Surface Characterization and Treatments in Transportation Infrastructure

A special issue of Coatings (ISSN 2079-6412). This special issue belongs to the section "Surface Characterization, Deposition and Modification".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 27902

Special Issue Editors

School of Transportation, Southeast University, Nanjing, China
Interests: asphalt mixture; cement concrete; cement composites; aggregate coating; pavement performance evaluation; pavement non-destructive testing; pavement surface treatments; data mining; artificial intelligence; pavement asset management
School of Transportation and Logistics, Dalian University of Technology, Dalian, China
Interests: solid propellant; viscoelastic properties; structural integrity; numerical simulation
Special Issues, Collections and Topics in MDPI journals
School of Civil Engineering, Central South University, Changsha 410075, China
Interests: pavement engineering; infrastructure materials; discrete element modelling
Special Issues, Collections and Topics in MDPI journals
College of Transportation Engineering, Chang’an University, Xi'an, China
Interests: road maintenance and rehabilitation; cement-treated materials; long-term pavement performance; mechanics-empirical pavement design method; data mining; transportation infrastructure digitization
Department of Civil Engineering, Nanjing University of Science and Technology, Nanjing, China
Interests: asphalt mixture; cement concrete; cement composites; soil mechanics; pavement management system; data mining

Special Issue Information

Dear Colleagues,

The strength, durability, toughness, and surface friction are the key performance of transportation infrastructure and have also benefited significantly from the surface characterization, modifications, and treatments for both construction materials and structure members. With the fast development and increasing applications of multiscale characterization, active coatings with coupling agents, corrosion resistance coating of steel members, concrete and asphalt sealing coats, and various pavement surface treatments, the new generation of transportation infrastructures will perform in a way that is 'stronger, safer, and more sustainable'.

Driven by the current state of knowledge of surface characterization and treatments, the need to improve the mechanical properties and sustainability for materials and structures has seen a huge demand on experimental, theoretical, and modeling activities. The purpose of this Special Issue is thus to collect the latest research and achievements and discuss progresses in surface characterization and treatments in building and maintenance of strong, safe, and sustainable transportation infrastructures.

This scope of this Special Issue will serve as a forum for papers in the following concepts:

  • Knowledge and new ideas in multiscale surface characterization of materials in transportation infrastructure;
  • Recent developments in surface modifications and coatings of solid waste;
  • Theoretical and experimental research on the silica sealing coats of cement concrete;
  • Design and evaluation of various asphalt and cement concrete pavement surface treatments;
  • Evaluation of interfaces in the materials for transportation infrastructure;
  • Testing and modeling of surface texture and friction performance of transportation infrastructure.

Prof. Dr. Qiao Dong
Prof. Dr. Changjun Zhou
Prof. Dr. Weimin Song
Prof. Dr. Shi Dong
Prof. Dr. Xueqin Chen
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • surface characterization of pavement materials
  • pavement material coatings and modification
  • pavement surface testing and evaluation
  • pavement surface treatment

Published Papers (15 papers)

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Research

18 pages, 10306 KiB  
Article
Enhancing Pavement Distress Detection Using a Morphological Constraints-Based Data Augmentation Method
by Zhengchao Xu, Zhe Dai, Zhaoyun Sun, Chen Zuo, Huansheng Song and Changwei Yuan
Coatings 2023, 13(4), 764; https://doi.org/10.3390/coatings13040764 - 13 Apr 2023
Viewed by 1167
Abstract
Pavement distress data in a single section usually presents a long-tailed distribution, with potholes, sealed cracks, and other distresses normally located at the tail. This distribution will seriously affect the performance and robustness of big data-driven deep learning detection models. Conventional data augmentation [...] Read more.
Pavement distress data in a single section usually presents a long-tailed distribution, with potholes, sealed cracks, and other distresses normally located at the tail. This distribution will seriously affect the performance and robustness of big data-driven deep learning detection models. Conventional data augmentation algorithms only expand the amount of data by image transformation and fail to enlarge the data diversity. Due to such a drawback, this paper proposes a novel two-stage pavement distress image augmentation pattern, in which a mask is generated randomly according to the geometric features of the distress in the first stage; and in the second stage, a distress-free pavement image with the fused mask is transformed into a pavement distress image. Furthermore, two convolutional networks, M-DCGAN and MDTMN, are designed to complete the generation task in two stages separately. In comparison with other generation algorithms, the quality and diversity of the generation results of proposed algorithms are better than other algorithms. In addition, distress detection tests are conducted which indicate that the expanded dataset can raise the IoU from 48.83% to 83.65% at maximum, and the augmented data by the proposed algorithm contributes more to the detection performance. Full article
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19 pages, 4113 KiB  
Article
Establishment and Analysis of the Relationship Model between Macro-Texture and Skid Resistance Performance of Asphalt Pavement
by Jie Ji, Wanyan Ren, Tianhao Jiang, Yuanshuai Dong, Yun Hou and Haimeng Li
Coatings 2022, 12(10), 1464; https://doi.org/10.3390/coatings12101464 - 04 Oct 2022
Cited by 2 | Viewed by 1478
Abstract
Pavement surface texture evaluation is mainly analyzed based on elevation data in previous research, and attention also need to be paid to wavelength information. Furthermore, a well-established relationship model between surface texture and skid resistance for real road sections still needs further investigation [...] Read more.
Pavement surface texture evaluation is mainly analyzed based on elevation data in previous research, and attention also need to be paid to wavelength information. Furthermore, a well-established relationship model between surface texture and skid resistance for real road sections still needs further investigation to help provide useful information on appropriate maintenance time considering skid resistance attenuation. In this research, the macro-texture of asphalt pavement was evaluated from different aspects, including elevation, wavelength information, and geometry, and the relationship models between the macro-texture and skid resistance (at both low and high speeds) were established and compared using the multiple linear regression (MLR) and back propagation (BP) neural network to recommend a suitable one. In order to achieve this, this study monitored anti-skidding performance and the macro-texture of six road sections for 18 months. Firstly, the Dynamic Friction Coefficient (DFC) test and core drilling were conducted on site at three different service times. Additionally, a laboratory accelerated loading test was carried out on specimens prepared by similar material composition to one of the road sections, and the British Pendulum Number (BPN) was tested after different passes of loading. Secondly, 3D laser scanning was carried out on core samples from road sections and laboratory specimens after different passes of loading. The correlation degree between macro-texture indexes and anti-skidding performance was analyzed with the grey correlation entropy analysis method. Finally, the relationship models between the anti-skidding performance at high and low speeds and macro-texture were established based on the MLR and BP neural network. The results indicate that the macro-texture indexes calculated based on elevation data to characterize vertical irregularities have a good correlation with the skid resistance despite the different service times and pavement types. Compared with the BP neural network model, the MLR model has low correlation and noticeable error. The relationship model between F60 (DFC at the speed of 60 km/h) and macro-texture could be well established by the BP neural network. In addition, the relationship between F20, BPN, and pavement surface macro-texture is poor, making it impossible to establish a model with good correlation. Generally, it is recommended to use the BP neural network to establish the relationship model between macro-texture and skid resistance. Full article
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21 pages, 5206 KiB  
Article
Evaluation and Characterization of the Use of Industrial-Solid-Waste Curing Agent instead of Cement on Improved Alluvial Silt
by Quanjun Shen, Peng Jiang, Xiaoning Zhang, Hao Sun, Yaohui Yang, Shuai Wang, Li Li and Hongfa Shang
Coatings 2022, 12(10), 1417; https://doi.org/10.3390/coatings12101417 - 27 Sep 2022
Viewed by 1239
Abstract
The silt in the Yellow River alluvial plain typically features low strength and poor water stability, and, thus, alluvial silt treatment needs an amount of cement to improve soil performance. The development of an alternative to reduce or replace the use of cement [...] Read more.
The silt in the Yellow River alluvial plain typically features low strength and poor water stability, and, thus, alluvial silt treatment needs an amount of cement to improve soil performance. The development of an alternative to reduce or replace the use of cement in soil stabilization has been a hot topic research for a long time. This paper develops an industrial-solid-waste (ISW) curing agent using a response surface methodology, which is a novel composite material made of steel slag, mineral slag, and two desulfurization products; its feasibility on improved silt is expected to be studied systematically. The comparative tests of ISW- and cement-improved silt were conducted to analyze performance and action mechanism. Variance and multiple regression analysis were used to study the effect of factors on responses statistically, and check the significance and correlation of the suggested models. Finally, the in-service performance of ISW-improved silt was evaluated through in-situ tests. Results show that ISW-improved silt can present good mechanical properties and durability, but is much weaker than cement-improved silt in the early curing stage. The strength enhancement amplitude of ISW-improved silt between curing ages of 7 days to 28 days is larger than that of cement-improved silt. The correlation between factors and responses is established with good agreement. Synergisms in the ISW curing agent are stimulated in the alkaline environment, and are conductive to connect the silt particles. The in-service performance of ISW-improved silt showed little difference to that of cement-improved silt; both of them meet the requirements from the perspective of in-situ application. Moreover, the unit cost of an ISW curing agent is less than 1/5 of that of cement. ISW-improved silt has advantages of cost saving, resource recycling and environmental protection. Full article
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14 pages, 3352 KiB  
Article
Deflection Prediction of Rehabilitation Asphalt Pavements through Deep Forest
by Yi Wu, Xueqin Chen and Dongqi Jiang
Coatings 2022, 12(8), 1057; https://doi.org/10.3390/coatings12081057 - 26 Jul 2022
Viewed by 1384
Abstract
The deep forest is a powerful deep-learning algorithm that has been applied in certain fields. In this study, a deep forest (DF) model was developed to predict the central deflection measured by a falling weight deflectometer (FWD). In total, 11,075 samples containing information [...] Read more.
The deep forest is a powerful deep-learning algorithm that has been applied in certain fields. In this study, a deep forest (DF) model was developed to predict the central deflection measured by a falling weight deflectometer (FWD). In total, 11,075 samples containing information related to pavement structure, traffic conditions, and weather conditions were extracted from the LTPP dataset. The performance of the DF model with custom backend settings was compared with that of models random forest (RF), multilayer perceptron (MLP), and DF built on the sklearn backend. All four deep-learning algorithms could identify the complex relationship between central deflection and relevant feature variables with high accuracy and stability. The learning and generalization abilities of DF was stronger than those of MLP and RF. The predictive performance and computation time of DF (custom) were better than those of DF (sklearn), indicating that the custom model was superior to the highly encapsulated model with sklearn as the backend. Feature importance analysis indicated that the drop load of FWD was the key factor influencing deflection. In addition, structural number, annual precipitation, and annual kilo equivalent standard axle load (kESAL) are very important features related with deflection. The feature importance of rehabilitation improvement thickness was less than the drop load, climatic factors, kESAL, structural number, and layer thickness. Full article
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20 pages, 5709 KiB  
Article
Research on High-Temperature Rheological Properties of Emulsified Asphalt Mastics and Their Influencing Factors
by Qing Wang, Haolei Chang, Decai Wang, Shengneng Hu, Pingrang Wang and Chengshi Zhang
Coatings 2022, 12(5), 635; https://doi.org/10.3390/coatings12050635 - 05 May 2022
Cited by 4 | Viewed by 1387
Abstract
The high-temperature rheological properties of emulsified asphalt mastics have a significant impact on the service performance of cold recycled mixtures with asphalt emulsions. In this paper, a dynamic shear rheological (DSR) test and a multiple stress creep recovery (MSCR) test are carried out [...] Read more.
The high-temperature rheological properties of emulsified asphalt mastics have a significant impact on the service performance of cold recycled mixtures with asphalt emulsions. In this paper, a dynamic shear rheological (DSR) test and a multiple stress creep recovery (MSCR) test are carried out to analyze the influence of tunneling coal gangue powder (TCGP), portland cement (PC), limestone powder (LP), and four kinds of filler binder ratio (F/B) on the high-temperature rheological properties of emulsified asphalt mastics before and after rolling thin film oven test (RTFOT) ageing. Based on the principle of time–temperature equivalence and a viscoelasticity material model, the main curve of emulsified asphalt mastics under frequency scanning test is established, and the rheological properties of emulsified asphalt mastics in a wide frequency domain are analyzed. Finally, the grey entropy theory is used to quantitatively analyze the correlation between different high temperature performance evaluation indices of emulsified asphalt mastics. The results show that the RTFOT ageing process can significantly enhance the high temperature deformation resistance of emulsified asphalt residue and its mastics. The rutting factor (G*/sin δ) of emulsified asphalt mastics increases exponentially with the increase of F/B, while the phase angle is less affected. TCGP mastics and PC mastics have better high temperature performances than those of LP mastics. The most suitable range of F/B is 0.9~1.2 when TCGP is used as the filler, and 1.2~1.5 when PC or LP is used as the filler. Grey entropy correlation analysis shows that there is a good correlation between the two evaluation systems of the DSR test and the MSCR test, and both can evaluate the high-temperature performance of emulsified asphalt mastics. Full article
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11 pages, 3146 KiB  
Article
Factors Influencing the Droplet Size of Asphalt Emulsion during Fabrication
by Xiaowei Chen, Yan Meng, Guihua Hu, Ji Zhou and Jian Ouyang
Coatings 2022, 12(5), 575; https://doi.org/10.3390/coatings12050575 - 23 Apr 2022
Viewed by 1688
Abstract
The size distribution of asphalt droplets greatly affects the overall technical properties of asphalt emulsion, while it did not obtain much concern previously. In order to fabricate a good-quality asphalt emulsion with a small droplet size distribution, the effect of preparation parameters on [...] Read more.
The size distribution of asphalt droplets greatly affects the overall technical properties of asphalt emulsion, while it did not obtain much concern previously. In order to fabricate a good-quality asphalt emulsion with a small droplet size distribution, the effect of preparation parameters on the asphalt droplet size distribution, such as emulsifier dosage, asphalt temperature, shear time, pH value, and soap solution temperature, were systematically studied. All preparation parameters can affect the droplet size distribution of asphalt emulsion as well as the representative droplet diameters for the 10th, 50th and 90th cumulative volume percentile (D10, D50, and D90). The order of preparation parameters are ranked as: emulsifier dosage > temperature of soap solution > pH of soap solution > shear time > asphalt temperature. Therefore, the emulsifier dosage, the temperature and pH of the soap solution should be carefully controlled to obtain asphalt emulsion with good droplet size distribution during fabrication. Compared to D10, the D50 and D90 are more easily affected by the fluctuant preparation parameters, which are recommended to be utilized to evaluate the emulsifying effect of asphalt emulsion and judge the asphalt droplet size distribution. Full article
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13 pages, 3695 KiB  
Article
Molecular Dynamics Study of the Diffusion between Virgin and Aged Asphalt Binder
by Yiqun Zhan, Hao Wu, Weimin Song and Lin Zhu
Coatings 2022, 12(3), 403; https://doi.org/10.3390/coatings12030403 - 18 Mar 2022
Cited by 20 | Viewed by 2502
Abstract
The diffusion between the virgin and aged asphalt binder in the recycled asphalt mixture is a crucial factor affecting its macro-mechanical performance. In this study, a combined model of the virgin-aged layered asphalt structure was assembled based on the molecular dynamics (MD) method. [...] Read more.
The diffusion between the virgin and aged asphalt binder in the recycled asphalt mixture is a crucial factor affecting its macro-mechanical performance. In this study, a combined model of the virgin-aged layered asphalt structure was assembled based on the molecular dynamics (MD) method. A four-component and twelve-category molecule were used to model the asphalt. The diffusion behaviors of the virgin and aged asphalt were characterized by mean square displacement (MSD), diffusion coefficient, relative concentration and cohesive energy density (CED). Results indicated that at the same temperature, the diffusion coefficient of the virgin asphalt was the largest, followed by the virgin-aged asphalt and the aged asphalt. As the temperature increased, the relative concentration on both sides of the virgin-aged asphalt overlapped to a certain extent. The covered lengths of the virgin asphalt were larger than those of the aged asphalt, indicating the diffusion between the virgin asphalt and aged asphalt was mainly manifested as the diffusion from the virgin asphalt to the aged asphalt. The development of CED and the fraction of free volume (FFV) indicated the mutual attractive interactions among the molecules in virgin and aged asphalt layers became strong and the cohesion properties inside the model became better. Full article
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16 pages, 4409 KiB  
Article
Relationship between the Void and Sound Absorption Characteristics of Epoxy Porous Asphalt Mixture Based on CT
by Xiaolong Li, Junfeng Gao, Hui Du, Jingpeng Jia, Xiaojie Zhao and Tianqing Ling
Coatings 2022, 12(3), 328; https://doi.org/10.3390/coatings12030328 - 01 Mar 2022
Cited by 5 | Viewed by 2057
Abstract
This study investigates the relationship between the void characteristics and sound absorption characteristics of an epoxy porous asphalt mixture. The specimens are scanned and reconstructed under different void fractions using X-ray computed tomography (CT) technology and digital image processing, and the sound absorption [...] Read more.
This study investigates the relationship between the void characteristics and sound absorption characteristics of an epoxy porous asphalt mixture. The specimens are scanned and reconstructed under different void fractions using X-ray computed tomography (CT) technology and digital image processing, and the sound absorption coefficients at different frequencies are obtained using an acoustic impedance tube. The relationship between void characteristics and sound absorption characteristics is analyzed using gray correlation. The test results exhibited a good correlation between the void characteristics of the epoxy porous asphalt mixture obtained by CT scanning (mesoscale) and the measured values (macroscale). The difference between the void fraction and connected void fraction gradually decreased with an increase in the void fraction. The relationship curve between the sound absorption coefficient and frequency exhibited a bimodal trend, and the peak value of the sound absorption coefficient increased with an increase in the void fraction. The order of the gray correlation degree between the peak and average values of the sound absorption coefficient and the void characteristic parameters is as follows: connected void fraction > void fraction > equivalent diameter of connected void > surface area of connected void > curvature. Full article
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18 pages, 3679 KiB  
Article
Low-Temperature Performance of Asphalt Mixtures Modified by Microencapsulated Phase Change Materials with Various Graphene Contents
by Yong-Xiang Ren and Pei-Wen Hao
Coatings 2022, 12(2), 287; https://doi.org/10.3390/coatings12020287 - 21 Feb 2022
Cited by 6 | Viewed by 1609
Abstract
Microencapsulated phase change materials (PCMs) added to conventional ones can store excessive heat energy and reduce thermal stresses. In this study, melamine–formaldehyde resin phase change microencapsulated PCMs, with different contents of graphene (CG), were added to asphalt mixtures, in order to reduce their [...] Read more.
Microencapsulated phase change materials (PCMs) added to conventional ones can store excessive heat energy and reduce thermal stresses. In this study, melamine–formaldehyde resin phase change microencapsulated PCMs, with different contents of graphene (CG), were added to asphalt mixtures, in order to reduce their low-temperature cracking, induced by thermal stresses. Low-temperature and heat-conducting/storing performance of the obtained mixtures was examined via beam bending tests, semi-circular bending low-temperature performance tests, thermal conductivity tests and volume-specific heat capacity tests. Besides, the prepared asphalt mixtures’ water stability and high-temperature stability values were obtained via freeze-thaw splitting and wheel tracking tests. The low-temperature performance of PCM-modified asphalt mixtures was evaluated via their bending strain energy densities, with one of the PCM-modified asphalt mixtures, namely CGMFPCM3, synthesized by the authors, was 1.7 times higher than that of the common asphalt mixture. Although the dynamic stability of all three PCM-modified mixtures was deteriorated by 68, 50, and 20% compared to the common one, that of CGMFPCM3 still complied with the standard requirement. Thermal conductivity and volume-specific heat capacity of the asphalt mixture at 278.15 K was enhanced by 5 and 43%, respectively, after adding CGMFPCM3. It is recommended for reducing the temperature variation-induced cracking in the asphalt pavement. Thermal conductivity and volume-specific heat capacity can be used for evaluating the temperature-regulating performance of asphalt mixtures. Full article
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12 pages, 1720 KiB  
Article
Viscoelastic Properties, Rutting Resistance, and Fatigue Resistance of Waste Wood-Based Biochar-Modified Asphalt
by Ran Zhang, Haoxiang Wang, Jie Ji and Hainian Wang
Coatings 2022, 12(1), 89; https://doi.org/10.3390/coatings12010089 - 13 Jan 2022
Cited by 10 | Viewed by 2139
Abstract
The purpose of this study is to explore the viscoelastic properties, rutting resistance, and fatigue resistance of waste wood-based biochar-modified asphalt. The biochar with 2%, 4%, and 8% mixing amounts and two kinds of particle size, 75–150 μm and <75 μm, were used [...] Read more.
The purpose of this study is to explore the viscoelastic properties, rutting resistance, and fatigue resistance of waste wood-based biochar-modified asphalt. The biochar with 2%, 4%, and 8% mixing amounts and two kinds of particle size, 75–150 μm and <75 μm, were used as modifiers of petroleum asphalt. Meanwhile, in the control group, a graphite modifier with a particle size of 0–75 μm and mixing amount of 4% was used for comparison. Aged asphalts were obtained in the laboratory by the Rolling Thin Film Oven (RTFO) test and the Pressure Aging Vessel (PAV) test. The viscoelastic properties, rutting resistance, and fatigue resistance of biochar-modified asphalt were evaluated by phase angle, critical high temperature, and fatigue cracking index by the Dynamic Shear Rheometer (DSR) test. In addition, the micromorphology of biochar and graphite was compared and observed by using the scanning electron microscope (SEM). The results show that increasing the mixing amount of biochar gave a higher elastic property and significantly better rutting resistance of the modified asphalt at high temperature. Compared with graphite, the biochar has a rougher surface and more pores, which provides its higher specific surface area. Therefore, it is easier to bond with asphalt to form a skeleton network structure, then forming a more stable biochar–asphalt base structure. In this way, compared to graphite-modified asphalt, biochar-modified asphalt showed better resistance to rutting at high temperature, especially for the asphalt modified with biochar of small particle size. The critical high temperature T(G*/sinδ) of 4% Gd, 4% WD, and 4% Wd was 0.31 °C, 1.57 °C, and 2.92 °C higher than that of petroleum bitumen. In addition, the biochar asphalt modified with biochar of small particle size had significantly better fatigue cracking resistance than the asphalt modified with biochar of large particle size. The fatigue cracking indexes for 2% Wd, 4% Wd, and 8% Wd were 29.20%, 7.21%, and 37.19% lower by average than those for 2% WD, 4% WD, and 8% WD at 13–37 °C. Therefore, the waste wood biochar could be used as the modifier for petroleum asphalt. After the overall consideration, the biochar-modified asphalt with 2%–4% mixing amount and particle size less than 75 μm was recommended. Full article
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18 pages, 2096 KiB  
Article
Maintenance Time of Permeable Asphalt Pavement Based on Entropy–Analytic Hierarchy Process Analysis
by Baoyang Yu, Zongguang Sun and Lin Qi
Coatings 2021, 11(12), 1516; https://doi.org/10.3390/coatings11121516 - 09 Dec 2021
Cited by 3 | Viewed by 2093
Abstract
Dust, sediment, and stone chips often block the rainwater-infiltration paths of permeable pavements, which, in conjunction with vehicle load, reduces drainage capacity. To restore this capacity, a reasonable maintenance time and suitable maintenance measures must be determined. Therefore, we investigated the void attenuation [...] Read more.
Dust, sediment, and stone chips often block the rainwater-infiltration paths of permeable pavements, which, in conjunction with vehicle load, reduces drainage capacity. To restore this capacity, a reasonable maintenance time and suitable maintenance measures must be determined. Therefore, we investigated the void attenuation and decline in drainage capacity of permeable asphalt pavements under the combined action of dust blockage and vehicle load. First, the water seepage coefficient decay and the decay rate under blocking and compaction were determined via clogging and compaction experiments. Second, experimental data were incorporated into an entropy–analytic hierarchy process analysis model, with the gross domestic product ratio, wind scale, and maximum five-year rainfall for the area. Finally, three test roads were studied as the weight to rank the maintenance urgency and predict the maintenance timing for each road under different rainfall conditions. The results demonstrate that the drainage capacity of permeable pavements obeys the parabolic exponential attenuation law. From the findings regarding road water storage capacity, the latest pavement maintenance time at different rainfall levels were obtained. This predicted maintenance time enables better decisions than regular time on code, which is the effect of drainage caused by multiple factors. Full article
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18 pages, 4128 KiB  
Article
Microstructure and Meso-Mechanical Properties of Asphalt Mixture Modified by Rubber Powder under a Multi-Scale Effect
by Sanqiang Yang, Shuang Sun, Lusheng Qin and Qian Li
Coatings 2021, 11(11), 1321; https://doi.org/10.3390/coatings11111321 - 29 Oct 2021
Cited by 4 | Viewed by 1481
Abstract
The applications of rubber-modified asphalt and its mixtures have received widespread attention due to the environmental and economic benefits of such materials. However, studies on the structural performance of rubber-powder-modified asphalt pavement are only concentrated on a certain scale, leading to research on [...] Read more.
The applications of rubber-modified asphalt and its mixtures have received widespread attention due to the environmental and economic benefits of such materials. However, studies on the structural performance of rubber-powder-modified asphalt pavement are only concentrated on a certain scale, leading to research on the structural performance of pavement mostly focusing on mechanical responses at a macro scale. Therefore, the present study adopts the concept of multi-scale research to analyze the viscoelasticity of high-dosage-modified asphalt and its mixtures at a microscopic scale from the perspective of meso-mechanical analysis. In this paper, to ensure the overall durability of a structure, the effective asphalt film thickness and coarse aggregate angularity index of the test material were measured first. The viscoelasticity of asphalt modified with rubber powder was then analyzed using a Brinell viscosity test, scanning electron microscopy (SEM), and a dynamic shear rheometer (DSR). We determined the optimal amount of rubber powder to be 30%. A universal testing machine was used to study the influence of different temperatures and loading frequencies on the viscoelastic properties of different asphalt mixtures. Research on the dynamic modulus found that the incorporation of rubber powder increases the elastic properties of the mixture such that the rubber-powder-modified asphalt mixture had a higher dynamic modulus. At the same time, the high-dosage-modified asphalt mixture was found to be closer to an elastomer under a low temperature and high frequency. At a high temperature and low frequency, the asphalt mixture changed into a viscoelastic body whose viscous properties were mainly affected by the asphalt binder. The addition of rubber powder changed the temperature sensitivity of the asphalt and then affected the viscoelastic properties of the asphalt mixture. Full article
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16 pages, 26689 KiB  
Article
Effect of Coarse Recycled Aggregate on Failure Strength for Asphalt Mixture Using Experimental and DEM Method
by Yongsheng Yao, Jue Li, Chenghao Liang and Xin Hu
Coatings 2021, 11(10), 1234; https://doi.org/10.3390/coatings11101234 - 11 Oct 2021
Cited by 13 | Viewed by 1548
Abstract
Coarse aggregate is the major part of asphalt mixture, and plays an essential role in mechanical performance of pavement structure. However, the use of poor-quality coarse recycled aggregate (CRA) reduces the strength and stability of the aggregate skeleton. It is a challenge to [...] Read more.
Coarse aggregate is the major part of asphalt mixture, and plays an essential role in mechanical performance of pavement structure. However, the use of poor-quality coarse recycled aggregate (CRA) reduces the strength and stability of the aggregate skeleton. It is a challenge to predict accurately the influence of CRA on the performance of asphalt mixture. In this study, both a uniaxial compression test and a direct tensile test were carried out to evaluate the failure strength of asphalt concrete with four CRA content. The discrete element method (DEM) was applied to simulate the specimen of asphalt concrete considering the distribution and properties of CRA. The results showed that temperature and loading rate have a significant influence on failure strength, especially when the CRA content was more than 20%. With the increase of CRA content, both cohesion force and internal friction angle were gradually weakened. The proposed model can be used to predict the failure strength of asphalt mixture, since both experimental and simulated results had a high consistency and repeatability. With the decrease of CRA strength, the nominal cohesion force of the specimen decreased, while the internal friction angle increased. Full article
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15 pages, 3427 KiB  
Article
Performance and Fracture Analysis of Composite Interfaces for Semi-Flexible Pavement
by Kuanghuai Wu, Xiaoyu Liu, Xu Cai, Wenke Huang, Jinlou Yu and Guihai Nie
Coatings 2021, 11(10), 1231; https://doi.org/10.3390/coatings11101231 - 09 Oct 2021
Cited by 6 | Viewed by 1671
Abstract
Semi-flexible pavement is widely used in pavement engineering due to its excellent rutting resistance; however, it mainly fails due to cracking. Therefore, it is important to understand the properties of the aggregate–mortar–asphalt interfacial transition zone, to better understand the cracking mechanism of the [...] Read more.
Semi-flexible pavement is widely used in pavement engineering due to its excellent rutting resistance; however, it mainly fails due to cracking. Therefore, it is important to understand the properties of the aggregate–mortar–asphalt interfacial transition zone, to better understand the cracking mechanism of the semi-flexible pavement. In this work, we used pull-off tests and digital image analysis technology to compare and analyze the interfacial tensile strength and granite–bitumen–mortar interactions in three types of asphalt (70# matrix asphalt, PG76-22 modified asphalt and S-HV modified asphalt) at different curing ages. The analysis results showed that, for the three different bitumen materials, with settled mortar, the peak interfacial tensile strength values all occurred at approximately 14 d of curing. In addition, the order of the tensile strength followed the order of asphalt penetration degree; the order of the interfacial water damage resistance from weak to strong was 70# asphalt cementation specimen, PG76-22 modified asphalt cementation specimen, and S-HV modified asphalt cementation specimen. The results of this analysis highlight the original contributions of the optimum curing time for the composite interface of semi-flexible pavement materials prepared with different asphalts to reach optimum crack resistance. Full article
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14 pages, 2427 KiB  
Article
Time-Domain Analysis of Tamper Displacement during Dynamic Compaction Based on Automatic Control
by Xi Li, Hui Yang, Jingyu Zhang, Guoping Qian, Huanan Yu and Jun Cai
Coatings 2021, 11(9), 1092; https://doi.org/10.3390/coatings11091092 - 09 Sep 2021
Cited by 31 | Viewed by 2235
Abstract
Crater depth is a vital issue in dynamic compaction (DC) because it is a controlling parameter in DC and a characterization index of soil properties. A continuous mathematical model capturing the time-domain process of tamper displacement is presented in this paper. The model [...] Read more.
Crater depth is a vital issue in dynamic compaction (DC) because it is a controlling parameter in DC and a characterization index of soil properties. A continuous mathematical model capturing the time-domain process of tamper displacement is presented in this paper. The model is simple and the parameters involved are easy to obtain. It was found that the accumulated crater depth increases but its increment in the crater depth decreases with multiple impacts. Three groups of large-scale DC tests with 10,000 kN∙m were conducted to evaluate the performance of the proposed model. The results showed that the proposed model captures the typical trends in the tamper displacement of single and multiple impacts. In addition, a concept of the crater depth ratio is proposed based on the proposed model, and the concept is used to evaluate the efficiency of DC and to predict the optimum tamping number of DCs. Full article
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