Journal of Road Engineering最新文献

{"title":"Investigation of indoor and field tests on asphalt pavement with inverted asphalt layers based on the vertical vibration compaction method","authors":"Yong Yi ,&nbsp;Yingjun Jiang ,&nbsp;Tian Tian ,&nbsp;Yu Zhang ,&nbsp;Jiangtao Fan ,&nbsp;Chenfan Bai ,&nbsp;Changqing Deng","doi":"10.1016/j.jreng.2024.01.007","DOIUrl":"10.1016/j.jreng.2024.01.007","url":null,"abstract":"<div><div>An inverted asphalt pavement is created by reversing the sequence of the lower and middle layers in a conventional asphalt pavement. The lower layer is composed of material with larger particle size and lower asphalt content, which improves its ability to withstand deformation caused by rutting. On the other hand, the middle surface has a higher asphalt content, specifically designed to resist fatigue cracking. This paper examines the mechanical response of two pavement structures and investigates the potential of two measures, inverted asphalt pavement and asphalt mixture design by vertical vibration compaction method (VVCM), in reducing stresses and stress levels in asphalt pavements. Additionally, a large thickness rutting and fatigue test method was developed to study the rutting resistance and fatigue life of the pavement structures, and to construct rutting deformation and fatigue life prediction models. Finally, test sections were paved to verify the feasibility of the inverted pavement and VVCM materials. The findings show that inverted pavement and VVCM materials have a minimal impact on pavement stress, but can reduce pavement shear and tensile stress levels by up to 18%–25%. Furthermore, inverted pavement and VVCM materials have positive effects on improving the rutting resistance and fatigue life of asphalt pavements.</div></div>","PeriodicalId":100830,"journal":{"name":"Journal of Road Engineering","volume":"4 4","pages":"Pages 478-489"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143286085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A review of road 3D modeling based on light detection and ranging point clouds","authors":"Bin Yu,&nbsp;Yuchen Wang,&nbsp;Qihang Chen,&nbsp;Xiaoyang Chen,&nbsp;Yuqin Zhang,&nbsp;Kaiyue Luan,&nbsp;Xiaole Ren","doi":"10.1016/j.jreng.2024.04.009","DOIUrl":"10.1016/j.jreng.2024.04.009","url":null,"abstract":"<div><div>Increasing development of accurate and efficient road three-dimensional (3D) modeling presents great opportunities to improve the data exchange and integration of building information modeling (BIM) models. 3D modeling of road scenes is crucial for reference in asset management, construction, and maintenance. Light detection and ranging (LiDAR) technology is increasingly employed to generate high-quality point clouds for road inventory. In this paper, we specifically investigate the use of LiDAR data for road 3D modeling. The purpose of this review is to provide references about the existing work on the road 3D modeling based on LiDAR point clouds, critically discuss them, and provide challenges for further study. Besides, we introduce modeling standards for roads and discuss the components, types, and distinctions of various LiDAR measurement systems. Then, we review state-of-the-art methods and provide a detailed examination of road segmentation and feature extraction. Furthermore, we systematically introduce point cloud-based 3D modeling methods, namely, parametric modeling and surface reconstruction. Parameters and rules are used to define model components based on geometric and non-geometric information, whereas surface modeling is conducted through individual faces within its geometry. Finally, we discuss and summarize future research directions in this field. This review can assist researchers in enhancing existing approaches and developing new techniques for road modeling based on LiDAR point clouds.</div></div>","PeriodicalId":100830,"journal":{"name":"Journal of Road Engineering","volume":"4 4","pages":"Pages 386-398"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143286093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pavement skid resistance properties for safe aircraft operations","authors":"T.F. Fwa","doi":"10.1016/j.jreng.2024.11.002","DOIUrl":"10.1016/j.jreng.2024.11.002","url":null,"abstract":"<div><div>Airport pavement engineers are required to maintain pavement skid resistance at a satisfactory level to minimize the likelihood of runway excursions. Runway overruns and skidding along rapid exit taxiways are the two most frequently encountered forms of runway excursion accidents. Currently only empirical statistical models based on historical accident data are available to predict the risks of runway excursions. All such models fail to account for the impacts of pavement skid resistance properties. Mechanistic solutions of the tire-fluid-pavement interaction problem are now available, and the impacts of pavement skid resistance properties on runway excursion accidents can now be quantitatively evaluated. This paper presents a state-of-the-art review of recent research developments on the topic. It highlights the Concept of Pavement Skid Resistance State which provides (i) a logical theoretical framework for mechanistic representation of tire-pavement skid resistance, and (ii) an approach for modeling of the physical process of aircraft skidding and hydroplaning. Next, runway excursion risk prediction models are presented for risk evaluation of aircraft hydroplaning, runway overruns, and rapid exit taxiway excursions. Also examined in detail mechanistically is the effectiveness of pavement grooving in reducing the risks of runway excursions. The review clearly confirms the capability of mechanistic approach in analyzing runway excursions for the purpose of enhancing safe aircraft operations on airport runways.</div></div>","PeriodicalId":100830,"journal":{"name":"Journal of Road Engineering","volume":"4 4","pages":"Pages 361-385"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143286091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recycling of waste E-cigarette butts as engineered pelletized fibres for sustainable stone mastic asphalt","authors":"Yunfei Guo ,&nbsp;Piergiorgio Tataranni ,&nbsp;Giulia Tarsi ,&nbsp;Filippo Balzano ,&nbsp;Jiasheng Dai ,&nbsp;Cesare Sangiorgi","doi":"10.1016/j.jreng.2024.11.001","DOIUrl":"10.1016/j.jreng.2024.11.001","url":null,"abstract":"<div><div>The disposal of discarded E-cigarette butts (E-CBs) presents significant environmental challenges due to their detrimental impacts on ecosystems. To find an environmentally sustainable method for managing this waste, the potential for recycling E-CBs in asphalt pavements was investigated in this study. By focusing on the two primary components of E-CBs, namely cellulose fibre and polylactic acid (PLA), this research introduced a novel approach for recycling E-CBs in stone mastic asphalt (SMA) as a fibre additive in engineered pellet form. The prepared fibre pellets were directly added to aggregates to produce the SMA mixture. The resulting mixtures underwent a comprehensive evaluation through a series of standardized laboratory tests, including assessments of volumetric properties, indirect tensile strength (ITS), stiffness modulus, moisture susceptibility, and rutting resistance. The results were compared with SMA mixtures containing conventional cellulose fibres. Additionally, to examine the potential influence of PLA, a third mixture was prepared, incorporating both cellulose fibre and PLA. The findings indicate that the SMA using pelletized fibre can satisfy the technical specifications regarding the tests performed in this study, showing higher ITS and rutting resistance compared to the reference mixture. Moreover, the incorporation of PLA plastic reduced air void content and improved tensile strength, stiffness, and rutting resistance. This study highlights the potential for recycling E-CBs in asphalt mixtures, offering technical support for further development of sustainable recycling methods for this waste.</div></div>","PeriodicalId":100830,"journal":{"name":"Journal of Road Engineering","volume":"4 4","pages":"Pages 468-477"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143286084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review and prospect of four-point bending fatigue test of asphalt mixture","authors":"Yongjun Meng ,&nbsp;Dichao Liu ,&nbsp;Hongliu Rong ,&nbsp;Xiaolong Yang","doi":"10.1016/j.jreng.2023.05.004","DOIUrl":"10.1016/j.jreng.2023.05.004","url":null,"abstract":"<div><div>Fatigue cracking is one of the principal failure modes of asphalt pavement. The chief factors affecting the fatigue failure of asphalt pavement are load, environment, pavement structure and the fatigue resistance of asphalt mixture itself. Among them, the most important part is the research on the fatigue resistance of asphalt mixture, which has been studied deeply at home and abroad. This paper summarized some important research results and fatigue characterization parameters of the four-point bending fatigue test method in recent years, and suggested the future research direction of the four-point bending test. In the analysis and comparison of loading modes of four-point bending test, further research on various analysis methods is required. Researchers can appropriately refine the test method to account for nonlinear viscoelastic energy dissipation, as well as plastic and permanent deformation per cycle. The fatigue evaluation index of asphalt mixture can be comprehensively evaluated by four indicators, and can be combined with new fatigue characterization parameters in the future. It is suggested to develop a complete set of four-point bending fatigue test methods under various stress states consistent with the service state of asphalt pavement. This method can be used to eliminate the influences of environment, test condition and specimen size on the fatigue test results of asphalt mixture to improve the effectiveness and completeness of asphalt mixture fatigue performance characterization.</div></div>","PeriodicalId":100830,"journal":{"name":"Journal of Road Engineering","volume":"4 4","pages":"Pages 446-467"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143286088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Local calibration of JPCP transverse cracking and IRI models using maximum likelihood estimation","authors":"Rahul Raj Singh ,&nbsp;Syed Waqar Haider ,&nbsp;James Bryce","doi":"10.1016/j.jreng.2024.05.004","DOIUrl":"10.1016/j.jreng.2024.05.004","url":null,"abstract":"<div><div>The calibration of transfer functions is essential for accurate pavement performance predictions in the Pavement-ME design. Several studies have used the least square approach to calibrate these transfer functions. Least square is a widely used simplistic approach based on certain assumptions. Literature shows that these least square approach assumptions may not apply to the non-normal distributions. This study introduces a new methodology for calibrating the transverse cracking and international roughness index (IRI) models in rigid pavements using maximum likelihood estimation (MLE). Synthetic data for transverse cracking, with and without variability, are generated to illustrate the applicability of MLE using different known probability distributions (exponential, gamma, log-normal, and negative binomial). The approach uses measured data from the Michigan Department of Transportation's (MDOT) pavement management system (PMS) database for 70 jointed plain concrete pavement (JPCP) sections to calibrate and validate transfer functions. The MLE approach is combined with resampling techniques to improve the robustness of calibration coefficients. The results show that the MLE transverse cracking model using the gamma distribution consistently outperforms the least square for synthetic and observed data. For observed data, MLE estimates of parameters produced lower SSE and bias than least squares (e.g., for the transverse cracking model, the SSE values are 3.98 vs. 4.02, and the bias values are 0.00 and −0.41). Although negative binomial distribution is the most suitable fit for the IRI model for MLE, the least square results are slightly better than MLE. The bias values are −0.312 and 0.000 for the MLE and least square methods. Overall, the findings indicate that MLE is a robust method for calibration, especially for non-normally distributed data such as transverse cracking.</div></div>","PeriodicalId":100830,"journal":{"name":"Journal of Road Engineering","volume":"4 4","pages":"Pages 433-445"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143286086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards green asphalt materials with lower emission of volatile organic compounds: A review on the release characteristics and its emission reduction additives","authors":"Xiwen Chang ,&nbsp;Feng Wang ,&nbsp;Rui Wu ,&nbsp;Chen Wang ,&nbsp;Yue Xiao","doi":"10.1016/j.jreng.2024.04.005","DOIUrl":"10.1016/j.jreng.2024.04.005","url":null,"abstract":"<div><p>Recently, researchers in the road field are focusing on the development of green asphalt materials with lower emission of volatile organic compounds (VOCs). The characterization methodology of asphalt VOCs and the influencing factors on VOCs release have always been the basic issue of asphalt VOCs emission reduction research. Researchers have proposed a variety of asphalt VOCs characterization methodologies, which also have mutually irreplaceable characteristics. Asphalt VOCs volatilization is affected by many factors. In this study, asphalt VOCs characterization methodologies were summarized, including their advantages, disadvantages, characteristics and applicable requirements. Subsequently, the influencing factors of VOCs release, such as asphalt types and environment conditions, are summarized to provide theoretical support for the emission reduction research. The classification and mechanism of newly-development asphalt VOCs emission reduction materials are reviewed. The reduction efficiencies are also compared to select better materials and put forward the improvement objective of new materials and new processes. In addition, the prospects about development of VOCs release mechanism of asphalt materials during the full life cycle and feasibility research of high-efficiency composite emission reduction materials in the future were put forward.</p></div>","PeriodicalId":100830,"journal":{"name":"Journal of Road Engineering","volume":"4 3","pages":"Pages 292-317"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2097049824000301/pdfft?md5=cfea4efe26cd0b7b39a22caffd0cf453&pid=1-s2.0-S2097049824000301-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predictive modelling of volumetric and Marshall properties of asphalt mixtures modified with waste tire-derived char: A statistical neural network approach","authors":"Nura Shehu Aliyu Yaro ,&nbsp;Muslich Hartadi Sutanto ,&nbsp;Noor Zainab Habib ,&nbsp;Aliyu Usman ,&nbsp;Abiola Adebanjo ,&nbsp;Surajo Abubakar Wada ,&nbsp;Ahmad Hussaini Jagaba","doi":"10.1016/j.jreng.2024.04.006","DOIUrl":"10.1016/j.jreng.2024.04.006","url":null,"abstract":"<div><p>The goals of this study are to assess the viability of waste tire-derived char (WTDC) as a sustainable, low-cost fine aggregate surrogate material for asphalt mixtures and to develop the statistically coupled neural network (SCNN) model for predicting volumetric and Marshall properties of asphalt mixtures modified with WTDC. The study is based on experimental data acquired from laboratory volumetric and Marshall properties testing on WTDC-modified asphalt mixtures (WTDC-MAM). The input variables comprised waste tire char content and asphalt binder content. The output variables comprised mixture unit weight, total voids, voids filled with asphalt, Marshall stability, and flow. Statistical coupled neural networks were utilized to predict the volumetric and Marshall properties of asphalt mixtures. For predictive modeling, the SCNN model is employed, incorporating a three-layer neural network and preprocessing techniques to enhance accuracy and reliability. The optimal network architecture, using the collected dataset, was a 2:6:5 structure, and the neural network was trained with 60% of the data, whereas the other 20% was used for cross-validation and testing respectively. The network employed a hyperbolic tangent (tanh) activation function and a feed-forward backpropagation. According to the results, the network model could accurately predict the volumetric and Marshall properties. The predicted accuracy of SCNN was found to be as high value ​&gt;98% and low prediction errors for both volumetric and Marshall properties. This study demonstrates WTDC's potential as a low-cost, sustainable aggregate replacement. The SCNN-based predictive model proves its efficiency and versatility and promotes sustainable practices.</p></div>","PeriodicalId":100830,"journal":{"name":"Journal of Road Engineering","volume":"4 3","pages":"Pages 318-333"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2097049824000313/pdfft?md5=445f20f2035b37202997ea33eb3227f7&pid=1-s2.0-S2097049824000313-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Condition indices for rigid pavements: A comparative analysis of state DOTs using Michigan PMS data","authors":"Rahul Raj Singh ,&nbsp;Mumtahin Hasnat ,&nbsp;Muhammed Emin Kutay ,&nbsp;Syed Waqar Haider ,&nbsp;James Bryce ,&nbsp;Bora Cetin","doi":"10.1016/j.jreng.2024.05.003","DOIUrl":"10.1016/j.jreng.2024.05.003","url":null,"abstract":"<div><p>Pavement infrastructure is vital in providing services and links between various sectors of society. Therefore, the preservation and maintenance of these roads are critical to attaining a pavement network in good condition throughout its service life. Various performance indicators like the international roughness index (IRI), pavement condition index (PCI), and present serviceability rating (PSR) have been used by the state department of transportation (DOT) and highway agencies for evaluating pavement surface conditions and planning future maintenance strategies. Limited data availability, multiple distresses depending on region, lack of correlation of these condition indices to maintenance strategies, and data collection limitations pose a challenge for applying these indices to local conditions. This paper compares condition indices of different states for rigid pavements. Further, using a specific condition index for local conditions is also highlighted. For this purpose, five states and their corresponding condition indices were evaluated and compared to the Michigan DOT distress index (DI). These states include Virginia, Minnesota, North Dakota, Louisiana, and Oregon. The corresponding distresses of each condition index were converted to make them compatible with the MDOT DI. This study used the MDOT's pavement management system (PMS) database to evaluate each condition index for 433 rigid pavement sections. Each distress index was plotted against MDOT DI and compared using a paired <em>t</em>-test. Results show that the condition indices of Virginia and Minnesota are comparable to DI in terms of the Spearman correlation value. The <em>t</em>-test results show that except for Virgina, condition indices from other states statistically differ from DI. Therefore, one can't use those directly for local conditions in Michigan. This paper presents the evaluation and data requirements for each condition index and its impact on selecting a maintenance treatment.</p></div>","PeriodicalId":100830,"journal":{"name":"Journal of Road Engineering","volume":"4 3","pages":"Pages 348-360"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2097049824000337/pdfft?md5=4421143f6e847a052e7a6d408c1fe9ac&pid=1-s2.0-S2097049824000337-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A review of the development of asphalt foaming technology","authors":"Qiang Li ,&nbsp;Shijie Song ,&nbsp;Jiaqing Wang ,&nbsp;Ning Wang ,&nbsp;Shuai Zhang","doi":"10.1016/j.jreng.2024.04.004","DOIUrl":"10.1016/j.jreng.2024.04.004","url":null,"abstract":"<div><p>To comprehensively assess the current state-of-art in asphalt foaming technology, the following four key aspects have been reviewed systematically: foaming principles, test methods, evaluation indicators, and influencing factors. Key findings reveal that asphalt foaming was primarily driven by the vaporization of water, with deterioration processes including bubble collapse and liquid film drainage. However, the current understanding of asphalt foaming principles remains limited, primarily due to difficulties in capturing and precisely measuring its microscopic behaviors during asphalt foaming process. Volume changes provided an intuitive means to evaluate the expansion capacity of asphalt and its foaming stability. Bubble evolution characteristics of foamed asphalt offered promising insights into its foaming performance. Traditional ruler and stopwatch-based assessments were being superseded by automated techniques like laser and ultrasonic ranging. Nevertheless, the current measuring equipment still lacks the capability to comprehensively evaluate the foaming effect of asphalt across various dimensions. Asphalt temperature and foaming water consumption significantly affected asphalt foaming performance, and the inclusion of foaming agents typically led to a notable increase in the half life of foamed asphalt. However, the interaction between foaming agents and asphalt, as well as the underlying mechanisms affecting the foaming effect, are still unclear and require further exploration. Future research should primarily focus on the correlation between asphalt foaming effect and mixture performance, aiming to guide the practical engineering application of foamed asphalt mixtures and enlarge the advantages of such low-emission and sustainable mixtures.</p></div>","PeriodicalId":100830,"journal":{"name":"Journal of Road Engineering","volume":"4 3","pages":"Pages 334-347"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2097049824000295/pdfft?md5=230c90a80023e12e80503913e6df1001&pid=1-s2.0-S2097049824000295-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}