small-scale geometry dimensions appears to be a suitable alternative to the full-size specimen when the full-size specimen cannot be produced. For 19.0- and 25.0-mm NMAS mixtures, the two small-scale geometries having a diameter of 50 mm appear to be suitable alternatives to the full-size specimen when the full-size specimen cannot be produced.
Author: Brian K. Diefenderfer Publisher: ISBN: Category : Asphalt concrete Languages : en Pages : 50
Book Description
The results of dynamic modulus testing have become one of the primarily used performance criteria to evaluate the laboratory properties of asphalt mixtures. This test is commonly conducted to characterize asphalt mixtures mechanistically using an asphalt mixture performance tester as developed in NCHRP Project 9-29. The typical test specimen geometry consists of a cylinder having a 100-mm diameter and a 150-mm height. This geometry is practical for laboratory-prepared specimens produced using a gyratory compactor. However, the specimen scale is problematic when the test specimen is prepared from field cores and the investigator wishes to isolate the testing to a single asphalt mixture material/layer. This is because most asphalt mixture layers, especially surface and intermediate layers, are placed having a thickness less than 150 mm. This study investigated the use of small-scale cylindrical specimens as an alternative means to conduct dynamic modulus testing of asphalt mixtures. To validate the small-scale approach, the dynamic modulus from small-scale specimens was compared to the dynamic modulus from full-size specimens (100 × 150 mm) using asphalt mixtures having a nominal maximum aggregate size (NMAS) of 9.5, 12.5, 19.0, and 25.0 mm. Small-scale cylindrical specimens having a diameter and height of 38 × 135 mm, 50 × 135 mm, 38 × 110 mm, and 50 × 110 mm were studied. Based on the findings of the study, for 9.5- and 12.5-mm NMAS mixtures, any of the four small-scale geometry dimensions appears to be a suitable alternative to the full-size specimen when the full-size specimen cannot be produced. For 19.0- and 25.0-mm NMAS mixtures, the two small-scale geometries having a diameter of 50 mm appear to be suitable alternatives to the full-size specimen when the full-size specimen cannot be produced.
Author: Erfan Hajibandeh Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Measuring the quality of as-built Asphalt Concrete (AC) mixtures provide useful information about the current and long-term performance of pavements. By the advent of the mechanistic-empirical pavement design method, the dynamic modulus has become one of the primary performance indicators required for characterizing the performance of AC mixtures. The dynamic modulus is commonly measured using cylindrical specimens having a 100 mm diameter and a 150 mm height (full-size specimens). Testing as-built AC mixtures using this geometry is rarely possible because the required specimen height is greater than the typical AC lift thickness. In this study, the feasibility of using small-scale cylindrical specimens to measure the dynamic modulus of AC mixtures was investigated. Initially, the specimens were prepared in the laboratory using loose mixtures obtained from the field. Dynamic modulus test was conducted on full-size and two small-scale (common height of 110 mm and two diameters of 38 and 50 mm) geometries extracted from gyratory compacted samples. A uniaxial hydraulic loading frame was used to test specimens at the standard temperatures and frequencies. Both small geometries showed similar performances to full-size specimens except at high temperature of 37.8°C, where they resulted in greater dynamic modulus values compared to full-size geometry. The coefficient of variation for 38mm-diameter specimens was found to be higher than two other geometries. Secondly, field cores were collected from highways to characterize as-built AC mixtures using three tests, including dynamic modulus, Hamburg Wheel-Tracking (HWT), and ignition oven. Ignition oven test was performed on field cores to mainly control the aggregate gradation of mixtures. For the dynamic modulus test, small-scale specimens were extracted from field cores, and stiffness values at 37.8°C were corrected using calibration factors obtained from the initial phase. For the HWT test, the heights of field cores were adjusted, and the test output parameters were correlated with the calibrated dynamic modulus values at 37.8°C. The results showed that small-scale specimens are capable of measuring the as-built dynamic modulus of AC mixtures and predicting their rutting performance in the laboratory.
Author: Vittorio Guglielmetti Publisher: CRC Press ISBN: 0415558549 Category : Technology & Engineering Languages : en Pages : 1336
Book Description
The design and construction of “long and deep” tunnels, i.e. tunnels under mountains, characterised by either considerable length and/or overburden, represent a considerable challenge. The scope of this book is not to instruct how to design and construct such tunnels but to share a method to identify the potential hazards related to the process of designing and constructing long and deep tunnels, to produce a relevant comprehensive analysis and listing, to quantify the probability and consequences, and to design proper mitigation measures and countermeasures. The design, developed using probabilistic methods, is verified during execution by means of the so called Plan for Advance of the Tunnel (PAT) method, which allows adapting the design and control parameters of the future stretches of the tunnel to the results of the stretches already finished, using the monitoring data base. Numerous criteria are given to identify the key parameters, necessary for the PAT procedure. Best practices of excavation management with the help of real time monitoring and control are also provided. Furthermore cost and time evaluation systems are analysed. Finally, contractual aspects related to construction by contract are investigated, for best development and application of models more appropriate for tunnelling-construction contracts. The work will be of interest to practising engineers, designers, consultants and students in mining, underground, tunnelling, transportation and construction engineering, as well as to foundation and geological engineers, urban planners/developers and architects.
Author: National Research Council (U.S.). Transportation Research Board Publisher: Transportation Research Board ISBN: 9780309048613 Category : Technology & Engineering Languages : en Pages : 196
Author: Wynand JvdM. Steyn Publisher: Transportation Research Board ISBN: 0309223660 Category : Technology & Engineering Languages : en Pages : 257
Book Description
"TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 433: Significant Findings from Full-Scale Accelerated Pavement Testing documents and summarizes significant findings from the various experimental activities associated with full-scale accelerated pavement testing (f-sAPT) programs that have taken place between 2000 and 2011. The report also identifies gaps in knowledge related to f-sAPT and where future research may be needed. NCHRP Synthesis 433 is designed to expand the f-sAPT base of knowledge documented in NCHRP Syntheses 325 and 235, both with the same title of Significant Findings from Full-Scale Accelerated Pavement Testing. f-sAPT is the controlled application of a wheel loading, at or above the appropriate legal load limit, to a pavement system to determine pavement response in a compressed time period. The acceleration of damage is achieved by one or more of the following factors: increased repetitions, modified loading conditions, imposed climatic conditions, and thinner pavements with a decreased structural capacity which have shorter design lives"--
Author: United States. Federal Highway Administration. Office of Pavement Technology Publisher: ISBN: Category : Pavements, Bituminous Languages : en Pages : 11
Book Description
This Technical Brief provides an overview of the asphalt materials input requirements in AASHTOWare® Pavement ME Design and how the Asphalt Mixture Performance Tester can be used to characterize asphalt mixtures for flexible pavement ME designs.
Author: KM. Chua Publisher: ISBN: Category : Asphalt emulsion mixtures Languages : en Pages : 18
Book Description
It is often desirable to be able to obtain a comprehensive characterization of the performance-related properties of asphalt concrete with as few tests as possible. The New Mexico State Highway and Transportation Department is interested in obtaining a comprehensive characterization of the performance-related properties of the four types of asphalt concrete mixtures that are commonly used in the state. These properties include: the strength, the resilient modulus, the rutting characteristics, and the fatigue/cracking characteristics. Typically, different tests are needed to determine these characteristics. However, the approach taken here to obtain the desired information is through dynamic testing with large (15 cm diameter x 30 cm high) cylindrical asphalt concrete specimens at four different load levels, frequencies, and temperatures. The load applied were 1112 N, 2224 N, 4448 N, and 8896 N; at frequencies of 1 Hz, 4 Hz, 8 Hz, and 16 Hz. Test temperatures were 4.4°C, 25°C, 37.8°C, and 60°C. Continuous haversine load cycles were applied for each test set and the response to the repeated loadings were recorded. Resilient modulus histories were obtained. Rutting characteristics of the material at different temperatures were obtained from the residual deformation histories. The thermal viscoelastic properties were determined from the deformation response at the different temperatures. The change in the damping characteristics with repeated loading were determined through analysis of the data in the frequency domain. Since damping properties can be related to the embrittlement and aging characteristics of materials, the fatigue properties were also inferred. Additionally, it is shown that the degree of susceptibility of the asphalt concrete to cracking and reflection cracking can also be estimated.
Author: Y. Richard Kim Publisher: CRC Press ISBN: 1315736756 Category : Technology & Engineering Languages : en Pages : 1966
Book Description
Asphalt Pavements contains the proceedings of the International Conference on Asphalt Pavements (Raleigh, North Carolina, USA, 1-5 June 2014), and discusses recent advances in theory and practice in asphalt materials and pavements. The contributions cover a wide range of topics:- Environmental protection and socio-economic impacts- Additives and mo
Author: K. Anupam Publisher: CRC Press ISBN: 1000343480 Category : Juvenile Nonfiction Languages : en Pages : 501
Book Description
Inspired from the legacy of the previous four 3DFEM conferences held in Delft and Athens as well as the successful 2018 AM3P conference held in Doha, the 2020 AM3P conference continues the pavement mechanics theme including pavement models, experimental methods to estimate model parameters, and their implementation in predicting pavement performance. The AM3P conference is organized by the Standing International Advisory Committee (SIAC), at the time of this publication chaired by Professors Tom Scarpas, Eyad Masad, and Amit Bhasin. Advances in Materials and Pavement Performance Prediction II includes over 111 papers presented at the 2020 AM3P Conference. The technical topics covered include: - rigid pavements - pavement geotechnics - statistical and data tools in pavement engineering - pavement structures - asphalt mixtures - asphalt binders The book will be invaluable to academics and engineers involved or interested in pavement engineering, pavement models, experimental methods to estimate model parameters, and their implementation in predicting pavement performance.
Author: Brian K. Diefenderfer
Author: Brian K. Diefenderfer
Author: Erfan Hajibandeh
Author: Vittorio Guglielmetti
Author: National Research Council (U.S.). Transportation Research Board
Author: Wynand JvdM. Steyn
Author: United States. Federal Highway Administration. Office of Pavement Technology
Author: KM. Chua
Author: Y. Richard Kim
Author: K. Anupam