Amplitude Sweep Test Research Articles

Effect of PAN fiber with bionic layered surface structure generated in situ by Fenton reaction on performance of SBS/RP asphalt binder

• Innovative application of Fenton reaction in the modification of polyacrylonitrile fibers. • Biomimetic multi-layered structure modified polyacrylonitrile fibers. • KF-PAN/SBS/RP modified asphalt had better viscoelastic performance. • KF-PAN/SBS/RP modified asphalt had better low temperature anti-cracking performance, high temperature stability and fatigue damage resistance. • KF-PAN/SBS/RP modified asphalt had better rutting resistance and high temperature adhesion performance. In this study, a surface modified polyacrylonitrile fiber (KF-PAN) with a fish-scale whisker-like biomimetic hierarchical structure was successfully prepared via in situ competition effect of Fenton reaction. The modified fibers were used as secondary modifiers to prepare fiber-reinforced styrene–butadienestyrene (SBS) block copolymers and rubber powder (RP) modified asphalt binders (KF-PAN/SBS/RP). Energy dispersive spectroscopy, scanning electron microscopy, and atomic force microscopy analyses revealed the successful construction of bionic hierarchy on the fiber surface, and confirmed rough surface of the KF-PAN fibers. The hierarchical structure of the fiber surface acted as a buffer in the asphalt and strengthened the mutual interaction of the fiber and asphalt. Dynamic rheometer shear and strip-tensile tests showed that the KF-PAN/SBS/RP modified asphalt exhibited better viscoelasticity, rutting resistance, and tensile properties than the PAN/SBS/RP modified asphalt. The linear amplitude sweep test showed that KF-PAN/SBS/RP modified asphalt had better fatigue resistance. Thermogravimetric analysis tests indicated that the surface bionic structure of KF-PAN fibers boosted thermal stability of the fibers, which in turn enhanced the thermal stability of KF-PAN/SBS/RP modified asphalt. Fluorescence microscopy analysis showed that incorporating KF-PAN fibers improved the SBS and RP microstructure inside the asphalt, forming a good mesh structure, and alleviating the stress concentration phenomenon in SBS/RP asphalt under external traffic load.

Comparison of Rubber Asphalt with Polymer Asphalt under Long-Term Aging Conditions in Michigan

The objective of this study is to compare the long-term aging performance of dry-processed rubber-modified asphalt mixture with styrene–butadiene–styrene polymer-modified asphalt mixture on heavy traffic volume roads in the wet-freeze environment of Michigan. The rutting performance was evaluated using the Hamburg wheel track device. The disc-shaped compact tension test was used to assess the fracture energy. The dynamic modulus experiment was used to estimate the load and displacement relationship. The asphalt binder properties were evaluated using multiple stress creep recovery and the linear amplitude sweep test. The pavement distresses were evaluated using the pavement mechanistic–empirical design. All three types of asphalt mixture show excellent rutting resistance after long-term aging conditions, while the fracture energy of the rubber mix is 17.1% to 30.5% higher than that of the control mix and 6.8% to 9.1% higher than that of the polymer mix. The rubber and polymer incorporated with the asphalt binder improved the resistance to permanent deformation and improved the fatigue life of the asphalt binder. In summary, the rubberized asphalt technology using the dry process shows better cracking resistance and fatigue life. Therefore, rubberized asphalt using the dry process will exhibit adequate performance when used for high-volume roads in the wet-freeze environment of Michigan.

Effect of the fiber surface treatment on the mechanical performance of bamboo fiber modified asphalt binder

• The properties of silane-treated bamboo asphalt, alkali-treated bamboo asphalt, and heat-treated bamboo asphalt were evaluated and compared. • Silane-treated bamboo fibers exhibit the best interfacial properties with asphalt. • The rheological properties of treated fiber asphalt are improved compared to untreated fiber asphalt. • Silane-treated fiber asphalt has the longest fatigue life of the three treated fiber asphalts. Bamboo fibers exhibit better interfacial properties with asphalt after surface treatment. Therefore, it is essential to evaluate the effect of bamboo fiber surface treatment on asphalt properties. In this paper, the adhesion of bamboo fibers to asphalt after silane coupling agent, alkali treatment, and heat treatment was investigated. And the rheological properties and fatigue performance of the fiber asphalt binder were evaluated. The adhesion and stripping work of the fibers and asphalt were characterized by measuring the contact angle. The microstructure of treated fibers was analyzed using a scanning electron microscope (SEM). The thermal stability of the fibers was then evaluated by thermogravimetric analysis (TG). Finally, the rheological properties and fatigue performance of fiber asphalt were studied by Dynamic Shear Rheological test (DSR), Multiple Stress Creep Recovery Test (MSCR), and Linear Amplitude Sweep tests (LAS). In the SEM images, it can be observed that the silane-treated fibers have a rough surface and multiple independently existing fibers, which can provide support for the fact that the silane-treated fiber asphalt has favorable adhesion. In addition, the silane-treated fibers showed the most significant improvements in wettability and rheology. The adhesion work of silane-treated fibers was 66.7% greater than that of untreated fibers. All treated fiber asphalt showed better rheological properties than untreated fiber asphalt. The addition of treated fibers resulted in lower δ values, higher G*/sin δ, and increased fatigue life of the asphalt. Silane-treated fiber asphalt has the largest G*/sin δ and fatigue life of tested asphalt. Based on the results, several fiber treatment methods are evaluated, improving the reference for choosing a suitable fiber surface treatment for bamboo asphalt.

Structural build-up and breakdown of sodium hydroxide-activated slag paste assessed using oscillatory rheology

Concentrated suspensions of inorganic binders are thixotropic fluids with non-Newtonian behaviour. In addition to the physical-chemical interactions responsible for the flocculation of the particles, the rheological behaviour in time is affected by the formation of the reaction products. In this paper, this topic was tackled using oscillatory rheology, namely, by increasingly used measurements at the constant strain amplitude and frequency over time (time sweep test), by the combination of these tests with an inserted rotational step (ORO test), and by almost unexplored oscillation amplitude sweep tests, leading to structural breakdown due to increasing strain amplitude. Common sodium hydroxide-activated slag paste was used for this purpose. The results showed that the recovery of the structure is not significantly altered if the sample is remixed at least after 30 minutes of reaction. In addition, the strain sweep tests suggested that the formation of the first reaction products started after about 15 minutes of reaction and had a decisive impact on the evolution of viscoelastic moduli and the corresponding stresses during this kind of test.

Design and evaluation of molecular organogel based on folic acid as a potential green drug carrier for oral route

Objective The low molecular weight organogels are interesting carriers for pharmaceutical compounds. However, their uses are limited due to the toxicity burden of the organic solvent used. Hence, this study aimed to prepare organogel using folic acid (FA) in different concentrations as a gelator for propylene glycol (PG) biocompatible solvent. Methods The simple mixing method followed by incubation in a water bath at 90 °C was used to prepare organogels. Then, formulations were assessed using different methods including differential scanning calorimetry (DSC), dropping method, attenuated total reflectance – Fourier transform infrared spectroscopy (ATR-FTIR), oscillatory rheology studies, scanning electron microscopy (SEM), and in vitro dissolution study. Results Gel formation and its consistency were highly depending on FA concentration. The results showed that increasing the concentration of FA in the organogel led to accelerating the gelation process, and the least amount of FA that could gel the PG was 0.25% w/w. However, higher concentrations were needed to create an organogel with excellent properties. The DSC and dropping studies revealed stable organogels formulations at body temperature. The ATR-FTIR showed interactions between the pteridine ring of FA and PG. The strain amplitude and frequency sweep tests demonstrated an increase in storage modulus values as the concentration of FA increased at 37 °C, which were frequency independent at high frequencies. In addition, the SEM exposed the fabrics like the structure of these organogels. Furthermore, the in vitro dissolution of organogel was pH-dependent, with a high possibility of taking place in the large intestine. Conclusion FA/PG organogel formulation is a promising carrier for drug and nutraceuticals compound for the oral delivery system.

Characterization of mortar film distribution of asphalt mixtures containing reclaimed asphalt pavement and its relationship with fracture performance using image analysis method

Fatigue cracking is an important pavement distress caused by repeated traffic loading that is known to be very sensitive to aging and climate conditions. A thorough understanding of the relationship between binder rheological and morphological characteristics and cracking resistance parameters of mixtures can contribute to the effective establishment of binder specifications. Therefore, this study aims to evaluate mortar film distribution and fatigue parameters of asphalt binder on fracture resistance of both virgin mixtures and recycled mixtures containing various softening oils and Reclaimed Asphalt Pavement (RAP). The mixtures were subjected to the short-term oven aging (4 h), long-term oven aging (8 h), and extended-term oven aging (16 h) using loose mix aging protocol at 135 °C. The mortar thickness was analyzed by using the 2D image from the sliced asphalt mixture samples. The statistical analysis was conducted to investigate the factors affecting the fracture performance of both asphalt binder and asphalt mixture. The results indicate the CT index of the mixture from the indirect tensile asphalt cracking test (IDEAL-CT) is significantly related to the parameters A and B of asphalt binder from linear amplitude sweep (LAS) test and the thickness of mortar. The mortar film thickness cannot judge the performance of the asphalt mixture alone. It is clearly shown in this study that thicker mortar film thickness within the RAP mixture can delay the weakening of fatigue fracture performance due to aging effect at intermediate temperature. The findings of this study might lead to a better cross-scale understanding of the fracture behavior of RAP mixtures.

Investigation on Preparation Method of SBS-Modified Asphalt Based on MSCR, LAS, and Fluorescence Microscopy

The preparation method of SBS-modified asphalt has a direct effect on its overall performance. Currently, the optimal process is usually determined by conventional performance properties, such as softening point, ductility, and penetration, which may deviate from practical field performance. This study aims to investigate the influence of different preparation methods on the performance and microstructure of SBS-modified asphalt based on fluorescence microscopy testing, the multiple stress creep recovery (MSCR) test, the linear amplitude sweep (LAS) test, as well as Burgers model fitting. SBS-modified asphalt was prepared with different shear rates, shear temperatures, shear times, development time, and sulfur addition. The results show that the optimal process for preparing SBS-modified asphalt is 2 h of shearing at 180 °C and 4000 r/min, followed by sulfurization and 6 h of development. The performance of SBS-modified asphalt is most notably influenced by sulfurization, which forms C–S bonds to make the polymer network stronger, thereby improving the high-temperature performance as well as the fatigue resistance. However, due to high-temperature sensitivity, C–S bonds may break during development, leading to weakened performance. The performance of SBS-modified asphalt without sulfur addition shows a monotonically increasing trend with the extension of development time.

Viscoelasticity and shear resistance at the aggregate scale of structured and organic carbon-free Chernozems

Soil rheology characterises the flow behaviour of soils at the particle-particle to aggregate scale. Amplitude sweep tests (ASTs) are often the method of choice for parameterizing soil flow properties, such as the shear strain values at the end of the linear viscoelastic range (i.e., the deformation is mainly elastic) and at the yield point (i.e., elastic equals plastic deformation). Samples from seven soil profiles and five soil depths of Chernozems, collected in the Maidanetske study area, close to Uman City of Ukraine, were analysed to evaluate the effect of soil organic carbon (SOC) on the parameters related to soil microstructural stability derived from ASTs. Soil organic carbon was removed with H2O2 to determine the soil texture-dependent values of soil rheological properties, which were compared to the values determined for samples with intact water-stable aggregates. The shear resistance-related parameters increased for aggregated soil samples compared to SOC-free soil samples, indicating an increase in soil stability due to SOC. In contrast, the values of the overall viscoelasticity and the shear strain were reduced for aggregated soil samples, indicating decreased soil stability. Pedotransfer functions were applied to predict the shear strain-dependent loss and storage moduli and shear stress values as a function of SOC depletion. Coarse particles (630–2 000 μm) and volumetric water content improved the models. We conclude that increased SOC content, through the gluing and cementing effects of SOC and altered aggregate shapes compared to SOC-free soil materials, contributes to higher microstructural strength. However, the increased water content in the SOC-containing soil samples reversed soil strengthening effect. This was due to the fact that a more rapid increase in positive water pressure under shear stress weakened the samples and the spherical aggregates began to rotate more easily, thus loosing energy, when compared to platy particles of the SOC-free soil materials.

A novel experimental approach to quantitatively evaluate the printability of inks in 3D printing using two criteria

Material extrusion enables deposition of filaments with designed structures, and such sub-categories as direct ink writing brings increasing possibilities for the fabrication of multi-material and complex-shaped high-performance fully dense components. It has been well understood that the critical requirement for successful direct ink writing is the printability of inks. To address this challenge, a novel experimental approach that takes advantages of the developed rotational rheology test and capillary rheology test, has been proposed to evaluate the printability of inks that were prepared from the water-based slurries of Al 2 O 3 , Y 2 O 3 and Nd 2 O 3 ceramic powders according to the stoichiometry ratio of Y 3 Al 5 O 12 /Y 2.982 Nd 0.018 Al 5 O 12 with different additions of hydroxyethyl cellulose. The parameters including the low strain value (0.4%) within the linear viscoelastic region and the high shear rate (85 s -1 ) of the inks have been determined by the amplitude sweep test and theoretical analysis. Two criteria - storage modulus and extrusion stress - have been first introduced to assess the success of inks applicable in direct ink writing. Using these criteria, the excellent qualities of printable inks have been quantitatively defined with the values in the range of 2300–6000 Pa and 401–430 Pa, respectively. Moreover, results of capillary extrusion experiments have provided a useful insight into the technology development of suppressing the appearance of bubbles. Finally, the correctness of the proposed approach has been further examined by another transparent ceramic ink, and the in-line transmittance (84.4%) of the transparent ceramic at 1064 nm that is close to the theoretical value has been observed.

Potential of rheometry in detecting cohesive soils in Brazil as an additional tool to morphological field description and tensile resistance quantification

Although an experienced pedologist quickly identifies soils with a cohesive character (similar to hardsetting soils) directly in the field, advances in its correct diagnosis are needed, since the description requires wet and dry soil situations and relies upon qualitative aspects. Taxonomic systems usually consider metrics for other diagnostic attributes (clay fraction activity, abrupt textural change, etc.), but not for the cohesive character, although the latter is environmentally important and is referred to in soil taxonomy systems. Research is especially required at the microscale, where adhesive and cohesive forces are manifested as particle interactions. The aim of this study was to determine whether rheological properties obtained in amplitude sweep tests can serve as indicators of hardsetting or cohesive soils to improve the understanding of underlying processes in such soils. We analyzed soil samples from horizons identified as either cohesive or non-cohesive from six Brazilian soils (Typic Paleudalf, Ultic Hapludalf, Typic Hapludalf, Typic Paleustult, Kandiudox and Hapludox), separated by depth in top, middle and bottom layers. As rheological properties we determined: strain at the end of the linear viscoelastic range (LVR) (γLVR), shear stress at the end of the LVR (τLVR), strain at the yield point (YP) (γYP), storage and loss modulus at the YP (G′G″YP), maximum shear stress (τmax), strain at the maximum shear stress (γ τ max), and integral z (Iz). Cohesion only affected γLVR in the base position, and had a significant effect on τmax and γ τ max in the top and middle positions, respectively. Three soil materials did not reach the yield point. The Iz was either higher or lower in cohesive soils compared to non-cohesive soils. Where the Iz was higher in non-cohesive soils, this seems to be linked to a small dilatancy as a consequence of the high friction between soil particles. Also, τmax and Iz showed significant interactions of soil type and cohesion by means of a two-way ANOVA. Soil type had a greater effect on rheological properties, and the Typic Paleudalf had generally higher values. Parallely determined iron, organic carbon and clay contents, bulk density and normal force at the beginning of the test had the greatest impact on rheology. Tensile strength, a property evaluated on the mesoscale, had the closest relationship with γτ max and τmax. In conclusion, rheometry can support common analyses to identify the cohesive character, however, for an independent evaluation based upon most sensitive rheological attributes, further testing is needed, with a greater diversity of soils and at different water contents. The possibility to promptly identify cohesive character by quantitative means is essential for effective measures for the mitigation of the mechanical impediments of cohesive soils for agriculture. With the existence of a single parameter to distinguish cohesiveness and its magnitude, different soil management strategies can be easily tested and compared to obtain greater soil workability and, therefore, improved fertility.

Effect of reactive ethylene terpolymer modification on bitumen’s microstructure, rheology, and porous asphalt mix properties

ABSTRACT The specific objective of this study was to investigate the effect of reactive ethylene terpolymer (RET) modification on bitumen properties at the nano and macro scales, as well as on porous asphalt (PA) mix properties. Measurements using the dynamic shear rheometer (DSR) and the bending beam rheometer (BBR) showed that RET modification of bitumen significantly improved the high-temperature properties, while intermediate- and low-temperature properties were similar to the base bitumen. The linear amplitude sweep (LAS) test conducted using the DSR showed that RET modification improved fatigue resistance. Consequently, chemical analysis and PeakForce™ Quantitative Nano-Mechanical™ (PF-QNM) atomic force microscopy (AFM) imaging were used to evaluate the microstructure and nanomechanical properties of the polymer modified bitumen (PMB) and the base bitumen before and after long-term ageing. The chemical analysis provided useful insights that complemented and helped to explain the AFM and rheology tests. The AFM results supported the LAS test findings in showing that RET modification improved the resistance of aged bitumens to cracking. The results of testing the PA mix showed significant improvements in moisture damage and ravelling resistance due to RET modification.

Evaluation of fatigue characteristics of asphalt mixtures using Cracking Tolerance index (CTIndex)

Evaluation of the cracking potential of asphalt mix during the design phase can considerably limit the fatigue cracking and increase the service life of the flexible pavement. Thus, attention needs to be paid to employing a simple yet reliable performance test indicator. Indirect Tension Asphalt Cracking Test (IDEAL-CT) is one such emerging test method and is widely used in research across the world. The present study examines the potential of using the cracking tolerance index (CTIndex) as an appropriate parameter to explain the fatigue resistance of mixtures with both unmodified and modified binders. This test can be conducted using a Marshall testing machine or multispeed tester, routinely used for asphalt mixture design in India and many other countries. To evaluate the effectiveness of this parameter, fatigue resistance indicators for different binders, i.e., recovery at 3.2 kPa stress level (R3.2) from multiple stress creep and recovery (MSCR) test, fatigue life (TNf3.5) from the time sweep (TS) test at 3.5% strain, fatigue life at 2.5% (LNf2.5), and 5% (LNf5) strain from linear amplitude sweep (LAS) test, as well as for different mixtures, i.e., fatigue life from Indirect tensile fatigue test (ITFT) at 150 microstrain were considered. Two unmodified (viscosity grade 30, viscosity grade 40) and three modified (polymer, crumb rubber, sasobit) binders were evaluated for their fatigue parameters which were further correlated with CTIndex. The CTIndex exhibited good to excellent correlations (R2 ∼ 0.85 to 0.92) with the fatigue lives of the binders and the mixtures. To examine the effect of rheology and chemistry of the binder on the CTIndex, correlations of complex shear viscosity using Dynamic Shear Rheometer (DSR) at 60 °C and asphaltenes content from Thin-layer chromatography with flame ionization detector (TLC-FID) with CTIndex were explored. Viscosity, asphaltenes content, and elastic recovery of the binders depicted good correlations (R2 ∼ 0.88) with CTIndex, indicating higher cracking tolerance of stiffer yet elastic binders. Further, the sensitivity of CTIndex to binder type, binder content, aggregate gradation, and test temperature was examined. Overall, the values of the CTIndex displayed less variability (coefficient of variation < 10%) in this study.The observed sensitivity of CTIndex to asphalt mix parameters and the correlations of the CTIndex with fatigue resistance indicating parameters suggested that the CTIndex is an effective parameter for evaluating the fatigue characteristics of asphalt mixes.

Effect of Organic-Montmorillonite on rheological performance of Bio-Asphalt composites with various oxidative aging

Several previous studies have demonstrated that bio-asphalt derived from Waste Cooking Oil (WCO) displays superior performance in cracking resistance at low and medium temperature, but inferior in high temperature rutting resistance. This study aims to further improve the rutting resistance of WCO based bio-asphalt by a compound modification with Organized Montmorillonite (OMMT). One neat asphalt binder with penetration grade of 90 is selected in this study. The WCO based bio-oils are firstly mixed with neat binders followed by further modified with the OMMT additives. The frequency sweep, linear amplitude sweep (LAS) and multiple stress creep recovery (MSCR) tests are respectively conducted for evaluation of the linear viscoelastic properties, fatigue and rutting resistance. Experimental results demonstrate again that the fatigue resistances of bio-binders are improved compared to the base asphalt whereas the addition of bio-oil obviously reduces the binder rutting resistance at high temperature. However, the OMMT addition into the bio-asphalt is found to effectively enhance the rutting resistance when increasing the OMMT content without compromising the fatigue performance. Therefore, it can be preliminary concluded that the Bio/OMMT compound modification approach can be utilized to address the rutting potential concern of WCO based bio-binders at high temperature. Furthermore, the Response Surface Methodology (RSM) is employed to model the rheological properties of Bio/OMMT compound modified binder under various modifier weights, in which the damage characteristic and performance index can be effectively estimated.

Influence of pre-structure orientation on the linear viscoelastic limit of magnetorheological elastomers

Magnetorheological elastomers (MREs) have been developed as a new class of smart materials for such diverse applications as adaptive vibration control of systems and energy dissipation. The linear viscoelastic (LVE) behavior of MREs is expected to play a significant role in determining filler morphology (structure, size, and aspect ratio) and working conditions. The LVE behavior of pre-structures, especially anisotropic structures, has not been clearly explained. To this end, this study aimed to analyze the LVE behavior and dynamic properties according to different pre-structures of magnetic particles. This is based on MRE pre-structures oriented at 0°, 30°, 45°, and 90° using oscillatory shear excitation as a function of frequency and amplitude sweep tests. For the latter, the excitation frequency and magnetic field intensity were analyzed. These analyses were performed for both storage modulus and loss factor corresponding to 10% strain amplitude from the roughly level linear line of the LVE region. The results showed that increasing the frequency or magnetic field intensity to increase anisotropy reduced the LVE limit. For every oriented pre-structure and analyzed frequency tested, the magnetic field decreased the LVE limit. Thus, the orientation of the carbonyl iron particles in the matrix enhanced the viscoelastic properties.

Comparing different fatigue test methods at asphalt mastic level

Latest research is focused on predicting the fatigue behavior of asphalt mixtures through cost-effective and simple test methods on asphalt mastic level (asphalt binder + mineral fines). There are numerous fatigue test methods for asphalt binders and mastic using the dynamic shear rheometer (DSR). However, up to now, the results of the different fatigue tests on DSR have not been directly compared. Therefore, four different asphalt mastic mixes were prepared, and each was tested with the two most popular fatigue tests [linear amplitude sweep (LAS) test and time sweep (TS) test] and then compared to each other. The TS tests were performed as stress-controlled and as strain-controlled tests. All LAS and TS tests were performed with cylindrical and hyperbolic specimen shapes to identify impact of specimen shape. Different fatigue criteria were applied for evaluation to investigate the comparability of the results. Stress-controlled TS tests, strain-controlled TS tests, and LAS tests reveal different rankings of fatigue performance. However, a dissipated energy approach can combine stress-controlled and strain-controlled TS tests into one fatigue curve. The hyperbolic specimen shape can be used for TS tests and results in the same rankings. The hyperbolic specimen shape is not applicable for LAS tests. A calculation model could be derived to establish a relationship between the measured and actual stresses and strains in the necking of a hyperbolic specimen. TS tests using the dissipated energy approach appear to be the most promising mastic fatigue tests.

Effect of PET Size, Content and Mixing Process on the Rheological Characteristics of Flexible Pavement

The performance of asphalt binder reinforced with waste plastic polyethylene terephthalate (PET) was investigated. Penetration, ductility, softening point, and rotational viscosity tests were conducted to check the performance of the PET-reinforced pavement. The rheological properties of the binder were determined using amplitude sweep and frequency sweep tests and performance grade (PG) measurements of aged and unaged specimens. PET size, mix mechanism, and mix temperature significantly influenced the physical properties of the AB and the penetration index (PI). The size and content of PET had pronounced effects on the PI and softening point than the blending temperature. Increasing the size of PET particles from 75 to 150 μm and the content from 0% to 10% of the bitumen resulted in the reduction of the penetration and ductility values from 96 to 85 mm and 100 to 78 cm, respectively, whereas the softening point increased from 46 to 56.6 °C. As a result, the PI value of the binder increased, which indicates that the temperature susceptibility was improved. The addition of 10% PET increased the viscosity of the baseline bitumen by threefold upto a temperature of 135 °C and dropped it by fourfold when the temperature was raised to 165 °C. Increasing the PET from 0% to 10% and the temperature from 21.1 to 54.4 °C increased the critical strain value (LVER) by 96%.

Performance evaluation of surface-treated montmorillonite nanoclay-modified bitumen binder at high- and intermediate-temperature conditions

The present study was carried out to assess the effectiveness of surface treated Montmorillonite Nano Clay (NC) on performance of bitumen. The modification of bitumen was prepared using VG-30 grade bitumen with different percentages of NC by weight of bitumen (3% to 6%). Prior to mixing, surface of NC modified with Octadecyl amine and Aminopropyltriethoxysilane. Temperature susceptibility was evaluated using activation energy parameter. Rutting behavior was characterized using temperature sweep and multiple stress creep recovery tests. Fatigue performance was assessed using temperature sweep and linear amplitude sweep tests. Results inferred the potential benefit of NC in lowering the degree of temperature susceptibility. The trend of performance parameters indicate significant improvement in rutting and fatigue cracking resistance. Moreover, optimum dosage of surface treated NC was found to be 4.5% at which the binder showed significant improvement in resistance to rutting, fatigue and high temperature aging without affecting the storage stability property.

A sustainable high-viscosity modified asphalt modified with multiple anti-aging agents: Micro-chemical analysis and macro-rheological characterization

This study aimed to use aging inhibition technology to actively improve the environmental aging resistance, thus achieving the sustainable and long-life application of high-viscosity modified asphalt (HVMA). The sustainable HVMAs with different anti-aging agents was prepared, and the long-term environmental aging effect, including solar radiation, heat, and moisture, was simulated using the accelerated environmental aging tester. Then, the chemical and molecular composition of sustainable HVMAs were investigated using Fourier transform infrared spectroscopy test, X-ray photoelectron spectroscopy test, and gel permeation chromatography test. Afterwards, the nano-indentation test was used to study the nanomechanical property of sustainable HVMAs. Finally, the dynamic shear rheology test and linear amplitude sweep test were applied to evaluate the aging resistance, crack resistance, and fatigue resistance of sustainable HVMAs. The results show that environmental aging leads to the rapid oxidation of asphalt molecules and substantial degradation of polymer molecules in HVMA, as evidenced by the transformation of carbon elements from CC/CH bonds to CO/CO bonds and sulfur elements from CSC bonds to SO/OSO bonds. A single anti-aging agent has a little aging inhibition effect, while the compounding of multiple anti-aging agents has a synergistic anti-aging enhancement effect. The combination of UV absorbers and UV blocking agents can absorb/reflect some of the UV rays and delay the UV aging process. However, they cannot effectively prevent the binding of UV-excited reactive radicals with oxygen. In contrast, incorporating antioxidants can allow hydrogen atoms to combine with UV-excited reactive radicals and prevent further oxidation of asphalt molecules. The compound incorporation of UV absorbers, UV blocking agents, and antioxidants can improve the rheology property, crack resistance, and fatigue resistance of aged HVMA, thus effectively promoting the sustainable and long-life application of HVMA.

Implementation of the Linear Amplitude Sweep Test to Evaluate Fatigue Resistance of Highly Polymerized Asphalt Binders

Implementation of the Linear Amplitude Sweep Test to Evaluate Fatigue Resistance of Highly Polymerized Asphalt Binders

Reclamation of waste oils in asphalt modification towards enhanced low-temperature performance of pavement in cold region

ABSTRACT To decrease the usage of petroleum asphalt and improve waste recovery, two different groups of recycled oils were selected to improve the low-temperature performance of asphalt binders in cold region. The multiple stress creeps recovery (MSCR) test, linear amplitude sweep (LAS) test and bending beam rheometer (BBR) test were performed to evaluate the rheological properties of recycled oil modified asphalt (ROMA). The thermal stress and double edge notched tension (DENT) tests were employed to characterise the low-temperature cracking resistance and ductile resistance of the ROMA, respectively. The results of this study showed that recycled oils significantly improved the low-temperature and fatigue performance of asphalt, which is manifested in a drop in the low-temperature critical cracking temperature of asphalt by 3°C, increase in crack tip opening displacement (CTOD) by 72.8%, and extension of fatigue life by 178.9%. The addition of recycled oils reduced the percentage of large molecule size (LMS) while increasing the percentage of medium molecule size (MMS) of the asphalt, which contributes to the better low-temperature performance of the ROMA. The results from this study provide insights into the reclamation of waste oils and developing the low-temperature modifier of asphalt pavements in cold region.