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Advances in Regenerated Asphalt Mixtures

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Construction and Building Materials".

Deadline for manuscript submissions: closed (20 January 2023) | Viewed by 24729

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Guest Editor
School of Civil Engineering and Architecture, Wuhan Institute of Technology, Wuhan 430205, China
Interests: novol asphalt materials; fast-repairing asphalt concretes; anti-ultraviolet aging technologies for asphalt materials; road maintenance technology

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Guest Editor
School of Civil Engineering and Architecture, Wuhan Institute of Technology, Wuhan 430073, China
Interests: pavement; structure design; material evaluation; construction materials recycling
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Guest Editor
Associate Professor, School of Qilu Transportation, Shandong University, Jinan 250100, China
Interests: the design and characterization of high-performance pavement material; the itilization of solid waste; road engineering intelligent maintenance; the intelligent detection of traffic infrastructure
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
School of Civil Engineering and Built Environment, Liverpool John Moores University, Byrom Street, L3 3AF, Liverpool, UK
Interests: smart road materials and technologies; molecular dynamics simulations; multiscale and multiphysics modelling; fatigue damage and healing of bituminous materials

Special Issue Information

Dear Colleagues,

The recycling of asphalt mixtures has significant contributions towards the reduction in greenhouse gasses, pollution, natural resources and energy consumption. Sustainable road materials and technologies can provide a powerful boost to “carbon-neutral strategies”, and so it is crucial to continue moving forward towards improving these technologies and theories.

This Special Issue will cover new findings in the field of regenerated asphalt mixtures, including the high-content regeneration of RAP, cold recycling technologies, regenerated mechanisms, eco-regenerating agents and anti-aged materials. Additionally, novel materials, fast maintenance technologies and functional materials are also encouraged in this Special Issue, such as bio-asphalt materials, intelligent transportation, self-healing technologies, solid waste resource applications, numerical simulations, smart road materials and technologies, etc. Topics related to new experimental and theoretical studies regarding these fields are highly welcome in this Special Issue.

We are pleased to invite you to submit your research and related papers to us. As well as publishing papers, we also make papers accessible worldwide to increase their downloads and citations.

We look forward to receiving your contributions.

Dr. Yuanyuan Li
Prof. Dr. Tao Bai
Dr. Jizhe Zhang
Dr. Yangming Gao
Guest Editors

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Keywords

  • high-content regeneration of RAP
  • cold recycling technologies
  • eco-regenerating agents
  • anti-aged materials
  • bio-asphalt materials
  • intelligent transportation
  • self-healing technologies
  • solid waste resource application
  • numerical simulation
  • smart road materials and technologies

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Published Papers (13 papers)

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Editorial

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4 pages, 173 KiB  
Editorial
Advances in Regenerated Asphalt Mixtures
by Yuanyuan Li, Tao Bai, Jizhe Zhang and Yangming Gao
Materials 2023, 16(7), 2872; https://doi.org/10.3390/ma16072872 - 4 Apr 2023
Viewed by 1183
Abstract
This Special Issue is devoted to research on asphalt pavement materials, including asphalt binders, asphalt mixtures and recycled asphalt pavement (RAP) [...] Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)

Research

Jump to: Editorial

21 pages, 4477 KiB  
Article
Effect of Phosphogypsum Based Filler on the Performance of Asphalt Mortar and Mixture
by Jiuming Wan, Tao Han, Kaifei Li, Suxun Shu, Xiaodi Hu, Wenxia Gan and Zongwu Chen
Materials 2023, 16(6), 2486; https://doi.org/10.3390/ma16062486 - 21 Mar 2023
Cited by 4 | Viewed by 1355
Abstract
This study introduced phosphogypsum coupled with steel slag powder to prepare the phosphogypsum based filler (PF) for asphalt mixture. Penetration, penetration index, softening point, ductility, equivalent softening point, moisture stability of asphalt mortars with different steel slag powder content, filler-asphalt ratio, and PF [...] Read more.
This study introduced phosphogypsum coupled with steel slag powder to prepare the phosphogypsum based filler (PF) for asphalt mixture. Penetration, penetration index, softening point, ductility, equivalent softening point, moisture stability of asphalt mortars with different steel slag powder content, filler-asphalt ratio, and PF content were studied. Mechanical properties of PF based asphalt mortar (P-AM) were then analyzed to determine the optimum steel slag content in PF. Overall desirability method was used to determine the optimum replacement ratio of PF content in limestone filler. Rheological properties of P-AM were also analyzed through dynamic shear rheometer. Volumetric performance, high-temperature performance, low-temperature performance, and moisture stability tests were carried out on PF based AC-20 asphalt mixture. Results showed that P-AM presented the optimum performance when the content of steel slag powder was 23% by mass of phosphogypsum. Fatigue and rutting factor of asphalt mortar were enhanced by PF. The optimum PF content in replacing limestone filler was 75% through overall desirability evaluation. PF developed the high-temperature performance and moisture stability of asphalt mixture. Additionally, volumetric and low-temperature performance were not significantly affected by PF. It is suggested that using PF which is based on phosphogypsum as a filler of asphalt mixture to partially replace traditional limestone filler was adequate. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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19 pages, 7705 KiB  
Article
Influence of Filler Type and Rheological Properties of Asphalt Mastic on the Asphalt Mastic–Aggregate Interaction
by Guangxun E, Jizhe Zhang, Quanjun Shen, Ping Ji, Jing Wang and Yushuai Xiao
Materials 2023, 16(2), 574; https://doi.org/10.3390/ma16020574 - 6 Jan 2023
Cited by 10 | Viewed by 1975
Abstract
The asphalt mastic–aggregate interaction plays an important role in the overall properties of asphalt mixtures and their durability in service in flexible pavements. This paper aims to study the influence of the physico-chemical features of fillers and the rheological properties of asphalt mastics [...] Read more.
The asphalt mastic–aggregate interaction plays an important role in the overall properties of asphalt mixtures and their durability in service in flexible pavements. This paper aims to study the influence of the physico-chemical features of fillers and the rheological properties of asphalt mastics on the bonding behavior between asphalt and aggregate, and the interfacial deterioration mechanism when subjected to static water immersion and pressured water immersion. It was found that the filler type (limestone powder, basalt powder, and granite powder) had a certain influence on the complex modulus of asphalt mastics, and its pore volume and specific surface area had significant effects on the phase angles and permeability of asphalt mastics. The effect of water pressure can accelerate the deterioration of bond strength of the asphalt mastic–aggregate interface in the short term, indicating that the dynamic water pressure generated by the driving load promotes the water damage process in asphalt pavements. In comparison, the residual bond strength ratio of the granite–asphalt mastic aggregate was the highest, while its bond strength was lower than that of the interface between limestone–asphalt mastics and limestone aggregate. This demonstrated that a low asphalt mastic complex modulus and a high phase angle are helpful in improving the durability of asphalt mixtures subjected to static and pressured water immersion conditions. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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21 pages, 4671 KiB  
Article
Swelled Mechanism of Crumb Rubber and Technical Properties of Crumb Rubber Modified Bitumen
by Hongbin Zhu, Min Zhang, Yuanyuan Li, Yingxue Zou, Anqi Chen, Fu Wang, Langrun Liu, Dengjun Gu and Shaoyun Zhou
Materials 2022, 15(22), 7987; https://doi.org/10.3390/ma15227987 - 11 Nov 2022
Cited by 9 | Viewed by 2228
Abstract
Crumb rubber modified bitumen (CRMB) has excellent high-temperature performance and fatigue resistance, and is widely used in asphalt pavement to cope with increasing traffic axle load and changing climate. Under conventional preparation conditions, the swelling degree of CR can directly impact the comprehensive [...] Read more.
Crumb rubber modified bitumen (CRMB) has excellent high-temperature performance and fatigue resistance, and is widely used in asphalt pavement to cope with increasing traffic axle load and changing climate. Under conventional preparation conditions, the swelling degree of CR can directly impact the comprehensive properties of CRMB; however, physical and chemical properties research on swelling crumb rubber (SCR) and crumb rubber recycled bitumen (CRRB) in CRMB is relatively lacking. In this paper, the working performance of CRMB and CRRB in high-temperature and low-temperature conditions were studied through physical and working performance testing of bitumen. The CR and SCR were tested by scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR), gel permeation chromatography (GPC), and particle size distribution (PSD) tests to study the physicochemical behavior and microscopic effects before and after CR swelling. The results showed that CR dosage was in the range of 10%, 15%, and 20%, as well as that CR dosages have a positive effect on the high- and low-temperature performance, storage stability, and elastic recovery of bitumen. The high-temperature PG grades of bitumen were directly improved by four grades, and the elastic recovery rate increased by 339.9%. CR improved the ultra-low temperature crack resistance of bitumen. Due to the absorption of lighter components by CR, the relative content of the heavy component of bitumen increased; however, its low-temperature performance decreased significantly. After swelling, the CR particle size increased and the range became wider, the surface complexity of CR became higher, and the specific surface area was larger. At the same time, CR carried out the transformation process from large and medium molecules to small molecules. During the swelling process, a new benzene ring structure appeared in the CR, and the C–C bond and C–S bond of CR broke, forming part of the C=C bond. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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18 pages, 5186 KiB  
Article
Investigation of the Rheological Properties and Chemical Structure of Asphalt under Multiple Aging Conditions of Heat, UV and Aqueous Solution
by Yingxue Zou, Ling Pang, Shi Xu, Shaopeng Wu, Miao Yuan, Serji Amirkhanian, Haiqin Xu, Yang Lv and Xiang Gao
Materials 2022, 15(16), 5711; https://doi.org/10.3390/ma15165711 - 19 Aug 2022
Cited by 8 | Viewed by 1727
Abstract
During the service period, asphalt materials are affected by various natural factors, including heat, ultraviolet light, oxygen and moisture, etc., resulting in the reduction of pavement performance, the increase of pavement distress and shortening of service life. This study aims to investigate the [...] Read more.
During the service period, asphalt materials are affected by various natural factors, including heat, ultraviolet light, oxygen and moisture, etc., resulting in the reduction of pavement performance, the increase of pavement distress and shortening of service life. This study aims to investigate the aging performance of asphalt under multiple aging conditions of heat, UV and aqueous solution. Thermal-oxygen aging, UV aging and hydrostatic erosion tests were carried out sequentially on asphalt. The rheological properties, chemical structure and element composition of asphalt were characterized before and after aging, and the effect mechanism of multiple conditions was discussed. The results show that the multiple conditions of heat and UV can increase the rutting resistance and weaken the cracking resistance of asphalt. However, the effect degree of UV decreases gradually with the deepening of aging degree. Additionally, the effect of water on the physicochemical properties is less than that of UV; however, water can increase the sensitivity of physicochemical properties to UV. In summary, this study explored the short-term cycling effect of heat, light and water on asphalt and provided an idea for simulation test of asphalt under multiple aging condition. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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17 pages, 4281 KiB  
Article
Bionic Synthesis of Mussel-like Adhesive L-DMA and Its Effects on Asphalt Properties
by Jinyi Wu, Quantao Liu and Shaopeng Wu
Materials 2022, 15(15), 5351; https://doi.org/10.3390/ma15155351 - 3 Aug 2022
Cited by 3 | Viewed by 1673
Abstract
Cracks are inevitable during the service life of asphalt pavement and the water at the fracture surfaces tends to cause the grouting materials to fail. Studies have shown that the catechol groups in adhesion proteins secreted by mussels can produce strong adhesion performance [...] Read more.
Cracks are inevitable during the service life of asphalt pavement and the water at the fracture surfaces tends to cause the grouting materials to fail. Studies have shown that the catechol groups in adhesion proteins secreted by mussels can produce strong adhesion performance in the water. In this paper, the mussel-like adhesive L-Dopa Methacrylic anhydride (L-DMA) was prepared based on the concept of bionic design and used to improve the properties of asphalt. By using Fourier-transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA), the thermal stability and structural composition of L-DMA were investigated. Then, the rheological and low-temperature properties of L-DMA-modified asphalt were investigated using the dynamic shear rheological (DSR) test and bending beam rheological (BBR) test. Moreover, the modification mechanism was explored by FTIR. It was found that L-DMA can be effectively synthesized and has good thermal stability. The incorporation of L-DMA increases the composite modulus, viscosity, creep recovery rate and rutting factor of asphalt binder, resulting in an enhancement of its high-temperature performance. At a high L-DMA content of 10%, the low-temperature performance of the modified asphalt was enhanced. The modification of L-DMA to asphalt is mainly a physical process. Hydrogen bonds and conjugated systems generated by the introduction of catechol groups enhance the adhesion properties of asphalt. In general, L-DMA improves the properties of asphalt and theoretically can improve the water resistance of asphalt, which will be explored in future research. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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18 pages, 6696 KiB  
Article
Quantitative Assessment of Road Performance of Recycled Asphalt Mixtures Incorporated with Steel Slag
by Zipeng Wang, Shaopeng Wu, Chao Yang, Jun Xie, Yongli Xiao, Zenggang Zhao, Fusong Wang and Lei Zhang
Materials 2022, 15(14), 5005; https://doi.org/10.3390/ma15145005 - 19 Jul 2022
Cited by 11 | Viewed by 1901
Abstract
Circular utilization of reclaimed asphalt pavement (RAP) has received extensive attention for its economic and environmental benefits. The application of recycled asphalt mixtures (RAM) in the upper layer of asphalt pavement faces the issue of inferior anti-slip performance and durability. This study aims [...] Read more.
Circular utilization of reclaimed asphalt pavement (RAP) has received extensive attention for its economic and environmental benefits. The application of recycled asphalt mixtures (RAM) in the upper layer of asphalt pavement faces the issue of inferior anti-slip performance and durability. This study aims to recycle steel slag as virgin aggregates in RAM and quantitatively evaluate the service performance of RAM with steel slag. Steel slag and basalt RAM were firstly fabricated and the five different RAP contents were involved. Then tests of Marshall stability, indirect tensile strength and Cantabro spatter loss were conducted to investigate the moisture susceptibility of RAM. Moreover, their high temperature stability, crack resistance and skid resistance were characterized. Indirect tensile fatigue test combined with Hamburg wheel tracking test were carried out to discuss the durability of RAM. The comprehensive performance of RAM with steel slag were quantitatively assessed based on an improved radar chart evaluation method. The results show that involving steel slag reveals a remarkable enhancement function on water stability, high and low temperature performance, skid resistance and fatigue resistance of RAM. Steel slag RAM with 50% RAP content demonstrates a rutting depth of 7.60 mm and a creep slope of 2.54 × 10−4, indicating its superior durability in high temperature and water environment. Compared with the comprehensive evaluation function of 0.5336 for basalt RAM with 30% RAP dosage, steel slag RAM reaches 0.7801, which represents its preferable road performance. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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12 pages, 3559 KiB  
Article
Impacts of Aggregate Gradation on the Volumetric Parameters and Rutting Performance of Asphalt Concrete Mixtures
by Weihua Li, Weidong Cao, Xianfu Ren, Shurong Lou, Shutang Liu and Jizhe Zhang
Materials 2022, 15(14), 4866; https://doi.org/10.3390/ma15144866 - 13 Jul 2022
Cited by 7 | Viewed by 2343
Abstract
The main objective of this study was to determine the effect of aggregate gradation (AG) on the volumetric parameters (VPs) and rutting performance (RP) of asphalt concrete (AC) mixtures. The boundary sieve (BS) between fine and coarse aggregates was 2.36 mm size, and [...] Read more.
The main objective of this study was to determine the effect of aggregate gradation (AG) on the volumetric parameters (VPs) and rutting performance (RP) of asphalt concrete (AC) mixtures. The boundary sieve (BS) between fine and coarse aggregates was 2.36 mm size, and 15 gradation curves of three nominal maximum aggregate sizes (13.2, 19.0, and 26.5 mm) were designed based on the percentage passing of the BS. A vibrating compaction test of coarse aggregates, Marshall compaction and wheel-tracking tests of AC mixtures with various gradations were conducted. It was found that AG had crucial effects on the VPs and RP of AC mixtures. The AC mixture can be designed as a skeletal dense structure provided that the percentage passing of the BS is appropriate. More notably, AC mixtures with a skeletal dense structure showed the best rutting resistance performance. Therefore, it is important to optimize AG for enhancing the high-temperature RP of AC mixtures. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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21 pages, 5790 KiB  
Article
Research on Design and Performance of Self-Compacting Cement Emulsified Bitumen Mixture (CEBM)
by Jinming Yi, Jianlin Feng, Yuanyuan Li, Tao Bai, Anqi Chen, Yangming Gao, Fan Wu, Shaopeng Wu, Quantao Liu and Chuangmin Li
Materials 2022, 15(14), 4840; https://doi.org/10.3390/ma15144840 - 12 Jul 2022
Cited by 2 | Viewed by 1666
Abstract
To meet the needs of the road industry for maintenance operations, a new cement emulsified bitumen mixture (CEBM) with early-strength, self-compacting, and room-temperature construction characteristics was designed. The strength formation mechanism of CEBM was revealed with a scanning electron microscope (SEM) and the [...] Read more.
To meet the needs of the road industry for maintenance operations, a new cement emulsified bitumen mixture (CEBM) with early-strength, self-compacting, and room-temperature construction characteristics was designed. The strength formation mechanism of CEBM was revealed with a scanning electron microscope (SEM) and the surface free energy (SFE) theory. The mechanical properties and road performance of the CEBM were investigated extensively. The results show that before the demulsification of emulsified bitumen, the SFE of the bitumen–aggregate–water three-phase system was reduced due to the replacement of the bitumen–aggregate interface with water. The adhesion work between the emulsified bitumen and the aggregate is negative, which means the adhesion between the emulsified bitumen and the aggregate will not occur spontaneously due to the existence of water. The liquid emulsified bitumen improves the workability of the mixture and ensures that the mixture can be evenly mixed and self-compacted. After demulsification, the work of adhesion between the residual bitumen and the aggregate is positive, which means residual bitumen and aggregate can bond spontaneously. In addition, the hydration products of cement and aggregate form a skeleton, and the emulsified bitumen film wraps and bonds the cement and aggregate together, creating strength. The emulsified bitumen, cement content, and curing conditions have significant effects on the stability of CEBM. The recommended dosage of emulsified bitumen and cement is 8% and 8–10%, respectively. This material integrates the hardening effect of cement and the viscoelastic performance of bitumen and has good workability, mechanical properties, and road performance. Therefore, the CEBM is technically feasible for application to bitumen pavement. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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18 pages, 7436 KiB  
Article
Research on the Road Performance of Asphalt Mixtures Based on Infrared Thermography
by Wei Chen, Kesen Wei, Jincheng Wei, Wenyang Han, Xiaomeng Zhang, Guiling Hu, Shuaishuai Wei, Lei Niu, Kai Chen, Zhi Fu, Xizhong Xu, Baogui Xu and Ting Cui
Materials 2022, 15(12), 4309; https://doi.org/10.3390/ma15124309 - 17 Jun 2022
Cited by 8 | Viewed by 1916
Abstract
Temperature segregation during the paving of asphalt pavements is one of the causes of asphalt pavement distress. Therefore, controlling the paving temperature is crucial in the construction of asphalt pavements. To quickly evaluate the road performance of asphalt mixtures during paving, in this [...] Read more.
Temperature segregation during the paving of asphalt pavements is one of the causes of asphalt pavement distress. Therefore, controlling the paving temperature is crucial in the construction of asphalt pavements. To quickly evaluate the road performance of asphalt mixtures during paving, in this work, we used unmanned aerial vehicle infrared thermal imaging technology to monitor the construction work. By analyzing the temperature distribution at the paving site, and conducting laboratory tests, the relationship between the melt temperature, high-temperature stability, and water stability of the asphalt mix was assessed. The results showed that the optimal temperature measurement height for an unmanned aerial vehicle (UAV) with an infrared thermal imager was 7–8 m. By coring the representative temperature points on the construction site and then conducting a Hamburg wheel tracking (HWT) test, the test results were verified through the laboratory test results in order to establish a prediction model for the melt temperature and high-temperature stability of y = 10.73e0.03x + 1415.78, where the predictive model for the melt temperature and water was y = −19.18e−0.02x + 98.03. The results showed that using laboratory tests combined with UAV infrared thermography could quickly and accurately predict the road performance of asphalt mixtures during paving. We hope that more extensive evaluations of the roadworthiness of asphalt mixtures using paving temperatures will provide reference recommendations in the future. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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18 pages, 4408 KiB  
Article
Optimization of Asphalt-Mortar-Aging-Resistance-Modifier Dosage Based on Second-Generation Non-Inferior Sorting Genetic Algorithm
by Yang Lv, Shaopeng Wu, Peide Cui, Serji Amirkhanian, Haiqin Xu, Yingxue Zou and Xinkui Yang
Materials 2022, 15(10), 3635; https://doi.org/10.3390/ma15103635 - 19 May 2022
Cited by 2 | Viewed by 1506
Abstract
The use of steel slag powder instead of filler to prepare asphalt mortar was beneficial to realize the effective utilization of steel slag and improve the performance of asphalt concrete. Nevertheless, the anti-aging properties of steel-slag powder–asphalt mortar need to be further enhanced. [...] Read more.
The use of steel slag powder instead of filler to prepare asphalt mortar was beneficial to realize the effective utilization of steel slag and improve the performance of asphalt concrete. Nevertheless, the anti-aging properties of steel-slag powder–asphalt mortar need to be further enhanced. This study used antioxidants and UV absorbers in steel-slag powder–asphalt mortar to simultaneously improve its thermal-oxidation and UV-aging properties. The dosage of modifier was optimized by second-generation non-inferior sorting genetic algorithm. Fourier-Transform Infrared Spectroscopy, a dynamic shear rheometer and the heavy-metal-ion-leaching test were used to evaluate the characteristic functional groups, rheological properties and heavy-metal-toxicity characteristics of the steel-slag-powder-modified asphalt mortar, respectively. The results showed that there was a significant correlation between the amount of modifier and G*, δ, and the softening point. When the first peak appeared for G*, δ, and the softening point, the corresponding dosages of x1 were 2.15%, 1.0%, and 1.1%, respectively, while the corresponding dosage of x2 were 0.25%, 0.76%, and 0.38%, respectively. The optimal value of the modifier dosage x1 was 1.2% and x2 was 0.5% after weighing by the NSGA-II algorithm. The asphalt had a certain physical solid-sealing effect on the release of heavy-metal ions in the steel-slag powder. In addition, the asphalt structure was changed under the synergistic effect of oxygen and ultraviolet rays. Therefore, the risk of leaching heavy-metal ions was increased with the inferior asphalt-coating performance on the steel-slag powder. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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20 pages, 6702 KiB  
Article
Physical Properties and Storage Stability of Buton Rock Asphalt Modified Asphalt
by Yue Su, Xiaodi Hu, Jiuming Wan, Shaopeng Wu, Yinglong Zhang, Xing Huang and Zhangjun Liu
Materials 2022, 15(10), 3592; https://doi.org/10.3390/ma15103592 - 18 May 2022
Cited by 9 | Viewed by 1792
Abstract
Buton Rock Asphalt (BRA) refers to the natural rock asphalt natively produced on the Buton island of Indonesia. It is often used as a modifier to enhance the performance of asphaltpavement. However, the segregation of BRA in BRA-Modified Asphalt (BRA-MA) has restricted its [...] Read more.
Buton Rock Asphalt (BRA) refers to the natural rock asphalt natively produced on the Buton island of Indonesia. It is often used as a modifier to enhance the performance of asphaltpavement. However, the segregation of BRA in BRA-Modified Asphalt (BRA-MA) has restricted its application. This study aims to investigate how the particle size and content of BRA affect the physical properties and storage stability of BRA-MA. Penetration, softening point, viscosity, and viscosity-temperature susceptibility (VTS) were analyzed. The evaluation method of storage stability was discussed and determined. The segregation of BRA in BRA-MA of static storage and transportation process were simulated and tested. The results suggest that the softening point and viscosity were positively correlated to BRA content and inversely determined by particle size. Penetration, VTS, and ductility were reduced due to the decline in particle size and increment of BRA content. The index of segregation value based on viscosity difference showed better statistical and quantitative significances than the softening-point difference in evaluating the storage stability. The particle size and content of BRA are positively correlated to the segregation of BRA-MA. Both the storage temperature and time were positively correlated to the segregation of BRA-MA. We prove that the relationship between specific surface area and segregation are power functional. BRA-MA with BRA whose 50% particle sizes are lower than 13.6 μm showed low segregation in transportation. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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18 pages, 6259 KiB  
Article
Effects of Tung Oil Composite Regenerating Agent on Rheological Properties and Microstructures of Reclaimed Asphalt Binder
by Qimin Wang, Qunshan Ye, Junhui Luo, Cheng Xie, Haobin Liu, Jianhua Liu and Mengnan Qin
Materials 2022, 15(9), 3197; https://doi.org/10.3390/ma15093197 - 28 Apr 2022
Cited by 5 | Viewed by 1816
Abstract
The single light oil regenerating agent has certain limitations on the performance recovery of aged asphalt. In this study, tung oil, dioctyl phthalate (DOP), C9 petroleum resin, and organic montmorillonite (OMMT) were used to prepare the composite regenerating agent, and its optimal mix [...] Read more.
The single light oil regenerating agent has certain limitations on the performance recovery of aged asphalt. In this study, tung oil, dioctyl phthalate (DOP), C9 petroleum resin, and organic montmorillonite (OMMT) were used to prepare the composite regenerating agent, and its optimal mix proportion was determined by the orthogonal experimental design. The rheological properties and anti-aging performance of reclaimed asphalt were studied by the dynamic shear rheometer (DSR) and bending beam rheometer (BBR); and the Fourier transform infrared (FTIR) spectrometer, gel permeation chromatography (GPC), and scanning electron microscope (SEM) were adopted to explore its microstructure, morphology, and mechanism of action. The results show that with the addition of tung oil composite regenerating agent, the rheological properties of aged asphalt can be effectively recovered, even better than that of base asphalt. By using the complex modulus aging index (CMAI) and phase angle aging index (PMAI) it is found that the anti-aging performance of reclaimed asphalt is better than that of base asphalt. With the optimal content of the tung oil composite regenerating agent, the contents of characteristic functional groups and macromolecular asphaltenes in the aged asphalt can be reduced, indicating that the composite regenerating agent is beneficial to the dispersion and dissolution of polar substances in the aged asphalt. After aging, a large number of wrinkles appear on the surface of the asphalt. However, the addition of the tung oil composite regenerating agent can make the asphalt surface smooth, which indicates that the tung oil composite regenerating agent can restore the microstructure and morphology of aged asphalt to a certain extent. Full article
(This article belongs to the Special Issue Advances in Regenerated Asphalt Mixtures)
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