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Christopher R Williams - One of the best experts on this subject based on the ideXlab platform.
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predicting Dynamic Modulus of asphalt mixture using data obtained from indirect tension mode of testing
arXiv: Computational Engineering Finance and Science, 2019Co-Authors: Parnian Ghasemi, Shibin Lin, Derrick K Rollins, Christopher R WilliamsAbstract:Understanding stress-strain behavior of asphalt pavement under repetitive traffic loading is of critical importance to predict pavement performance and service life. For viscoelastic materials, the stress-strain relationship can be represented by the Dynamic Modulus. The Dynamic Modulus test in indirect tension mode can be used to measure the Modulus of each specific layer of asphalt pavements using representative samples. Dynamic Modulus is a function of material properties, loading, and environmental conditions. Developing predictive models for Dynamic Modulus is efficient and cost effective. This article focuses on developing an accurate Finite Element (FE) model using mixture elastic Modulus and asphalt binder properties to predict Dynamic Modulus of asphalt mix in indirect tension mode. An Artificial Neural Network (ANN) is used to back-calculate the elastic Modulus of asphalt mixtures. The developed FE model was verified against experimental results of field cores from nine different pavement sections from five districts in the State of Minnesota. It is demonstrated that the ANN modeling is a powerful tool to back-calculate the elastic Modulus and FE model is capable of accurately predicting Dynamic Modulus.
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nondestructive quality assessment of asphalt pavements based on Dynamic Modulus
Construction and Building Materials, 2016Co-Authors: Shibin Lin, Jeramy C Ashlock, Christopher R WilliamsAbstract:Abstract Dynamic Modulus has been recognized as an objective and sensitive material property for designing and evaluating pavement systems. To accurately measure the in situ elastic Modulus ( E = 2(1 + ν) ρV s 2 ) for nondestructive quality assessment of asphalt pavements, field measurements of density ( ρ ) via an electromagnetic gauge and shear-wave velocity ( V s ) via surface-wave testing were examined for four paving projects covering a range of mixes and traffic loads. A quality control/quality assurance (QC/QA) procedure was developed to correct the in situ moduli at different field temperatures to a common reference temperature using a fitting function from experimental data for QC and using master curves from laboratory Dynamic Modulus tests for QA. The corrected in situ moduli can then be compared against the maximum moduli for an assessment of the actual pavement performance.
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preliminary Dynamic Modulus criteria of hma for field rutting of asphalt pavements michigan s experience
Journal of Transportation Engineering-asce, 2011Co-Authors: Shu Wei Goh, Zhanping You, Christopher R Williams, Xinjun LiAbstract:This paper presents a comparative study of laboratory results of both Dynamic Modulus testing and field rutting performances of hot-mix asphalt (HMA) in the state of Michigan. Fourteen field-produced mixtures at various traffic levels and aggregate sizes were evaluated and compared to those of field rutting. These mixtures were collected from job sites and compacted with a Superpave gyratory compactor to imitate the common air void level used in Mich., which is 7%. Dynamic Modulus E∗ was measured at temperatures ranging from −5 to 39.2°C and frequencies ranging from 0.1 to 25 Hz. The results show that the Dynamic Modulus values increased when the designed traffic level for HMA mixtures increased. The field rutting performance was evaluated based on theoretical pavement rutting life index. Two parameters, | E∗ | and | E∗ | /sin (φ) , were compared to the theoretical pavement rutting index. Based upon the preliminary study, it was found that E∗ was a suitable parameter in comparing the field and laboratory ...
Andrew Lacroix - One of the best experts on this subject based on the ideXlab platform.
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reduced testing protocol for measuring the confined Dynamic Modulus of asphalt mixtures
Transportation Research Record, 2011Co-Authors: Andrew Lacroix, Shane B Underwood, Richard Y KimAbstract:Research project NCHRP 9-19 identifies the confined Dynamic Modulus as one of three favorable indicators for evaluating the rutting potential of a mixture. Though important, Dynamic Modulus testing at multiple confining pressures takes too long for state highway agencies to use it routinely. Therefore, several methods have been suggested to measure and predict confined Dynamic Modulus values without the need to run numerous tests. Experimental results show that the linear viscoelastic properties of an asphalt mixture are not affected by different confinements and that all confining stress effects are manifest in the elastic Modulus at equilibrium, similar to unbound granular materials. The proposed method uses a Prony series representation of the Dynamic Modulus curve and master curve shift factors obtained from unconfined testing. This method uses the elastic Modulus values predicted from a modified version of the universal material model to predict Dynamic moduli at different levels of confinement. Beyo...
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predicting the resilient Modulus of asphalt concrete from the Dynamic Modulus
Transportation Research Record, 2007Co-Authors: Andrew Lacroix, Ardalan Mosavi A Khandan, Youngsoo Richard KimAbstract:The NCHRP 1-37A Guide for Mechanistic-Empirical Design of New and Rehabilitated Design Structures introduces the Dynamic Modulus as the material property to characterize asphalt concrete. This is a significant change from the resilient Modulus used in the previous AASHTO pavement design guide. This paper presents an analytical method of calculating the resilient Modulus from the Dynamic Modulus. It involves the application of multiaxial linear viscoelastic theory to linear elastic solutions for the indirect tension test developed by Hondros. The prediction method is verified by using three 12.5-mm surface course mixtures with different aggregate shapes and binder types and one 25.0-mm base mixture. Results show that the predicted and measured resilient Modulus values are in close agreement. The results provide a forward model for the potential back-calculation of the Dynamic Modulus from resilient Modulus databases already available in highway agencies, such as the Long-Term Pavement Performance Materials...
Youngsoo Richard Kim - One of the best experts on this subject based on the ideXlab platform.
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predicting the resilient Modulus of asphalt concrete from the Dynamic Modulus
Transportation Research Record, 2007Co-Authors: Andrew Lacroix, Ardalan Mosavi A Khandan, Youngsoo Richard KimAbstract:The NCHRP 1-37A Guide for Mechanistic-Empirical Design of New and Rehabilitated Design Structures introduces the Dynamic Modulus as the material property to characterize asphalt concrete. This is a significant change from the resilient Modulus used in the previous AASHTO pavement design guide. This paper presents an analytical method of calculating the resilient Modulus from the Dynamic Modulus. It involves the application of multiaxial linear viscoelastic theory to linear elastic solutions for the indirect tension test developed by Hondros. The prediction method is verified by using three 12.5-mm surface course mixtures with different aggregate shapes and binder types and one 25.0-mm base mixture. Results show that the predicted and measured resilient Modulus values are in close agreement. The results provide a forward model for the potential back-calculation of the Dynamic Modulus from resilient Modulus databases already available in highway agencies, such as the Long-Term Pavement Performance Materials...
Meor Othman Hamzah - One of the best experts on this subject based on the ideXlab platform.
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characterization of effects of reclaimed asphalt pavement rap source and content on Dynamic Modulus of hot mix asphalt concrete
Construction and Building Materials, 2019Co-Authors: Ali Jamshidi, Greg White, Mehdi Hosseinpour, Kiyofumi Kurumisawa, Meor Othman HamzahAbstract:Abstract The effects of the reclaimed asphalt pavement (RAP) source and content on the Dynamic Modulus (E*) of hot mix asphalt concrete were characterized. Two parameters were proposed: the non-dimensional Dynamic Modulus-temperature index ( ∇ E T * ) and non-dimensional Dynamic Modulus-frequency index ( ∇ E fr * ). Parameter ∇ E fr * indicates the increase of relative E* per unit percent RAP from different sources during frequency and temperature sweeps, while ∇ E T * characterizes the reduction of relative E* per 1 °C temperature increase. An analysis of the results showed that ∇ E T * of RAP mixes were 6.80% to 12% higher than those of the control samples, indicating less temperature susceptibility. Furthermore, an analysis of ∇ E fr * trends showed temperature independency at higher temperature ranges. In addition, the results showed that the activation energy (AE) of the mixes was 1.51 MJ/mol/K to 9.86 MJ/mol/K higher than that of the control samples (without RAP), which depends on the RAP content and source. Moreover, E* linearly increases as AE increases. In conclusion, the increase of intermolecular forces owing to the higher AE in the blended binders increased the mix stiffness, which resulted in a higher E* in mixes containing RAP.
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evaluation of the Dynamic Modulus of asphalt mixture incorporating reclaimed asphalt pavement
Indian Journal of Engineering and Materials Sciences, 2013Co-Authors: Zulkurnain Shahadan, Meor Othman Hamzah, Ahmad Shukri Yahya, Ali JamshidiAbstract:This paper presents the effects of temperature and loading frequency on the Dynamic Modulus and phase angle of asphalt mixtures incorporating reclaimed asphalt pavement (RAP) using the asphalt mixture performance tester. Milling waste from Damansara-Puchong Expressway is incorporated in asphalt mixtures in proportions of 0%, 10%, 20%, 30% and 40%. The asphalt mixtures are tested for Dynamic Modulus at three temperatures (20, 40, 50°C) and six loading frequencies (0.1, 0.5, 1, 5, 10 and 25 Hz). At constant temperature, the Dynamic Modulus increased as the loading frequency and RAP content increased. For a given frequency, the Dynamic Modulus decreased while the phase angle increased as the temperature increased. From statistical analysis, test temperature and frequency have significant effects with high effect size on the measured Dynamic Modulus and phase angle. The interaction effect of frequency and RAP give the highest effect size among the interaction effects in the Dynamic Modulus test. The results also indicated that the highest performance in terms of rutting and fatigue factors can be attained when the frequency of cumulative traffic loading was from 15 to 20 Hz.;
Richard Y Kim - One of the best experts on this subject based on the ideXlab platform.
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new predictive models for the Dynamic Modulus of hot mix asphalt
Construction and Building Materials, 2015Co-Authors: Maryam S Sakhaeifar, Richard Y Kim, Pooyan KabirAbstract:Abstract This paper presents a fundamental modeling framework for prediction of Dynamic Modulus of hot mix asphalt mixtures based on viscoelastic principles. The outcomes are two closed-form models that can be used to predict the mixture Dynamic Modulus for a wide range of temperatures (−10°, 4.4°, 37.8°, and 54.4 °C) recommended in the American Association of State Highway and Transportation Officials (AASHTO) TP62-03 test protocol. To develop and verify the models a large database that covers the complete range of potential input conditions was assembled. In general, the proposed models predict the Dynamic Modulus with a very good level of accuracy.
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reduced testing protocol for measuring the confined Dynamic Modulus of asphalt mixtures
Transportation Research Record, 2011Co-Authors: Andrew Lacroix, Shane B Underwood, Richard Y KimAbstract:Research project NCHRP 9-19 identifies the confined Dynamic Modulus as one of three favorable indicators for evaluating the rutting potential of a mixture. Though important, Dynamic Modulus testing at multiple confining pressures takes too long for state highway agencies to use it routinely. Therefore, several methods have been suggested to measure and predict confined Dynamic Modulus values without the need to run numerous tests. Experimental results show that the linear viscoelastic properties of an asphalt mixture are not affected by different confinements and that all confining stress effects are manifest in the elastic Modulus at equilibrium, similar to unbound granular materials. The proposed method uses a Prony series representation of the Dynamic Modulus curve and master curve shift factors obtained from unconfined testing. This method uses the elastic Modulus values predicted from a modified version of the universal material model to predict Dynamic moduli at different levels of confinement. Beyo...
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ltpp computed parameter Dynamic Modulus
2011Co-Authors: Richard Y Kim, B Underwood, Sakhaei M Far, Newton Jackson, J PuccinelliAbstract:The Dynamic Modulus, |E*|, is a fundamental property that defines the stiffness characteristics of hot mix asphalt (HMA) mixtures as a function of loading rate and temperature. In spite of the demonstrated significance of |E*|, it is not included in the current Long-Term Pavement Performance (LTPP) materials tables because the database structure was established before |E*| was identified as the main HMA property in the Mechanistic Empirical Pavement Design Guide (MEPDG). The objective of this study was to use readily available binder, volumetric, and resilient material properties in the LTPP database to develop |E*| estimates. This report provides a thorough review of existing prediction models. In addition, several models have been developed using artificial neural networks for use in this project. This report includes assessments of each model, quality control checks applied to the data, and the final structure and format of the Dynamic Modulus data added to the LTPP database. A program was also developed to assist in populating the LTPP database, and the details of the program are provided in this report.
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application of artificial neural networks for estimating Dynamic Modulus of asphalt concrete
Transportation Research Record, 2009Co-Authors: Maryam Sadat Sakhaei Far, Shane B Underwood, Richard Y Kim, Ranji S Ranjithan, Newton JacksonAbstract:This paper presents outcomes from a research effort to develop models for estimating the Dynamic Modulus (|E*|) of hot-mix asphalt (HMA) layers on long-term pavement performance test sections. The goal of the work is the development of a new, rational, and effective set of Dynamic Modulus |E*| predictive models for HMA mixtures. These predictive models use artificial neural networks (ANNs) trained with the same set of parameters used in other popular predictive equations: the modified Witczak and Hirsch models. The main advantage of using ANNs for predicting |E*| is that an ANN can be created for different sets of variables without knowing the form of the predictive relationship a priori. The primary disadvantage of ANNs is the difficulty in predicting responses when the inputs are outside of the training database (i.e., extrapolation). To overcome this shortcoming, a large data set that covers the complete range of potential input conditions is needed. For this study, Modulus values from multiple mixtures and binders were required and were assembled from existing national efforts and from data obtained at North Carolina State University. The data consisted of measured moduli from both modified and unmodified mixtures from numerous geographical locations across the United States. Prediction models were developed by using a portion of the data from these databases and then verified by using the remaining data in the databases. When these new ANN models are used, the results show that the predicted and measured |E*| values are in close agreement.
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air void models for the Dynamic Modulus fatigue cracking and rutting of asphalt concrete
Journal of Materials in Civil Engineering, 2007Co-Authors: Youngguk Seo, Omar Elhaggan, Mark King, Joon S Lee, Richard Y KimAbstract:A laboratory study has been carried out to develop mechanical models for the Dynamic Modulus, fatigue life, and rutting performance of asphalt concrete as a function of air void content. The experimental program includes an axial compression complex Modulus test, indirect tensile (IDT) fatigue test, and triaxial repeated load permanent deformation (TRLPD) test on the two most commonly used asphalt–aggregate mixtures in North Carolina. The Dynamic moduli are determined using axial compression tests with and without confining pressure, and the results are compared to evaluate the effect of confining pressure on the Dynamic Modulus. The relationship between the Dynamic moduli that are determined from the uniaxial compression test and the air void content is developed. The growth of the tensile strain and axial permanent strain is measured from the IDT fatigue test and TRLPD test, respectively, and is used to determine the fatigue life and rutting behavior of the mixtures. The fatigue and rutting models adopt...
