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The impact of incorporating medical mask waste fibers on the rheological properties of asphalt in the review of the Asphalt Stiffness Modulus (E*) using the Dynamic Shear Rheometer (DSR) tool needs to be done, to determine the improvement of asphalt rheological properties, so that the garbage from masks produced during the Covid-19 pandemic might be utilized as an additive for asphalt. This test is carried out with 3 conditions, namely the initial condition, the condition of the Rolling Thin Film Oven Test (RTFOT), and the condition of the Pressure Aging Vessel (PAV). In the initial condition, the results showed an increase in the value of the Asphalt Stiffness Modulus with the addition of 1% mask fiber increased by between 6% - 78%, the addition of 2% mask fiber increased by between 39% - 148%, and the addition of 3% mask fiber increased by between 70% - 253%. The decrease in the value of the Asphalt Stiffness Modulus of Asphalt + 3% mask indicates the increasing temperature of asphalt at high temperatures when deformation occurs (Rutting), namely for all initial conditioning (75.1°C) and RTFOT residual asphalt (69.7°C). On the other hand, the E* value is too large because the addition of 3% mask fiber tends to crack fatigue earlier at low temperatures. This can be proven by the increasing value of E* at low temperatures when fatigue cracking occurs, namely for PAV residual asphalt conditioning (26.0°C). This study is limited to laboratory testing, so using mask fibers in asphalt requires long-term evaluation for real-world reliability. The research proposes using medical mask waste to improve asphalt's rheological properties, potentially reducing environmental impact and enhancing performance. Initial results are promising, but further research is needed to confirm sustainability and effectiveness in practical applications.

The impact of incorporating medical mask waste fibers on the rheological properties of asphalt in the review of the asphalt stiffness modulus (E*) using the dynamic shear rheometer (DSR) tool needs to be done, to determine the improvement of asphalt rheological properties, so that the garbage from masks produced during the Covid-19 pandemic might be utilized as an additive for asphalt. The method used is laboratory experiments by adding mask waste fibers with variations in levels of 1%, 2%, and 3% to the total weight of asphalt and making a test specimen design. This test is conducted under three conditions: initial condition, rolling thin film oven test (RTFOT) condition, and pressure aging vessel (PAV) condition. In the initial condition, the asphalt stiffness modulus increased by 6-78% with 1% mask fiber, 39-148% with 2% mask fiber, and 70-253% with 3% mask fiber. The decrease in the asphalt stiffness modulus of asphalt with 3% mask fiber indicates higher asphalt temperature during deformation (rutting), with initial conditioning at 75.1 °C and RTFOT residual asphalt at 69.7 °C. Conversely, the large asphalt stiffness modulus (E*) value with 3% mask fiber suggests a tendency for earlier fatigue cracking at low temperatures, evidenced by the increasing asphalt stiffness modulus (E*) value during fatigue cracking in PAV residual asphalt conditioning at 26.0 °C. This study is limited to laboratory testing, so using mask fibers in asphalt requires long-term evaluation for real-world reliability. The research proposes using medical mask waste to improve asphalt's rheological properties, potentially reducing environmental impact and enhancing performance. Initial results are promising, but further research is needed to confirm sustainability and effectiveness in practical applications. [ABSTRACT FROM AUTHOR]

In general, the physical and rheological properties of asphalt binder are directly affecting the resistance of asphalt mix to the permanent deformation (rutting), water damage, and thermal cracking. The degradation in these properties leads to severe distresses that appear in the pavement and, consequently, make the repair and maintenance very expensive. Since the modified-asphalt cement may help to minimize such aforementioned distresses, this research is established for this purpose. It aims to investigate the physical and rheological properties of modified-asphalt cement with silicone, dense silicone rubber, and ethylene propylene diene monomer rubber. Five contents for each type of hot glue are investigated; 0.4, 0.8, 1.2, 1.6, and 2% of the asphalt cement weight. Conventional asphalt cement tests such as penetration, softening point, dynamic viscosity, and ductility tests are conducted to evaluate the hot glue-modified asphalt cement properties. Moreover, the Marshall and indirect tensile strength tests are conducted to examine the effect of hot glue on the performance of the asphalt mixtures at concentrations of 0.8 and 1.6% of the asphalt cement weight. The results show that the hot glue-modified asphalt cement leads to an increase in the hardness and consistency, and a reduction in the temperature susceptibility of asphalt cement. These features lead to better Marshall stability and tensile strength ratio, as compared with the standard asphalt cement mixture. [ABSTRACT FROM AUTHOR]

The increased cost of virgin material, declining resources and increasing plastic wastes have turned the research momentum towards sustainable and green pavements. Reclaimed Asphalt Pavement (RAP) from the construction industry and plastic wastes disposal is the main problem for Pakistan as well as other developing countries in the face of fewer funds for the construction, repair, and rehabilitation of the extensive road network. In this research, the attempt has been made to study the use of Reclaimed Asphalt Pavement and plastic wastes to counter these issues. Virgin binder was modified with three different contents (2%, 4%, and 6%) of Polyethylene Terephthalate and three contents (20%, 30%, and 40%) of Reclaimed Asphalt Pavement. Conventional properties of the modified binder were determined by penetration and softening point. At the same time, thermal stability was checked by Thermal Gravimetric Analysis, and resistance against rutting was evaluated with the help of Dynamic Shear Rheometer. It is observed that modified binder remains stable up to a temperature of 470 °C and showed improved resistance against rutting. Marshall mix properties were determined and compared to specifications of the National Highway Authority of Pakistan. Optimum Marshall stability was observed with 4% Polyethylene Terephthalate, and 30% Reclaimed Asphalt Pavement, while flow and air voids remained in limits. As per the results, utilisation of plastic wastes in asphalt pavements enhances the performance and helps to reduce the environmental pollution and landfill problems due to Reclaimed Asphalt Pavement and plastic wastes.

Copyright of Journal of Henan University of Science & Technology, Natural Science is the property of Editorial Office of Journal of Henan University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The dynamics properties of a new "next generation" model asphalt system that represents SHRP AAA-1 asphalt using larger molecules than past models is studied using molecular simulation. The system contains 72 molecules distributed over 12 molecule types that range from nonpolar branched alkanes to polar resins and asphaltenes. Molecular weights range from 290 to 890 g/mol. All-atom molecular dynamics simulations conducted at six temperatures from 298.15 to 533.15 K provide a wealth of correlation data. The modified Kohlrausch-Williams-Watts equation was regressed to reorientation time correlation functions and extrapolated to calculate average rotational relaxation times for individual molecules. The rotational relaxation rate of molecules decreased significantly with increasing size and decreasing temperature. Translational self-diffusion coefficients followed an Arrhenius dependence. Similar activation energies of ~42 kJ/mol were found for all 12 molecules in the model system, while diffusion prefactors spanned an order of magnitude. Viscosities calculated directly at 533.15 K and estimated at lower temperatures using the Debye-Stokes-Einstein relationship were consistent with experimental data for asphalts. The product of diffusion coefficient and rotational relaxation time showed only small changes with temperature above 358.15 K, indicating rotation and translation that couple self-consistently with viscosity. At lower temperatures, rotation slowed more than diffusion. [ABSTRACT FROM AUTHOR]

Featured Application: This study provides guidelines for asphalt binder modifier selection to produce low modulus binders (softer binders) to meet desired quality. The research focuses on reducing expected cracking susceptibility of modified asphalt binders after long-term aging. The study recommends the development of engineered modifiers for specific paving applications. In recent years, increased use of recycled asphalt materials (RAP) has created a need for softer binders to compensate stiffer binder coming from RAP. Economic alternatives, like recycled oils and proprietary bio-based oils, can be potential modifiers that will reduce the dependence on petroleum-based alternatives. However, there is limited information on the long-term rheological performance of binders modified with proprietary modifiers. These modifiers are chemically complex and their interaction with binders further complicates the binder chemistry. Therefore, the objective of this study was to evaluate the impact of modifier chemistry on modified binders' long-term cracking potential. A base binder of Superpave Performance Grade (PG) 64-22 was used to develop PG 58-28 binder using six different modifiers. An unmodified PG 58-28 was included for a comparative analysis. A few modified binders rheologically outperformed the base binder and others performed similarly. The modifier derived from recycled engine oil showed the worst performance. Chemical analysis indicated that the best performing modified binders had significant amounts of nitrogen in the form of amines. On the other hand, poor performing modified binder had traces of sulfur. Additionally, modifiers with lower average molecular weights appeared to have a positive impact on the performance of aged binders. [ABSTRACT FROM AUTHOR]

The increased cost of virgin material, declining resources and increasing plastic wastes have turned the research momentum towards sustainable and green pavements. Reclaimed Asphalt Pavement (RAP) from the construction industry and plastic wastes disposal is the main problem for Pakistan as well as other developing countries in the face of fewer funds for the construction, repair, and rehabilitation of the extensive road network. In this research, the attempt has been made to study the use of Reclaimed Asphalt Pavement and plastic wastes to counter these issues. Virgin binder was modified with three different contents (2%, 4%, and 6%) of Polyethylene Terephthalate and three contents (20%, 30%, and 40%) of Reclaimed Asphalt Pavement. Conventional properties of the modified binder were determined by penetration and softening point. At the same time, thermal stability was checked by Thermal Gravimetric Analysis, and resistance against rutting was evaluated with the help of Dynamic Shear Rheometer. It is observed that modified binder remains stable up to a temperature of 470 °C and showed improved resistance against rutting. Marshall mix properties were determined and compared to specifications of the National Highway Authority of Pakistan. Optimum Marshall stability was observed with 4% Polyethylene Terephthalate, and 30% Reclaimed Asphalt Pavement, while flow and air voids remained in limits. As per the results, utilisation of plastic wastes in asphalt pavements enhances the performance and helps to reduce the environmental pollution and landfill problems due to Reclaimed Asphalt Pavement and plastic wastes. [ABSTRACT FROM AUTHOR]

Abstract In this study, the effect of silica nanoparticles (NS) and temperature on the rheological properties with ultimate shear stress and weight loss of the oil well cement (class H) modified with NS were investigated. The NS content was varied up to 1% by the weight of the cement. The total weight loss at 800 °C for the oil well cement decreased from 6.10% to 1.05%, a 83% reduction when the cement was mixed with 1% of NS. The results also showed that 1% of NS increased the rheological properties of the cement slurry. The NS modification increased the yield stress (τ o) and by 5% to 65% based on the NS content and the temperature of the cement slurry. The addition of 0.5% and 1% NanoSiO 2 increased the initial electrical resistivity of the cement by 17% and 35% respectively. The shear thinning behavior of the cement slurry with and without NS has been quantified using the Vipulanandan rheological model and compared with the Herschel-Bulkley model. Based on the Vipulanandan rheological model the maximum shear stress produced by the cement slurry modified with 0% and 1% of NS at the temperature of 25 °C were 148 Pa and 179 Pa respectively hence an increase of 21% in the ultimate shear stress due to the addition of NS. The addition of 1% of NS increased the compressive strength of the cement by 14% and 42% after 1 day and 28 days of curing respectively. Effects of NS content and the temperature on the model parameters have been quantified using a nonlinear model (NLM). The NLM quantified the effect of NS treatment on all the model parameters. [ABSTRACT FROM AUTHOR]

In recent years, increased use of recycled asphalt materials (RAP) has created a need for softer binders to compensate stiffer binder coming from RAP. Economic alternatives, like recycled oils and proprietary bio-based oils, can be potential modifiers that will reduce the dependence on petroleum-based alternatives. However, there is limited information on the long-term rheological performance of binders modified with proprietary modifiers. These modifiers are chemically complex and their interaction with binders further complicates the binder chemistry. Therefore, the objective of this study was to evaluate the impact of modifier chemistry on modified binders’ long-term cracking potential. A base binder of Superpave Performance Grade (PG) 64-22 was used to develop PG 58-28 binder using six different modifiers. An unmodified PG 58-28 was included for a comparative analysis. A few modified binders rheologically outperformed the base binder and others performed similarly. The modifier derived from recycled engine oil showed the worst performance. Chemical analysis indicated that the best performing modified binders had significant amounts of nitrogen in the form of amines. On the other hand, poor performing modified binder had traces of sulfur. Additionally, modifiers with lower average molecular weights appeared to have a positive impact on the performance of aged binders.

With growing global concerns related to energy security and sustainability, interest in bio-fuels has increased significantly. Production of biofuel mostly begins with pyrolysis, a process that converts the biomass to liquid biooil, solid biochar and gases. A large amount of carbonaceous biochar is generated as a by-product during the pyrolysis. However, no major effort has been made in the past decade to utilize the biochar in pavement applications, especially as a bio-modifier to asphalt binders. In this study, an attempt was made to evaluate the carbonaceous biochar, obtained during bio-fuel production through pyrolysis of Mesua ferrea seed cover waste, as an asphalt modifier/extender to obtain bio-asphalts. Physical and chemical characterizations of biochar were carried out using scanning electron microscopy, Fourier transform infrared spectroscopy and energy dispersive X-ray analysis. This was followed by rheological characterization of asphalt binders (from two sources) modified with various concentrations of biochar (0, 5, 10, 15, and 20% by weight of binder). Flow behaviour, permanent deformation, and fatigue characteristics of bio-asphalts were evaluated and compared with control binders (no biochar). Aging susceptibility of biochar modified binders was also evaluated and compared for biochar contents and binder sources. Permanent deformation behaviour evaluated through multiple stress creep and recovery (MSCR) test indicated that the use of biochar improved the rutting resistance of binders. Improved binder performance against the effects of aging and deformation with the use of biochar makes it a promising asphalt modifier, especially for the warm tropical climatic conditions prevalent in India.

Over-stabilized asphalt emulsion is normally used in cement asphalt emulsion (CA) composites. The mixing stability of asphalt emulsion with cement is vital to the workability and mechanical properties of CA composites. However, the effect of cement on the demulsifying behavior of asphalt emulsion during mixing is not clearly understood. To reveal the demulsifying behavior, effect of pH value and Ca 2+ on the rheological properties and mixing stability of over-stabilized asphalt emulsion are studied. Results indicate that cationic emulsions have no obvious change in the tested pH value and Ca 2+ concentration range. Ca 2+ ion is very harmful to the chemical stability of anionic emulsion. There are three stages in the demulsifying process of pure emulsion: (1) small asphalt droplet coalescence along with trapped water; (2) trapped water diffuses out from coalesced asphalt droplets; (3) complete demulsification. There are two demulsifying behaviors when asphalt emulsion is mixed with fine solid. One is asphalt droplet coalescence, which is dominant in the mixing with limestone powder. The other is the direct droplet adhesion on solid surface, which is dominated in the mixing with cement. This difference is due to that the adsorption ability of cement is much stronger than that of limestone powder. The ions of OH − and Ca 2+ released by cement hydration cannot greatly destabilize asphalt emulsion. However, emulsions with better resistance to the invasion of OH − and Ca 2+ still have a better mixing stability. Therefore, reducing the adsorption ability of cement and increasing the resistance of emulsions to hydrate ions can improve the mixing stability of asphalt emulsion with cement. [ABSTRACT FROM AUTHOR]

Mastic properties play important role in the performance of asphalt concrete, especially for high temperature performance. The objective of this paper was to describe the viscoelastic behavior of asphalt mastic at high temperatures and determine the regression constants of the models. Two different asphalt binders namely AS-70 base asphalt binder and SBS modified asphalt binder were selected to mix with the mineral filler. For each asphalt binder, asphalt mastic samples were prepared at five different mass percentages, as 0.6, 0.9, 1.2, 1.5 and 1.8. The viscosity and rheological properties were tested under different temperatures using Brookfield RVDV-III rotating viscosimeter and Dynamic Shear Rheometer (DSR). The test results indicated that, for the modified asphalt mastic, increasing mineral filler content in the mastic caused a significant increase in the viscosity, while the effects were not significant on the base asphalt mastic. The filler showed no obvious effect on the temperature sensitivity of the mastic. The creep characteristic of base asphalt mastic can be modeled by the Maxwell model. The Burgers model was the most appropriate to model the creep characteristic for the modified asphalt mastic. The relaxation function of Burgers model can successfully fit relaxation behavior of the mastic. [ABSTRACT FROM AUTHOR]

Pavement preservation is playing an increasingly significant role in maintaining our aged pavement infrastructure under severe budget constraints. One important component is the use of surface treatments based on application of sealants. Recently, a number of new products, called bio sealants, have been used to treat aging pavement surfaces. The objective of this study is to investigate rheological properties of the binders treated with these materials to understand the mechanism by which they may improve pavement performance. One plain asphalt binder and four types of sealants, two oil-based sealants, one water-based sealant, and one traditional emulsion were used in the experimental work. The results obtained using a dynamic shear rheometer and a bending beam rheometer were used to determine the changes in rheological properties and the change in performance grade. It was observed that the oil-based sealants have a significant softening effect of the control binder compared to the water-based sealants. The transverse cracking histories from field investigation were used to verify the laboratory findings. [ABSTRACT FROM AUTHOR]

Recent efforts are being conducted to develop alternative asphalt binders from various bio-mass resources for future flexible pavements construction due to their renewability and the increasing costs of conventional petroleum-based asphalt. The objective of this paper is to investigate the potential of using the waste cooking oil (WCO) based bio-oil as a modifier for petroleum based neat asphalt binder and Styrene-Butadiene-Styrene (SBS) modified binder by means of chemical and rheological approaches. A series of tests were conducted for such purpose, including the infrared spectroscopy test, frequency sweep rheological test, multiple stress creep recovery test, and linear amplitude sweep test. The infrared spectroscopy results indicate identical chemical functional groups between the bio-oil and the petroleum asphalt binder though acid, ether, ester and alcohol compounds were also observed within the bio-oil. The bio-oil modified binders display increased carbonyl index with increasing the bio-oil percent weight whereas the sulfoxide index almost exhibits the same level as that of the control asphalt. Frequency sweep tests show that the bio-oil addition obviously decreased the binder stiffness according to the dynamic shear modulus master curve. Due to this softening effect from the bio-oil modifier, the weakened rutting resistance of bio-binders are demonstrated for both neat and SBS binders at the high temperature range. The fatigue life of bio-binders at intermediate temperature under cyclic fatigue loading are found to be significantly improved by increasing bio-oil content but the binder yield energy simultaneously decreased. It can be preliminarily concluded that the WCO based bio-oil tested in this study could be used as a potential bio-modifier to produce a sustainable asphalt binder. [ABSTRACT FROM AUTHOR]

Copyright of Roads & Bridges / Drogi i Mosty is the property of Road & Bridge Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Asphalt binder characterization is a complex and difficult task due to its rheological behaviour. Indeed it has been traditionally realized by means of simple tests at an established temperature. An added challenge is that low temperatures, as well as binder aging, lead to significant changes in the viscoelastic behaviour of binders. This study aimed to characterize asphalt binders, not through the traditional procedures, but through the ductility and tenacity that they provide to a mixture, being these two properties directly related to the cracking response of the binder. To this end, a new approach for asphalt binder characterization was proposed based on the application of the Fénix test on a standard mixture with a defined aggregate gradation and composition, without fines or filler, manufactured with different types of binders and tested at different temperatures, as well as subjected to accelerated aging in laboratory. The obtained results showed the thermal susceptibility of binders, which evidence the need to characterize binder performance at different temperatures to obtain a reliable cracking response. In addition, binder aging results in a more brittle cracking fracture, being the aging effects more pronounced in high penetration binders. [ABSTRACT FROM AUTHOR]

Previous studies have shown that graphene oxide (GO) could improve the mechanical and rheological properties of polymers. However, the GO-asphalt interaction and the effects of GO on asphalt pavement performance are still not clear. In this paper, the GO modified asphalt binders were prepared by melt blending method, the GO-asphalt interaction was investigated by the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and gas chromatography-mass spectrometer (GC-MS). The GO effects on the pavement performance of asphalt binders were also studied. In addition, the thermal properties of GO modified asphalt were studied by thermo gravimetric (TG) analysis. The results show that the gas released from GO modified asphalt is the CO 2 . There is no chemical reaction between the GO and asphalt binders, as much as the CO 2 is produced by the decomposition of GO. After being mixed with asphalt binders, the lamella structure of GO is completely stripped, and scattered to a single layer in asphalt binders. The GO has many advantages in improving the pavement performance. [ABSTRACT FROM AUTHOR]

In this study, a modified asphalt based trackless tack coat material (TTCM) was prepared by adding styrene–butadiene–styrene, uintaite mastic asphalt, anti-rut asphalt master batch and Sasobit wax to 50# base asphalt (penetration grade). Mehcnaimcal properties like track resistance, shear strength, pull-off strength, and rheological as well as temperature performance of TTCM were studied. Results showed that the adhesive bond strength of TTCM was greater than cohesive forces within hot mix asphalt layer, track-free time was less than 1 min and it did not deteriorate upon contact with tyres at 60 °C. Furthermore, bonding mechanism of TTCM was proposed. Surface morphology and functional group characterization were achieved using SEM and FTIR, respectively. The present approach utilizing routine raw materials and ease of operation for the synthesis of novel modified asphalt based TTCM with enhanced performance can be effectively applied on industrial level production for practical applications. [ABSTRACT FROM AUTHOR]

This study investigated the crack healing ability of aged and unaged AC-13 basalt asphalt mixtures using five healing agents. Notched semicircular asphalt mixtures were cracked and healed using the healing agents and the recovered critical load at fracture was adopted as a healing indicator. Crack healing was found to be dependent on the type of healing agent, healing time and aging of mixture. A maximum healing up to 73% was obtained after 8 days of uninterrupted healing. Multiple fracturing-rehealing of the healed mixture didn’t significantly affect the healing index (HI) of the successive cycles. The re-healing performance was sensitive to the drying rate of healing agents, and a high drying rate reduced the re-healing performance. The first day of healing had the highest contribution to the ultimate healing potential, and further increase in the healing duration resulted in a steady increase in healing index. The high healing performance indicated that carefully selected healing agents have the potential to heal cracks in asphalt pavements. [ABSTRACT FROM AUTHOR]

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 to increase. Recycled binders are significantly stiffer than base binders; however, the performance grade can be restored by inclusion of recycling agents. Nevertheless, intermediate temperature cracking performance evaluated by the Glover-Rowe (G-R) parameter indicated that the effect of the recycling agents is not sustained with subsequent aging, which could jeopardize its effectiveness in service. The AFM images provided microstructural information, which offer indications about changes in molecular mobility and degree of association with aging, presence of agglomerations, and the dispersive effect of recycling agents. [ABSTRACT FROM AUTHOR]

The Shift-Homothety-Shift in time-Shift (SHStS) transformation, derived from the 2S2P1D model, represents one of the most convenient and simple solution for describing the rheological behavior of asphalt materials, when the transformation parameter α is known. In this paper, a simple expression for predicting the SHStS transformation parameter α is proposed. First a set of binders and eighteen different mix designs are used together with the Hirsch model and the 2S2P1D model to derive a regression equation linking α to the binder content and to the fractal dimension of the aggregate gradation. Then, a second set of binders and mixtures is used to experimentally verify the prediction of the α parameter obtained with the newly proposed formulation. It is found that the values of the transformation parameter are in relatively close agreement. [ABSTRACT FROM AUTHOR]

The simultaneous polymer degradation and asphalt oxidation of polymer modified asphalt (PMA) binder make it difficult to understand the rheological behavior of PMA in the aging process. The present study was meant to investigate the rheological behavior of various PMAs before and after aging (Rolling Thin Film Oven Test (RTFOT) and Pressure Aging Vessel (PAV)) by using rheological master curves in combination with Gel Permeation Chromatography (GPC). The GPC test was performed to obtain the average molecular weight (Mw) of the polymer and distribution of asphaltenes and maltenes. The properties of chemical and rheological were analyzed comprehensively and the results indicated that the phase angle (δ) is more sensitive to asphalt composition (sulfur contents, polymer and base binder characteristic) than the complex shear modulus. Besides, the δ shape can strongly reflect the differences between the rheological responses of the modified asphalts under the different aging conditions. A plateau would occur if the SBS network was formed. Thus the δ shape of SBS modified asphalt will be closer to that of base binder when SBS structure was completely destroyed. Although the degradation of polymer became severer when sulfur was added, sulfur can promote the formation of three-dimensional structures of styrene–butadiene–styrene (SBS) and improve the rheological property of aged PMAs. [ABSTRACT FROM AUTHOR]

The aim of the study is to evaluate the performance of Hot Mix Asphalt (HMA) and bitumen by modifying bitumen with nano materials according to Superpave™ mix design procedure. In this study, bitumen is modified by silica nanopowder (SiO 2 NP). Nano powders are mixed with base bitumen at contents of 0.1, 0.3 and 0.5% by weight. Rutting and fatigue performance of bitumens are determined. HMA is prepared with nano modified bitumens at optimum binder content (OBC). Moisture susceptibility of modified HMA is evaluated according to Modified Lottman test procedure. Nano modified bitumens are also evaluated by scanning electron microscopy (SEM) whether the modification is uniform or not. As a result, better performance is obtained by SiO 2 NP at a content of 0.3% modification. Performance Grades (PG) of all modified bitumens are determined as PG 64-22. OBCs are decreased by modification. HMA sample modified by SiO 2 NP at a content of 0.3% is determined 26.25% higher resistive to moisture compared to reference sample. Homogenous mixture is obtained according to SEM results. It is found that the agglomeration of nano materials is mostly lower than 4 μm in the mixtures. As a result, SiO 2 NP 0.3% shows satisfying results. [ABSTRACT FROM AUTHOR]

The purpose of this study aims at investigating the effect of warm-mix additive Sasobit/Deurex on properties of APAO modified asphalt binder (AMB). The physical properties were measured through penetration, softening point and ductility tests. Besides, rotational viscosity (RV), dynamic shear rheometer (DSR) and bending beam rheometer (BBR) test were utilized to determine the rheological characteristics of warm-mix asphalt binders before and after aging. Fourier transform infrared spectroscopy (FTIR) test was used to describe the chemical characteristics of Sasobit/Deurex warm-mixed APAO modified asphalt binder (AMB). The results showed that incorporation of Sasobit/Deurex into AMB could effectively reduce the viscosity and exert a distinct modification on high temperature performance of asphalt binders in terms of reduced penetration, increased softening point and decreased ductility. Dynamic shear rheometer (DSR) test showed that warm-mix asphalt had bigger complex modulus and smaller phase angle than blank AMB. Bending beam rheometer (BBR) test indicated that minor addition of Deurex (2%) have improved the low temperature rheological performance of AMB while Sasobit had negative effect on it. Moreover, the FTIR analysis showed that chemical reactions might happen during the mixing of Sasobit/Deurex with AMB. In overall consideration, 4% Sasobit and 2% Deurex were optimal dosages for the AMB in this experiment concerning the rheological characteristics, construction workability and economic benefits. [ABSTRACT FROM AUTHOR]

The use of recycled bitumen (such as the Recycled Asphalt Pavement, RAP) in production of new pavements is becoming an important issue, owing to the potential economic and environmental benefits derivable from the replacement of virgin materials with recycled ones. Nevertheless, the properties of RAP negatively affect the final behavior of pavement, reducing, therefore, its practical use. With the aim of modifying RAP behavior, rejuvenating additives are often used; anyway, their effects have to be carefully studied, according to the properties of both RAP and virgin bitumen. In this work, simulated aged bitumens were used to test the effects of two rejuvenating agents; rheological fundamental tests in steady and dynamic condition were carried out in a wide range of temperature using both shear and extensional kinematic conditions with the aim of investigating material behavior and additive effects both at high and low temperature. Moreover, the bitumen microstructure was investigated with Nuclear Magnetic Resonance (NMR) to better understand the change in material behavior. The rheological characterization has shown itself able to evidence the changes caused by simulated long- and short-term aging. Moreover, the positive effects of additives were highlighted at both high and low temperature and the rheological results were confirmed by NMR characterization showing that the most promising agent is able to restore a structure, based on asphaltene and maltene phases, very similar to those of the short-term aged system and virgin material. [ABSTRACT FROM AUTHOR]

The fundamental material for production of high-modulus asphalt (HMAC) is high modulus asphalt binder (HMAB), which is normally manufactured from hard-grade asphalt, rock asphalt modification, and polyolefin modification. This paper investigated rheological properties and performance of HMAB as compared to Styrene-Butadiene-Styrene (SBS) modified binder and neat binder using comprehensive laboratory performance tests. Specifically, the performance of HMAB modified with two different high modulus additives, rock asphalt (RA) and polyolefin (PR), were compared. The performance indicators include linear viscoelasticity characterized by temperature sweep and frequency sweep tests, rutting resistance by multiple-stress creep recovery (MSCR) test, and fatigue resistance by linear amplitude sweep (LAS) test. The effects of high-modulus modifier on master curve of dynamic shear modulus of HMAB were found identical. The temperature dependencies of asphalt binder were found to be significantly dependent on the material source of neat binder. However, the rutting resistance of HMAB modified by rock asphalt and polyolefin is better than that of SBS modified binder and neat binder. The polyolefin modified HMAB showed better rutting resistance than rock asphalt modified HMAB; while the comparison results was opposite for fatigue resistance. The simplified viscoelastic continuum damage (S-VECD) theory was employed to interpret the LAS test results for fatigue life prediction of asphalt binder. The SBS binder showed the best fatigue performance followed by HMAB and neat binder. [ABSTRACT FROM AUTHOR]

This study compares the behaviors of asphalt concrete level track and cant track under static and dynamic loadings. The asphalt tracks were constructed with attached and embedded gauges for measuring earth pressure, settlement of the structure, and strain at the bottom of asphalt layer. Full-scale tests were performed to simulate train movements on the rail tracks. According to the measurement results, there are certain differences in the earth pressure, settlement, and strain between level track and cant track, and between the outer and inner sides of cant track. Both level track and cant track are applicable in long-life service. [ABSTRACT FROM AUTHOR]

The purpose of this work is to research the influence of multi-dimensional nanomaterials composed of surface modified nano-zinc oxide (nano-ZnO) and organic expanded vermiculite (OEVMT) on rheological characteristics of styrene butadiene rubber modified asphalt (SBRMA) before and after different aging methods. The styrene butadiene rubber modified asphalts (SBRMAs) with various proportions multi-dimensional nanomaterials were produced by melt blending method. All binders were aged by rolling thin film oven test (RTFOT), pressure aging vessel (PAV) and ultraviolet (UV) aging. Dynamic shear rheometer (DSR) was utilized to test the rheological properties of all samples, as well as the performance grade (PG) of all binders was checked. The results show that the addition of multi-dimensional nanomaterials can enhance the shear deformation resistance and elastic behavior of SBRMA. Based on the RTFOT, PAV and UV aging test results, both thermal oxidative and photo oxidative aging resistance of SBRMA can be improved significantly by introducing multi-dimensional nanomaterials. Moreover, the optimal proportion of multi-dimensional nanomaterials in SBRMA is confirmed as 1%OEVMT + 3%nano-ZnO. Besides, the PG test result verifies that the PG of SBRMA after 1%OEVMT + 3%nano-ZnO modifying maintains unchanged. [ABSTRACT FROM AUTHOR]

This study evaluated the potential use of wood lignin as partial substitute and performance modifier in asphalt binder. The rolling thin film oven (RTFO) and pressure aging vessel (PAV) methods were performed on asphalt samples to simulate different aging conditions. The Rotational Viscosity (RV), Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR) tests were utilized to explore the influence of adding lignin on the rheological properties of asphalt binder. The Fourier Transform Infrared Spectroscopy (FTIR) was used to evaluate the anti-aging performance of lignin on asphalt binder. The rutting resistance of lignin modified asphalt binder at the high temperature was evaluated using Multi Stress Creep and Recovery (MSCR) test, while the fatigue life of asphalt binder was characterized using Linear Amplitude Sweep (LAS) test. The viscosity test results showed that the addition of wood lignin into asphalt binder caused stiffening effect. The DSR and BBR test results implied that adding lignin positively affected high-temperature rutting performance without adversely influencing low-temperature. The MSCR results indicated that the lignin improved the elastic recovery and reduced non-recoverable deformation of asphalt binder. The FTIR results indicates that the presence of lignin can help resist the formation of carbonyl structure in the aging process, and thus improved aging resistance of asphalt binder. The LAS test results showed that fatigue resistance of asphalt was negatively affected by lignin. The study results suggest that wood lignin is a promising modifier for asphalt materials with economic savings and environmental benefits. [ABSTRACT FROM AUTHOR]

This study reports the results of a comprehensive experimental campaign aimed at demonstrating the feasibility of using river gravels in substitution of ordinary crushed aggregates for the production of high strength Steel Fiber-River Gravel-Self Compacting Concrete (SFRGSCC). Due to geomorphological reasons, the river gravels represent the most common type of aggregates used in Amazon region for ordinary structural concrete production but only few researches focused on the use of this kind of raw material for the production of high performance cement-based composites. In fact, the river gravels present different intrinsic characteristic in comparison with crushed rocks such as, higher density and elastic modulus, rounded shape with a smoother surface and a more brittle behavior. As a consequence, when embedded in a cement-based matrix they can significantly affect the rheology and mechanical performance of both self-compacting concrete matrices (RGSCC) and Fiber Reinforced Concrete (SFRGSCC). In this context, the present study firstly analyzes the physical and mechanical properties of the alternative aggregates and then, investigates how the complete replacement of crushed aggregate by river gravel can influence the flowability, segregation potential, yield stress and plastic viscosity of the RGSCC and SFRGSCC in the fresh state as well as the stress-strain behavior under compression, direct tension and bending in the hardened state. The results highlight as the river gravel aggregates shape and surface roughness have relevant effects on the concrete performance as they improve the concrete rheology increasing the concrete flowing and reducing the corresponding yield stress and entrapped air while, on the other hand, reduce the strain capacity of the matrix resulting in a more fragile mechanical response under compression, tension and bending. The addition of steel fiber to the RGSCC resulted being more beneficial than to the reference crushed aggregate SCC. The reinforcement significantly enhanced the RGSCC toughness being this improvement even more pronounced when the samples were submitted to direct tension and bending loads. [ABSTRACT FROM AUTHOR]

Chemically functionalized graphene oxide (GOM) was synthesized by the chemical reaction of polyether amine with graphene oxide (GO). The mechanical properties, rheological properties, dispersion effectiveness, slump retention behavior and the mechanism of GOM modified cement were also researched. The results show that GOM have more effective toughing function than cement with GO. And GOM can increase the slump flow of cement. The slump flow, the dispersion effectiveness and slump retention of GOM modified cement increased with the increasing molecular weight of polyether amine. The main chain (sheets structure) of GOM adsorbed on the cement surface, and the branched chains (polyether amine) stretched into the water. The electrostatic repulsive forces of adsorption layers and steric hindrance of branched chains endowed the good fluidity of cement. [ABSTRACT FROM AUTHOR]

The rheological properties of three asphalt cements containing reacted and activated rubber (RAR) are evaluated to quantify the relative effects of swelling, splitting, and absorption. Rheological testing and electron microscopy are used to measure the dynamic shear modulus, | G ∗ |, and rubber particle changes respectively. It is found that | G ∗ | increased for all RAR and that particles swell 15.8–49.3% with those in softer asphalt showing the greatest swelling. Micromechanical models are used to predict | G ∗ | of the materials. The Hashin and Christensen models are found to accurately predict the measured moduli after accounting for the swelling, splitting, and absorption. [ABSTRACT FROM AUTHOR]

This study is an investigation of the rheological properties of bituminous binders and the mechanical properties of hot mix asphalts (HMAs) when a combination of styrene-butadiene-styrene (SBS) and American Gilsonite (AG) is added to bitumen. In this work, HMAs were prepared with two binders containing a single additive (5% SBS and 18% AG) and three binders containing two different additives (4% SBS + 6% AG, 3%SBS + 10%AG, and 2% SBS + 13%AG), which have the same Superpave performance levels. Tests carried out on the mixes demonstrated that the most effective additives relative to Marshall stability, retained Marshall stability, and indirect tensile strength values were 18% AG and 3% SBS + 10% AG; the most effective additives relative to stiffness and fatigue life were 18% AG, 2% SBS + 13%AG, and 3% SBS + 10% AG; and the most effective additives against moisture-induced damage were 5% SBS, 2% SBS + 13%AG, and 3% SBS + 10% AG. A consideration of all of the study's findings indicate that the utilization of a combination of SBS and AG is provides more benefits than utilizations of SBS or AG alone. [ABSTRACT FROM AUTHOR]

Waste cooking oil (WCO), in many cases, can rejuvenate aged asphalt and restore its properties. However, the influence of WCO qualities on rejuvenation behaviors of aged asphalt has not been investigated in detail. The objective of this paper was to evaluate the effects of WCO viscosity and acid value on the basic, rheological, and chemical properties of a typical rejuvenated asphalt. Penetration, ring and ball (R and B) softening point, and ductility were tested to evaluate the influence of WCO qualities on basic properties of rejuvenated asphalts. Then, the rheological properties of rejuvenated asphalt were characterized based on rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR) test results. Further, SARA (saturates, aromatics, resins, and asphaltenes) fraction analysis and Fourier transform infrared spectroscopy (FTIR) tests were performed to investigate the effects of WCO qualities on asphalt chemical composition. Finally, grey correlation coefficients were calculated and the relationships between WCO qualities and rejuvenated asphalt properties were quantitatively evaluated. The experimental results indicated that WCO qualities influence the rejuvenation behaviors of aged asphalt significantly, and the WCO with higher qualities (low acid value and viscosity, as defined in this research) tends to achieve better rejuvenation effects. Based on the results of grey correlation analyses, the acid value is, relatively, a better indicator than viscosity in predicting the rejuvenation efficiency of WCO. The rejuvenation thresholds of WCO are varied with the categories of properties of rejuvenated asphalts, and WCO with an acid value of 0.4–0.7 mg KOH/g, or a viscosity of 140–540 mm2/s, can meet all of the performance requirements for asphalt rejuvenation used in this research. [ABSTRACT FROM AUTHOR]

Traditional rejuvenators normally have a great deal of heavy fuel oils to supply the light oil component of asphalt binders, which decreases throughout a long-term aging process. However, heavy fuel oils can easily volatilize at a high recycling temperature (above 180°C), and this leads to a limited portion of reclaimed asphalt pavement (RAP) materials utilized in the recycled asphalt mixture (with a recycling rate less than 30%). Vegetable oils are rich in unsaturated fatty acids, which are similar to the light oil components, and have a better temperature resistance. Therefore, there is potential that vegetable oils can be utilized to recover the aged asphalt binder based on the asphalt rejuvenating mechanism. In this study, two rejuvenators with waste cooking vegetable oils (corn oil and soybean oil) to replace heavy oils and a commercial rejuvenator were used to recover the aged asphalt (extracted from RAP materials) with different ratios (by weight of asphalt) of 2,4,6, 8, and 10%. Dynamic shear rheometer (DSR) and rotational viscosity (RV) tests were used to evaluate the physical properties of the recovered asphalt binder. The low-temperature performance of the recovered asphalt binder was also evaluated by the bending beam rheometer (BBR) test. The laboratory tests and statistical analysis of variance (ANOVA) results show that the vegetable oil rejuvenators can effectively decrease the viscosity and stiffness of aged asphalt binder, which is beneficial for both fatigue and low-temperature cracking resistance. Furthermore, the rejuvenator can lower the viscosity and stiffness of the aged asphalt binder with a larger amount of vegetable oil. Overall, the vegetable oil content (6% to 8%) in the rejuvenator is proposed for recovering the aged asphalt binder in consideration of the rutting resistance under high temperatures. [ABSTRACT FROM AUTHOR]

In this research, a polyphosphoric acid (PPA) additive was used to modify a performance graded binder (PG 58-22). Experimental program included use of three PPA contents (0.5%, 1%, and 1.5%) by weight of bitumen and use of antistripping limestone aggregates. High-temperature rheological properties of asphalt binders were evaluated through the frequency sweep test. Complex modulus test was also used to evaluate rutting characteristics of asphalt mixtures. Results showed that PPA significantly improved rutting resistance of both unmodified asphalt binder and unmodified asphalt mixture, especially for the asphalt binder. [ABSTRACT FROM PUBLISHER]

The present research study addresses the fatigue life of different asphalt mixtures by means of 4PBF test. To this end, the fatigue behavior of unmodified asphalt mixtures and modified mixtures with styrene-butadiene-styrene polymer and crumb rubber as modifier were investigated in low and medium strain levels. Results showed that there is an excellent correlation between the fatigue lives of different asphalt mixtures in terms of the dissipated energy approach. It can be observed from result that the amount of initial dissipated energy at the 50th loading cycle predicted the fatigue life of asphalt mixtures without performing millions of loading cycles. Furthermore, the initial dissipated approach provides more reliable results from fatigue life of asphalt mixtures in comparison to the traditional fatigue tests. [ABSTRACT FROM PUBLISHER]

The styrene-butadiene-styrene copolymer (SBS)–modified asphalt was aged by pressure aging vessel test. The effect of different content of rejuvenators on the physical and rheological properties of aged SBS-modified asphalt was investigated. The results showed that with the increase of the content, the physical and rheological properties of the aged SBS-modified asphalt are restored more significantly. Three kinds of rejuvenators were used to rejuvenate the properties of aged SBS-modified asphalt. It can be concluded that the improvement of rejuvenator-III on the properties of aged SBS-modified asphalt is the most obvious. The results also indicate that the rheological behavior of the aged SBS-modified asphalt is improved obviously by the rejuvenator. [ABSTRACT FROM AUTHOR]

The present work discusses the combined effect of High Density Polyethylene Homo polymer and Styrene-Butadiene-Styrene on properties of Viscosity Grade 30 asphalt commonly used in India. Six blends of binders were prepared using varying percentages of both polymers and were evaluated for rheological properties. Use of both polymers leads to higher viscosity, while blending with HDPH polymer only leads to marginal increase in viscosity when compared to unmodified binder. Comparison of dynamic modulus and phase angle master curves indicated, significant differences were found among master curves obtained with different aging conditions when compared to unaged condition especially at lower reduced frequencies. [ABSTRACT FROM PUBLISHER]

The group chemical composition of oil fractions refined at Kinef Ltd. is shown to change with time. The oxidation rate and penetration index of asphalt obtained from heavy residual increase as the penetration increases. The extensibility of road asphalt decreases markedly as the paraffin content increases. Road asphalt meeting PNST 1-2012 specifications was produced by compounding asphalts oxidized to different degrees. [ABSTRACT FROM AUTHOR]

Bituminous binders are thermoplastic liquids which behave as viscoelastic materials. Their deformation behavior can be determined by rheological parameters. The changes of both viscous and elastic properties with temperature and time are measured as the response of the material to deformation by periodic forces. The paper presents the most used parameters and rheological properties for the characterization of the rutting resistance of bituminous binders and asphalt mixtures. Rheological properties (G*, δ, η*) are determined for four bituminous binders (unmodified and polymer modified) at temperature 46 – 60 o C (80 o C). And resistance to deformation of asphalt concrete mixtures is determined by rutting test. The higher value of complex shear modulus, the stiffer bituminous binder is able to resist deformation. [ABSTRACT FROM AUTHOR]

The deformational properties and fatigue of asphalt courses are conditional for the design and assessment of semi-rigid and flexible pavements. The term Functional conditions includes properties of asphalt mixtures which are defined by various tests (fatigue test, rutting test, triaxial test). It is possible to use several types of tests to measure fatigue and complex modulus, but in our laboratory was carried out the Two-point Bending Test on trapezoid-shaped samples which was supplemented with the KATEMS assessment software. The long-term research lead to estimation of deformational characteristics and fatigue of different types of asphalt mixtures. The tests have shown a positive impact of additives (ground rubber, hydrate lime component) on the results of these mixtures. This article is focused on assessment of deformational properties and fatigue of selected types of asphalt mixtures. [ABSTRACT FROM AUTHOR]

Warm mix asphalt (WMA) has gradually become more popular in the roading industry as compared to HMA, WMA can bring numerous benefits, such as lower energy consumption, lower emissions, and higher ability of incorporating a high proportion of reclaimed asphalt pavement (RAP) in WMA mixtures. Incorporating RAP in WMA can increase the sustainability benefits and enhance the performance of WMA. This study investigated the performance of WMA adding RAP with different proportions, from 0 to 70% by mass of WMA. The performance of mixtures was compared with a control HMA. One type of binder, 80/100 penetration grade, and two types of additives were used, including a chemical warm mix additive and a rejuvenator. Tests were done on the binder’s viscosity and mechanical performance of mixtures such as moisture resistance, fatigue cracking and rutting resistance. The results showed that the two additives reduced the viscosity of the binder. Mixtures with the chemical additive performed better than other mixtures in terms of moisture resistance. Only WMA mixture with the rejuvenator showed a higher number of cycles to fatigue failure than the control HMA. For rutting resistance, the increase in RAP proportion greatly improved the performance of WMA mixtures. WMA without RAP had a lower number of cycles to reach maximum rut depth than the HMA. All WMA-RAP mixtures showed considerably better rutting resistance than the HMA. [ABSTRACT FROM AUTHOR]

This paper deals with fatigue and complex modulus for three hot mixes. The Brazilian asphalt binders used in this work are classified by penetration grade 10/20, 30/45 and 50/70. It was observed a critical temperature variation in the Cole-Cole plane and in the fatigue test, where the smallest strain for one million cycles occurs at 30 °C for the mixture with penetration grade binder 10/20, and at 20 °C for the mixture with penetration grade binder 30/45, in relation to the mixtures prepared with conventional penetration grade binder 50/70, in which larger viscous component of the modulus normally occurs at 10 °C. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate rutting, fatigue, and rheological performances of a SBS co-polymer modified binder (PMB40) blended with different percentages (i.e., 0%, 15%, 25% and 40%) of reclaimed asphalt pavement (RAP) binder. The change in viscosity, mixing and compaction temperatures, and temperature susceptibility of PMB40 binder mixed with RAP were measured using Brookfield viscometer. Furthermore, linear viscoelastic range (LVE) and time-temperature sweep tests were conducted to characterize binders. The rutting and fatigue performance of PMB40 binder with varying percentages of RAP was evaluated using multi stress creep and recovery (MSCR) and linear amplitude sweep (LAS) tests, respectively. The change in chemical composition of PMB40 binder with addition of RAP was determined by Fourier transform infrared (FTIR) spectroscopy. The results showed that addition of RAP makes PMB40 binder stiff and less temperature susceptible, however, it did not change mixing and compaction temperatures significantly. Furthermore, high temperature performance grade (PG) of PMB40 binder was unaltered with addition of RAP, which is contrary to findings reported in literature. The MSCR test showed significant reduction in recovery and increment in non-recoverable creep compliance of PMB40 binder with addition of RAP, indicating a poor rutting resistance of the binder with inclusion of RAP. The LAS test showed that rate of damage increases and number of cycles to fatigue failure of PMB40 binder decreases with addition of RAP. The FTIR test confirmed increase in sulfoxide and carbonyl content with addition of RAP. A good correlation was found for ICO and ISBS indices obtained from FTIR with rheological properties of PMB40 binder. It is to be noted that the findings presented in this paper are based on one modified binder and one RAP source, thus it is recommended that effects of different RAP sources on performance of SBS modified binder be studied in detail. Further, effects of ageing (short term and long term) should be studied to have insight into characterization of RAP blended binders. It is also recommended that binder's rheological performance tests be validated by conducting laboratory tests on asphalt mixes. [ABSTRACT FROM AUTHOR]