Editorial

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2 pages, 116 KiB

Open AccessEditorial

New Developments in Asphalt Pavement: Enhancing Durability, Sustainability, and Cost-Effectiveness

by Qiaoyi Li, Guangqing Yang, Chundi Si and Biao Li

Coatings 2024, 14(1), 34; https://doi.org/10.3390/coatings14010034 - 26 Dec 2023

Viewed by 780

Abstract

Asphalt pavement is the most widely used high-grade form of pavement in road construction [...] Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

Research

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19 pages, 8359 KiB

Open AccessArticle

Investigation on the Performance of Modified Corn Stalk Fiber AC-13 Asphalt Mixture

by Kun Wang, Lu Qu, Liang Tang, Peng Hu, Qiong Wu, Xiaofei Zhang and Hao Xu

Coatings 2024, 14(4), 436; https://doi.org/10.3390/coatings14040436 - 07 Apr 2024

Viewed by 469

Abstract

As an agricultural waste, a large amount of corn stalk will cause environmental pollution. In order to realize the resource utilization of waste and meet the strict requirements of modern traffic on pavement strength and durability, it was modified and applied to an [...] Read more.

As an agricultural waste, a large amount of corn stalk will cause environmental pollution. In order to realize the resource utilization of waste and meet the strict requirements of modern traffic on pavement strength and durability, it was modified and applied to an AC-13 asphalt mixture to study its influence on the road performance of asphalt mixture and its mechanism. The road performances of modified corn stalk fiber, lignin fiber, and ordinary asphalt mixtures were evaluated via the wheel tracking test, low-temperature bending test, water immersion Marshall test, freeze–thaw splitting test, and fatigue test. Based on the results of three-point bending fatigue test, the viscoelastic parameters and indexes of the fiber asphalt mixture were obtained by fitting the loading specimen and deflection data with the Burgers constitutive model, and the creep strain response was analyzed by applying dynamic load, so as to explore the relationship between the viscoelastic characteristics and creep behavior of modified corn stalk fiber and AC-13 mixture. The long-term high-temperature performance test of the asphalt mixture with the best fiber content was carried out by using the long-term pavement intelligent monitoring equipment independently developed by the group of investigators. According to the findings, the ideal fiber contents for modified corn and lignin in asphalt mixture are 0.2% and 0.3%, respectively. Among them, the modified corn stalk fiber with a 0.2% content has the best effect on road performance, viscoelastic performance, and the asphalt mixture’s creep behavior under dynamic load. Compared with the 0.3% lignin fiber asphalt mixture, its dynamic stability, bending stiffness modulus, immersion residual stability, freeze–thaw splitting strength ratio, and loading times at failure increased by 19.9%, 18.28%, 4.19%, 8.6%, and 9.15%, respectively. Compared with ordinary asphalt mixture, it increased by 47.0%, 28.72%, 7.65%, 15%, and 75.81%, respectively. Moreover, when modified corn stalk fiber is added at 0.2%, the viscoelastic delay time of asphalt mixture is the longest, the strain peak value and rut depth are at a minimum, and the viscoelastic properties, creep properties, and long-term high-temperature properties are the best. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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19 pages, 15365 KiB

Open AccessArticle

Gradation Optimization Based on Micro-Analysis of Rutting Behavior of Asphalt Mixture

by Qingliang Guo, Hao Xu, Junjie Wang, Jiezhou Hang, Kun Wang, Peng Hu and Hongzhen Li

Coatings 2023, 13(11), 1965; https://doi.org/10.3390/coatings13111965 - 18 Nov 2023

Viewed by 842

Abstract

This study investigates the microscopic mechanism of the force on particles of different particle sizes in the asphalt mixture during rutting formation. The gradation was optimized by analyzing the particle force results. The enhanced discrete element method (EDEM) was used to simulate the [...] Read more.

This study investigates the microscopic mechanism of the force on particles of different particle sizes in the asphalt mixture during rutting formation. The gradation was optimized by analyzing the particle force results. The enhanced discrete element method (EDEM) was used to simulate the rutting test, study the correlation state between different particle sizes in the rutting process, and analyze the rutting of asphalt pavement from the aggregate level. From a microscopic perspective, the specific forces acting on particles at different times were determined to investigate the particle size range of stressed particles in two types of asphalt mixtures. Furthermore, the role of particles with different sizes in the rutting process was analyzed. The force limit values of particles with different particle sizes are fitted, and the force of particles in two types of asphalt mixtures is compared and analyzed. After that, the gradation of the asphalt mixture is optimized, and the feasibility of the gradation optimization method is verified by laboratory experiments. The results show that the change rule of the rutting simulation test is gradually transformed from compacted rutting to unstable rutting. The force of the asphalt concrete-13 (AC-13) asphalt mixture is borne by the particles with a radius greater than 1.8 mm. The force of the stone matrix asphalt-13 (SMA-13) asphalt mixture is borne by the particles with a radius greater than 3.6 mm, and the small particle size particles play a filling role. When the particle radius is less than 5.1 mm, the force value of AC-13 asphalt mixture particles is greater than that of SMA-13. When the particle radius exceeds 5.1 mm, the force value of SMA-13 asphalt mixture particles is greater than that of AC-13. The force of particles with a radius of 5.7 mm and 7.3 mm in the SMA-13 asphalt mixture is 30% higher than that in AC-13, and the force limit of particles is proportional to the particle size. The dynamic stability, flexural tensile strength, water immersion residual stability, and freeze-thaw splitting strength ratios of the optimized asphalt mixture are improved compared with those before optimization. The AC-13 asphalt mixture is increased by 8.5%, 9.2%, 1.6%, and 1.9%, respectively, and the SMA-13 asphalt mixture is increased by 10.6%, 7.3%, 0.7%, and 2.1%, respectively. It shows that the grading optimization method is feasible. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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24 pages, 4523 KiB

Open AccessArticle

Investigation on the Rheological Properties and Microscopic Characteristics of Graphene and SBR Composite Modified Asphalt

by Lijun Wang, Fengxiang Liang, Zixia Li and Qiang Zhao

Coatings 2023, 13(7), 1279; https://doi.org/10.3390/coatings13071279 - 21 Jul 2023

Cited by 2 | Viewed by 917

Abstract

Styrene-butadiene rubber (SBR) is commonly used as a modifier to enhance the low-temperature performance of asphalt. However, it is worth noting that while SBR modified asphalt exhibits good low-temperature performance, its high-temperature performance is comparatively inferior. This limitation significantly restricts the widespread use [...] Read more.

Styrene-butadiene rubber (SBR) is commonly used as a modifier to enhance the low-temperature performance of asphalt. However, it is worth noting that while SBR modified asphalt exhibits good low-temperature performance, its high-temperature performance is comparatively inferior. This limitation significantly restricts the widespread use of SBR modified asphalt. As a new type of nanomaterial, graphene (GR) can change the microstructure of asphalt binder and provide asphalt with better mechanical, thermal, and adhesion properties. The main purpose of this study is to explore the influence of GR and SBR composite incorporation on the performance indexes of modified asphalt, and to study its compatibility and modification mechanism from the microscopic point of view of asphalt. The weight factor optimization system of modified asphalt was established by an analytic hierarchy process, and the optimum content of GR was determined to be 0.1% in a quantifiable way. The test results demonstrate that the inclusion of graphene substantially enhances the high-temperature rutting resistance of asphalt, reduces the temperature sensitivity of modified asphalt, and improves its storage stability. However, its effect on the low-temperature performance of asphalt is relatively minimal. Microscopic experimental results reveal the formation of a stable structure at the interface between GR and SBR in the composite modified asphalt. Furthermore, the dispersed phase exhibits improved uniformity, which positively impacts the stability of the asphalt binder. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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19 pages, 10319 KiB

Open AccessArticle

Wastepaper Sludge Ash and Acid Tar as Activated Filler Aggregates for Stone Mastic Asphalt

by Volodymyr Gunka, Volodymyr Hidei, Iurii Sidun, Yuriy Demchuk, Vitalii Stadnik, Pavlo Shapoval, Khrystyna Sobol, Nataliya Vytrykush and Michael Bratychak

Coatings 2023, 13(7), 1183; https://doi.org/10.3390/coatings13071183 - 30 Jun 2023

Cited by 1 | Viewed by 967

Abstract

Nowadays, the most common ways to dispose of acid tars and paper production waste are burial or incineration, but it is ecologically and economically expedient to use such waste in building materials. A new variant of filler aggregate—wastepaper sludge ash (paper production waste) [...] Read more.

Nowadays, the most common ways to dispose of acid tars and paper production waste are burial or incineration, but it is ecologically and economically expedient to use such waste in building materials. A new variant of filler aggregate—wastepaper sludge ash (paper production waste) and a chemical activator for filler aggregates—acid tar (oil-refining industry waste) is proposed. Elemental and mineralogical compositions of wastepaper sludge ash for comparison with commodity limestone mineral powder are established. Chemical activation of wastepaper sludge ash and limestone mineral powder was carried out and the wetting properties of the obtained materials were investigated by means of primary and neutralized acid tar. The physical and mechanical properties of stone mastic asphalt samples with different filler aggregate variants were studied. The possible chemical transformations in stone mastic asphalt using limestone mineral powder and wastepaper sludge ash activated by acid tar are shown. The possibility of replacing traditional limestone mineral powder with industrial wastepaper sludge ash has been proven, and the effectiveness of activating filler aggregates by acid tar has been confirmed. It was established that acid tar as an activator for filler aggregates does not require neutralization because stone mastic asphalt, in this case, demonstrates better properties compared to acid tar neutralization. As a result of our research, the application of wastepaper sludge ash is possible as a filler aggregate for stone mastic asphalt. And to obtain improved stone mastic asphalt characteristics, wastepaper sludge ash is required to activate 5 wt.% acid tar. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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19 pages, 3608 KiB

Open AccessArticle

Correlation between the Rheological Properties of Asphalt Mortar and the High-Temperature Performance of Asphalt Mixture

by Song Li, Xingxing Shi, Chundi Si, Binshuo Bao and Mengmeng Hu

Coatings 2023, 13(6), 1058; https://doi.org/10.3390/coatings13061058 - 07 Jun 2023

Cited by 2 | Viewed by 1076

Abstract

The performance of an asphalt mixture is significantly affected by the properties of its asphalt mortar, which consists of an asphalt binder, mineral fillers, fine aggregates and air voids. The aim of this work was to evaluate the correlations between the high-temperature performance [...] Read more.

The performance of an asphalt mixture is significantly affected by the properties of its asphalt mortar, which consists of an asphalt binder, mineral fillers, fine aggregates and air voids. The aim of this work was to evaluate the correlations between the high-temperature performance of an asphalt mixture and the rheological properties of its corresponding asphalt mortar. The multisequence repeated loading (MSRL) test was used to estimate the high-temperature performance of the asphalt mixture. Six different gradations, AC-13, SMA-13, SUP-13, AC-20, SUP-20 and AC-25, and two styrene–butadiene–styrene (SBS)-modified asphalt binders were considered and used to prepare the asphalt mixture specimens. The gradations and asphalt types of asphalt mortars were consistent with their asphalt mixtures. A modified multiple-stress creep–recovery (MSCR) test was proposed for evaluating the rheological properties of asphalt mortar with a dynamic shear rheometer (DSR). Based on the basic form of the Hirsh model, a multiple regression model was established, and its coefficient of determination (R-square) was 0.96. The rheological response of the asphalt mortar presented great correlation with the high-temperature behaviour of the asphalt mixture. In addition, the MSCR indicators (nonrecoverable compliance and percent recovery) obtained at 12.8 kPa creep stress represented the rheological status of asphalt mortar in asphalt mixture well. Therefore, the mechanical behaviours of asphalt mixture at high temperature could be accurately predicted by the MSCR indicators of asphalt mortar and its coarse aggregate parameters. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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12 pages, 10185 KiB

Open AccessArticle

Mechanical Characterization of Asphalt Mixtures Based on Polymeric Resin and Thixotropic Filler as a Substitute for Bitumen

by Carina Emminger, Umut D. Cakmak, Michael Lackner and Zoltan Major

Coatings 2023, 13(5), 932; https://doi.org/10.3390/coatings13050932 - 16 May 2023

Cited by 1 | Viewed by 1035

Abstract

Transportation infrastructure relies heavily on asphalt pavement, but conventional bitumen-based mixtures present several drawbacks. This study assesses the potential of poly(methyl methacrylate) resins and thixotropic fillers as substitutes for bitumen to improve pavement performance. The research concentrates on enhancing current formulations that incorporate [...] Read more.

Transportation infrastructure relies heavily on asphalt pavement, but conventional bitumen-based mixtures present several drawbacks. This study assesses the potential of poly(methyl methacrylate) resins and thixotropic fillers as substitutes for bitumen to improve pavement performance. The research concentrates on enhancing current formulations that incorporate a thermosetting polymer and mineral (stiffening) fillers, with the objective of increasing durability, extending the product life cycle, and optimizing raw material usage. Utilizing dynamic thermomechanical analyses, the viscoelastic characteristics of resins are examined, with a focus on their mechanical properties’ dependence on load frequency and temperature. The investigation also evaluates the impact of different fillers, including silica sand, silica dust, and basalt sand, on viscoelastic behavior and load-bearing capacity, offering valuable insights into the relationships between material structure and properties. The findings reveal that stiffness is predominantly affected by the quantity of silica dust, whereas the force plateau depends on the amount of sand. This study contributes crucial information for the development of more sustainable and robust pavement materials for future applications. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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13 pages, 4476 KiB

Open AccessArticle

Study on High and Low Temperature Performance of Mineral Powder Modified Rubber Asphalt Mortar

by Weichao Liu, Ce Zhang, Lingyun Li, Lianfang Wang, Lipeng Wang, Changyu Pu and Guangqing Yang

Coatings 2023, 13(4), 791; https://doi.org/10.3390/coatings13040791 - 19 Apr 2023

Cited by 1 | Viewed by 979

Abstract

With the increase of coal mining in China, a large amount of waste coal gangue is produced. How to reuse waste coal gangue is an important research direction. The research results showed that the improvement of base asphalt mortar by coal gangue powder [...] Read more.

With the increase of coal mining in China, a large amount of waste coal gangue is produced. How to reuse waste coal gangue is an important research direction. The research results showed that the improvement of base asphalt mortar by coal gangue powder could improve the performance of matrix asphalt, however, search of rubber asphalt mortar modified by coal gangue powder is rarely reported. High and low-temperature performance is the critical performance of asphalt mortar. So the limestone powder modified base asphalt mortar (LPMBAM), limestone powder modified rubber asphalt mortar (LPMRAM), and coal gangue powder modified rubber asphalt mortar (CGPMRAM) are prepared, the high and low-temperature performance of asphalt mortar are analyzed by cone penetration tests and bending beam rheological tests (BBR). The results show that the cone penetration of asphalt mortar decreases with the increase of the filler-asphalt ratio and the decrease of the temperature. The shear strength and the stiffness modulus increase with the rise in the filler-asphalt ratio and the decrease in temperature. At the same filler-asphalt ratio and temperature, the order of cone penetration is CGPMRAM < LPMRAM < LPMBAM, and the order of shear strength is CGPMRAM > LPMRAM > LPMBAM, so the high-temperature performance of CGPMRAM is better than that of LPMRAM, much better than LPMBAM, the order of stiffness modulus is LPMRAM < CGPMRAM < LPMBAM so the low-temperature performance of LPMRAM and CGPMRAM is better than that of LPMBAM. By the double linear model, the optimum filler-asphalt ratio is determined to be 0.44~0.46 for LPMRAM and 0.42~0.43 for CGPMRAM. Microscopic tests show that the surface of coal gangue powder is rougher than that of limestone powder. The content of active oxides such as SiO₂ and Al₂O₃ in coal gangue is about 7.8 times that of limestone powder. These physical and chemical properties make coal gangue powder able to adsorb rubber asphalt better and improve the high-temperature performance of CGPMRAM while slightly worsening the low-temperature performance of CGPMRAM but still better than LPMBAM. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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17 pages, 3025 KiB

Open AccessArticle

Study on Thixotropic Properties of Asphalt Mastics Based on Energy Viewpoint

by Xiaoyan Ma, Yubo Wang, Junpeng Hou, Yanping Sheng, Wanpeng Zheng and Shujuan Wu

Coatings 2023, 13(3), 650; https://doi.org/10.3390/coatings13030650 - 20 Mar 2023

Cited by 3 | Viewed by 1196

Abstract

An asphalt mastic has thixotropic characteristics that significantly influence its fatigue and healing performance. Therefore, understanding the thixotropy of an asphalt mastic is clearly of great importance. However, research in this area is still in the early stages. This study focuses on self-heating [...] Read more.

An asphalt mastic has thixotropic characteristics that significantly influence its fatigue and healing performance. Therefore, understanding the thixotropy of an asphalt mastic is clearly of great importance. However, research in this area is still in the early stages. This study focuses on self-heating as one of the biasing performances of asphalt material by analyzing the viscosity, stress, and hysteresis loops the of asphalt mastics under cyclic shear loading. Twelve types of asphalt mastics fabricated with asphalt, as well as different types of mineral filler, were selected to examine thixotropy. In addition, the filler/asphalt ratio was examined via the hysteresis technique to analyze the hysteresis loop and the viscosity–shear rate. The thixotropic potential function was also studied from the energy viewpoint. The results show that asphalt mastics with different asphalt binders, mineral fillers, and filler volume fractions showed hysteresis loops for shear stress versus shear rate diagrams. With an increase in the loading times of the cyclic load, the area of the hysteresis loop gradually decreases, and the hysteresis area most likely features a relatively stable value. The thixotropy of the asphalt can be significantly reduced by adding filler, and different types of mineral filler can slightly influence the thixotropy. The viscosity decreases with an increase in the shear rate, and it gradually recovers with a decrease in the shear rate. The greater the filler/asphalt ratio, the greater the viscosity, and the faster the viscosity’s descent is with the prolongation of time. Due to the existence of a higher amount of filler content, the recovery of a viscosity crack is more difficult. For asphalt mastics with high filler/asphalt ratios, the thixotropic mechanism can be explained via particle agglomeration and the depolymerization theory. For asphalt mastics with low and medium filler/asphalt ratios, the thixotropic mechanism can be explained via the particle chain theory. The damage and recovery of the internal structure of an asphalt mastic can be characterized by the structural failure potential function and the structural recovery potential function, respectively. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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15 pages, 3667 KiB

Open AccessArticle

Utilizing Imaging Analysis to Determine the Internal Structure Characteristics of Asphalt Mixtures for Permeability and Moisture Damage Performance

by Nithinan Hemnithi and Preeda Chaturabong

Coatings 2023, 13(3), 584; https://doi.org/10.3390/coatings13030584 - 08 Mar 2023

Cited by 1 | Viewed by 923

Abstract

Moisture is a significant problem in standard pavements, causing asphalt mixtures to deteriorate due to insufficient water permeability. This failure from moisture damage is often caused by precipitation accumulation or poor drainage, which allows water to weaken adhesion by seeping between the aggregates [...] Read more.

Moisture is a significant problem in standard pavements, causing asphalt mixtures to deteriorate due to insufficient water permeability. This failure from moisture damage is often caused by precipitation accumulation or poor drainage, which allows water to weaken adhesion by seeping between the aggregates and the asphalt. The relationship between permeability and aggregate contact length is believed to be inverse. To effectively assess water permeability performance and moisture damage, an asphalt concrete design criterion was established using the Image Processing and Analysis System (IPAS) to determine aggregate contact lengths. The objective of this research was to use laboratory experiments in conjunction with IPAS to investigate air-void-controlled asphalt mixtures with various material properties and assess the correlation of water permeability with other factors. The results show that AC60/70, AC60/70+Carbon Black, and AC60/70+SBS combinations with coconut peat filler had the lowest permeability coefficient (k) among similar mixtures, with values of 0.056 × 10⁻⁵ cm/s, 0.010 × 10⁻⁵ cm/s, and 1.508 × 10⁻⁵ cm/s, respectively. Both the dense and porous gradations of the modified asphalt binder demonstrated positive linear relationships between TSR and permeability. This study found a strong linear relationship between TSR (tensile strength ratio) and k (permeability coefficient) in both dense and porous modified asphalt binder gradations, with R² values of 0.79 and 0.74, respectively. Additionally, we found that the number of contact points and contact length in the skeleton strongly influenced the mixes’ permeability, with a linear trend of 0.93 for both indices. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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11 pages, 4779 KiB

Open AccessArticle

Panoramic UAV Image Mosaic Method and Its Application in Pavement Paving Temperature Monitoring

by Rishuang Sun, Jinliang Xu and Huan Zhang

Coatings 2023, 13(3), 528; https://doi.org/10.3390/coatings13030528 - 27 Feb 2023

Cited by 1 | Viewed by 940

Abstract

The low-altitude technology of unmanned airborne infrared detection system is used to effectively monitor the temperature segregation in the paving stage and realize the temperature uniformity control of asphalt pavement construction. The image mosaic method can splice two images with overlapping areas together [...] Read more.

The low-altitude technology of unmanned airborne infrared detection system is used to effectively monitor the temperature segregation in the paving stage and realize the temperature uniformity control of asphalt pavement construction. The image mosaic method can splice two images with overlapping areas together to form a panoramic image. In order to solve the problems of long time-consuming and low accuracy of aerial image mosaic algorithm, the low-temperature area of the whole pavement can be obtained quickly and accurately. In this paper, threshold segmentation technology is introduced to convert the image captured by the unmanned aerial vehicle (UAV) into a binary greyscale image so as to compensate for the mosaic error caused by temperature difference. In order to improve the efficiency and accuracy of splicing, a reference plate is used, which can provide enough feature points for splicing. Finally, the image mosaic method proposed in this paper can quickly obtain the image of the whole low-temperature area of the newly paved asphalt pavement, which has practical value and positive significance for the quality control of asphalt pavement. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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13 pages, 3741 KiB

Open AccessArticle

Research on Automatic Pavement Crack Recognition Based on the Mask R-CNN Model

by Pengcheng Wang, Chao Wang, Hongwu Liu, Ming Liang, Wenhui Zheng, Hao Wang, Shichao Zhu, Guoqiang Zhong and Shang Liu

Coatings 2023, 13(2), 430; https://doi.org/10.3390/coatings13020430 - 14 Feb 2023

Cited by 2 | Viewed by 1435

Abstract

Pavement will inevitably be damaged in the process of use; pavement damage detection and assessment are an important part of maintenance management. In order to prevent road diseases, it is necessary to fix the road cracks and implement automatic road crack inspection and [...] Read more.

Pavement will inevitably be damaged in the process of use; pavement damage detection and assessment are an important part of maintenance management. In order to prevent road diseases, it is necessary to fix the road cracks and implement automatic road crack inspection and monitoring. In this paper, the automatic identification of road cracks is realized by constructing the Mask R-CNN model. The labeled area can be segmented by pixels and positioned at the original data by integrating the image data used for training and the labeled data into a network model. The effect of the training model can be improved by increasing the number of data sets, the pixel of the fracture image, the background of the fracture, and the marking method of the fracture type. The validity and accuracy of the test results were characterized by RPN bounding-box loss, classification loss, mask loss, and total loss. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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14 pages, 2191 KiB

Open AccessFeature PaperArticle

Laboratory Evaluation of the Relationship of Asphalt Binder and Asphalt Mastic via a Modified MSCR Test

by Binshuo Bao, Jie Liu, Song Li, Chundi Si and Qipeng Zhang

Coatings 2023, 13(2), 304; https://doi.org/10.3390/coatings13020304 - 29 Jan 2023

Cited by 5 | Viewed by 1391

Abstract

Asphalt mastic, which consists of an asphalt binder and a mineral filler, provides critical adhesion and viscoelasticity to an asphalt mixture. The rheological response of the asphalt mastic is mainly derived from its asphalt binder. In this study, a simple laboratory test method [...] Read more.

Asphalt mastic, which consists of an asphalt binder and a mineral filler, provides critical adhesion and viscoelasticity to an asphalt mixture. The rheological response of the asphalt mastic is mainly derived from its asphalt binder. In this study, a simple laboratory test method is proposed to estimate the relationship of asphalt binder and its mastic. Two modified binders (3.5% and 4.0% styrene–butadiene–styrene (SBS) of asphalt binder by mass) were blended with a limestone filler at six different mineral filler contents to produce mastic samples. A modified multiple stress creep-recovery (MSCR) test was conducted on both the asphalt binder and its mastic with the same testing protocols, and the stress conditions and rheological response of asphalt binder in the mastic with linear or nonlinear viscoelasticity were both investigated. The results show that the stress of the asphalt binder in its mastic decreased with increasing filler contents. However, for the linear-viscoelasticity mastic, the decrease rate of the stress began to slow down when the filler content had reached 100% or 120%. For the rheological properties of the asphalt binder in the mastic, the %R of the asphalt binder was improved by adding filler, especially for the nonlinear-viscoelasticity mastic. The asphalt binder of the linear-viscoelasticity asphalt mastic also showed a linear viscoelastic response and a good recovery property. The performance of the asphalt mastic and rheological properties of its asphalt binder were highly related to its filler content. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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17 pages, 3559 KiB

Open AccessArticle

Laboratory Investigation of the Water Damage Resistance of Tuff Asphalt Mixture Modified with Additives

by Xiaoyuan Zhang, Yu Zhang, Hui Yang, Qiong Lin and Boming Tang

Coatings 2023, 13(2), 302; https://doi.org/10.3390/coatings13020302 - 29 Jan 2023

Cited by 4 | Viewed by 1258

Abstract

To improve the water damage resistance performance of a tuff asphalt mixture, a tuff mixture with cement and a liquid anti-stripping agent was used as the research object, and limestone and tuff mixtures without additives were selected as contrast samples. Through an improved [...] Read more.

To improve the water damage resistance performance of a tuff asphalt mixture, a tuff mixture with cement and a liquid anti-stripping agent was used as the research object, and limestone and tuff mixtures without additives were selected as contrast samples. Through an improved boiling test and a water stability test before and after aging, the modification effect of the tuff mixture with additives of different types and contents on water damage resistance was evaluated to obtain the appropriate type and content of additives. On this basis, the other road performance measures of the selected mixture were further evaluated by immersion rutting and beam bending tests to verify the modification effect of the additive on the tuff mixture. Results showed that adding the appropriate cement content to the tuff mixture provided excellent resistance to the water damage effect. An optimal content of 2% cement additive in the mixture was obtained, and its high-temperature anti-rutting and low-temperature bending performance were also verified. Adhesion between tuff aggregates and asphalt polymer under water conditions was significantly improved and close to that of limestone aggregates. The modification effect of water stability after mixture aging was better than that of the anti-stripping agent. The residual stability and freeze–thaw splitting strength ratio of 2% cement content mixture were increased by about 21.5% and 16.7%, respectively, compared with those of the tuff mixture control. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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16 pages, 8043 KiB

Open AccessArticle

Fatigue Prediction Model and Stiffness Modulus for Semi-Flexible Pavement Surfacing Using Irradiated Waste Polyethylene Terephthalate-Based Cement Grouts

by Muhammad Imran Khan, Muslich Hartadi Sutanto, Shabir Hussain Khahro, Salah E. Zoorob, Nur Izzi Md. Yusoff, Abdulnaser M. Al-Sabaeei and Yasir Javed

Coatings 2023, 13(1), 76; https://doi.org/10.3390/coatings13010076 - 31 Dec 2022

Cited by 2 | Viewed by 1750

Abstract

Semi-flexible pavement surfacing, or grouted macadam, is an alternative to conventional flexible and rigid pavement. It is constructed by injecting cementitious grout into the voids of an open-graded asphalt surfacing. The cement used in cementitious grouts has adverse environmental effects because of the [...] Read more.

Semi-flexible pavement surfacing, or grouted macadam, is an alternative to conventional flexible and rigid pavement. It is constructed by injecting cementitious grout into the voids of an open-graded asphalt surfacing. The cement used in cementitious grouts has adverse environmental effects because of the carbon dioxide emission in cement production. The objective of this study was to investigate the potential of using irradiated waste polyethylene terephthalate (PET) and fly ash (FA) as a (partial) cement replacement in cementitious grouts for semi-flexible pavement surfacing. This study sought to assess the stiffness modulus and fatigue properties of the semi-flexible specimens prepared with control grout, regular PET (2.57% PET + 10% FA) and irradiated PET (4.75% PET + 10% FA)-based grouts and compares the stiffness modulus and fatigue properties of semi-flexible specimens with the conventional hot mix asphalt (HMA) concrete. The semi-flexible surfacing specimens showed superior performance, higher stiffness modulus, and better fatigue life than the hot mix asphalt. The difference in fatigue cycles was apparent at lower stress ratios of 25 and 30%. The semi-flexible pavement mixtures exceeded 100,000 cycles at the lowest stress ratio of 25%, while the HMA fatigue cycles were less than 100,000 cycles. Furthermore, the semi-flexible specimen with irradiated PET (which contain a higher amount of waste PET than the regular PET) showed similar stiffness modulus and fatigue life as the specimens with regular PET and control grout. The irradiation technique offers a sustainable solution for recycling higher amounts of waste PET in highway materials for semi-flexible pavement surfacing. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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21 pages, 10381 KiB

Open AccessArticle

Development of a Road Pavement Structure Diagnostic Procedure Based on the Virtual Inertial Point Method

by Csaba Tóth and Péter Primusz

Coatings 2022, 12(12), 1944; https://doi.org/10.3390/coatings12121944 - 10 Dec 2022

Cited by 7 | Viewed by 1442

Abstract

Falling weight deflectometers (FWD) are utilised worldwide to analyse the condition and the load-bearing capacity of road pavement structures. One of the FWD measurement results, the deflection bowl, may provide surplus information that is suitable for better road pavement structure diagnostics, based on [...] Read more.

Falling weight deflectometers (FWD) are utilised worldwide to analyse the condition and the load-bearing capacity of road pavement structures. One of the FWD measurement results, the deflection bowl, may provide surplus information that is suitable for better road pavement structure diagnostics, based on the novel approach presented in this paper. This study presents a computational method that can calculate the layer thicknesses from the deflection data recorded by the non-destructive FWD device. The motivation for this research is that FWD and GPR equipment are often not available at the same time. However, the back-calculation of the pavement layer moduli from the deflections requires knowledge of the exact thicknesses. The developed method is based on the inertia point principle and provides not only the total pavement thickness but also the total asphalt thickness at each FWD drop point. From 25,200 linear elastic layered pavement models, 350 virtual inertia points could be identified. To describe the relationship between the structural model characteristics of the pavement (thickness and subgrade modulus) and the virtual inertia points, we chose the Gaussian process regression, a widely used method in machine learning. In addition to the thicknesses, the point of inertia can also be used to calculate the bearing modulus of the subgrade with high accuracy. Based on the data from the experimental road section, the radius value of the inertia point

r_{c}

is not sensitive to the stiffness of the layers that compose the pavement structure, depending only on the total pavement thickness and the bearing capacity of the subgrade. The calculation was compared with the AASHTO (1993) procedure, and very similar values for the subgrade-bearing capacity were obtained. Moreover, in the near future, the method can be further developed to provide an estimation of layer thicknesses, together with a deflection measurement, especially adapted to continuous deflection measurement devices (Curviameter and Rolling Wheel Deflectometer). Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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18 pages, 5141 KiB

Open AccessArticle

Research on Distribution Model and Detection Spacing of Compaction Degree of Asphalt Pavement Based on the PQI Method

by Yanli Li, Haiwei Zhang, Yatao Peng, Yan Li and Ke Wang

Coatings 2022, 12(11), 1751; https://doi.org/10.3390/coatings12111751 - 15 Nov 2022

Cited by 1 | Viewed by 1211

Abstract

The pavement quality indicator (PQI) is a non-destructive piece of equipment for detecting the compaction degree of asphalt pavement, which can avoid primary damage to the pavement compared with the traditional core-drilling method. In this paper, the PQI method was applied to evaluate [...] Read more.

The pavement quality indicator (PQI) is a non-destructive piece of equipment for detecting the compaction degree of asphalt pavement, which can avoid primary damage to the pavement compared with the traditional core-drilling method. In this paper, the PQI method was applied to evaluate the compaction quality of asphalt pavement through data collection, calibration and statistical analysis, and the probability-distribution characteristics of compaction degree were also explored, by fitting the data with probability-distribution models. Furthermore, the optimal detection-spacing was determined by comparing the statistical results of compaction degree measured at different detection-spacings. Test results showed that the calibrated PQI data was close to the actual data of the core sample, and their error rate was within 1%. The compaction degree of the test road was mostly located between 92% and 99%, and the variable coefficient was entirely below 2%, demonstrating that the pavement-compaction quality was satisfactory and uniform. The normal distribution model, lognormal distribution model and extreme-value distribution model had relatively high accuracy in fitting the compaction-degree frequency data, while the sine-wave distribution model was low in fitting accuracy. By comparing the predicted value with the actual value of compaction degree, the normal distribution model was determined as the most appropriate model for describing the frequency distribution of compaction degree. In addition, the detection spacing was selected as 50 m, considering the reliability, accuracy and efficiency. The research results provide technical support for the compaction quality-control of asphalt pavement in a non-destructive, timely, accurate and multi-point manner, ultimately contributing to the excellent service performance and service life of asphalt pavement. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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17 pages, 8499 KiB

Open AccessArticle

Comparative Study of the Mesomechanical Response of Asphalt Bridge Deck Pavement under Multiple Loads

by Yaning Cui, Chundi Si, Song Li and Taotao Fan

Coatings 2022, 12(11), 1665; https://doi.org/10.3390/coatings12111665 - 02 Nov 2022

Cited by 1 | Viewed by 1185

Abstract

Asphalt bridge deck pavement is a weak bridge structure area, and early damage usually occurs in this area under vehicle loads. Due to the complexity and diversity of vehicle loads and material structures, it is difficult to truly reflect the mechanical response of [...] Read more.

Asphalt bridge deck pavement is a weak bridge structure area, and early damage usually occurs in this area under vehicle loads. Due to the complexity and diversity of vehicle loads and material structures, it is difficult to truly reflect the mechanical response of bridge deck pavement under vehicle loads. This paper studies the vehicle road interaction from a microscopic perspective. In this research, the dynamic response of asphalt bridge deck pavement under multiple loads is comparatively studied, considering the mesoscopic structure of the asphalt materials. First, the compressive properties, tensile properties and interlaminar shear properties of each layer were studied through laboratory tests. Second, the asphalt mixture bridge deck pavement model, including mesostructured, was established. Then, the subprograms of the sinusoidal vibration load, rolling load and vehicle road coupling load were realised using the discrete element method (DEM). Finally, the mesomechanical response of asphalt bridge deck pavement under those three dynamic loads was comparatively studied. The study finds that there is a large difference in the mechanical response of bridge deck pavement under multiple loads. A sinusoidal vibration load can simply be the moving load, the edge of the loading area and the bottom of the lower layer bear large tensile stress, and the shear stress at the edge of the loading area is approximately 4 times that of the middle area. The rolling load can better reflect the status of the vehicle. There is a certain difference in the shear stress response between the rolling load and the sinusoidal vibration load, and the lower layer bears compressive–tensile alternating stress. Under the vehicle road coupling load, the volatility of the dynamic response is obvious due to the road roughness. Therefore, it is of vital importance to improve the abrasion resistance of the surface layer. The results show that the comprehensive consideration of multiple loads and the mesostructure can provide a more reliable method for the dynamic design of bridge deck pavement, which is of great significance for improving the durability of the pavement. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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