Thin Film Oven Test Research Articles

The natural bitumen additive Selenizza® SLN: A promising alternative for producing high-performance asphalt mixes

The purpose of this paper is to highlight the benefits of using natural bitumen in the context of global environmental change and increasing transportation demands in terms of traffic volume and loads. Despite the advantages of using these additives as binder modifiers to implement high modulus asphalt mixes characterized by high stiffness, high durability, superior resistance to permanent deformation, and good fatigue resistance, they remain still largely unknown and far from being effectively exploited. The paper displays for the first time a collection of scientific data based on previously published research works, enriched by new laboratory testing, whose results are not published yet. It aims to provide a comprehensive understanding of various aspects of the natural bitumen Selenizza® (extracted from the deposit located in southeast Albania) and the role that this natural additive plays in achieving the desired asphalt pavement performance. The dynamic rheological and Modulated Differential Scanning Calorimetry (MDSC) analysis proved that natural bitumens are fully compatible with straight-run bitumen and contribute to increasing the consistency, viscosity, and stability of natural bitumen-modified binders. The Rolling Thin-Film Oven Test (RTFOT), followed by Pressure Aging Vessel (PAV) aging analysis of road bitumen modified with Selenizza®, revealed that the resulting binders are resistant to aging and relatively efficient at low temperatures. A Life Cycle Assessment study compared the environmental impact of the Albanian natural bitumen production process with that of conventional crude oil bitumen, leading to the conclusion that the CO2 emission released during the production of Selenizza® is reduced by approximately 44 % compared to that of crude oil bitumen. The various research works described in this paper provide evidence that the natural bitumen-based asphalt mixes feature enhanced quality in terms of mechanical and rheological properties compared to reference asphalt mixes produced with equivalent traditional paving grade bitumen.

Research on the anti-aging mechanism of SBS-modified asphalt compounded with multidimensional nanomaterials based on atomic force microscopy

Styrene-butadiene-styrene (SBS)-modified asphalt binders age during road service, affecting the road performance. To improve the anti-aging performance of SBS-modified asphalt, layered silicates (organically expanded vermiculite (OEVMT) and organic montmorillonite (OMMT)), which can reduce the oxidation behavior of asphalt, and nanometer-scale titania (nano-TiO2), which has good anti-ultraviolet aging properties, were selected for the preparation of composite modifiers due to their properties. The composite modifiers are multidimensional nanomaterials, OEVMT/TiO2 and OMMT/TiO2. The asphalt samples were aged by a thin film oven (TFOT) test, pressure aging vessel (PAV) test, and ultraviolet aging test. Through physical performance tests, rheological performance tests, and atomic force microscopy, the performance of asphalt samples before and after aging was analyzed, and the action mechanism of multidimensional nanomaterials was discussed. The test results showed that OEVMT/TiO2 or OMMT/TiO2 increased the viscosity and high-temperature performance of asphalt. The dispersibility and stability of the SBS modifier in asphalt were also improved. The addition of multidimensional nanomaterials to SBS-modified asphalt not only inhibited the oxidation rate of the asphalt but also reduced the impact of ultraviolet light on the asphalt during aging. As the degree of aging increased, the area of the “bee structure” in the asphalt gradually increased, and the surface roughness gradually decreased. However, the addition of OEVMT/TiO2 or OMMT/TiO2 to SBS-modified asphalt inhibited the increase in the area of the “bee structure” and improved the surface roughness of the aged asphalt. The comprehensive analysis found that the multidimensional nanomaterials improved the thermal-oxidative aging resistance and ultraviolet aging resistance of SBS-modified asphalt.

How Organic Waste Improves Bitumen’s Characteristics

The organic fraction derived from the differentiated collection of urban waste is mainly composed of fatty acids, medium molecular weight hydrocarbons and cellulose. This peculiar composition gave us insight into the possible use of organic waste to improve bitumen’s characteristics (possible antioxidant, regenerating and/ or viscosifying additive for road pavements). The issue of the disposal of organic waste is a global one and it’s constantly of increasing concern. This study looks to alleviate this problem by finding ways for this waste fraction to be utilized for the greater good- in this case, as an additive for bitumen binder in road pavements. The present study is focused on the use of waste as it is and waste treated by the FENTON process (treatment with ferrous sulphate and hydrogen peroxide solution). Dynamic Shear Rheology (DSR) and aging tests (Rolling Thin Film Oven Test, RTFOT) showed that two of the additives tested in this study proved effective: one can be utilised as a viscosifying agent and the other can be us ed as a filler.

Rheological and morphological evaluation of nanoclay modified asphalt binder

The performance characteristics of asphalt can be improved by using nanomaterials. In this study, the effect of nanoclay as an additive on the performance features of the asphalt binder was assessed; this nanoclay was produced from montmorillonite modified with organic compounds and hexadecyltrimethylammonium bromide additive. The structural properties of the additive were investigated using X-ray diffraction analysis. The morphological structure and modification mechanism of modified asphalt binders formed by adding the nanoclay to the asphalt were determined by two analyses namely scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. In addition, differential scanning calorimetry analysis was used in order to investigate the thermal properties of the additive and modified asphalt binders. The rheological and physical properties of the modified asphalt were measured using penetration, ductility, softening point, dynamic shear rheometer, rotational viscometer, rolling thin film oven test, and pressure-aging vessel. The results indicated that the additive increased the asphalt’s consistency rutting, and short-term aging resistance, and decreased fatigue resistance after long-term aging. In addition, the optimal additive concentration to enhance the performance features of the asphalt binder was found to be 8% based on the experimental data.

Chemical, Physical, and Rheological Evaluation of Aging Behaviors of Terminal Blend Rubberized Asphalt Binder

Terminal blend rubberized asphalt (TBRA) is widely used as binder of asphalt mixtures due to its technical characteristics of storage stability. However, its road performance deteriorates due to the aging process of TBRA. The purpose of this study is to evaluate the aging characteristics of TBRA binders containing 0%, 5%, 10%, 15%, and 20% content of crumb rubber (CR) by weight of the neat binder. All the binders were treated with rolling thin-film oven test (RTFOT) and pressure aging vessel (PAV), respectively. The chemical compositional changes were monitored by attenuated total reflection (ATR)-Fourier transform infrared spectroscopy (FTIR), and physical and rheological properties were tested on neat asphalt and TBRA binders. FTIR test results show that TBRA binders offer greater long-term aging resistance than the neat asphalt binder, and E10TB (10% by weight CR) exhibits the highest long-term aging resistance. With the increase of CR, the temperature sensitivity property of the TBRA binders increases, whereas their high-temperature stability decreases. After PAV aging, blending CRs into neat asphalt causes a higher phase angle aging index and Jnr aging index, and lower critical temperature aging index, complex modulus aging index, softening point increment, and rutting factor aging index, indicating their superior long-term aging resistance. Moreover, based on the correlation analysis, the critical temperature aging index (CTAI) has a good linear relationship with the physical aging index (SPI) and chemical aging index (ΔICA).

Aging Resistance of Silica Fume/Styrene-Butadiene-Styrene Composite-Modified Asphalt

The influences of silica fume content and aging on the rheological properties of silica fume/styrene-butadiene-styrene composite-modified asphalts were investigated via rolling thin-film oven test simulations. The asphalts rheological properties before and after aging were measured using three-major-indices, dynamic shear rheology, and bending beam rheometer tests. Fourier transform infrared spectroscopy was used to examine the changes in the functional groups of the asphalt. The silica fume did not chemically react with the modified asphalt, and its original structure was maintained. The aging resistance improved significantly after adding the silica fume. At 6% silica fume content, the relaxation of the asphalt was the highest, indicating that the asphalt had the best low-temperature crack resistance at this mixing proportion. Furthermore, the carbonyl index value of this sample exhibited the smallest increment among all of the samples, and this asphalt sample had the strongest short-term aging resistance. Thus, the optimum silica fume content in the composite-modified asphalt was determined to be 6%. This information may be used to fabricate an asphalt mixture that can improve the service life and aging resistance of pavements.

The pros and cons of using calcium lignosulfonate as a recycled anti-aging additive on engineering properties of bituminous mastics

High temperature and traffic loading are two primary threats for asphalt pavement during the pavement's life cycle. The mentioned threats lead to significant distractions, namely bitumen's oxidative aging, rutting, and fatigue failure. In this study, calcium lignosulfonate (CLS) obtained from lignin was investigated as an anti-aging bitumen additive. After morphology analysis of CLS particles based on field emission scanning electron microscopy (FESEM) technique, the CLS was mixed with the bitumen of 60/70 penetration grade at four quantities (i.e., 5%, 10%, 15%, and 20%). Then, the rolling thin film oven test (RTFOT) was used to simulate bitumen aging. In the next step, physical tests (penetration, softening point, and ductility), rheological tests (rotational viscosity and dynamic shear rheometer), and performance tests (multiple stress creep recovery and linear amplitude sweep) were conducted on both aged and un-aged samples. Finally, to evaluate the change of bitumen's chemical components during the aging process, the Fourier transform infrared spectroscopy (FTIR) was carried out. Results showed that CLS particles had a bumpy structure. Moreover, the addition of CLS into the bitumen increased the stiffness and high-temperature performance of bitumen. Although CLS modified bitumen needed more energy for mixing and compaction to compare with virgin bitumen, CLS modified bitumen had lower rutting susceptibility than virgin one. The presence of CLS within the bitumen increased the binder's brittleness, leading to fatigue life degradation. Based on FTIR analysis and aging indices, CLS as a recycled bitumen additive can significantly inhibit bitumen's oxidative reaction.

An Attempt to Track Two Grades of Road Bitumen from Different Plants Using Fourier Transform Infrared Spectroscopy.

This study aimed to evaluate the possibility of using Fourier Transform Infrared (FTIR) spectroscopy to track binders produced by three different plants: plants A, B, and C. The work included the quality assessment of 80 bituminous materials graded as BND 70/100 and 100/130 according to GOST 33133 (Russian interstate standard) and chemical analyses using FTIR spectroscopy. FTIR analyses were conducted before and after short-term ageing in a Rolling Thin Film Oven Test (RTFOT). Thus, the number of binder samples was multiplied by two (2) for a final total of 160 infrared (IR) spectra. All infrared spectra were normalised to ensure the reliability of results, and the standard deviation and variance coefficient were included. The principal purpose of the present work was to track the origin and the ageing extent of the bituminous binders under study.

Evaluating the Rheological, Chemical and Morphological Properties of SBS Modified Asphalt-Binder under Multiple Aging and Rejuvenation Cycles

To investigate the influence of multiple cycles of aging and rejuvenation on the rheological, chemical, and morphological properties of styrene–butadiene–styrene (SBS)-modified asphalt-binders, the asphalt-binders were aged using two laboratory simulation methods, namely a rolling thin film oven (RTFO) test for short-term aging and pressure aging vessel (PAV) for long-term aging. The asphalt-binders were then rejuvenated with three types of rejuvenators (Type I, II, and III) with different dosages (i.e., 6%, 10%, and 14% for the first, second, and third rejuvenation, respectively). A dynamic shear rheometer (DSR) was then used to analyze the effect of rejuvenators on the rheological properties of all the asphalt-binders. The changes in the functional groups and microscopic morphology in the process of multiple aging and rejuvenation cycles were studied using Fourier transform infrared (FTIR) and atomic force microscopy (AFM). The results indicated that the three rejuvenators could soften the stiffness and restore the microstructures of the aged asphalt-binders in the process of repeated aging and rejuvenation from DSR and AFM testing. Considering the rutting and fatigue properties, the Type I rejuvenator exhibited the potential to achieve the desired rejuvenation effects under multiple rejuvenation cycles. During the multiple aging and rejuvenation cycles, the aging resistance of SBSMA decreased gradually from the FTIR results. This inherently limited the number of repeated rejuvenation cycles. This research is conducive to promoting the application of repeated penetrating rejuvenation.

Physical and anti-aging characteristics of nano-TiO2/irganox 1010 composite modified asphalt

Asphalt aging is the main cause of fatigue failure from asphalt pavements, and it can be divided into thermaloxidative and ultraviolet (UV) aging. In this study, nano-TiO2/Irganox 1010 were added to neat asphalt to simultaneously improve the aging phenomenon of asphalt in a variety of complex conditions of asphalt. We then analyzed and discussed physical properties of nano-TiO2/Irganox 1010 modified asphalt composites. In addition, MSCR (Multiple Stress Creep Recovery) and DSR (Dynamic Shear Rheometer) rheological tests were performed on nano-TiO2/Irganox 1010 modified asphalt with different contents. Aging simulation of nano-TiO2/Irganox 1010 modified asphalt was conducted through the TFOT (The Thin Film Oven Test) and UV test, and microstructure of UV aging was analyzed through scanning electron microscopy. Data analysis showed that the nano-TiO2/Irganox 1010 increased softening point and reduced penetration (25 °C) and ductility (5 °C). The nano-TiO2/Irganox 1010 also improved the creep resistance and rheological properties of the composites. Finally, the analysis of test results under different conditions showed that the addition of nano-TiO2/Irganox 1010 significantly enhanced the ability of asphalt to deal with aging in a variety of complex environments.

Investigation of anti-aging mechanism of multi-dimensional nanomaterials modified asphalt by FTIR, NMR and GPC

Asphalt is susceptible to being aged when exposed to thermal, oxygen and photo environment during construction or service period. To solve this issue, researchers used different sorts of nanomaterials to bring improvements to anti-aging properties of asphalt. Multi-dimensional nanomaterials (MDN) are the substances composed of two or more kinds of nanomaterials with different dimensions. Previous studies have proved the anti-aging efficiency of MDN but its mechanism is still unclear. In this paper, base asphalt was firstly modified by 1% organic expanded vermiculite (OEVMT) and 3% inorganic particles (nano-zino oxide (ZnO), nano-silica (SiO2), nano-titania (TiO2)). Then thin film oven test (TFOT), pressure aging vessel (PAV) test and ultraviolet (UV) aging test were employed on all samples. Macroscopic properties changes were characterized by physical and rheological tests while microscopic chemical structure changes were observed by Fourier transform infrared spectrometer (FTIR), Nuclear transform infrared (NMR) and Gel permeation chromatography (GPC). Results showed that MDN decreases the increment in softening point, viscosity aging index and complex modulus aging index while increases the retained penetration and phase angle aging index. Meanwhile, the addition of MDN reduces length of straight chains of unaged materials shown by NMR results, which demonstrates that the internal friction decreases when asphalt molecules move. According to GPC results, the decreased amount of large molecules is attributed to the intercalated /exfoliated structure formed by OEVMT. FTIR test results illustrated that MDN is helpful to reduce the number of sulfoxide function groups because of the absorbing/ reflecting effects of inorganic nanoparticles on ultraviolet radiation.

Laboratory evaluation of the properties of high-cured crumb rubber modified asphalt containing sulfur and polymer after the oxidative aging procedure

The crumb rubber modified asphalt (CRMA) prepared by terminal blend (TB) process with high interaction temperature (260 °C) and extended curing time (6 h) is called high-cured CRMA, which has the characteristics of good storage stability and easy construction. The composition of the material has an important influence on the performance of high-cured CRMA after the oxidative aging procedure. In this study, the properties of high-cured CRMA containing sulfur and styrene–butadiene–styrene (SBS) after the oxidative aging procedure were studied. All binders were aged using rolling thin film oven test and pressure aging vessel, respectively. Fluorescence microscopy tests and rheological property tests of all binders were performed. The chemical composition of all binders was monitored using Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy. Fluorescence microscope observation shows that the particles of the SBS phase are significantly reduced and their distribution becomes uniform with the increase of the sulfur content in the high-cured crumb rubber hybrid binder before aging. Besides, the SBS phase in high-cured crumb rubber hybrid binder gradually decreases and the distribution becomes more uniform after aging. 0.3% sulfur has a certain effect on the rutting resistance of high-cured crumb rubber hybrid binder before aging, while low sulfur content has little effect on the rutting resistance. Moreover, sulfur can retard the growth of carbonyl groups of high-cured crumb rubber hybrid binder, and improve the resistance to thermal oxidation in the rheological indexes of high-cured crumb rubber hybrid binder.

Evaluating the Rheological Properties and ageing Resistance of Waste PET-Modified Bitumen Binder

Reusing waste plastic can significantly contribute to saving the environment from further pollution and the economy from extra expenses. Waste plastics have a vital role in the current asphalt applications. Trial sections of roads made with waste plastic modified asphalt during 2019 in Australia, highlighted the significant importance of laboratory assessments; however, they are yet to be conducted. This study investigates the impact of using local waste Polyethylene Terephthalate (PET) plastic in bitumen binder class C320, which is a common bitumen type used for local road surfacing in Australia. The evaluation of numerous contents of waste PET modified bitumen is carried out before and after ageing conditions. Dynamic Shear Rheometer (DSR), Rolling Thin Film Oven (RTFOT) and Pressure ageing Vessel (PAV) tests were utilised to examine the rutting, fatigue, and ageing of bitumen binder. The results displayed that the use of waste plastics results in enhanced rutting and ageing resistances. Based on DSR results, bitumen samples modified with waste PET display improved performance in terms of rising the complex shear modulus and reducing the bitumen’s susceptibility to deformation at high temperatures. Furthermore, 8% of waste PET increases the fatigue cracking resistance as it shows a low fatigue factor. Further rutting and fatigue tests on asphalt mixtures samples are recommended to better understand the mechanical properties of waste PET plastic on modified C320 asphalt mixtures.

Differential Scanning Calorimetry as a New Method to Evaluate the Effectiveness of Rejuvenating Agents in Bitumens

To date, few methods allow distinguishing a fluxing effect of an additive for bitumen from a regenerating effect. This research aims at identifying a method to accurately establish whether an oxidized bitumen has been regenerated or has simply been fluxed by a softener. Oxidized bitumens, simulating the aging process that results in road pavement lifetime, were prepared by the Rolling thin film oven test (RTFOT) procedure for 225 min and the Pressure Aging Vessel (PAV) procedure. Their asphaltene parts were extracted and analyzed by calorimetry (Differential Scanning Calorimetry DSC), and the results were compared with the presence and absence of a fluxing agent and real rejuvenators. The self-consistent results showed that the thermal properties of the asphaltene fractions is a sound probe to monitor the effect of rejuvenation clearly distinguishable from the mere fluxing effect. This preliminary study might allow the creation of standard protocols capable of identifying a priori the rejuvenating effect of an additive in the future. Furthermore, given the widespread use of calorimetry for the characterization, it tends to become a widely accessible and useful tool for this purpose in material characterization laboratories.

Laboratory Properties of Waste PET Plastic-Modified Asphalt Mixes

Commercial polymers have been used in pavement modification for decades; however, a major drawback of these polymers is their high cost. Waste plastic polymers could be used as a sustainable and cost-effective additive for improving asphalt properties, attaining combined environmental–economic benefits. Since 2019, in Australia, trial segments of roads have been built using waste materials, including plastic, requiring that laboratory evaluations first be carried out. This study aims to examine and evaluate the effect of using a domestic waste plastic, polyethylene terephthalate (PET), in modifying C320 bitumen. The assessment of several contents of PET-modified bitumen is carried out in two phases: modified bitumen binders and modified asphalt mixtures. Dynamic shear rheometer (DSR) and rolling thin film oven tests (RTFOT) were utilised to investigate the engineering properties and visco-elastic behaviour of plastic-modified bitumen binders. For evaluating the engineering properties of the plastic-modified asphalt mixtures, the Marshall stability, Marshall flow, Marshall quotient and rutting tests were conducted. The results demonstrated that 6–8% is the ideal percentage of waste plastic proposed to amend and enhance the stiffness and elasticity behaviour of asphalt binders. Furthermore, the 8% waste PET-modified asphalt mixture showed the most improvement in stability and rutting resistance, as indicated by increased Marshal stability, increased Marshall quotient and decreased rut depth. Future fatigue and modulus stiffness tests on waste plastic-modified asphalt mixtures are suggested to further investigate the mechanical properties.

Research on Aging Performance of AH-90 and PG70-28SBS Modified Asphalt

This paper studied the aging effect of the rolling thin film oven test (RTFOT) , pressurized aging vessel (PAV) and natural ultraviolet radiation aging method on AH-90 and PG70-28 asphalts. penetration degree , penetration degree index,softening point and ductility tests were used to evaluate the high temperature stability, low temperature split and temperature susceptibility of the two aged asphalts , it is pointed that the aging damaged the low temperature performance of the asphalts, improved the high temperature stability and the temperature susceptibility of the asphalts. Compared with the AH-90 asphalt, PG70-28 modified asphalt has better aging performance. The antiaging property and temperature susceptibility of two asphalts after ultraviolet photooxidation and thermal oxidation , were investigated by testing their viscosity index , antiaging index. which indicated that the viscosity index is correlative nearly with the penetration degree index and the influence of 10.5 kJ·cm-2 ultraviolet photooxidation on asphalt performance is more serious than PAV thermal oxidation. The results indicate that ultraviolet photooxidation research on asphalt is necessary in the intensive ultraviolet radiation region of Neimeng.

Development on recycling, aging simulation and regeneration methods of reclaimed styrene-butadiene-styrene modified asphalt

To develop the recycling, aging simulation and regeneration methods of reclaimed styrene-butadiene-styrene (SBS) modified asphalt, the centrifugation method of reclaimed asphalt pavement (RAP) was first optimized. Then the relationship between asphalt performance indexes and aging duration of rolling thin film oven test (RTFOT) was studied. Also, two regeneration methods of reclaimed asphalt were discussed and the regeneration mechanism was revealed by fluorescence microscope, Fourier transform infrared spectrometer and X-ray diffraction tests. Results indicate that RAP should be soaked by the trichloroethylene for 4 times and each time is for 30 min. The developed method for removing the mineral powder in the extraction solution through twice statically keeping and separating the extraction solution is feasible to replace the conventional method using high speed centrifuge. Afterwards, a practicable aging simulation method of SBS modified asphalt using the delayed RTFOT is developed, which shows obvious advantages in test efficiency and result accuracy. Moreover, the SBS modifier content of 4 wt% and the proportion between fresh SBS modified asphalt and reclaimed asphalt of 2:1 are proposed to reconstruct a network structure in rejuvenated asphalt I, improving the high-temperature thermal stability and low-temperature cracking resistance. The regenerant content of 9 wt% is recommended to add in reclaimed asphalt, increasing the content of light components in rejuvenated asphalt II and activating the secondary modification effect of residual SBS modifier, so that the low-temperature cracking resistance and anti-fatigue performance of rejuvenated asphalt II are improved. Finally, the content of aged products including sulfoxide, ketones and carboxylic acids in the rejuvenated asphalt I and II samples are decreased, while the interlayer spacing and crystallite size are increased. The properties of reclaimed asphalt are regenerated using the developed regeneration method I and II. This study develops new recycling, aging simulation and regeneration methods of reclaimed SBS asphalt.

Laboratory and field ageing of SBS modified bitumen: Chemical properties and microstructural characterization

Styrene-butadiene-styrene (SBS) modified bitumen is a widely-used civil engineering material with a variety of applications. The properties and durability of bitumen greatly depend on its chemical composition. Due to its organic nature bitumen is highly prone to oxidation. The main cause of bitumen oxidation is the interplay of sunlight (photo-oxidation), atmospheric oxidation with reactive oxygen species (ROS), mechanical ageing and thermal oxidation. However, current standardized ageing methods, such as rolling thin film oven test (RTFOT) and pressure ageing vessel (PAV) do not include photo-oxidation and lack realistic ageing simulation. In this work, different laboratory aging procedures like PAV, RTFOT and UV radiation are applied to SBS modified binder. At the same time field aged bitumen with 19 years service in the road is analysed. The surface has been treated with UV radiation and ROS, resulting in deformation of surface microstructures and change in chemical composition. Since ageing mainly affects the surface of bitumen, a layer study on field aged bitumen samples was conducted to demonstrate ROS penetration depth. Fluorescence spectroscopy indicated that the ROS penetration mainly affected the first centimetres of the surface and a rapid decrease of ROS diffusion could be discovered. Fluorescence excitation-emission matrix (FEEM) results show that the overall fluorescence intensity decreases with ageing. The link between chemical and morphological change due to ageing could be given with fluorescence microscopy. The colloidal nature of bitumen exerts in the microstructural composition, which undergoes undergo a major chemical and morphological change with progressive ageing. We recorded the first fluorescence image of the typical surface microstructures with previously unattainable resolution with fluorescence microscopy, highlighting fluorescing Catana and Peri phase of the surface domains while Para phase exhibited less fluorescence intensity. The link between chemical and morphological change could be given with atomic force microscopy (AFM). Finally, AFM and fluorescence microscopy indicated that photo-oxidation promoted a gradual deformation of the chemically inhomogeneous surface structures toward shrink in size, deformation of the catana pattern and a drastic increase in microstructure height compared to neat bitumen, which encourages the importance of inclusion of atmospheric photo-oxidation to standardized bitumen testing methods. • Ageing trends of 19 years field aged unaged and laboratory aged bitumen. • Gradual decrease of reactive oxygen penetration depth into the bulk material. • Photooxidation causes major structural and chemical changes on the surface features. • Fluorescence microscopy demonstrates fluorescing catana and peri phase.

Effect of rejuvenator type and dosage on rheological properties of short-term aged binders

Using reclaimed asphalt pavement (RAP) material in pavement construction is typically an environmentally friendly practice. However, the asphalt available in RAP is already oxidized and stiffened due to various environmental processes. To compensate these problems, rejuvenators can be mixed with aged binder with the aim of restoring its original properties. This study investigates the performance of aged binders blended with three different types of rejuvenators. Thin film oven test aged PG 58–28 binder was mixed with raw waste cooking oil (R1), modified waste cooking oil (R2), and Hydrolene H90T (R3) at the concentrations of 3%, 6% and 9% by the weight of the total binder. To enhance rutting resistance, styrene–butadiene–styrene was also blended with rejuvenated binders and tested. Frequency sweep testing at a wide range of temperatures and frequencies was conducted in the Dynamic Shear Rheometer, and time–temperature superposition was used to obtain parameters including Superpave, Glover-Rowe, Shenoy, Crossover frequency and Rheological index parameters. In addition, the Multi Stress Creep Recovery test was performed to gain an in-depth understanding of the rutting performance of the binders. Based on the comparative study of different rejuvenated binders, the binder rejuvenated using a chemically modified waste cooking oil seems to most be effective in improving the overall performance of the binder without compromising its rutting resistance. In addition, the relationship between different cracking parameters indicated that they are not all compatible with each other in terms of ranking binder performance. Finally, the MSCR parameter seems to more effectively capture the influence of rejuvenation and SBS addition to rejuvenated binders more than other parameters.

Effects of short-term aging on the physical and rheological properties of plastic waste-modified bitumen

The current study aimed at examining the potential use of recycled low-density polyethylene (LDPE) plastic waste as a modifier for bituminous binders. Plastic bags were collected, cleaned, shredded and were characterized by using Fourier transform infrared spectroscopy analysis, thermogravimetry, and differential scanning calorimetry (TGA–DSC) test. The LDPE plastic waste was blended with 35/50 penetration grade bitumen at three concentrations (1%, 3%, and 5% by weight of bitumen). The physical properties of the modified bitumen were determined using softening point and penetration test, while the rheological properties were evaluated using a dynamic shear rheometer test. The tests were conducted on the unaged binders and on the rolling thin film oven test residue. The test results showed that when plastic waste had been added into bitumen, the penetration values decreased, whereas the softening point increased. Furthermore, the rheological properties were improved at high in-service temperatures leading to a decrease in thermal and kinetic sensitivities and an increase in the rutting resistance of bitumen. The modified bitumen with 3% of plastic waste was the most consistent and least sensitive to aging. In addition to improving the properties of bitumen binders, industrial waste use practices will also protect the environment.