Bending Beam Rheometer Research Articles

Evaluation of pine needle oil recycled asphalt: Rheological characterization and molecular dynamics simulation

The regenerant based on bio-oil has the potential to lower carbon emissions, conserve natural resources, and shows promising prospects for application. In this paper, pine needle oil (PNO) and dioctyl phthalate (DOP) were utilized as base materials for asphalt rejuvenator. The primary aim of this research was investigate the impact of the rejuvenator on the rheological characteristics of asphalt and the compatibility between the rejuvenator and aged asphalt. The rheological properties of the asphalt were evaluated by the bending beam rheometer (BBR) and the dynamic shear rheometer (DSR). The glass transition temperature of the asphalt was tested by differential scanning calorimetry (DSC). Finally, the glass transition temperature (Tg), mean square displacement (MSD), cohesive energy density (CED), and solubility parameter (δ) were calculated and analyzed through molecular dynamics simulation to clarify the mechanism of PNO and DOP on asphalt. In the tested temperature range, the creep stiffness modulus of the PNO compound DOP recycled asphalt had decreased by 43.7∼68.4 % compared with the aged asphalt, and the rutting factor had decreased by 59.6∼75.3 %, but it was still better than the original asphalt. This showed that the regenerant had significantly restored the rheological properties of the asphalt. At 413.15 K, the difference of solubility parameters between PNO and DOP was the lowest, which was 1.37 and 0.17 (J/cm3)0.5, respectively. At this time, the compatibility between the PNO regenerant and aged asphalt was the best. The addition of the PNO softened the aged asphalt, reduced the rutting factor, adjusted the composition of the aged asphalt, improved its colloidal structure, and thereby enhanced its low temperature performance. The PNO regenerant also improved the diffusion of the four components of the aged asphalt and positively influenced the diffusion and fusion process of the system. DOP molecules lowered the asphalt's glass transition temperature, increased the amount of free space available for the thermal motion of asphalt molecules, and improved the compatibility of the asphalt with the regenerant.

Effect of waste crab shell powder on matrix asphalt

Abstract In order to solve the problems of depleting petroleum asphalt resources and deteriorating pollution of marine products, a systematic study was carried out on the application prospect of waste crab shell (WS) powder as asphalt modifier. In this study, the physical properties of WS powder modified asphalt (WSA) were tested by blending different contents of WS powder into matrix asphalt; the high and low temperature rheological properties of WS powder modified asphalt were characterized by using Dynamic shear rheometer, Bending beam rheometer, and Multiple stress creep recovery test. In addition, the microscopic chemical properties and modification mechanism were analyzed by Differential scanning calorimetry, Fourier transform infrared spectroscopy, Atomic force microscopy, and Scanning electron microscope. It was shown that the WS powder enhanced the viscoelastic properties, temperature sensitivity properties, and permanent deformation resistance of asphalt. In addition, there was no obvious chemical reaction between the WS powder and the matrix asphalt, and no new chemical substances were generated; at the microscopic level, the WS powder and the matrix asphalt had good compatibility. In conclusion, the use of WS powder as a bio-based asphalt modifier to improve the resources and environmental issues have certain prospects.

Assessing pavement characteristics: An in-depth evaluation of waste engine oil and Buton rock asphalt composite modified asphalt and its mixture

To investigate the cooperative influence of waste engine oil (WEO) and Buton rock asphalt (BRA) on asphalt characteristics, the WEO/BRA composite modified asphalt and its mixture with varied dosages were prepared. The high-, moderate-, and low-temperature assessments of WEO/BRA composite modified asphalt were conducted through temperature sweep tests, multiple stress creep and recovery (MSCR), and bending beam rheometer (BBR) tests. The softening point difference was used to analyze the storage stability of composite modified asphalt. Based on the Fourier transform infrared spectroscopy (FTIR) and fluorescence microscope (FM) test, the microscopic feature and chemical constitution of WEO/BRA composite modified asphalt were analyzed. Rutting test, low-temperature bending test, immersed Marshall test, freeze-thaw splitting test, and four-point fatigue bending test were carried out to verify the pavement properties of the WEO/BRA composite modified asphalt mixture. The results indicated that WEO improved the capability in low-temperature conditions and fatigue properties of asphalt modified with BRA. BRA enhanced the high-temperature property of asphalt modified with WEO. The synergistic effect of WEO, BRA, and neat asphalt was a physical reaction, and these modifiers were uniformly distributed in the asphalt. Meanwhile, WEO/BRA composite modified asphalt had excellent storage stability for the single modified asphalt. The test results of the asphalt mixture verified the results, indicating that WEO/BRA composite modified asphalt can be considered a new green and durable asphalt pavement material.

Extraction solvents effect on asphalt binder properties

Asphalt industries are actively pursuing the integration of recycled asphalt pavement (RAP) into their constructions to promote sustainable pavement solutions amidst resource scarcity. However, challenges persist in the extraction and recovery processes, potentially affecting asphalt pavement performance assessments. This study investigates the impact of three common solvents—n-propyl bromide (nPB), trichloroethylene (TCE), and a toluene-ethanol blend (85 %/15 %)—on the rheological properties of recovered binders, particularly aiming to identify a substitute for TCE in light of its proposed ban by the Environmental Protection Agency (EPA) in the USA. Tests were conducted on six different performance-graded (PG) binders from diverse sources, assessing high-temperature properties using Dynamic Shear Rheometer (DSR) and Multiple Stress Creep Recovery (MSCR) tests, as well as low-temperature properties via Bending Beam Rheometer (BBR). Fourier Transform Infrared (FTIR) spectroscopy confirmed the absence of solvents in the recovered binders. Although minor variations were observed in measured properties between original and recovered binders due to solvent use, these differences did not affect the resulting performance grades. Thus, the toluene-ethanol blend can potentially substitute for TCE. However, it is noteworthy that the toluene-ethanol blend (85 %/15 %) displayed a slower solubility rate compared to nPB and TCE, underscoring the need for caution in its usage.

Performance evaluation of bio-oil and high rubber content modified asphalt: More effective waste utilization

In this study, the bio-oil was used to reduce the viscosity and preparation temperature of high content of rubber-modified asphalt. The high rubber content modified bio-asphalt (RMBA) was prepared, the rubber and bio-oil contents were 20 %-30 % and 5 %-15 % (mass ratio of neat asphalt), respectively. The viscosity, temperature sweep (TS), frequency sweep (FS), multi-stress creep recovery (MSCR), and bending beam rheometer (BBR) tests were performed to assess the properties of RMBA. The Fourier Transform infrared spectroscopy (FTIR), Fluorescence microscopy (FM), and Scanning electron microscope (SEM) tests were conducted to explore the microscopic morphology of RMBA. Besides, the economic analysis and life cycle assessment (LCA) were assessed. Bio-oil contributed to the viscosity-reduction of the RMBA. When the rubber content was 30 %, the viscosity decreased by 48.16 % with a bio-oil content of 15 %. The temperature and frequency sensitivity of RMBA were lower than neat asphalt. Rubber improved the creep recovery and anti-rutting deformation behavior for bio-asphalt. The absorption peaks appeared at 1010 and 1038 cm−1, which represented the SO function group. The rubber did not absorb enough bio-oil for solubilization. This resulted in the functional group of SO appeared in 30 %+B-10 % and R-30 %+B-15 %. FM and SEM test results indicated that the rubber in RMBA exists in different states: undissolved rubber and dissolved rubber. The high content rubber could be partially dissolved in bio-asphalt and retained its elastic properties. The dissolved rubber particles exhibited a large crosslinked network structure. The raw material cost of RMBA decreased significantly with the rise of rubber and bio-oil contents. The reasonable application of waste rubber is beneficial to the alleviation of black pollution. The efficient application of rubber and bio-oil could contribute to the development of waste utilization and green transportation.

Waste coffee biochar and bi-oil composite modified rejuvenated asphalt: Preparation, characterization, and performance evaluation

In the realm of sustainable road construction, bio-oil has emerged as a promising and eco-friendly alternative for rejuvenating aged asphalt. Nevertheless, challenges arise due to poor stability, diminished performance at elevated temperatures, and limited anti-aging properties. This study introduces an innovative approach by blending biochar, obtained from the pyrolysis of waste coffee grounds, into bio-oil to create a composite modified regenerator. Initially, the study conducts a microscopic characterization of the biochar using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Subsequently, the rheological properties of this composite rejuvenated asphalt are evaluated across low, moderate, and high-temperature ranges using bending beam rheometer (BBR), linear amplitude sweep (LAS), and multiple stress creep and recovery (MSCR) tests. Departing from the traditional emphasis on initial property restoration, it further delves into performance alterations after re-aging of rejuvenated asphalt through temperature sweep (TS) and Fourier transform infrared spectroscopy (FTIR) tests, providing a comprehensive assessment of the anti-aging characteristics of rejuvenated asphalt. Additionally, gel permeation chromatography (GPC) is employed to quantitatively analyze the changes in asphalt molecular weight distribution. The microscopic characterization reveals the development of a rough and porous structure within the biochar, facilitating enhanced adhesion and interaction between the rejuvenator and the asphalt binder. Moreover, bio-oil rejuvenated asphalt exhibits excellent low-temperature crack resistance and moderate-temperature fatigue resistance. Following the incorporation of biochar, notable enhancements in high-temperature rutting resistance and anti-aging properties are observed, validating the efficacy of the biochar with bio-oil composite modified regenerator. To achieve optimal performance outcomes, a biochar content of 6 % (as a proportion of aged asphalt), corresponding to a 1:1 ratio of biochar to bio-oil, is recommended. Under this condition, the properties of the composite modified rejuvenated asphalt demonstrate comparability to those of the original asphalt. In summary, this research underscores the potential for integrating waste coffee biochar material into infrastructure development, thereby promoting circular economy principles and advancing more sustainable construction practices.

Study on Rheological Properties of Waste Cooking Oil and Organic Montmorillonite Composite Recycled Asphalt

Pre-treated waste cooking oil (WCO) and organic montmorillonite (OMMT) were employed for the recycling of aged asphalt, which resulted in the improvement of the design of WCO asphalt rejuvenators and the enhancement of high-temperature performance of WCO-recycled asphalt. The effect of the rejuvenator and the properties of recycled asphalt were evaluated by viscosity, dynamic shear rheometer (DSR), bending beam rheometer (BBR) and scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) tests. The results indicated that aged asphalt could be obviously softened and restored to the level of original asphalt by adding 6% WCO. However, the high-temperature properties of recycled asphalt would be declined by adding too large a dose of WCO rejuvenator. The high-temperature performance of recycled asphalt was significantly improved by the WCO-OMMT complex rejuvenator, and the viscosity and rutting factor of recycled asphalt were increased. Light components of aged asphalt could be supplemented by WCO of the complex rejuvenator. The volatilization of small molecules could be slowed down by the peel structure formed by OMMT and small molecules of the asphalt, which resulted in the proportion of small molecular substances (SMS) being increased by 4% and improvement of the colloidal structure of aged asphalt. The high-temperature and low-temperature performance of recycled asphalt can be improved concurrently by the combination of 6% WCO and 1% OMMT, and this was evidenced by the fact that the high-temperature and low-temperature PG were all upgraded by one level.

Study on the low-temperature performance of chemically cross-linked polyethylene composite modified asphalt binder

The great disadvantage of polyethylene modified asphalt in terms of low-temperature performance has led to limitations in its large-scale application. The aim of this study was to investigate whether peroxides and silane coupling agents can significantly improve the low-temperature performance of modified asphalt through chemical cross-linking. Therefore, nine experimental groups were designed through orthogonal experiments, and the low-temperature properties of matrix asphalt, control asphalt, and nine modified asphalt groups were evaluated by using a bending beam rheometer, and microscopic analyses were carried out using FM, SEM, and FTIR tests. The experimental results showed that the 5 °C ductility increased to a maximum of 136.3 % and 166.2 % compared to the matrix asphalt and control asphalt, and the cross-linking between the polymer and the asphalt was enhanced microscopically. Chemical cross-linking of asphalt and polymer using peroxide and silane coupling agent provides a feasible method to expand the application of polymer in pavement engineering.

Effect of Chemical Composition on Rheological Properties of Asphalt Binders Modified with Rap Binders and Rejuvenator

Conventional rejuvenating agents such as virgin binders, polymers and so on, poses environmental, technical, and economic challenges. The objective of this study is to investigate the interaction between chemical components and rheological behavior of hot mix asphalt modified with RAP binder and diesel engine waste oil (DEWO) as rejuvenator. 7.2% DEWO was added to the RAP binder to achieve the modified binder (MB), and the effects of the rejuvenator through the MB were evaluated at varying percentages (0 to 100% by weight of the virgin binder) using Dynamic Shear Rheometer (DSR) under short and long-term aging at high and intermediate temperatures, as well as low temperatures using Bending Beam Rheometer (BBR). Saturates, aromatics, resins, and asphaltenes (SARA)-separation, Indirect tensile stiffness modulus test (ITSM), and fatigue life test were also employed to investigate the interaction between chemical components and rheological properties of binder. Results indicated that incorporating 50% modified RAP binder significantly enhanced the performance of the asphalt mixtures, it was also discovered that 100% of RAP content meets standard specifications when modified with oil rejuvenators. This research suggests that large quantities of diesel engine waste oil can be diverted from landfills and employed as useful resource in asphalt production.

Research on the Rheological Performance of Fast-Melting SBS-Modified Asphalt under Complex Environmental Factors

Currently, fast-melting SBS (Styrene-Butadiene-Styrene)-modified asphalt is widely used in pavements. However, in practical applications, complex environmental factors accelerate the deterioration of asphalt material properties, significantly affecting the service life of roads during their operational period. This study aims to examine the effects of complex environmental factors, including thermal oxidation, ultraviolet radiation, and various concentrations of salt solutions, on the high and low-temperature rheological properties of fast-melting SBS-modified asphalt (abbreviated as SBS-T-modified asphalt). Pressure aging–ultraviolet aging coupling and pressure aging–ultraviolet aging different concentration salt solution coupling were selected as the aging groups to simulate complex environmental conditions. Additionally, base asphalt and pressure-aged asphalt were used as control groups. The rheological properties of SBS-T-modified asphalt were evaluated using a dynamic shear rheometer (DSR) and bending beam rheometer (BBR). The results indicate that multiple-factor coupling aging reduces both the high-temperature and low-temperature performance of SBS-T-modified asphalt compared to single-factor aging, although the impact on rheological properties is not consistent across all conditions. After the combined effects of UV aging and pressure aging, the rutting resistance and high-temperature performance of SBS-T-modified asphalt are most severely impacted. However, when coupled with salt-solution aging, the rutting resistance of SBS-T-modified asphalt improves, with the complex modulus increasing by approximately 30%. This indicates that the presence of the salt solution enhances the high-temperature performance of the asphalt. An analysis of the low-temperature rheological properties of SBS-T-modified asphalt based on Burgers model shows that the low-temperature rheological performance of SBS-T-modified asphalt worsens under three-factor coupling aging compared to two-factor or single-factor aging, leading to poorer crack resistance. Notably, after adding salt solutions, the thermal sensitivity of SBS-T-modified asphalt increases significantly, with the ΔTc value decreasing approximately sixfold for every 2% increase in salt concentration.

Evaluation of foaming performance for polymer modified and virgin asphalt binders

The pavement suffers rapid deterioration as a result of the weak bonding strength exhibited by the foamed virgin asphalt in the mixture. Consequently, it is crucial to develop a modified asphalt suitable for foaming. The expansion height and bubble size of foamed asphalt can be continuously and simultaneously monitored by binocular ranging equipment. By analyzing these dynamic responses, the evolution of the spatial domain expansion characteristics and the geometric features of the surface bubbles of foamed thermoplastic resin modified asphalt (TRA) was analyzed. Meanwhile, multi-stress creep recovery (MSCR) and bending beam rheometer (BBR) tests were conducted to analyze its rheological properties. Subsequently, the dispersibility of foamed TRA in the mixture was explored. The results showed that thermoplastic resin significantly improved the physical performance stability of foamed asphalt, as evidenced by an increase in its half-life by 2–3 times compared to the virgin asphalt when the dosage of thermoplastic resin reached 8 %. Foamed modified asphalt has fewer bubbles, but it has larger bubble sizes and more uniform distribution of bubbles. Meanwhile, the TRA exhibited excellent high-temperature deformation resistance and elastic recovery ability. The dispersion uniformity of foamed TRA in the mixture was superior to that of virgin asphalt. This study serves as a valuable reference for the exploration of foaming behavior in modified asphalt and the utilization of foamed modified asphalt in the mixture.

Sewage sludge ash as filler in asphalt mastic: Low-temperature towards high-temperature performance

The sewage sludge ash (SSA) is characterized as a by-product used in the pavement industry to mitigate the environmental risks, enhance the landfill capacity and conserve the non-renewable resources. This research utilized SSA as a filler substitute in asphalt mastic, and its performance-based properties from low towards high temperatures were evaluated. For this goal, the physical and chemical properties of SSA and rock powder (used as base filler) were determined using BET surface area measurement, X-ray fluorescence, and scanning electron microscopy tests. The performance of base and SSA-modified asphalt mastics in four filler/bitumen weight ratios (0.6, 0.8, 1, and 1.2) was investigated using dynamic shear rheometer, multiple stress creep and recovery, linear amplitude sweep, and bending beam rheometer tests across a wide temperature range. The results indicate that SSA has a higher specific surface area, better bitumen absorption, and lower density compared to the base filler. Additionally, unlike the acidic nature of the base filler, SSA possesses strong basic properties, leading to a stronger chemical bond with bitumen and enhanced resistance to aging, particularly at high temperatures. Moreover, the lower density of SSA escalates the amount of filler per unit volume of the SSA-modified asphalt mastic, leading to the increased stiffness and elasticity. This trend improves resistance to permanent deformation and cracking at medium temperatures, although it has an adverse effect on performance of mastic at low temperatures. Moreover, due to the improved performance of SSA-modified asphalt mastic, this study can contribute to the sustainable development of the pavement industry.

A comparative study into the effect of spent coffee powder and ash on improving the mechanical properties of bitumen

Nowadays, waste and renewable materials are used to modify bitumen and asphalt, reduce costs, decrease the use of natural resources, and maintain ecological balance, and have thus received much attention. This study aimed to improve the rheological properties of bitumen and reduce spent coffee grounds' (SCG) waste by partially replacing it with SCG powder and ash. SCG powder and ash were added in percentages of 0, 1, 3, 5, and 8 wt percent of bitumen to check the properties of control and modified bitumens. Microstructural properties were evaluated by Fourier transform infrared spectroscopy, thermal gravimetric analysis, X-ray fluorescence spectroscopy (XRF), and scanning electron microscopy (SEM). Penetration, softening point, and ductility tests were performed to check the physical properties of bitumens, along with the storage stability test. Rheological tests (viscosity, bending beam rheometer (BBR), dynamic shear rheometer (DSR), multiple stress creep and recovery (MSCR), and linear amplitude sweep (LAS) were also carried out. According to the BBR results, adding SCG powder up to −12 °C and adding SCG ash up to −6 °C increased the resistance to low temperatures. Based on DSR and MSCR results, SCG, either in the form of ash or powder, increased the resistance to rutting, and adding SCG ash improved the high temperature performance of bitumen by 1 grade. At 64 °C, adding 8 % of SCG powder increased the rutting resistance by 43 %, and adding SCG ash raised the rutting resistance by about 113 %. LAS results also showed that SCG ash outperforms SCG powder in fatigue. Although both SCG powder and ash performed well in high, moderate, and low temperatures, SCG powder performed better in cold regions, and SCG ash performed better in regions with temperate and tropical climates.

Effects of antioxidants on chemical and rheological properties of asphalt binders from different crude oil sources

Antioxidants can effectively mitigate or delay the oxidative aging degradation of asphalt binder, thereby improving pavement durability. While research has largely concentrated on the application of antioxidants to asphalt binders from a single source, limited studies have explored their effects on binders derived from different crude oil sources. Moreover, the relationship between the chemical and rheological properties of antioxidant-modified asphalt binders remains insufficiently understood. In this study, three antioxidants - zinc diethyldithiocarbamate (ZDC), Irganox 1010 and kraft lignin - were utilized and blended with base binders sourced from three distinct regions globally. Fourier transform infrared spectroscopy (FTIR) was utilized to analyze the impact of these antioxidants on the chemical composition of aged binders. Additionally, dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests were conducted to assess the high- and low-temperature performance of the antioxidant-modified binders, identifying the most effective antioxidant. The linear amplitude sweep (LAS) test further evaluated the performance of ZDC across binders from different crude oil sources. The results revealed three key findings: first, chemical functional group changes due to antioxidants are not always reflected in rheological performance; second, ZDC demonstrated superior performance across different base binders, as evidenced by improved aging indices, high-temperature rutting resistance, and enhanced fatigue and low-temperature cracking resistance; and third, asphalt binders from different crude oil sources exhibit varying sensitivities to antioxidant type and dosage. This study underscores the necessity of determining optimal antioxidant dosages for different asphalt binders, as the relationship between antioxidant dosage and effectiveness is not straightforward.

Study on the performance of ground melon vine straw fiber modified asphalt

In order to reduce the waste of resources and the pollution of ecological environment caused by the large amount of waste crop straw accumulation or incineration, and to realize the high-value utilization of waste straw resources, this paper adopts the mechanical crushing method, acid and alkali solution treatment method to prepare the groundnut seedling straw fibers, and compares and analyzes the micro-morphology and chemical composition and thermal stability of the groundnut seedling straw fibers prepared by the physical method, the NaOH solution method, and the HCL solution method, through the scanning electron microscope, infrared spectroscope and the thermogravimetric analysis test; secondly, the optimal blending range of the groundnut seedling straw fibers is preferred. Secondly, the optimal dosage range of ground melon vine straw fiber was selected, the preparation process of ground melon vine straw fiber modified asphalt was proposed, five different dosages of ground melon vine straw fiber modified asphalt were prepared, and the basic properties, viscosity and temperature characteristics, and storage stability of ground melon vine straw fiber modified asphalt were analyzed; and then, a dynamic shear rheometer was used. Dynamic Shear Rheometer and Bending Beam Rheometer tests were used to study the high and low temperature rheological properties and resistance to permanent deformation of ground melon vine straw fiber modified asphalt, and the optimal dosage of groundnut seedling straw fibers was determined; finally, through Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy tests, the chemical components of ground melon vine straw fiber modified asphalt were clarified, and the chemical components of ground melon vine straw fiber modified asphalt were revealed to be the most important. The toughening mechanism of ground melon vine straw fiber modified asphalt was revealed. The results showed that the chemical alkali treatment method was the best preparation process for groundnut straw fiber, and the process flow was to use NaOH solution with a mass fraction of 3 % to treat the ground melon vine straw fiber for 50 min at a temperature of 60 °C; compared with the matrix asphalt, the needle penetration and elongation of the ground melon vine straw fiber modified asphalt decreased with the increase of the blending amount, and the softening point, the equivalent softening point, and the temperature sensitivity of the asphalt increased. Sensitivity enhancement, softening point difference in line with the specification requirements, but the ductility in the low dosage improved; with the increase in the dosage of ground melon vine straw fiber, ground melon vine straw fiber modified asphalt rutting factor, creep modulus, 0.4 %–1 % dosage of the creep rate and creep recovery rate increased, while 1.3 %–1.6 % dosage of the creep rate and the amount of unrecoverable creep flexibility decreased The results show that 0.4 %–1.6 % dosage of melaleuca alternifolia straw fiber modified asphalt high temperature performance and resistance to permanent deformation performance, and 0.4 %–1 % dosage of melaleuca alternifolia straw fiber low temperature performance has also been improved, the overall consideration, to determine the optimal dosage of melaleuca alternifolia straw fiber 1 %; melaleuca alternifolia straw fibers (NaOH) and the asphalt combined with the production of new functional groups, and melaleuca alternifolia straw fibers with each other. Lap cross to form a fiber skeleton grid structure, can play a role in the entire material to transfer stress and crack resistance, asphalt to play the role of enhanced toughening effect.

Rheological and Aging Properties of Nano-Clay/SBS Composite-Modified Asphalt.

Nano-organic montmorillonite (OMMT) not only inhibits the harmful asphalt fume generation during the production and construction processes of asphalt mixtures but also effectively improves the performance of asphalt pavements. In order to prepare asphalt materials with smoke suppression effects and good road performance, this study selects nano-OMMT and SBS-modified asphalt for composite modification of asphalt mixtures and systematically investigates its road performance. Through the temperature sweep test, the frequency sweep test, the multiple stress creep recovery (MSCR) test, the bending beam rheometer (BBR) test, and the atomic force microscope (AFM) test, the high-temperature rheological properties, low-temperature rheological properties, high-temperature properties and aging resistance of the modified asphalt are studied. The research findings indicate that OMMT can effectively reduce the sensitivity of modified asphalt to load stress and improve its high-temperature rheological properties. SBS-modified asphalt shows increased creep stiffness and a decreased creep rate after OMMT modification, resulting in reduced flexibility and decreased low-temperature crack resistance. After short-term and long-term aging, the complex modulus aging index of OMMT/SBS composite-modified asphalt is lower than that of SBS-modified asphalt, and the phase angle aging index is higher than that of SBS-modified asphalt, demonstrating that OMMT enhances the aging resistance of SBS-modified asphalt. OMMT inhibits oxidation reactions in the asphalt matrix, reducing the formation of C=O and S=O bonds, thereby slowing down the aging process of modified asphalt and improving its aging resistance.

Synergistic effects of buton rock asphalt and BBOEA on the enhanced temperature resistance and flexibility of asphalt

To improve the toughness of transportation infrastructure and develop asphalt composite materials with both elasticity and toughness, this paper prepared Buton rock asphalt (BRA)/Bis[2-(2-butoxyethoxy)ethyl] adipate BBOEA composite modified asphalt. The evolution of high and low-temperature performance of the composite modified asphalt was explored through key asphalt indicators, dynamic shear rheology, and bending beam rheometer (BBR) tests. The performance improvement mechanism of the asphalt was investigated using Fourier transform infrared spectroscopy (FTIR). The addition of Buton rock asphalt effectively improved the high-temperature performance of the asphalt, raising the high-temperature PG grade from 64 to 70 and enhancing resistance to permanent deformation. The inclusion of 1.5 % BBOEA further enhanced low-temperature performance, reducing the stiffness modulus of BRA modified asphalt from 365 MPa to 260 MPa, a decrease of 26.9 %. This improvement is attributed to the polar adipate functional groups in BBOEA, which promote hydrogen bonding and dipole–dipole interactions with polar groups in the resins, reducing micelle size and asphalt rigidity. With the high-temperature performance remaining robust and low-temperature flexibility and strain relaxation greatly improved, the optimal BBOEA content is recommended at 1.5 % of the asphalt mass.

Development of eco-friendly and high-content rubberized asphalt modified by waste cooking oil desulfurized crumb rubber and waste crumb rubber

To conserve non-renewable petroleum-based asphalt resources and address the limitations of incorporating high-content waste crumb rubber (CR) in conventional crumb rubber modified asphalt (CRMA), this study examines the feasibility of utilizing waste cooking oil desulfurized crumb rubber (ODR) in conjunction with CR to prepare high-content rubberized asphalt (HCRA). The basic, chemical, rheological, and asphalt-aggregate adhesion properties of HCRA, both with and without a small quantity of styrene-butadiene-styrene (SBS) copolymer modifier, were evaluated using infrared spectroscopy (FTIR), dynamic shear rheometer (DSR), bending beam rheometer (BBR), asphalt-aggregate pull-off test, contact angle test, and atomic force microscopy (AFM). The results showed that the modification involving ODR and CR primarily constitutes a physical process, rather than a chemical reaction, as evidenced by the lack of new functional groups. Similarly, the addition of an SBS modifier predominantly results in physical modifications accompanied by minor chemical interactions. The improved desulfurization degree of ODR diminishes the elastic stiffening effect of CR on the matrix asphalt at the high-temperature (low-frequency) domain and reduces adhesion properties between HCRA and aggregates, while enhancing the flexibility of HCRA at the low-temperature (high-frequency) domain. The inclusion of a small quantity of SBS modifier allows HCRA to demonstrate high-temperature performance and adhesion properties on par with CRMA, alongside superior low-temperature stress relaxation, phase stability, storage stability, and water damage resistance. These attributes indicate that the HCRA with a small quantity of SBS modifier has a broader service temperature range compared to CRMA. This study achieves approximately 33.3 % replacement of asphalt materials while preserving the performance of rubberized asphalt.

Unveiling the composite rejuvenator efficacy on performance improvement of asphalt binder including high RAP contents

Since the incompatibility between crumb rubber (CR) and reclaimed asphalt binder (RAB) can cause sedimentation and limit its application, this study employed waste cooking oil (WCO) to pre-treat CR particles at different CR/WCO ratios, and assessed its impact on performance of asphalt binders including 30 % and 50 % RABs. Anti-aging and rejuvenation potentials of corresponding composite rejuvenators in binder blends were explored by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) tests, while the performance of corresponding binder blends was evaluated by bending beam rheometer (BBR), linear amplitude sweep (LAS), and multiple stress creep recovery (MSCR) tests. Furthermore, correlation analyses were performed to explore the relationships between the chemical and rheological parameters with a significance level below 0.05. The results confirmed the rejuvenation efficacy of composite rejuvenators in high RAB, and improvement in the critical low temperature of binder blends to a higher performance grade (PG) level compared to the non-treated CR modified binder. In addition, the fatigue cracking resistance was improved at the strain levels higher than 4 % in LAS test. However, the pre-swelled CR fairly compromised the rutting performance of binder blends compared to non-treated CR, its performance was still better than virgin binder. The correlation analysis suggested that it is possible to use chemical parameters as indicators for evaluating certain rheological properties.

Utilization of molybdenum tailings as an alternative mineral filler in asphalt mastic: Rheological performance and environmental aspects

The generation and accumulation of molybdenum tailings (MT) have led to various environmental problems. This paper explores the feasibility of MT as a filler instead of limestone filler (LF) from the perspective of asphalt mastic. The physical and chemical properties of LF and MT are analyzed using Laser particle size, X-ray diffraction, X-ray fluorescence, and scanning electron microscopy tests. Four filler/asphalt weight (F/A) ratios (0.3, 0.6, 0.9, 1.2) are selected to prepare asphalt mastic. The rotational viscosity test, dynamic shear rheometer test as well as bending beam rheometer test, were conducted to study the rheological properties of mastics. Results show that physical interactions dominate the interaction between MT and asphalt. MT particles have large particle size, rough surface and tight internal structure. MT is conducive to bonding with asphalt. MT increased the viscosity, complex modulus, rutting factor and creep stiffness of asphalt. MT reduced the viscosity temperature sensitivity index, phase angle and creep rate. From the perspective of rheological properties, MT has great potential as filler to replace LF in asphalt mixture and reduce environmental pollution.