Poisson's Ratio of Asphalt Concrete Mixes Using Indirect Tensile Test

Poisson's Ratio of Asphalt Concrete Mixes Using Indirect Tensile Test
Author: Peter Lindelöf
Publisher:
Total Pages: 13
Release: 2018
Genre: Asphalt concrete
ISBN:
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Increased interest in mechanistic evaluation of flexible pavement structures has brought a demand for accurate and practical methods, models, or both to estimate the mechanical properties of asphalt concrete mixtures. One of these properties is the Poisson's ratio (?) of asphalt concrete mixtures, which is often assumed to have a constant value of 0.35 in asphalt concrete evaluations. However, investigations have reported that mixture type, air void content, and temperature produce considerable variation in measured?-values that could have a significant effect on evaluations of asphalt concrete mixes. The objective of this study was to evaluate the effect of air voids, binder type, and testing conditions on the measured?-values. Indirect tensile (IDT) tests were conducted to measure?-values. The study indicated that the Poisson's ratio of the asphalt concrete mixes, on average, attained a maximum value at a particular level of air void content. Furthermore, when comparing the Poisson's ratio values in relation to the dynamic modulus, calculated using the Mechanistic Empirical Pavement Design Guide (MEPDG) equation, higher?-values were attained. This demonstrates the importance of measuring the Poisson's ratio of a mix type.Increased interest in mechanistic evaluation of flexible pavement structures has brought a demand for accurate and practical methods, models, or both to estimate the mechanical properties of asphalt concrete mixtures. One of these properties is the Poisson's ratio (?) of asphalt concrete mixtures, which is often assumed to have a constant value of 0.35 in asphalt concrete evaluations. However, investigations have reported that mixture type, air void content, and temperature produce considerable variation in measured?-values that could have a significant effect on evaluations of asphalt concrete mixes. The objective of this study was to evaluate the effect of air voids, binder type, and testing conditions on the measured?-values. Indirect tensile (IDT) tests were conducted to measure?-values. The study indicated that the Poisson's ratio of the asphalt concrete mixes, on average, attained a maximum value at a particular level of air void content. Furthermore, when comparing the Poisson's ratio values in relation to the dynamic modulus, calculated using the Mechanistic Empirical Pavement Design Guide (MEPDG) equation, higher?-values were attained. This demonstrates the importance of measuring the Poisson's ratio of a mix type.Increased interest in mechanistic evaluation of flexible pavement structures has brought a demand for accurate and practical methods, models, or both to estimate the mechanical properties of asphalt concrete mixtures. One of these properties is the Poisson's ratio (?) of asphalt concrete mixtures, which is often assumed to have a constant value of 0.35 in asphalt concrete evaluations. However, investigations have reported that mixture type, air void content, and temperature produce considerable variation in measured?-values that could have a significant effect on evaluations of asphalt concrete mixes. The objective of this study was to evaluate the effect of air voids, binder type, and testing conditions on the measured?-values. Indirect tensile (IDT) tests were conducted to measure?-values. The study indicated that the Poisson's ratio of the asphalt concrete mixes, on average, attained a maximum value at a particular level of air void content. Furthermore, when comparing the Poisson's ratio values in relation to the dynamic modulus, calculated using the Mechanistic Empirical Pavement Design Guide (MEPDG) equation, higher?-values were attained. This demonstrates the importance of measuring the Poisson's ratio of a mix type.

Evaluation of Poisson's Ratio of Asphalt Concrete

Evaluation of Poisson's Ratio of Asphalt Concrete
Author: Elvis Alexander Castillo Camarena
Publisher:
Total Pages: 54
Release: 2016
Genre: Asphalt concrete
ISBN:
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Poisson's ratio can be defined as the negative ratio of strains perpendicular to the load direction to the strains parallel to the loading direction. If elastic or viscoelastic models are used, Poisson's ratio, together with elastic modulus, is a main input used to predict distresses in flexible pavement structures such as rutting and cracking. In asphalt concrete, Poisson's ratio is commonly measured using two different testing configurations: indirect tension (IDT) and uniaxial. However, results from these two testing configuration can potentially have differences. Design methodologies such as the Mechanistic Empirical Design Guide (MEPDG, now PavementME) have been shown to be very sensitive to variations of Poisson's ratio. The objective of this research is to determine whether or not there are significant differences between the values of Poisson's ratio measured in indirect tension configuration and uniaxial configuration. This work also aims to investigate the potential variations of values of Poisson's ratio among a number of asphalt mixture treated with different types of asphalt modifiers: poplyphosphoric acid (PPA) alone and in combination with liquid anti-stripping agent (LAA). Cylindrical shaped samples specified in AASHTO T 342 were used to measure Poisson's ratio in uniaxial configuration, and disc shaped samples specified in AASHTO T 322 were used to measure Poisson's ratio in an IDT configuration. Samples were tested at each combination at the following temperatures, -10 °C, 4 °C, 21 °C, 37 °C, and 54 °C, and frequencies, 25 Hz, 10 Hz, 5 Hz, 1 Hz, 0.5 Hz, and 0.1 Hz. No statistical difference was found in values of Poisson's ratio measured within each testing configuration. IDT Poisson's ratio were significantly different to those of uniaxial configuration (3:1). This reduction of Poisson's ratio by about 60% could lead to an increment of predicted distresses, such as longitudinal cracking, using PavementME by more than 400% of its design limit.

Guidelines for Implementing NCHRP 1-37A M-E Design Procedures: Literature review

Guidelines for Implementing NCHRP 1-37A M-E Design Procedures: Literature review
Author:
Publisher:
Total Pages: 126
Release: 2009
Genre: Pavements
ISBN:
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Highway agencies across the nation are moving towards implementation of the new AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) for pavement design. The benefits of implementing the MEPDG for routine use in Ohio includes (1) achieving more cost effective and reliable pavement designs, (2) lower initial and life cycle costs to the agency, and (3) reduced highway user impact due to lane closures for maintenance and rehabilitation of pavements. Implementation of the MEPDG is a process that requires time and agency resources (staffing, training, testing facilities including equipment, and so on). A key requirement is validating the MEPDG's nationally calibrated pavement distress and smoothness prediction models when applied under Ohio conditions and performing local calibration if needed. Feasibility of using the MEPDG's national models in Ohio was investigated under this study using data from a limited number of LTPP projects located in Ohio. Results based on limited data showed inadequate goodness of fit and significant bias in a number of the MEPDG new HMA pavement and JPCP performance prediction models. Limited recalibration of these models showed promising results indicating that a full-scale recalibration effort using a more extensive database assembled from projects located throughout the state is feasible.

Guide for the Local Calibration of the Mechanistic-empirical Pavement Design Guide

Guide for the Local Calibration of the Mechanistic-empirical Pavement Design Guide
Author:
Publisher: AASHTO
Total Pages: 202
Release: 2010
Genre: Technology & Engineering
ISBN: 1560514493
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This guide provides guidance to calibrate the Mechanistic-Empirical Pavement Design Guide (MEPDG) software to local conditions, policies, and materials. It provides the highway community with a state-of-the-practice tool for the design of new and rehabilitated pavement structures, based on mechanistic-empirical (M-E) principles. The design procedure calculates pavement responses (stresses, strains, and deflections) and uses those responses to compute incremental damage over time. The procedure empirically relates the cumulative damage to observed pavement distresses.

Consideration of Preservation in Pavement Design and Analysis Procedures

Consideration of Preservation in Pavement Design and Analysis Procedures
Author:
Publisher:
Total Pages: 72
Release: 2015
Genre: Pavements
ISBN: 9780309308823
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"TRB's National Cooperative Highway Research Program (NCHRP) Report 810: Consideration of Preservation in Pavement Design and Analysis Procedures explores the effects of preservation on pavement performance and service life and describes three different approaches for considering these effects in pavement design and analysis procedures. The report may serve as a basis for developing procedures for incorporating preservation in the American Association of State Highway and Transportation Officials (AASHTO) Mechanistic-Empirical Pavement Design Guide: A Manual of Practice (MEPDG) and the AASHTOWare Pavement ME Design software. Initially, the scope of this project intended to develop procedures for incorporating pavement preservation treatments into the MEPDG design analysis process that would become part of the MEPDG Manual of Practice. However, it was determined that sufficient data were not available to support the development of such procedures. Appendices A through I are available online only." --

Review of the New Mechanistic-empirical Pavement Design Guide - a Material Characterization Perspective

Review of the New Mechanistic-empirical Pavement Design Guide - a Material Characterization Perspective
Author:
Publisher:
Total Pages: 19
Release: 2005
Genre:
ISBN:
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Characterization of pavement materials in the three hierarchical design levels of the proposed mechanistic-empirical pavement design (MEPD) guide involves application of the dynamic modulus technique for asphalt concrete and the resilient modulus for unbound materials. This approach, if adequately implemented, is expected to improve the road design processes. The advance design level recommends using actual laboratory test data of the dynamic and resilient modulus determined under simulated environmental and traffic loading conditions. To circumvent the need for conducting the mechanical test in lower design levels, predictive equations and correlations established with physical properties are used to estimate the mechanistic properties needed as input to the design software. This paper examines the simplifications incorporated in the model using results of dynamic and resilient modulus tests performed at the National Research Council Canada (NRC). For the covering abstract of this conference see ITRD number E211426.