Eyad Masad

Eyad Masad
Texas A&M University at Qatar | TAMU Qatar

About

311
Publications
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Publications

Publications (311)
Article
There has been growing interest in the use of polyethylene (PE) in the asphalt industry as one way to mitigate the adverse environmental impact of waste plastics. The main goal of this study was to evaluate the potential use of low-density polyethylene (LDPE) as a modifier for use in asphalt mixtures. In addition, this study also explored the poten...
Article
Full-text available
This study presents a novel methodology to generate computational replicates of nanostructures of multiphase materials, such as asphalt binders, by integrating image analysis techniques with stochastic random field (RF) modeling. Image analysis techniques are used to identify and segment nanostructure images obtained by atomic force microscopy, whi...
Conference Paper
The past decades have stood witness to nanotechnology's domination in countless fields of science and engineering. Nanotechnology has greatly contributed to major advances in developing and improving infrastructure materials. Nanoparticles have been used in asphalt production in order to improve the performance of asphalt pavements. This paper is f...
Article
Transportation agencies are increasingly incorporating reclaimed asphalt pavement (RAP) in asphalt mixtures due to the scarcity and increased costs of virgin resources. The usage of RAP brings both economic as well as environmental benefits. Nonetheless, because RAP is an aged, stiff, and brittle material, utilizing it in large quantities can make...
Article
The main objective of this study is to explore the effects of various asphalt binder modifiers, including styrene-butadiene-styrene (SBS), elemental sulfur, reactive ethylene terpolymer (Elvaloy), and polyphosphoric acid (PPA) polymers on the nanostructural and nano-mechanical (elastic and viscoelastic) properties of low-density polyethylene (LDPE)...
Article
This study evaluates the potential of producing warm-mix asphalt (WMA) using a wax-based additive (Sasobit) in a binder modified using crumb rubber (CR). This binder is formulated for very hot climates and has a grade of PG 82E-16. Three proportions of Sasobit were added to the binder (1%, 2%, and 3%). In the compaction temperature range (130°C–145...
Chapter
This study aimed to evaluate the nano-mechanical properties of RAP blended binders and investigate their relationship with the bulk (macro-scale) properties. The tests were conducted on asphalt binders with different RAP contents (0, 15, 25, 35, 100% RAP). In the nanoindentation test, a trapezoidal loading waveform was applied using the Berkovich t...
Article
This paper provides a review of the research on use of polymers for soil stabilization in pavement and geotechnical engineering. First, the properties impacting the effectiveness of widely used polymer classes, including geopolymers, biopolymers, and synthetic organic polymers are discussed. These include types and ratios of the precursor and activ...
Article
The use of high amounts of reclaimed asphalt pavement (RAP) in asphalt pavements has many economic and environmental benefits; however, there are concerns about brittleness and potential cracking of asphalt mixtures. One of the solutions to address this concern is through the inclusion of recycling agents (rejuvenators). The purpose of this study w...
Article
This study presents two approaches for evaluating damage and recovery characteristics of asphalt mixtures. The first approach focuses on deter- mining damage by extracting recoverable viscoelastic strain that has no damage and comparing it with the strain response of a material that has damage. The second approach is based on identifying the capaci...
Article
Full-text available
In recent years, the use of polyethylene (PE) for asphalt modification has been gaining increased attention due to the environmental sustainability and cost-saving benefits. To optimize the performance of the PE-asphalt blends, it is necessary to understand the polymer-binder interactions and their impact on the properties of the modified asphalt b...
Article
Full-text available
Understanding the concrete-steel interface's behavior at cryogenic temperatures is important for designing concrete for direct liquefied natural gas (LNG) containment; such behavior is currently unclear. Hence, the work conducted involved pull-out testing in providing insights on the bond-slip relationship and the development of internal strains, w...
Article
There are various models for predicting the friction or skid number of asphalt pavements based on inputs such as aggregate characteristics, aggregate gradation, and traffic level. However, existing models are deterministic as they incorporate mean values of the input parameters and yield an average skid number value for a pavement section. Conseque...
Conference Paper
This study aimed to evaluate the nano-mechanical properties of RAP blended binders and investigate their relationship with the bulk (macro-scale) properties. The tests were conducted on asphalt binders with different RAP contents (0, 15, 25, 35, 100% RAP). In the nanoindentation test, a trapezoidal loading waveform was applied using the Berkovich t...
Article
This paper presents a comprehensive analysis of blended asphalt binders extracted from mixtures that contain various amounts of reclaimed asphalt pavements (RAP). The analysis is performed within a thermodynamically consistent non-linear viscoelastic (NVE) modeling framework, which has the advantage of accounting for the contributions of each of th...
Article
This paper presents a comprehensive analysis of blended asphalt binders extracted from mixtures that contain various amounts of reclaimed asphalt pavements (RAP). The analysis is performed within a thermodynamically consistent non-linear viscoelastic (NVE) modeling framework, which has the advantage of accounting for the contributions of each of th...
Conference Paper
In this study, the resistance of various RAP blended binders to permanent deformation was analyzed with consideration to the nonlinear response of asphalt binders. Multiple creep and recovery (MSCR) and repeated creep and recovery with multiple stress levels (RCRMS) were performed on the RAP blended binders at 64oC. For the binder used in this stud...
Conference Paper
Nowadays, the use of polyethylene (PE) for bitumen modification has become widespread due to the major advantage of environmental sustainability. For the application of PE modified binder, it is necessary to first study the compatibility of polyethylene and bitumen. In this study, low density polyethylene (LDPE) was blended with the binder in five...
Article
Full-text available
The use of reclaimed asphalt pavement (RAP) in road construction has become a common practice in the asphalt industry due to environmental and economic benefits. However, since RAP is an aged material, recycling agents are typically used to reduce the stiffness of the recycled asphalt mixture and make it less prone to cracking at high RAP contents....
Article
Motivated with sustainability and economic factors, there is a rapid increase in the use of recycled asphalt pavement (RAP) material in the construction of new asphalt pavements. This necessitates the development of better understanding of the interaction between recycled and virgin binders, as well as studying the influence of this interaction on...
Article
Skid resistance is a key factor in road safety. Surface friction characteristics of roads are dependent on the microtexture and macrotexture of the surface. The decay of skid resistance with time is a function of traffic level and aggregate characteristics. This study developed predictive models for skid resistance of asphalt pavements and seal coa...
Article
This study aims to (1) determine an optimum amount of Reclaimed Asphalt Pavement (RAP) such that its addition does not adversely impact the fracture resistance of asphalt mixtures, and (2) determine the amount of RAP binder that is active in the total mix. For this purpose, the asphalt mixtures containing three RAP contents (15, 25 and 35%) and the...
Technical Report
Full-text available
This report presents a review of advances and challenges in using virgin and recycled polyethylene (PE) for asphalt modification. There have been various applications of PE-modified asphalt since the 1980s with different trade names (Novophalt, Polyphalt, Ditecpesa, and Plastiphalt). In recent years, PE modification has received less attention comp...
Conference Paper
The polymer-modified asphalt (PMA) reveals different types of advantageous properties depending on the type of polymer. However, one of the unwanted changes in PMA is the required higher temperature for mixing and compaction. To reduce these temperatures, different percentages of warm mix additive (WMA) have been utilized. However, the addition of...
Article
The goal of this study is to model the creep and recovery response of fine asphalt mixtures using a thermodynamically consistent nonlinear viscoelastic model. The model considers asphalt mixture to consist of two constituents: aggregate structure incorporating the asphalt-aggregate interface and asphalt binder. The efficacy of the model is evaluate...
Conference Paper
This study aims to characterize the mechanical and microstructural properties of asphalt binders prepared with 25 and 35% of RAP contents. A base binder of pen 60/70 (PG 64-22) was used in this study. The binders were characterized by conducting performance grading, multiple stress creep recovery, and frequency sweep tests. The performance of RAP b...
Article
The goal of this study is to investigate the chemical constituents and rheological properties of three different binders used in the State of Qatar. Binders were designated as WL (source 1, low density), WH (source 1, high density) and AH (source 2, high density). Binder composition analysis was carried out using the saturates, aromatics, resins an...
Article
Fatigue damage is one of the major distress modes that have a critical impact on the performance and serviceability of asphalt pavements. High variability in testing results poses a challenge for predicting the fatigue life of asphalt mixtures using conventional deter- ministic modeling approaches. This study examined the efficacy of using a probab...
Conference Paper
Full-text available
The pore structure, which controls the main properties of concrete, evolves due to phase changes in the pore network during cryogenic freezing of concrete. This study investigates the influence of such pore structure evolution on the thermal conductivity of different concrete mixtures. Such information would be useful in the design of low thermally...
Article
This paper provides analysis of the chemical composition of two asphalt binders that were subjected to various environmental factors (i.e. oxygen, heat, UV radiation, and moisture) in an accelerated weathering tester. The analysis was performed with the aid of Fourier Transform Infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The results...
Article
Full-text available
The skid resistance of a pavement surface is an important characteristic that influences traffic safety. Previous studies have shown that skid resistance varies with temperature. However, relatively limited work has been carried out to study the effect of temperature on skid resistance in hot climates. Recent developments in computing and computati...
Conference Paper
The influence of test conditions such as test speed, pavement condition (wet or dry) and tire temperature on pavement friction measurements and texture-friction relationship was investigated. The skid resistance of an asphalt pavement section in Qatar was measured at test speeds of 35 and 50 km/h in dry and wet conditions, respectively, using a Gri...
Article
This paper presents results on the evolution of the macroscopic appearance and surface microstructure of asphalt binders aged in an accelerated weathering tester. Two binders used in hot mix asphalt and two binders used in warm mix asphalt were aged in the presence of UV radiation, heat, oxygen and moisture. The same binders were previously aged us...
Conference Paper
Maintaining adequate level of skid resistance on highways is essential for the safety of motorists. Among other factors, skid resistance of asphalt pavements depends on aggregate shape characteristics and its re-sistance to abrasion and polishing. This study investigated the effect of aggregate blending on improving the frictional characteristics o...
Conference Paper
This study documents the use of high-resolution X-Ray Computed Tomography to characterise air void distribution in fine aggregate mixtures (FAM) prepared using Warm Mix Asphalt (WMA) additives (W-FAM). Specimens were imaged before and after subjecting them to repeated creep and recovery test. The produced images were digitally analysed to measure t...
Article
This research assesses the influence of temperature variation on GripTester (Findlay Irvine, Penicuik, Scotland) skid resistance measurements of asphalt pavements in Qatar. It evaluated a test road with six different sections and four major highways during winter and summer seasons with ambient temperature ranging from 18 to 44°C. Close-range photo...
Article
This study utilizes close range photogrammetry (CRP) to measure the texture of asphalt pavement surfaces with a view to explaining the variation of friction measurements obtained using a GripTester. A handheld camera was employed to capture images at different locations on both lanes of pavement sections using a scale rule for identification of con...
Conference Paper
Maintaining adequate level of skid resistance is essential for road safety. As part of their regular maintenance program, many departments of transportation collect skid data on roads to ensure sufficient traction between road surface and vehicle tires. This study developed models for skid resistance of asphalt mix and seal coat surfaces. These mod...
Article
In this study, the effect of recycling agents on recycled blends obtained from base and recycled asphalt binders and the performance of the rejuvenated binders with aging was investigated by means of Atomic Force Microscopy (AFM) and Dynamic Shear Rheometer (DSR). This study arises as the amount of recycled materials in asphalt pavements continues...
Article
Interfacial bonding among asphalt binder and aggregates plays a significant role in asphalt concrete performance and potential for moisture damage. Previous studies have established experimental procedures to quantify the adhesive bond strength between asphalt binder and aggregates using techniques such as contact angles, adsorption isotherms, and...
Article
This paper presents analysis of chemical changes in asphalt binder samples that were aged using an accelerated weathering tester, which involves UV radiation and direct aging of the binder surface. It also provides a comparison with chemical changes in the same binders but aged with standard methods. Fourier Transform Infrared (FTIR) and X-ray phot...
Article
Full-text available
This study evaluates the potential of selected ionic polymers to act as pavement subgrade binders. Investigations were based on their relative performance with a Qatari soil which was selected as typical of a pavement subgrade to be found in the Middle East and North African region. The polymeric binders chosen were three synthetic ionic variations...
Article
In this study, a recently developed methodology to assess aging of pavements by using Low Field Nuclear Magnetic Resonance (LF-NMR) was applied to asphalt mix samples at different aging states. The ultimate objective of this method is to monitor the long-term aging of asphalt binder in mixture cores without binder extraction. The asphalt samples we...
Article
The fatality rate in Qatar is significantly higher than many of the best performing nations in the world. Severe single-vehicle rollover crashes are predominant in the country. Vehicle tires failure (such as tread separation and blowouts) and incorrect tires use significantly contribute to loss of control and rollover accidents. This paper presents...
Article
Full-text available
Warm-mix asphalt (WMA) technologies have been used extensively in the last decade. The benefits of WMA have motivated stakeholders to expedite the implementation of this technology. However, some research studies have raised concerns regarding WMA laboratory performance in terms of resistance to moisture damage, while WMA has demonstrated good perf...
Article
The quality of the interfacial bonding between asphalt binder and aggregates plays a significant role in determining the durability of asphalt mixtures. Warm mix asphalt (WMA) modifiers have been used extensively in the last decade primarily to reduce production and compaction temperatures as well as to improve workability of asphalt mixtures. This...
Chapter
Compaction has a significant effect on the performance of asphalt mixtures. This is confirmed by the results of many studies on the effects of compaction methods on mixture mechanical properties and field performance. However, there is little research on the effect of compaction on skid resistance of asphalt pavements. The skid resistance of asphal...
Article
Fatigue cracking is one of the most serious distress modes affecting the serviceability of asphalt pavement structures. The inherent variability of asphaltic materials exhibited in fatigue test results, especially for specimens acquired from field pavements, makes the task of accurately predicting the material’s fatigue characteristics rather diffi...
Article
Warm-Mix Asphalt (WMA) is a widely used product, which proved a contribution to the reduction in asphalt mixing and compaction temperatures. This reduction leads to lower fuel consumption and smoke emission in asphalt plants. Most of the characterisation of binders used in WMA has focused in the past on measuring linear viscoelastic properties and...
Article
A state-of-the-art review of key parameters that influence measurement and modeling of skid resistance of asphalt pavements is provided. Tire-pavement interaction/friction is discussed and the current harmonization method of friction measurements questioned. The latest developments on pavement surface texture measurement and characterization are hi...
Article
This paper presents findings on the evolution of the surface microstructure of two asphalt binders, one unmodified and one polymer modified, directly exposed to aging agents with increasing durations. The aging is performed using an accelerated weathering tester, where ultraviolet radiation, oxygen and an increased temperature are applied to the as...
Article
Full-text available
A set of governing equations comprising linear momentum, mass, and heat transfer is presented for thermoelastic freezing of a porous material. The theory of unsaturated freezing porous media is introduced to model deformation of concrete, a traditional building material, whose pore network is pressurized by the wet air, frozen ice, and unfrozen wat...
Article
This paper presents a computational modelling approach to evaluate moisture damage in hot mix asphalt (HMA) materials. The approach combines a methodology to randomly generate HMA microstructures and a finite element (FE) formulation that uses a coupled mechanical-moisture continuum damage constitutive relationship. Probable two-dimensional HMA mic...
Article
Thermal deformation behavior of concrete mixtures from limestone and trap rock aggregates has been related to microcracking during cryogenic cooling. The study was aimed at comparing the suitability of the concretes for direct containment of liquefied natural gas (LNG). The results showed strong correlation between the thermal strain rate and the a...
Article
The quality of compaction significantly influences the performance of asphalt mixtures. Insufficient compaction often leads to excessive premature permanent deformation, excessive aging, and/or moisture damage. The research reported in this paper was aimed at developing a prediction model for laboratory compaction of asphalt mixtures. The model was...
Conference Paper
Full-text available
Warm-mix asphalt (WMA) additives are environmentally friendly and cost-effective products that lower the viscosity of bituminous binders to allow reduc-tion of mixing and compaction temperatures in asphalt mix production. In this study, two WMA additives were used; Sasobit® and Advera®. Both were mixed in the lab with unmodified 60/70 Pen and modif...
Article
This work presents a novel modeling technique to investigate the role of certain microstructural properties on the mechanical performance of asphalt mixtures. The methodology initiates by randomly creating probable microstructures of asphalt mixtures. Then, these random microstructures are implemented in a Finite Element (FE) software to evaluate t...
Article
Abstract There is a great interest in developing and implementing new technologies for real-time evaluation of the uniformity of the construction of asphalt layers. In this study, the researchers developed a system for monitoring and documenting the compaction process of asphalt mixtures in the field. This system is called the compaction monitoring...
Conference Paper
The population and economy in Qatar have been expanding significantly in the past six years. Accordingly, Qatar is encountering huge development in infrastructure. The existing mix design methods have been developed in the past to protect against rutting given the high temperatures in Qatar. However, these mixtures might be susceptible to fatigue d...
Conference Paper
Full-text available
Warm-Mix Asphalt (WMA) technology is widely used in the paving industry due to its impact on reduction of asphalt mixing and compaction temperatures. Characterisation of WMA in the past had focused on evaluat-ing the linear viscoelastic properties and associated Superpave specifications. In this study, evaluating the non-linear viscoelastic respons...
Article
The suitability of six concrete mixtures for use in direct containment of liquefied natural gas (LNG) was assessed using nuclear magnetic resonance (NMR), x-ray computed tomography (XRCT) and acoustic emission (AE). The mixtures were prepared with river sand as fine aggregate using different coarse aggregates. The mixtures were cooled from ambient...
Article
Full-text available
This paper presents microstructural analysis of two original and their respective warm mix asphalt (WMA) binders, obtained with the addition of Advera® and Sasobit®. The binders were analysed before and after long-term ageing with the aid of atomic force microscopy (AFM). The AFM images highlighted the effect of ageing using rolling thin film oven...
Article
Full-text available
This paper introduces an innovative methodology for estimating the ageing of asphalt concrete cores without extracting the binder. Asphalt concrete samples at different ageing stages (unaged, 3-month and 6-month aged) and with different percent air voids (4%, 7% and 10%) were analysed with low-field nuclear magnetic resonance (NMR). The transverse...
Article
Moisture diffusion is one of the mechanisms by which water can reach the microstructure of asphalt mixtures and negatively affect their performance. In this work, a finite element model and computational simulations were used to study the response of asphalt pavement layers subjected to the coupled effects of moisture diffusion and mechanical loadi...
Article
The ground-penetrating radar (GPR) is a proven technology that is used typically to determine the thicknesses of pavement layers. This paper explores the applicability of the GPR to assess the density of the asphalt layer in pavements. The measurements were conducted on three test sections that were constructed using different asphalt mixtures. Eac...