Laboratory Determination of Resilient Modulus for Flexible Pavement Design

Laboratory Determination of Resilient Modulus for Flexible Pavement Design
Author:
Publisher:
Total Pages: 54
Release: 2004
Genre: Pavements
ISBN:

"This digest represents key findings from NCHRP Project 1-28A, 'Harmonized test methods for laboratory determination of resilient modulus for flexible pavement design, ' conducted by the Univerisity of Maryland-College Park. The digest is an abridgement of portions of the project final report by the princincipal investigator, Matthew W. Witczak ..."--P. [1].

Geotechnical Aspects of Pavement Engineering

Geotechnical Aspects of Pavement Engineering
Author: Nishantha Bandara
Publisher: Momentum Press
Total Pages: 102
Release: 2018-02-25
Genre: Technology & Engineering
ISBN: 1606505416

Familiarity with geotechnical aspects of pavement engineering is essential for the practicing pavement engineer. When designing pavements, accurate characterization of the existing subgrade condition becomes a crucial task. In the past, traditional geotechnical exploration and testing methods have been used to characterize existing subgrade conditions. However, with the introduction of the Mechanistic-Empirical (ME) pavement design, there is a need for improved and more appropriate methods of subgrade characterization, for prediction of future pavement conditions with better accuracy. Hence, this handbook will present a useful tool for practicing pavement engineers.

Alternative Test Method for Resilient Modulus of Fine-Grained Subgrades

Alternative Test Method for Resilient Modulus of Fine-Grained Subgrades
Author: EC. Drumm
Publisher:
Total Pages: 14
Release: 1996
Genre: Subgrades
ISBN:

The mechanistic design of flexible pavement systems requires the specification of mechanical properties for asphaltic concrete, base course, and soil subgrade. The stiffness of the soil subgrade is represented by the resilient modulus, Mr, which is determined in the laboratory from cyclic triaxial tests and is usually a function of the level of applied stress. For a typical pavement project where numerous soils are encountered, cyclic triaxial testing to determine Mr for each subgrade soil may be too complex and time consuming to be applicable on a production basis. Therefore, alternative methods for the determination or estimation of Mr are appropriate and are in fact suggested in the 1993 AASHTO Guide for Design of Pavement Structures (AASHTO Guide 1993).

Pavement Design and Materials

Pavement Design and Materials
Author: A. T. Papagiannakis
Publisher: John Wiley & Sons
Total Pages: 660
Release: 2024-05-29
Genre: Technology & Engineering
ISBN: 1394150180

Practical guide for all aspects of pavement engineering, updated with the latest techniques, standards, and software The newly revised and updated Second Edition of Pavement Design and Materials offers a comprehensive treatment of pavement materials, structural analysis, design, evaluation, and economic analysis of asphalt and portland concrete pavements. Written by two highly qualified engineering professors with a wealth of experience in the field, Pavement Design and Materials provides readers with: State-of-the-art techniques for material characterization, including a linear viscoelasticity primer Methods and software for the analysis of flexible and ridgid pavements including the AASHTOWare Pavement ME Design State-of-the-art pavement evaluation techniques including moduli backcalculation methods Pavement economic analysis techniques including the most up-to-date user cost relationships. The book companion website provides: Solved examples in each chapter and the electronic files associated with them An instructor solutions manual for the problems provided at the end of each chapter PowerPoint presentations by chapter to facilitate lecture delivery Pavement Design and Materials is an essential up-to-date textbook on the subject for upper-level undergraduate and graduate level courses on pavement materials and pavement design. It is also a valuable reference for practicing professional engineers involved in the various aspects of roadway pavement material selection and structural design.

An Improved Alternative Test Method for Resilient Modulus of Fine Grained Soils

An Improved Alternative Test Method for Resilient Modulus of Fine Grained Soils
Author:
Publisher:
Total Pages:
Release: 2003
Genre:
ISBN:

Flexible Pavement is usually composed of several asphalt concrete layers, a granular base course and a soil subgrade. For mechanistic design of pavement systems based on elastic theory a modulus of elasticity must be designated for each design layer including the soil subgrade. The resilient modulus is used to characterize the soil in pavement design. The resilient modulus is defined as [equation] Where [symbol] is the deviator stress or the difference between the axial and confining stress, and [symbol] is the recoverable axial strain. The standard procedure for obtaining [symbol] is a repeated load tri-axial test at a constant confining pressure. There is not a singular resilient modulus value for a particular soil but rather the modulus is a function of the stress state. The standard test produces a range of resilient modulus values in a series of stress conditions. The resilient modulus test is inherently complicated, time consuming, and expensive. For these reasons, most commercial and design laboratories will not conduct these tests but instead rely on empirical relationships. Therefore, it has been recommended that alternative tests be developed to approximate resilient modulus. The Alternative Test Method was developed to be a simple and effective way of determining resilient modulus. The ATM design was based on a single degree of freedom, lumped mass spring system in which a hammer of known mass falls onto a volume of soil. Originally, there appeared to be good correlation between the Alternative Test Method and the standard test method for obtaining resilient modulus. However, subsequent testing failed to produce consistent results or confirm the correlation. Improvements have been made to the ATM to improve the overall consistency of results and correlation with the standard resilient modulus test results. The improvements to the ATM device include a new, more consistent drop mechanism, better data acquisition software, and a new calculation method. ATM tests were conducted on 4 different soils from TDOT research sites. Standard tri-axial resilient modulus tests were conducted for comparison with ATM resilient modulus tests. The improved ATM appears to measure a material response that correlates reasonably well with the standard triaxial resilient modulus test results for those soils tested. Furthermore, the Improved ATM produces much more consistent results than the Original ATM. It is also believed that the limitations of the device are outweighed by its simplicity and commonality with other lab tests. Therefore, the improved Alternative Test Method for resilient modulus of fine grained soils is believed to be a viable alternative to the standard test method for obtaining resilient modulus values.