Effects of moisture on warm mix asphalt containing Sasobit

, Article Scientia Iranica ; Volume 24, Issue 4 , 2017 , Pages 1866-1873 ; 10263098 (ISSN) Nabizadeh, H ; Naderi, B ; Tabatabaee, N ; Sharif University of Technology

Sharif University of Technology 2017

Abstract

The asphalt industry has been at the forefront of sustainable development. Warm Mix Asphalt (WMA) has been developed to cope with issues such as high energy prices and air pollution. These mixes require less energy and generate fewer pollutants during production in comparison with conventional Hot Mix Asphalt (HMA). Although a promising technology, the durability of WMA is not clear because long-term WMA field performance data is limited. This study investigated the susceptibility of Sasobit-modified WMA to moisture, since moisture damage is a major cause of premature pavement failure in asphalt concrete. To this end, WMA samples were made using different concentrations of Sasobit and the...

Wigner function formalism and the evolution of thermodynamic quantities in an expanding magnetized plasma

, Article Physical Review D ; Volume 101, Issue 7 , 2020 Tabatabaee, S. M. A ; Sadooghi, N ; Sharif University of Technology

American Physical Society 2020

Abstract

By combining the Wigner function formalism of relativistic quantum kinetic theory with fundamental equations of relativistic magnetohydrodynamics (MHD), we present a novel approach to determine the proper time evolution of the temperature and other thermodynamic quantities in a uniformly expanding hot, magnetized, and weakly interacting plasma. The aim is to study the contribution of quantum corrections to this evolution. We first determine the corresponding Wigner function in terms of the solution of the Dirac equation in the presence of a constant magnetic field. Using this function, we then compute the energy-momentum tensor of the above-mentioned plasma, which eventually yields its...

Aging characteristics of neat and modified asphalt binders based on rheological evaluations at intermediate temperatures

, Article Construction and Building Materials ; Volume 322 , 2022 ; 09500618 (ISSN) Farrokhzade, F ; Sabouri, M ; Tabatabaee, N ; Sharif University of Technology

Elsevier Ltd 2022

Abstract

This study examined the aging of neat and modified binders at intermediate temperatures. The neat binder was modified using two crumb rubber (CR) and styrene–butadiene–styrene (SBS) contents. The linear and non-linear rheological test results and parameters exhibited different aging susceptibilities for each binder. A new aging/cracking parameter is introduced based on the Christen-Anderson model. The limiting values are defined to assess cracking potential after PAV aging. The SBS binders were highly sensitive to aging, but the addition of sulfur noticeably improved their rheological and cracking properties and aging resistance. Among the studied parameters, four were deemed suitable to...

Experimental and numerical investigation of low-temperature performance of modified asphalt binders and mixtures

, Article Road Materials and Pavement Design ; 2016 , Pages 1-22 ; 14680629 (ISSN) Jahanbakhsh, H ; Karimi, M. M ; Tabatabaee, N ; Sharif University of Technology

Taylor and Francis Ltd 2016

Abstract

Thermal cracking is the prevalent type of distress experienced by asphalt pavements in cold regions. It is widely assumed that when thermal stresses induced in the pavement exceed the tensile strength of the asphalt surface layer, cracking occurs; however, the role of thermal fatigue should not be ignored. To better describe the low-temperature (LT) performance properties of modified asphalt binders, a new parameter, normalised tensile stress (NTS), was defined in this research. NTS values were compared with bending beam rheometer (BBR), direct tension (DT) and semi-circular bending (SCB) fracture test results. The m-value parameter of the BBR test specifies the type of asphalt binder. This...

Experimental and numerical investigation of low-temperature performance of modified asphalt binders and mixtures

, Article Road Materials and Pavement Design ; Volume 18, Issue 6 , 2017 , Pages 1353-1374 ; 14680629 (ISSN) Jahanbakhsh, H ; Karimi, M. M ; Tabatabaee, N ; Sharif University of Technology

2017

Abstract

Thermal cracking is the prevalent type of distress experienced by asphalt pavements in cold regions. It is widely assumed that when thermal stresses induced in the pavement exceed the tensile strength of the asphalt surface layer, cracking occurs; however, the role of thermal fatigue should not be ignored. To better describe the low-temperature (LT) performance properties of modified asphalt binders, a new parameter, normalised tensile stress (NTS), was defined in this research. NTS values were compared with bending beam rheometer (BBR), direct tension (DT) and semi-circular bending (SCB) fracture test results. The m-value parameter of the BBR test specifies the type of asphalt binder. This...

Relaxation of hardening in asphalt concrete under cyclic compression loading

, Article Journal of Materials in Civil Engineering ; Volume 29, Issue 5 , 2017 ; 08991561 (ISSN) Jahangiri, B ; Karimi, M. M ; Tabatabaee, N ; Sharif University of Technology

American Society of Civil Engineers (ASCE) 2017

Abstract

The present experimental study investigated the behavior of hot-mix asphalt (HMA) under repetitive creep and recovery loading. Cylindrical samples of HMA were subjected to trapezoidal and haversine loading followed by unloading. Different amounts of unloading (stress reduction) and relaxation periods (rest periods in complete unloading) were tested. The measured vertical deformation was decomposed into viscoelastic and viscoplastic components. It was observed for cyclic loading that an increase in unloading and/or relaxation period increased the recovery of viscoelastic strain, which in turn increased the accumulated viscoplastic strain in subsequent loading cycles. It appears that...

A comparative evaluation of crumb rubber and devulcanized rubber modified binders

, Article Petroleum Science and Technology ; Volume 35, Issue 11 , 2017 , Pages 1091-1096 ; 10916466 (ISSN) Ghasemirad, A ; Asgharzadeh, S. M ; Tabatabaee, N ; Sharif University of Technology

Taylor and Francis Inc 2017

Abstract

One of the most prominent uses of ground tire rubber (GTR) is in rubber-modified asphalt industry. Besides improving performance properties of binders, GTR induces some drawbacks like weak storage stability and inferior low temperature (LT) performance. This study sought to rectify these shortcomings through using devulcanized rubber (DVR) in place of common GTR. Binder performance grading, multiple stress creep and recovery, and storage stability tests were conducted. More resistance against traffic loads at high temperatures was observed as DVR's advantages over GTR, while its weaker LT characteristics and lower storage stability can prevent it from being a viable alternative. © 2017...

Development of a computer program for calculation of the alpha parameter in the linear amplitude sweep test and comparison with rheological parameters

, Article Transportation Research Record ; Volume 2674, Issue 7 , 2020 , Pages 284-298 Abdollahi, S. F ; Farrokhi, M ; Tabatabaee, N ; Sharif University of Technology

SAGE Publications Ltd 2020

Abstract

Characterizing and modeling the fatigue performance of an asphalt binder is important when designing asphalt mixtures which can resist premature fatigue failure. Performance grading (PG) standards include the fatigue factor (G*.sinδ) to evaluate the fatigue resistance of asphalt binders. This criterion seems to be inaccurate, especially when applied to modified asphalt binders. American Association of State Highway and Transportation Officials (AASHTO) TP 101 has been designed to evaluate the fatigue resistance of asphalt binders using Schapery’s work potential theory. The damage evolution rate (α parameter) is the key element of this method and is calculated from the rheological properties...

The effect of gypsum cementation on the mechanical behavior of gravely sands

, Article Geotechnical Testing Journal ; Volume 28, Issue 4 , 2005 , Pages 380-390 ; 01496115 (ISSN) Haeri, S. M ; Hamidi, A ; Tabatabaee, N ; Sharif University of Technology

2005

Abstract

The behavior of a cemented gravely sand is studied using triaxial tests. Drained and undrained tests were performed on dry and saturated specimens, and stress-strain characteristics of the soil, along with volumetric and pore pressure changes, were identified. The gypsum plaster was used as the cement agent and was mixed with the soil in different percentages. The tests were done in the usual range of confining pressures, from 25 to 500 kPa. Test results show that dilation occurs even at the highest confining stress and the least cement content. The behavior of the cemented soil is found to be more brittle in drained condition than the undrained one. However, the brittleness of soil...

Microstructure-based visco-elastoplastic continuum model of asphalt concrete

, Article RILEM Bookseries ; Volume 11 , 2016 , Pages 37-48 ; 22110844 (ISSN) Zahabi, M. H ; Karimi, M. M ; Tabatabaee, N ; Sharif University of Technology

Kluwer Academic Publishers 2016

Abstract

Asphalt concrete is a heterogeneous and multi-phase material that consists of aggregates, asphalt binder, and pores. These components create a complex microstructure. There is no consensus on how to quantify the microstructure and the required parameters from two-dimensional images. The load transfer can be managed by aggregate-aggregate or aggregate-mastic interactions that depend on the gradation, aggregate internal structure, and asphalt binder viscoelastic properties. The most important internal structure indices affecting the behavior of HMA are aggregate orientation, contact orientation, contact length, and number of contact points. In this paper, the influence of aggregate structure...

Network-level pavement roughness prediction model for rehabilitation recommendations

, Article Transportation Research Record ; Issue 2155 , 2010 , Pages 124-133 ; 03611981 (ISSN) Kargah Ostadi, N ; Stoffels, S. M ; Tabatabaee, N ; Sharif University of Technology

2010

Abstract

Pavement performance models are key components of any pavement management system (PMS). These models are used in a network-level PMS to predict future performance of a pavement section and identify the maintenance and rehabilitation needs. They are also used to estimate the network conditions after the application of various maintenance and rehabilitation alternatives and to determine the relative cost effectiveness of each maintenance and rehabilitation alternative. Change in pavement surface roughness over time is one of the most important performance indicators in this regard. A model for changes in the international roughness index (IRI) over time was developed through artificial neural...

A thermodynamic-based large deformation viscoplastic constitutive relationship for asphalt concrete compaction

, Article International Journal of Solids and Structures ; Volume 165 , 2019 , Pages 192-216 ; 00207683 (ISSN) Karimi, M. M ; Darabi, M. K ; Tabatabaee, N ; Sharif University of Technology

Elsevier Ltd 2019

Abstract

This research proposes a large deformation, time-dependent viscoplastic constitutive relationship to enhance the prediction of the compaction degree of asphalt concrete materials under laboratory and field conditions. A large-deformation thermodynamic-based framework is presented. The Helmholtz free energy and rate of energy dissipation functions were assumed to derive rate-dependent constitutive relationships to relate multi-axial state of stresses to the recoverable and non-recoverable deformation response of asphalt concrete during compaction. A straightforward method that allows the calibration of the proposed model against laboratory compaction data (e.g., data from Superpave Gyratory...

Local calibration of the Hirsch model to determine the degree of blending between aged and virgin asphalt binders

, Article Road Materials and Pavement Design ; Volume 23, Issue 9 , 2022 , Pages 2132-2150 ; 14680629 (ISSN) Zokaei Ashtiani, M ; Mogawer, W. S ; Tabatabaee, N ; Sharif University of Technology

Taylor and Francis Ltd 2022

Abstract

Aged asphalt binder in reclaimed asphalt pavement (RAP) or recycled asphalt shingles (RAS) blends only partially with the virgin binder. To better understand this state of blending, the asphalt mixtures in this study were designed, mixed, and compacted using different RAP and RAS contents. The asphalt binders were extracted and recovered from RAP and RAS and then blended with different proportions of a virgin binder. The master curves for the asphalt mixtures and asphalt binder blends were then constructed from the measured data. A locally calibrated Hirsch model was developed to estimate master curves for the asphalt mixtures from the corresponding binder-blend data. Pairwise comparison of...

Performance and Rheological Characteristics of Modified Binders

, M.Sc. Thesis Sharif University of Technology Tabatabaee, Hassan Ali (Author) ; Tabatabaee, Nader (Supervisor)

Abstract

The ever increasing usage of modified binders in road construction requires that the effect of different modifiers on the performance characteristics of the asphalt binder be determined through laboratory testing. The current Superpave protocol for performance grading asphalt binders has proven to be insufficient to properly characterize modified binders, thus researchers have searched for other testing methods to complement or possibly replace some of the Superpave tests. Most notable are the time sweep test for fatigue resistance, the multiple stress creep and recovery test (MSCR) for rutting resistance and the direct tension test (DTT) for low temperature cracking characteristics. In the...

Cracking performance of rubberized RAP mixtures with Sasobit

, Article Construction and Building Materials ; Volume 319 , 2022 ; 09500618 (ISSN) Abdollahi, S. F ; Karimi, M. M ; Jahanbakhsh, H ; Tabatabaee, N ; Sharif University of Technology

Elsevier Ltd 2022

Abstract

Incorporation of reclaimed asphalt pavement (RAP) and crumb rubber (CR) materials into asphalt mixtures have been of great importance from sustainability point of view. Although, inclusion of RAP materials in asphalt mixtures improves the rutting resistance at high temperature, the low temperature (LT) and intermediate temperature (IT) cracking performance of RAP mixtures may need additional considerations. In this regard, different schemes of modification have been applied to RAP mixtures to address its performance weaknesses. This study evaluated the effect of RAP and CR in combination with Sasobit and hydrated lime on the cracking performance of asphalt mixtures. The LT and IT...

An Investigative Study on Iranian Bitumens Compatibility with SHRP Performance Grading System, and Production of the Needed Grades

, Ph.D. Dissertation Sharif University of Technology Aflaki, Sasan (Author) ; Tabatabaee, Nader (Supervisor)

Abstract

This investigative study intends to identify and characterize bitumen from seven Iranian bitumen production plants according to the Superpave Performance Grading (PG) system, conventional classic tests, and chemical separation tests. The study then compares the identified performance grades with the thirteen performance-grade binders required for specific climatic zones in Iran. It is observed that the variety of available binders is not adequate to fully cover the required PGs. Blending was initially considered as a suitable and economic method for production of the missing performance grades. However due to similar rheological properties of bitumen samples, resulting in nearly identical...

Evaluation of Rutting Resistance of Modified Asphalt Mixtures

, M.Sc. Thesis Sharif University of Technology Teymourpour, Pouya (Author) ; Tabatabaee, Nader (Supervisor)

Abstract

Rutting is a primary cause of premature deterioration of asphalt pavements and modifying asphalt binders is a common way to improve binder characteristics and field performance. Two types of parameters are used to characterize asphalt rutting. One type includes binder parameters such as zero-shear viscosity and the Superpave rutting resistance index (G*/sinδ) derived from oscillatory loading tests such as the dynamic shear rheometer. The other type is derived from static and repeated loading creep tests on mixtures and binders. Researchers have pointed out that these parameters can rank modified binder and mixture rut susceptibility differently. In this study the rutting resistance of...

Rheological Evaluation of Ageing Properties of Modified Bitumens

, M.Sc. Thesis Sharif University of Technology Naderi, Koorosh (Author) ; Tabatabaee, Nader (Supervisor)

Abstract

Bitumen ageing is one of the principal factors causing the deterioration of asphalt pavements. Ageing is a complex process that is affected by different parameters.With the rapid growth of modified binders in road paving applications over the past twodecades, it is important to study the ageing properties of these binders. A number of laboratory methods are used tosimulatethe bitumenageing at various stages of the production and service of hot mix asphalt.Recent studies have shown that Superpave testing protocol does not fully address the ageing of modified binders. To study the ageing properties of modified binders, three different types of binder modifiers, plastomer, elastomer, and ground...

Evaluation of Warm Mix Asphalt containing Sasobit

, M.Sc. Thesis Sharif University of Technology Naderi, Behzad (Author) ; Tabatabaee, Nader (Supervisor)

Abstract

Warm mix asphalt has received considerable attention over the past decade particularly due to its potential environmental benefit such as lower energy consumption and emission, its ability to be placed at lower ambient temperatures making it a suitable material for areas with short construction season. There are three warm mix asphalt (WMA) techniques are available; organic additive, foaming, and chemical additive. This study examined Sasobit, a micro crystalline wax which is an organic additive. The concentrations tested were 1.5, 2.5 and 3.5 percent of the base binder. A PG 64-22 asphalt binder from an Iranian refinery (Tehran refinery) was used as the base binder. Superpave binder...

Modeling of Moisture-Induced Damage in Asphalt Mixtures

, M.Sc. Thesis Sharif University of Technology Bozorgzad, Ashkan (Author) ; Tabatabaee, Nader (Supervisor)

Abstract

The deleterious effect of moisture on the structural integrity of asphalt mixtures has been recognized as one of the main causes of early deterioration of asphalt pavements. This phenomenon, usually referred to as moisture damage, is defined as the progressive loss of structural integrity of the mixture. Moisture damage is associated with the development of different physical, mechanical and chemical processes occurring within the microstructure of the mixture at different intensities and rates. Although there have been important advancements in identifying and characterizing this phenomenon, there is still a lack of understanding of the damage mechanisms occurring at the...