Oxidation Of Asphalt Research Articles

WITHDRAWN: Investigating the Polymer Structure Effects on SBS-Modified Asphalt Binders under Short-Term Aging through the Artificial Neural Networks, Genetic Algorithms, and Fuzzy Logic

SBS-modified asphalt (SBSMA) exhibits complicated aging behavior in the weathering environment due to oxidation of the matrix asphalt, degradation of the SBS, and disruption of the SBS-asphalt relationship. The weathering process of SBS-modified asphalt has been studied extensively. However, most of this research has taken a broad, environmental approach. This research delved into the nuanced effects of aging on low polymer-modified asphalt (LPMA) compositions integrated with a rejuvenating agent (RA), leveraging advanced computational intelligence methodologies. The study uniquely employed fuzzy logic, Artificial Neural Networks (ANN), and genetic algorithms to forecast and analyze the performance dynamics of distinct asphalt mixtures. Five asphalt mixtures were examined: a PG 58-28 binder served as the foundational benchmark, while the subsequent four used modified PG 58-28 with different ratios of Ethylene Vinyl Acetate (EVA) and sesame oil (RA). Assessment methodologies comprised the Resilient Modulus Test, Wheel Track Test, Flow Time, Direct Tension, and Quarter-Circle Bend tests. The ANN framework was instrumental in predicting rutting and crack trajectories, while fuzzy logic facilitated understanding the intricate interplays between component ratios and resultant performance metrics. Genetic algorithms optimized the EVA and RA ratios for enhanced efficacy. Initial results demonstrated that the amalgamation of EVA and RA strengthened the overall lifespan and rutting resilience of the asphalt composites. Enhanced blends, optimized using the genetic algorithm, exhibited improved resistance to initial crack formations relative to the baseline. As the aging process advanced, the modified blend's resilience to recurrent stress-induced cracks experienced minor reductions but paralleled the foundational benchmark. A harmonized combination, pinpointed via the genetic algorithm containing 6.5% EVA and 6% RA, emerged as the most proficient in amplifying durability, resistance against deformations, and immediate crack resistance.

Evaluation of the failure planes in concrete containing reclaimed asphalt pavement (RAP) aggregates

Asphalt cohesion failure is mostly attributed to the lower performance of concrete systems containing reclaimed asphalt pavement (RAP) aggregates. However, there could be other modes of failure depending on several parameters primarily the mineralogy of aggregates, rheology of asphalt binder, asphalt aging intensity, and characteristics of cement-mortar paste; identification of the dominating failure pattern may help in enhancing the potential of RAP for concrete composites. In the present study, the influence of these parameters on the failure mechanism of RAP concrete is studied by understanding the intermolecular interactions through surface-free energy concept and interfacial bond strengths adopting pull-off tensile strength approach; the studied materials are limestone (basic), granite (acidic), and sandstone (slightly acidic to neutral) as parent aggregates, three asphalt binders having viscosities in the range of 800–4800 P with and without aging (short & two stages of long term aging), and four cement-mortar systems with varying characteristics strength between 10 and 40 MPa (M10-M40). The results revealed that the failure mechanism in RAP-concrete is a function of all the studied variations. The failure mode associated with RAP-concrete made with granite aggregates was found to be mostly an adhesive failure at the aggregate-asphalt interface. Cohesive failures were dominant in limestone and sandstone aggregates when used for mortar grades ≤ M20, whereas, when the same combinations were used for higher mortar grades, they failed in adhesion mode at the mortar-asphalt interface. Also, the failure mechanism was observed to be dependent on the degree of oxidation of asphalt with aged asphalt mostly exhibiting cohesion failure.

Molecular simulation and experimental analysis on co-aging behaviors of SBS modifier and asphalt in SBS-modified asphalt

ABSTRACT Styrene-butadiene-styrene block copolymer (SBS) is the most commonly used asphalt modifier. Studying the aging process of SBS-modified asphalt and clarifying the role of SBS and asphalt in the aging process can provide a basis for the targeted regeneration of SBS-modified asphalt. In this research, the physical and chemical changes of SBS and asphalt in the aging process were studied by FTIR (Fourier Transform Infrared Spectroscopy) analysis and SARA (Saturate, Aromatic, Resin, and Asphaltene) analysis. The effects of the thermal oxidation of asphalt and SBS on the viscosity and tensile properties of the SBS-modified asphalt were investigated by Brookfield Rotational Viscosity Test, force ductility test, and molecular dynamics simulation. Furthermore, the influence of asphalt and SBS aging on the adhesion property of the asphalt-aggregate interface was analyzed. The results show that the impact of SBS aging on the increase of viscosity and tensile yield stress was far less than that of asphalt aging. The adhesion energy of the modified asphalt-silica interface increases with both aging of SBS and asphalt. SBS and asphalt jointly influence the performance of modified asphalt in the aging process, but asphalt aging is the dominant factor.

Degradation characteristics of SBS polymer and its contribution to weathering aging of modified asphalt

Under the weathering environment, the aging behavior of SBS-modified asphalt (SBSMA) is complex, including oxidation of matrix asphalt, degradation of SBS, and disruption of SBS-asphalt interaction. However, most studies on the weathering mechanism of SBS-modified asphalt have mainly been considered from its overall perspective and based on environmental variables. In order to investigate the aging mechanism of SBSMA more clearly, the paper proposes a novel method of SBS-independent weathering to determine the aging behavior of SBS under accelerated weathering conditions and its effect on the performance of modified asphalt. Finally, by correlating its samples (M1) with the behavior of different fresh SBSMA(M2) and weathering aged SBSMA(M3), the SBS effective content equation under weathering conditions and the conversion coefficient between different aging methods were determined. Furthermore, by analyzing the physicochemical properties of SBS polymers before and after weathering and comparing them with the calculated results of SBS effective content within modified asphalt, it is discussed that the swelling effect of SBS under this method differs due to different aging levels, which affects the complete separation of matrix asphalt oxidation and SBS degradation. The macroscopic rheological behavior of samples was evaluated by dynamic shear rheology experiments (DSR), the variation of their chemical component and molecular weight were analyzed by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC), and the microscopic network was observed by fluorescence microscopy (FM). The results illustrate that the degradation pattern of weathering SBS follows a single exponential decay function. The SBS effective content decreases to 66.7 %, 50 %, and 33.3 % after accelerated weathering for 5.8 h, 10.5 h, and 14.5 h, respectively. In addition, the conversion relationship between the effective content of SBS under two modes of SBS independent weathering aging and SBSMA weathering aging was established. The effective content of SBS within SBSMA at different service stages and its remaining modification capacity can be reasonably predicted by simple SBS weathering tests.

Engineered nanocomposites in asphalt binders

Abstract Recently, nanotechnology has been effectively used in the field of road pavement. Oxidation and aging of asphalt cause deterioration of road pavements and increase asphalt-related emissions. We propose an anti-aging strategy to interrupt the asphalt deterioration by using engineered clay/fumed silica nanocomposites. In this research, the morphological, chemical, thermal, mechanical, and rheological properties of nano-modified asphalt binders are meticulously analyzed in various conditions. The experiment results proved that this composite efficiently disrupts the chemical oxidation and decomposition in the mixture and reduces the aging rate. Remarkably, asphalt binder rheology experiments revealed that the addition of 0.2–0.3 wt% of nano-reinforced materials maximized their rheological resistance after short- and long-term aging. Moreover, nanoparticles improve the moisture resistance efficiency and in turn overcome the critical issue of moisture in low production temperature within the framework of warm mix asphalt technology. This cost-effective, facile, and scalable approach in warm mix asphalt mixtures can contribute to increased sustainability and lifespan of pavements and a reduction in greenhouse gas emissions.

Evaluation of NOx Reduction Effect and Impact on Asphalt Pavement of Surface Treatment Technology including TiO2 and Asphalt Rejuvenator

Nitrogen oxide (NOx), emitted at the highest rate among automobile exhaust gases, is the main cause of air pollution, and various construction technologies are being developed to reduce NOx emissions. In this study, the NOx reduction effect of surface treatment technology for road pavements, and the effect of the photocatalytic reaction on asphalt pavements, were evaluated using a photocatalyst. Three types of titanium dioxide (TiO2) were used as photocatalysts, and an asphalt rejuvenator used to recover aged asphalt was applied as a surface treatment agent. To evaluate the NOx reduction effect, a test device capable of testing large-sized specimens was manufactured and compared with the ISO method, which only allowed the testing of small specimens. In addition, the effect of TiO2 and the asphalt rejuvenator on the asphalt mixture was analyzed through chemical analysis. The test results of the newly manufactured mixed-tank photo reactor showed the same trend as the ISO test results concerning the evaluation of its NOx removal performance. As a result of the performance evaluation of the surface treatment using TiO2, the NO removal rate was up to 7.83% when Anatase-type TiO2 with excellent light efficiency was applied. In addition, when the rejuvenator was used, the oxidation of asphalt, caused by the photoreaction of TiO2, was reduced.

Analysis of relationship between component changes and performance degradation of Waste-Oil-Rejuvenated asphalt

In this study, the underlying causes of the performance degradation of three typical waste-oil-rejuvenated asphalts (i.e., asphalts rejuvenated by waste cooking oil (WCO), waste bio-oil (WBO), and waste engine oil (WEO)) after secondary aging are explored via SARA fractions analysis. The rejuvenation provided by WCO is found to be mainly based on supplementing aged asphalt with saturates, which causes the newly formed colloids to easily lose light components and exhibit low stability. Further, WEO contains some metal residues that catalyze the oxidation and polycondensation process of asphalt. Consequently, the performance of the asphalts rejuvenated separately by WCO and WEO is severely degraded during aging. By contrast, WBO has a stable colloidal structure and lacks ashes; thus, WBO-rejuvenated asphalt exhibits the most stable and reasonable performance degradation in the aging process. Our research suggests that the effect of rejuvenation on aged asphalt cannot be judged only by the difference between the performances of the rejuvenated asphalt and the original asphalt. The performance maintenance of the rejuvenated asphalt during the secondary aging process requires further investigation.

Nanoscale Evaluation of Multi-Walled Carbon Nanotube’s Performance on Resisting Oxidization of Asphalt

Nanotechnology has contributed significantly to different subfields of the construction industry, including asphalt pavement engineering. The improved properties and new functionalities of the nanomaterials have provided different desired properties of asphalt. In this study, the effectiveness of multi-walled carbon nanotubes (MWCNT) in resisting the oxidation of polymer-modified asphalt was measured. A total of three different percentages (0.5%, 1%, and 1.5%) of MWCNT were used to modify the Styrene-Butadiene (SB) and styrene–butadiene–styrene (SBS) modified asphalt (4% and 5%). The laboratory oxidized asphalt samples were evaluated by an atomic force microscopy machine. The oxidation of the polymer-MWCNT modified asphalt is measured by simulating the existing functional group of the asphalt and as a function of the adhesive force. It is observed that the use of MWCNT in SB and SBS can increase the resistance to oxidation.

Modeling the Oxidative Aging Kinetics and Pathways of Asphalt: A ReaxFF Molecular Dynamics Study

The ReaxFF molecular dynamics simulations, which can predict chemical reactions, were performed on integral asphalt and individual asphalt molecules at different temperatures and oxygen levels to investigate the oxidation mechanism of asphalt and develop a molecular model suitable for aged asphalt. The simulation of integral asphalt suggests that the main oxidation products of asphalt are C–O, H–O, and S–O bonds. The oxygen level has the greatest influence on the yield of C–O bonds, and the temperature has the greatest influence on the H–O bonds. The simulation of individual asphalt molecules indicated that the oxidation of asphalt is accompanied by the decomposition of the aromatic rings, and thus, the aromaticity of the oxidized asphalt is decreased. Oxidation of asphaltenes starts with the oxygen molecules attacking the aromatic ring and generating a ketone, while the initial reactions of the other components are diverse. In addition, the simulation results were validated with Fourier transform infrared spectroscopy and nuclear magnetic resonance tests and were used to study the effects of oxidation on the characteristics of asphalt. The results suggested that the introduction of oxygen-containing functional groups decreases the component compatibility of asphalt and causes the aged asphalt to be harder and more viscous.

Effect of thermal aging on high viscosity modified asphalt binder: Rheological property, chemical composition and phase morphology

Currently, the high viscosity modified asphalt (HVMA) is widely used in the porous asphalt pavement (PA) in China. HVMA provides good raveling resistance and rutting resistance for PA due to the excellent rheological property of it. However, the high construction temperature and the well-developed void structure of PA lead to a severe aging of HVMA. In order to understand the thermal aging behavior and mechanism of HVMA, the changes of rheological property, chemical composition, and phase morphology of HVMA, SBS modified asphalt (SBSMA) and PEN70 asphalt (70#A) during thermal aging process were investigated in this study. Rotational viscosity (RV) test, frequency sweep test, and multiple stress creep recovery (MSCR) test were used to evaluate the rheological property of HVMA. Then, Fourier transform infrared spectroscopy (FTIR) test and Gel permeation chromatography (GPC) test were used to determine the effect of thermal aging on the chemical composition of HVMA. Moreover, the phase morphology of HVMA, and SBSMA were observed by Fluorescence microscopic (FM) test. Test results indicate that the rotational viscosity, softening point, and strain recovery of HVMA show a decreasing trend initially and then increase with the process of thermal aging. The polymer phase structure of HVMA degrades obviously in short-term aging process, which leads to a deteriorated rheological property of HVMA. After long-term aging, the oxidation of base asphalt is the main reason for the changes in rheological property of HVMA. The aging resistance of HVMA is better than 70#A and SBSMA. As the amount of polymers increases, the aging resistance of HVMA is further improved. During thermal aging process, the polymer phase structure of HVMA is more abundant than SBSMA, which contributes to the superior anti-aging property of HVMA.

Modelling of Asphalt's Adhesive Behaviour Using Classification and Regression Tree (CART) Analysis.

The modification by polymers and nanomaterials can significantly improve different properties of asphalt. However, during the service life, the oxidation affects the constituents of modified asphalt and subsequently results in deviation from the desired properties. One of the important properties affected due to oxidation is the adhesive properties of modified asphalt. In this study, the adhesive properties of asphalt modified with the polymers (styrene-butadiene-styrene and styrene-butadiene) and carbon nanotubes were investigated. Asphalt samples were aged in the laboratory by simulating the field conditions, and then adhesive properties were evaluated by different tips of atomic force microscopy (AFM) following the existing functional group in asphalt. Finally, a predictive modelling and machine learning technique called the classification and regression tree (CART) was used to predict the adhesive properties of modified asphalt subjected to oxidation. The parameters that affect the behaviour of asphalt have been used to predict the results using the CART. The results obtained from CART analysis were also compared with those from the regression model. It was observed that the CART analysis shows more explanatory relationships between different variables. The model can predict accurately the adhesive properties of modified asphalts considering the real field oxidation and chemistry of asphalt at a nanoscale.

One-Step Preparation of Green Fluorescent Graphene Quantum Dots from Petroleum Asphalt

Inherently benefiting from the natural nanosize graphene-structure in raw asphalt material. Asphalt-derived graphene quantum dots ( GQDs ) are prepared through, a facile route, one-step chemical oxidation of cheap petroleum asphalt. The as-prepared GQD sample may be well dissolved in water with a good homogeneous size at an average diameter of 2.44 nm, luminescing bright green light by excitation of 365 nm with a high quantum yield up to 16.13%. Furthermore, they are much smaller and thinner than most of the reported GQDs, presenting excellent fluorescent properties, such as excitation-tuned photoluminescence and good resistance to photobleaching. They are much smaller and thinner than most of the reported GQDs

A novel approach to evaluate fracture surfaces of aged and rejuvenator-restored asphalt using cryo-SEM and image analysis techniques

Low temperature cracking potential is a primary concern for asphalt mixtures with high RAP contents. To minimize the thermal cracking, various rejuvenators have been utilized in the past. In this study, Fourier Transform Infrared Spectroscopy (FTIR) was used to determine the level of oxidation of asphalt. To evaluate the low-temperature cracking potential of aged asphalt with and without rejuvenators, the fracture surface images were captured using Cryo-Scanning Electron Microscopy (Cryo-SEM). The Cryo-SEM images were then analyzed using the image processing technique. The rejuvenated asphalt specimens exhibited less fractured surface than the aged asphalt. Finally, the Fracture Index was computed to rank each asphalt sample in terms of low-temperature cracking potential. Based on the test results, it can be concluded that the use of the Cryo-SEM technology combined with the image processing technique is a promising method to visually observe the fracture surface of asphalt and compute the Fracture Index to estimate the low-temperature cracking susceptibility.

Thermooxidative aging mechanism of crumb‐rubber‐modified asphalt

ABSTRACTWe investigated the thermooxidative aging mechanism of crumb‐rubber‐modified asphalts (CRMAs) by tracing the evolution of the chemical structure and physical properties of CRMA during aging. The chemical structural evolution of crumb rubber (CR) in various aged CRMAs was characterized by measurement of the crosslink structure and composition of extracted CR. The residual asphalt of the aged CRMA was investigated by IR spectroscopy. The physical properties of CRMA were characterized by conventional testing before and after aging. We found that the change in the physical properties of CRMA correlated well with both the evolution of the rubber network and the oxidation of asphalt. The thermooxidative aging resistance of CRMA was improved with increasing CR dosage; this further illustrated that aging promoted the dissolution of CR into asphalt. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43323.

Evaluation of VMA and Film Thickness Requirements in Hot-Mix Asphalt

The asphaltic mixture consists of three main parts: the aggregate, the binder and air voids between the granules. The percentage of air void is important, where high air voids will produce crack sensitive pavement due to oxidation of asphalt or filling the voids by water which will cause striping of aggregate. The asphalt content is important too, where low content will increase stiffness of pavement and high content will increase skidding problems, therefore; the sum of air voids and asphalt content is called Voids in Mineral Aggregate (VMA), where it had been found by several researchers and transportation departments that VMA depends on maximum aggregate size where, for 19 mm maximum aggregate size, VMA is 14% and 13% for 12.5 mm aggregate size. Besides VMA, it had been found that average thickness of asphalt film coating the aggregate of 8 microns will produce durable mixture. VMA limit has not been included in Iraqi standards, therefore, this study focused on collecting literatures on these parameters, analyzing mixtures prepared under current standards to evaluate VMA and film thickness where, for surface course (12.5 mm aggregate size) VMA was 10% and film thickness was 9 microns and for binder course (19 mm aggregate size) VMA was 10% and film thickness was 9.6 microns. The final conclusion was to use VMA and film thickness as parameters in the design of asphaltic mixture as well as current standards and the study included the necessary equations to be used in the calculations of VMA and average film thickness.

Effect of Aging on the High-Temperature Rheological Properties of SBS Modified Asphalt

the aging existing in use and construction of bituminous pavement will directly resulting in shortening of the pavement’s service life. It is provide the theoretical basis of the design and construction of the SBS modified asphalt mixture to analyze the influence of aging to the rheological property of SBS modified asphalt under high temperature. The testing for the rheological property of three kinds SBS modified asphalt under high temperature has been finished before and after the aging in construction by Brookfield DV Ⅱ+ type of rotation viscometer. The results indicated that viscosity will be increased and the sensitivity of SBS modified asphalt to viscosity will also be lowered along with increase of aging degree. The testing for the rheological property of three kinds of SBS modified asphalt has been finished before and after aging in usage period by the dynamic shear rheometer (DSR). The results shown that G* will be continually increased along with increase of aging degree and this is consistent with change of base asphalt. And this shown that the increase of G* can only come down to oxidation and aging of base asphalt contained in the modified asphalt and also, asphaltene in SBS modified asphalt will be changing in the mode same with that of base asphalt.

UV-Aging Resistance of Packaging Waste PE Modified Asphalts

The recycled packaging waste PE was adopted to modify the asphalt and the UV-aging resistance of the modified asphalt was studied through the UV-aging experiment. The results showed that the changing trends of softening point aging index, penetration aging index, elastic recovery aging index and viscosity aging index at 135°C of the modified and unmodified asphalt are similar. FTIR analysis and the microscopic structure of the asphalt indicated that there existed two kinds of reactions taking place in the aging process of packing waste PE modified asphalt, the oxidation of raw asphalt and the aging of the polymer.

Improving the aging resistance of asphalt by addition of Zinc dialkyldithiophosphate

The aging properties of asphalts are evaluated using high pressure-gel permeation chromatography (HP-GPC) and Fourier Transform Infrared (FTIR) spectroscopy. The effect of a small amount (1 wt%) of zinc dialkyldithiophosphate (ZDDP) on the chemical and physical properties, and molecular weight distribution of asphalts is studied. The asphalts are aged by means of the Thin Film Oven Test (TFOT) under different conditions. The occurrence of carbonyl groups and the increase in asphalt molecular weight are the aging results in oxidation of base asphalt. ZDDP modified asphalts are resistant to the formation of carbonyl and can keep the asphalt molecular weight nearly unchanged, indicating the improvement of aging resistance of asphalts by the addition of ZDDP. ZDDP as an antioxidant can retard the oxidation of asphalt through the inhibition of peroxides and radical scavenging.

Effect of Oxygen Pressure on Asphalt Oxidation Kinetics

The oxidation of asphalt is a major cause of pavement failure. At a given temperature and pressure, the asphalt oxidizes in two stages: (1) a rapid-rate period followed by (2) a long period with constant oxidation rate. The degree of oxidation that occurs in the constant-oxidation region is asphalt-dependent and varies with oxygen pressure and with temperature. Using pavement-temperature oxidation kinetics obtained for eight asphalts in this study, it has been determined that the activation energies for the constant-rate region are dependent on the oxygen pressure and can be related to the asphaltene composition of the asphalt. An oxidation kinetic model is developed to predict the rate of oxidation in the constant-rate region knowing an initial asphaltene composition variable for the asphalt.

OXIDATION KINETICS OF ASPHALT CORBETT FRACTIONS AND COMPOSITIONAL DEPENDENCE OF ASPHALT OXIDATION

ABSTRACT This paper investigates the oxidation kinetics of asphalt generic fractions and the contribution of each individual fraction to the oxidation of the whole asphalt. Polar aromatic (PA) and naphthene aromatic (NA) fractions of five Strategic Highway Research Program (SHRP) core asphalts (AAA-1, AAD-1, AAF-1, AAG-1 and AAM-1) were prepared and aged at multiple conditions to obtain their kinetic parameters. Aromatics/saturates/asphaltenes blends of four of the five asphalts were also aged to deduce the influence of saturates and asphaltenes. Carbonyl growth in the PA and NA fractions as a result of oxidation follows a similar profile as the whole asphalts. The kinetic parameters of the NA fractions occur in two groups, one with high reaction order and activation energy, and the other with low values of each. The kinetic parameters of the PA fractions all fall into the low-values group. Although the PA fraction is the most reactive portion in an asphalt, its kinetic parameters (reaction order and activation energy) may be much different from those of its parent asphalt. Saturates have only a dilution effect. The data indicate that the addition of asphaltene increases the oxidation rate. The data also indicate that the PA and NA fractions age faster in a separated state than in a mixed state. This study shows that the kinetic characteristics of an asphalt are determined not only by the kinetic characteristics of the fractions but also by the interactions and molecular associations between the fractions.