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Der-hsien Shen - One of the best experts on this subject based on the ideXlab platform.

  • EVALUATION OF BUILDING MATERIALS RECYCLING ON HMA Permanent Deformation
    Construction and Building Materials, 2004
    Co-Authors: Der-hsien Shen, Jia-chong Du
    Abstract:

    Abstract Reclaimed building materials (RBM) for recycling are examined on hot mix asphalt (HMA) Permanent Deformation performance. Four types of aggregates used for mixtures are: (a) 100% river crush stone (CS); (b) 100% RBM; (c) 50% coarse and fine RBM plus 50% coarse and fine CS (50% RBM plus 50% CS); and (d) coarse RBM plus fine CS (C-RBM plus F-CS). Two types of asphalt cement AC-10 and AC-20 are used as a binder for mixtures. The test results indicate 50% RBM plus 50% CS mixed with AC-10 or AC-20 has the lowest wheel path Deformation at 25 °C, but the highest Permanent Deformation at 60 °C. Concerning the Permanent Deformation, 100% RBM and C-RBM plus F-CS mixed are better than 100% river crush stone mixtures. The analysis of variance of Permanent Deformation shows that the types of aggregate have a significant effect, no matter what test temperatures and binders are used. The asphalt cement either AC-10 or AC-20 does not significantly affect the Permanent Deformation performance.

  • evaluation of building materials recycling on hma Permanent Deformation
    Construction and Building Materials, 2004
    Co-Authors: Der-hsien Shen
    Abstract:

    Reclaimed building materials (RBM) for recycling are examined on hot mix asphalt (HMA) Permanent Deformation performance. Four types of aggregates used for mixtures are: (a) 100% river crush stone (CS); (b) 100% RBM; (c) 50% coarse and fine RBM plus 50% coarse and fine CS (50% RBM plus 50% CS); and (d) coarse RBM plus fine CS (C-RBM plus F-CS). Two types of asphalt cement AC-10 and AC-20 are used as a binder for mixtures. The test results indicate 50% RBM plus 50% CS mixed with AC-10 or AC-20 has the lowest wheel path Deformation at 25 epartmentC, but the highest Permanent Deformation at 60 degrees C. Concerning the Permanent Deformation, 100% RBM and C-RBM plus F-CS mixed are better than 100% river crush stone mixtures. The analysis of variance of Permanent Deformation shows that the types of aggregate have a significant effect, no matter what test temperatures and binders are used. The asphalt cement either AC-10 or AC-20 does not significantly affect the Permanent Deformation performance. (A) "Reprinted with permission from Elsevier".

Tom Scullion - One of the best experts on this subject based on the ideXlab platform.

  • hot mix asphalt Permanent Deformation evaluated by hamburg wheel tracking dynamic modulus and repeated load tests
    Transportation Research Record, 2012
    Co-Authors: Lubinda F Walubita, Jun Zhang, Allex E Alvarez, Xiaodi Hu, Charles Mushota, Tom Scullion
    Abstract:

    Permanent Deformation (or rutting) is a common distress in hot-mix asphalt (HMA) pavements. As part of the HMA mix and structural design processes to optimize field performance, the Hamburg wheel-tracking, dynamic modulus, and uniaxial repeated load Permanent Deformation tests have been developed to characterize the HMA rutting resistance potential. The primary objective of this study was to compare the three laboratory rutting tests of HMA mixes and to relate their rutting predictive potential to actual field performance. The research methodology incorporated a two-phase approach: laboratory testing and field performance monitoring of selected mixes under both conventional traffic loading and accelerated pavement testing. For the HMA mixes evaluated, a good correlation was observed in the three laboratory tests and in comparison with actual in situ field performance. Overall, the findings indicated that the Hamburg wheel-tracking test was the most feasible test for daily routine HMA mix design and screen...

  • verification and modeling of three stage Permanent Deformation behavior of asphalt mixes
    Journal of Transportation Engineering-asce, 2004
    Co-Authors: Fujie Zhou, Tom Scullion, Lijun Sun
    Abstract:

    In laboratory testing of asphalt mixtures, the relationship between the number of load repetitions and Permanent Deformation has been found to include three distinct stages, namely the primary, secondary and tertiary stages. Similar Permanent Deformation behavior has also been observed in the field accelerated pavement testing data. It is argued that the three-stage Permanent Deformation behavior is a basic material property and to comprehensively model asphalt layer behavior, it is necessary to develop a model that accurately characterizes this behavior. In this paper, each of the well-known models critically reviewed appears that they are limited to characterizing only the primary stage. Therefore, a new three-stage model is proposed to describe all three stages. Moreover, an algorithm is established to determine the model parameters from typical laboratory data. The algorithm can also be used to identify the transition point between stages, such as flow number. The proposed model and algorithm are demonstrated through laboratory test results. The analysis results match the field performance.

  • preliminary field validation of simple performance tests for Permanent Deformation case study
    Transportation Research Record, 2003
    Co-Authors: Fujie Zhou, Tom Scullion
    Abstract:

    Simple performance tests (SPTs) to be used with the Superpave® volumetric mixture design procedure were recently recommended by NCHRP Project 9-19 (Simple Performance Test for Superpave Mix Design). Field validation of the SPTs is critical to their final acceptance and implementation in Superpave mixture design practice. Special Pavement Studies-1 (SPS-1) prematurely rutted sections on US-281 in Texas were used to validate the SPTs for Permanent Deformation, including the dynamic modulus test and repeated-load test and associated rutting indicators E*/sin δ and flow number (Fn), respectively. The results of this case study clearly show that both the dynamic modulus test and E*/sin δ and the repeated-load test and Fn can effectively distinguish the good mixtures from the bad. Compared with E*/sin δ, Fn can better differentiate the performance of asphalt mixtures. These results preliminarily validated both SPTs for Permanent Deformation. In addition, the location of the tertiary point in the plot of permane...

Dallas N Little - One of the best experts on this subject based on the ideXlab platform.

  • a modified viscoplastic model to predict the Permanent Deformation of asphaltic materials under cyclic compression loading at high temperatures
    International Journal of Plasticity, 2012
    Co-Authors: Masoud K Darabi, Rashid Abu K Alrub, Eyad Masad, Chienwei Huang, Dallas N Little
    Abstract:

    When subjected to cyclic creep (ratcheting) loading with rest periods between the loading cycles, the viscoplastic behavior of asphaltic materials changes such the rate of accumulation of the viscoplastic strain at the beginning of the subsequent loading cycle increases comparing to that at the end of the preceding loading cycle. This phenomenon is referred to as the hardening-relaxation (or viscoplastic-softening) and is a key element in predicting the Permanent Deformation (rutting) of asphalt pavements which is one of the most important distresses in asphalt pavements. This paper presents a phenomenological-based rate-dependent hardening-relaxation model to significantly enhance the prediction of the Permanent Deformation in asphaltic materials subjected to cyclic-compression loadings at high temperatures. A hardening-relaxation memory surface is defined in the viscoplastic strain space as the general condition for the initiation and evolution of the hardening-relaxation (or viscoplastic-softening). The memory surface is formulated to be a function of an internal state variable memorizing the maximum viscoplastic strain for which the softening has been occurred during the Deformation history. The evolution function for the hardening-relaxation model is then defined as a function of the hardening-relaxation internal state variable. The proposed viscoplastic-softening model is coupled to the nonlinear Schapery’s viscoelastic and Perzyna’s viscoplastic models. The numerical algorithms for the proposed model are implemented in the well-known finite element code Abaqus via the user material subroutine UMAT. The model is then calibrated and verified by comparing the model predictions and experimental data that includes cyclic creep-recovery loadings at different stress levels, loading times, rest periods, and confinement levels. Model predictions show that the proposed approach provides a promising tool for constitutive modeling of cyclic hardening-relaxation in asphaltic materials and in general in time- and rate-dependent materials.

  • three dimensional simulations of asphalt pavement Permanent Deformation using a nonlinear viscoelastic and viscoplastic model
    Journal of Materials in Civil Engineering, 2011
    Co-Authors: Chienwei Huang, Eyad Masad, Rashid Abu K Alrub, Dallas N Little
    Abstract:

    The writers recently developed a nonlinear viscoelastic-viscoplastic constitutive model, in order to represent the response of asphalt mixtures under different temperatures and rates of loading. This model has been implemented in the finite-element (FE) code Abaqus via the user material subroutine UMAT, and it was verified through comparisons with experimental data of asphalt mixtures at various stress levels and temperatures. This research develops a three-dimensional FE model using Abaqus to represent a three-layer pavement structure and to simulate the viscoelastic and viscoplastic responses under repeated loading at different temperatures. The results demonstrate the capability of the model in simulating the influence of temperature on Permanent Deformation and in predicting viscoelastic and viscoplastic strain distributions in the asphalt layer. The simulations show that tensile viscoplastic strain accumulates at the pavement surface, a phenomenon that could be associated with cracking of asphalt pavements. In addition, the results show that at high pavement temperature (40°C), tensile viscoplastic strain develops at the sides of the applied load due to asphalt mixture heave associated with Permanent Deformation and dilation.

  • characterization of asphalt binder resistance to Permanent Deformation based on nonlinear viscoelastic analysis of multiple stress creep recovery mscr test
    Journal of the Association of Asphalt Paving Technologists, 2009
    Co-Authors: Eyad Masad, Chienwei Huang, John Dangelo, Dallas N Little
    Abstract:

    This paper describes how the multiple stress creep recovery (MSCR) test has been developed and how it was used recently to characterize the resistance of asphalt binders to Permanent Deformation. In this test, an asphalt binder is subjected to creep loading using different stress levels with recovery periods between stresses. The current analysis method of the MSCR test uses the strain accumulated at the end of the test to derive an index describing the resistance of asphalt binders to Permanent Deformation. However, the limitation of this analysis method is that the accumulated strain does not necessarily consist of only Permanent strain but it can also include viscoelastic strain that might not fully recover given the limited recovery time used in the test. The viscoelastic strain would fully recover provided that enough time is allowed for this to happen. This paper presents a Plasto-Viscoelastic approach to analyze the MSCR test results. The approach relies on identifying the viscoelastic response (recoverable with time) and the actual Permanent strain (irrecoverable). A nonlinear viscoelasticity theory is employed in this approach to analyze the recoverable response. The Permanent strain is used to develop an index by which to evaluate the resistance of asphalt binders to Permanent Deformation. The new analysis approach is corroborated by analyzing asphalt binders that have been used as part of the Accelerated Loading Facility (ALF) experiment of the Federal Highway Administration (FHWA). The new Permanent Deformation index shows excellent correlation with the performance of the ALF sections.

  • numerical and graphical method to assess Permanent Deformation potential for repeated compressive loading of asphalt mixtures
    Transportation Research Record, 2000
    Co-Authors: Rajesh K Bhairampally, Robert L Lytton, Dallas N Little
    Abstract:

    Repeated-load Permanent Deformation testing has long been a popular way to characterize the performance of asphalt mixtures and to account for damage that leads to rutting. A number of empirical models have been used to fit repeated-load Permanent Deformation data. One such model, developed by Tseng and Lytton in 1989, fits Permanent Deformation data of most asphalt mixtures well. However, some mixtures exhibit a rate of damage that is in excess of that predicted by the 1989 Tseng and Lytton model. A numerical adaptation of the Tseng and Lytton empirical model is presented that readily characterizes such damage-susceptible mixtures. The excessive rate of damage is explained and reconciled in terms of plastic work theory and dissipated strain energy. The numerical approach is used to demonstrate the corrective effects of two types of additives to the mixtures: a recycled coproduct and hydrated lime.

Mohamed Rehan Karim - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of Permanent Deformation of CRM-Reinforced SMA and Its Correlation with Dynamic Stiffness and Dynamic Creep
    2020
    Co-Authors: Nuha Salim Mashaan, Mohamed Rehan Karim
    Abstract:

    Today, rapid economic and industrial growth generates increasing amounts of waste materials such as waste tyre rubber. Attempts to inspire a green technology which is more environmentally friendly that can produce economic value are a major consideration in the utilization of waste materials. The aim of this study is to evaluate the effect of waste tyre rubber (crumb rubber modifier (CRM)), in stone mastic asphalt (SMA 20) performance. The virgin bitumen (80/100) penetration grade was used, modified with crumb rubber at four different modification levels, namely, 6%, 12%, 16%, and 20% by weight of the bitumen. The testing undertaken on the asphalt mix comprises the indirect tensile (dynamic stiffness), dynamic creep, and wheel tracking tests. By the experimentation, the appropriate amount of CRM was found to be 16% by weight of bitumen. The results show that the addition of CRM into the mixture has an obvious significant effect on the performance properties of SMA which could improve the mixture's resistance against Permanent Deformation. Further, higher correlation coefficient was obtained between the rut depth and Permanent strain as compared to resilient modulus; thus dynamic creep test might be a more reliable test in evaluating the rut resistance of asphalt mixture

  • evaluation of Permanent Deformation characteristics of unmodified and polyethylene terephthalate modified asphalt mixtures using dynamic creep test
    Materials & Design, 2014
    Co-Authors: Taher Baghaee Moghaddam, Mehrtash Soltani, Mohamed Rehan Karim
    Abstract:

    One of the major types of plastics that can be found in Municipal Solid Waste (MSW) is Polyethylene Terephthalate (PET) which is a non-biodegradable semi-crystalline thermoplastic polymer, and is considered as polyester material. Generating large amount of waste PET, mainly as bottles, would cause environmental hazards by disposing in landfills. This paper aims to evaluate effects of utilizing waste PET flakes as modifier in asphalt mixture as an alternative solution to overcome the potential risks arise from producing large amount of waste PET as well as evaluating the Deformation characteristics of unmodified and PET modified asphalt mixtures. To achieve this aim, different percentages of PET were designated for this investigation, namely: 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1% by weight of aggregate particles, and dynamic creep test was performed at different stress levels (300 kPa and 400 kPa) and temperatures (10 C, 25 C and 40 C). Consequently, Zhou three-stage model was developed. The results showed that Permanent Deformation characteristics of asphalt mixture were considerably improved by utilization of PET modification, when the Permanent strain was remarkably decreased in PET modified mixture compared to the conventional mixture at all stress levels and temperatures. Besides, based on Zhou model, it was concluded that elastic and visco-elastic properties of asphalt mixture were improved by application of PET modification.

Mohammad Molayem - One of the best experts on this subject based on the ideXlab platform.

  • evaluation the effects of nanoclay on Permanent Deformation behavior of stone mastic asphalt mixtures
    Construction and Building Materials, 2017
    Co-Authors: Mahmoud Ameri, Reza Mohammadi, Mostafa Vamegh, Mohammad Molayem
    Abstract:

    Abstract In stone mastic asphalt (SMA) mixtures the binder phase has an important role in the integrity of the mixture and should withstand the applied shear forces. Due to platy structure of nanoclay particles and having a large length over width ratio, they have considerable effects in enhancing properties of bitumens. In this paper the effects of nanoclay on high temperature properties of two distinct categories of SMA mixtures namely those with fibers and polymers have been investigated. A 60/70 pen grade neat bitumen, limestone aggregates, cellulose fibers and Styrene Butadiene Styrene (SBS) polymer alongside different dosages of montmorillonite nanoclay particles in the range of 1–4 percent by the weight of bitumen were used. Performance characteristics of different asphalt materials were evaluated in terms of the storage stability of modified asphalt binders as well as Marshall stability and flow, creep properties and rutting resistance of SMA mixtures having different amounts of nanoclay particles. Results revealed that the nanoclay polymer asphalt binders have higher storage stability as well as better performance characteristics. SMA mixtures with polymer modified asphalt binder have better Permanent Deformation characteristics (higher rutting resistance). Moreover, the SMA mixture containing 3% of nanoclay has the highest rutting resistance.