Price of recycled asphalt + Buy and sell wholesale recycled asphalt
To accurately describe the self-healing behavior of recycled asphalt created by residue oil of straw liquefaction, five ROSL contents of 2%, 4%, 6%, 10%, and 15% were added to aged asphalt to represent recycled asphalt (ROSL).
recycled asphalt
ROSL-2, ROSL-4, ROSL-6, ROSL-10, and ROSL-15 are the names of the five ROSL contents.
The molecular simulation was used to simulate how nano cracks would heal. The decision was made to build a three-layer system with asphalt molecules on the outside and a 30 vacuum layer in the middle.
The vacuum layer represented the internal nano cracks in the asphalt. The results show that the combined effect of model volume compression and asphalt molecule stretching caused cracks to disappear during the self-healing process.
The van der Waals forces between molecules play an important role in self-healing. The ROSL content of recycled asphalt has a direct impact on how quickly it self-heals; the higher the ROSL content, the higher the diffusion coefficient, which is better for self-healing.
The ideal ROSL content is 10% because the time for ROSL-10 and ROSL-15 to reach the equilibrium distribution of relative concentration and density stability is essentially the same, and ROSL-10's diffusion coefficient is essentially the same as that of virgin asphalt.
Reusing leftover asphalt pavement components to create recycled asphalt pavement (RAP) benefits both solid waste reduction and raw material conservation, as well as lowering the cost of new road construction. It is one of the most recycled materials on the planet.
The asphalt in old pavement oxidizes and ages as a result of the combined effects of environment and load, changing its composition by causing the volatilization of light components and an increase in the concentration of polar molecules (such as asphaltene), which is easily agglomerated.
In comparison to virgin asphalt, RAP binder undergoes oxidation and hardening during the service period.
As a result, the combination of virgin asphalt and RAP binder produces a stiffer binder than virgin asphalt, raising a number of issues such as poor durability, peeling, and cracking3.
These problems can be solved by adding a rejuvenator to old asphalt, which softens the RAP asphalt binder and makes it more suitable for blending with new asphalt.
According to research4, rejuvenators can improve the characteristics of old asphalt while also conforming to specifications for new asphalt.
There are two types of rejuvenators: petroleum-based and bio-based5, but bio-based rejuvenators have received more attention due to economic and environmental considerations. Bio-oil made from used cooking oil, for example, can be used to soften aged asphalt.
It also improves low-temperature performance and workability, compensates for the light components of aged asphalt, and prevents polar components from polymerizing.
Asphalt molecular conformation can be restored using compound rejuvenators made from high-protein algae and high-fat animal manure, as well as the material's physical, chemical, and rheological properties.
Furthermore, Oldham et al. discovered that bio-oil made from pig manure can improve asphalt's resistance to water damage.
There are three types of rejuvenators, according to Zadshir et al.: bio-oil made from pig manure, chemically altered vegetable oil, and petroleum-based oil.
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According to their findings, the three rejuvenators effectively restored the thermodynamic properties of aged asphalt and balanced the disturbed colloidal structure of the asphalt9. They also succeeded in lowering the size ratio of macromolecules in aged asphalt.
Yu et alrejuvenators.'s were waste vegetable oil and aromatic extraction. However, the rejuvenators were unable to recreate the microstructure of the aged asphalt.
The findings revealed that recycled asphalt had mechanical properties that were comparable to both virgin and aged asphalt.
A rejuvenator made from soybean oil can lower the glass transition temperature of the asphalt binder and improve its low-temperature performance.
The asphalt mixture can be mixed at a lower temperature using waste wood bio-oil, which improves high-temperature performance but degrades medium- and low-temperature performance.
Recycled asphalt made from residue oil from straw liquefaction (ROSL) has good performance indices and can significantly improve the low-temperature capabilities of virgin asphalt.
According to Dong et al's investigation into the performance of recycled asphalt mixtures made from corn residue15, recycled asphalt can partially replace petroleum-based asphalt.
The studies already mentioned cover the research on bio-oil as a rejuvenator. All bio-oil rejuvenators improve asphalt performance, and some researchers have described the corresponding modification mechanism from a micro perspective.
Asphalt self-healing research has recently concentrated on the macroscopic, microscopic, and nanoscale levels.
For example, Bai et al. used a dynamic shear rheometer to assess the impact of oil derived from waste wood on the self-healing capabilities of recycled asphalt in terms of energy and chemical structure.
recycled asphalt pavement
Hao et al. investigated the effects of temperature, time, aging degree, damage degree, rejuvenator type, and rejuvenator content on the self-healing performance and fatigue life of recycled asphalt in a time scanning mode during fatigue healing and cyclic loading tests.
Su et al. investigated the self-healing mechanism of aged asphalt microencapsulated with a rejuvenator at the microscale using environmental scanning electron microscopy (ESEM), thermogravimetric analysis (TGA), and fluorescence microscopy.
The authors then used scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform attenuated total reflectance infrared (FTIR-ART) to examine the final state of the microcapsules in the asphalt binder after self-healing.
Atomic force microscopy (AFM) combined with the phase field method is an effective tool for studying the asphalt self-healing mechanism at the nanoscale. Furthermore, the molecular dynamics (MD) simulation technique is widely used at the nanoscale.
Numerous studies have been conducted on the self-healing capacity of asphalt, crack evolution during self-healing in asphalt, self-healing of asphalt with cohesive failure26.
self-healing and interfacial properties of rubber-modified asphalt, and self-healing characteristics of asphalt, which cover all aspects of factors affecting self-healing.
The preceding studies show that using MD as a nanoscale research technique provides a novel approach to understanding asphalt self-healing behavior.
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Finally, bio-oil from various sources can be used to revitalize asphalt, and previous research has shown that bio-oil has effective modification performance. Researchers have also briefly investigated the rejuvenator ROSL's modification performance.
However, the majority of these studies on ROSL-modified asphalt ignore the self-healing behavior and mechanism of ROSL on recycled asphalt in favor of focusing solely on macromechanical and micromechanical properties.
In order to investigate the aforementioned issues, the self-healing behavior of recycled asphalt prepared by ROSL is studied in this paper using MD simulations.
MD used the parameters for density, glass transition temperature, and solubility to create and validate the asphalt molecular model.
An interface system was created to study the evolution of the self-healing process by embedding a vacuum pad of 30 between two groups of asphalt models.
The diffusion rate factors were also compared between old and new asphalt. To make the figures and descriptions easier to understand, the terms ROSL and rejuvenator are used throughout the rest of this paper. ROSL is an abbreviation for residue oil of straw liquefaction.
Because of the complexity of the compounds that comprise asphalt, it is technically extremely difficult to separate the pure monomers of these compounds.
According to previous research, the physical and chemical properties of asphalt can be effectively studied by using an average molecular structure to represent real asphalt.
Asphaltene, aromatic, and saturate are the three main components of the three-component model, and the asphaltene structure is commonly used in the literature.
The asphalt model has evolved in recent years from component and component models to a component, molecule model.
Guo et al. described aromatics using dimethyl aphthalene and saturating molecular structure using n-docosane (n-C22H46). Asphaltene: saturate: aromatic = 20:20:6023 was the molecular mass ratio of the three components.
The majority of the 4-component model is made up of asphaltene, saturate, naphthene aromatic, and polar aromatic molecules.
Chu36 and Yu37 used the component asphalt model to investigate the interface interactions between asphalt and aggregate, as well as the interactions between asphalt molecules and water molecules. Their positive outcomes validated the model's effectiveness.
recycled asphalt path
The component, molecule model is currently the most widely used molecular model. It is constantly improved on the basis of the 3- and 4-component models and the component structures are more precise.
In Li et alproposed improved.'s 12-molecule asphalt model, the proportion of various molecular numbers was changed to make it more consistent with the three representative asphalts in the Strategic Highway Research Program (SHRP): AAA-1, AAK-1, and AAM-1.
The sensitive functional groups that are easily oxidized in virgin asphalt are replaced with ketones and sulfoxides in the aged asphalt model.
Hu and Qu et al. considered the oxidation level of asphalt molecules and suggested adjusting the number of ketones and sulfoxides to represent asphalt molecular models at various oxidation levels.
For this study, models of virgin asphalt and aged asphalt were built in accordance with AAA-1, and Cui et al. and Greenfield38 have previously confirmed that they are plausible.
The main constituents of ROSL have been chemically characterized using gas chromatography-mass spectrometry (GC-MS).
The concentration ratios of 2H-Pyran-2-one, tetrahydro-6-methyl, Dioxane, methyl, Propanoic acid, dimethyl, Butene, dimethoxy, and Epoxyhexanol are all 1:1.28:1.63:1.18:2.82, and the molecular number ratio calculated using these concentration ratios is 1:1:2:1:3.
To represent the molecular weight of recycled asphalt, five ROSL contents of 2% (3 ROSL molecules), 4% (6 ROSL molecules), 6% (10 ROSL molecules), 10% (17 ROSL molecules), and 15% (27 ROSL molecules) were added to the aged asphalt.
These ROSL contents are labelled ROSL-2, ROSL-4, ROSL-6, ROSL-10, and ROSL, in that order.
The time required for the relative concentration to reach a uniform distribution decreased by 15%. The 6% content was a watershed moment.
when compared to ROSL-4, the relative concentration of ROSL-6 took less time to reach a uniform distribution (330 to 140 ps) and the density to stabilize (355-255 ps).
Once the rejuvenator content reached 10%, the time it took for ROSL-10 to reach the equilibrium distribution of relative concentration and the time it took for the density to stabilize both decreased; however, the time difference between ROSL-10 and ROSL-6 was less than the time difference between ROSL-6 and ROSL-4.
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When the 15% content is compared to the 10% content, it is clear that ROSL-15 stabilized faster, albeit not by much, and that the time it took for their respective concentration distributions to reach a balanced distribution was close.
Furthermore, when the rejuvenator addition was 10%, the diffusion coefficient of ROSL-10 matched that of brand-new asphalt.
Although the diffusion coefficient of ROSL-15 was higher than that of ROSL-10, it is recommended that 10% of the rejuvenator content be used because adding too much rejuvenator could reduce the high-temperature performance of recycled asphalt and increase the likelihood of water damage.
It should be noted that asphalt ages for a variety of reasons and do not always age in the same way.
Qu et al. proposed 12 molecular models of short-term aged asphalt and long-term aged asphalt based on the Rolling Thin Film Oven Test (RTFOT) and the Pressure Aging Vessel (PAV) tests.
In this paper, his long-term aged asphalt model was used; 10% ROSL is appropriate for this long-term aged asphalt.
The suggested material has been confirmed by Ding et al. They put ROSL-prepared bio asphalt to the test.
The results showed that the bio-asphalt containing 10% ROSL performed well. The content of the ROSL is consistent with the recommendations made in this study.
New asphalt heals the fastest, while old asphalt heals the most slowly. The cracks in the aged asphalt did not disappear in the same simulation time, indicating that aging reduces the capacity of the asphalt for self-healing.
The recycled asphalt self-healing rate was in the middle of these two rates.
During the aged asphalt's self-healing process, there were several "platform periods," each lasting a longer period of time. Because the "platform period" occurred more frequently, the asphalt self-healing rate was slower.
Asphalt can be treated with Rejuvenator to improve self-healing and reduce the frequency of "platform periods."
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In recycled asphalt, the rejuvenator had the highest diffusion coefficient, followed by the saturate, polar aromatic, and naphthene aromatics, with asphaltene having the lowest diffusion coefficient.
As the rejuvenator content increased, the average molecular diffusion coefficient of recycled asphalt increased, and the average molecular diffusion coefficient of ROSL-10 was nearly equal to that of virgin asphalt.
By adding a rejuvenator, the intermolecular forces in old asphalt can be reduced while also increasing the molecules' capacity for diffusion.
As a result, recycled asphalt self-heals faster than old asphalt. Following a thorough analysis of the relative concentration distributions, density changes, and diffusion coefficients during the self-healing process, 10% was proposed as the ideal ROSL content.
The nanoscale self-healing behavior of recycled asphalt prepared by ROSL was investigated in this study. Despite not having been used in engineering, it provides strong theoretical justification for asphalt pavement reclamation.
Additional analysis of the microstructure and properties of recycled asphalts prepared with ROSL is required to determine the relationship between the components of recycled asphalt and service performance.
More research is needed to determine how temperature, crack width, and humidity affect recycled asphalt's self-healing capacity.
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