Traditional stationary or low speed deflection measurements become problematic on roads with high traffic densities. Traffic safety is decreased when survey vehicles like low speed deflectographs or stationary falling weight devices carry out measurements on highway networks. This paper describes how the Greenwood High Speed Deflectograph applies Laser Doppler Technology to provide information about pavement response to traffic load. The information obtained is the deflection velocity, the vertical velocity of the pavement surface due to a wheel load. The results from the tests show that the High Speed Deflectograph provides repeatable data comparable to similar information obtained with the Falling Weight Deflectometer. For the covering abstract see ITRD E118503.
{"title":"Non-contact Deflection Measurement at High Speed","authors":"S. Rasmussen, J. Krarup, G. Hildebrand","doi":"10.1201/9781003078814-8","DOIUrl":"https://doi.org/10.1201/9781003078814-8","url":null,"abstract":"Traditional stationary or low speed deflection measurements become problematic on roads with high traffic densities. Traffic safety is decreased when survey vehicles like low speed deflectographs or stationary falling weight devices carry out measurements on highway networks. This paper describes how the Greenwood High Speed Deflectograph applies Laser Doppler Technology to provide information about pavement response to traffic load. The information obtained is the deflection velocity, the vertical velocity of the pavement surface due to a wheel load. The results from the tests show that the High Speed Deflectograph provides repeatable data comparable to similar information obtained with the Falling Weight Deflectometer. For the covering abstract see ITRD E118503.","PeriodicalId":11581,"journal":{"name":"Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1","volume":"29 3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74756714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-20DOI: 10.1201/9781003078814-68
W. Haegeman
The subgrade and foundation of a pavement have an important role to play in the design and performance of pavements because failure of these layers will inevitably lead to total reconstruction of the pavement. One method of ensuring a stiff foundation is to specify a minimum surface stiffness as an end product requirement for the completed foundation. Belgian practice is to use the plate load test as a practical and quick method of measuring this surface stiffness. For the construction of the ramps of a road bridge, two sand embankments were put in place and compacted with rollers. Compaction of the sand base course was evaluated using this plate load test and showed satisfactory results. However for stability reasons it was necessary to assess the quality of the sand densification due to compaction at greater depth. So addditionally cone penetration tests and non-destructive seismic testing were used to evaluate stiffness profiles within the sand embankment. Both the CPT and SASW results showed good agreement. This paper focuses on the in situ assessment of the stiffness of the sand out of the PLT, CPT and SASW measurements. Correlations will be formulated between plate load moduli, dynamic shear moduli and point resistances for the compacted sand material. Finally the feasibility of the SASW method to determine the compaction quality at depth in a fast and economical way is discussed. For the covering abstract see ITRD E118503.
{"title":"In Situ Assessment of Stiffness of a Road Sand Embankment","authors":"W. Haegeman","doi":"10.1201/9781003078814-68","DOIUrl":"https://doi.org/10.1201/9781003078814-68","url":null,"abstract":"The subgrade and foundation of a pavement have an important role to play in the design and performance of pavements because failure of these layers will inevitably lead to total reconstruction of the pavement. One method of ensuring a stiff foundation is to specify a minimum surface stiffness as an end product requirement for the completed foundation. Belgian practice is to use the plate load test as a practical and quick method of measuring this surface stiffness. For the construction of the ramps of a road bridge, two sand embankments were put in place and compacted with rollers. Compaction of the sand base course was evaluated using this plate load test and showed satisfactory results. However for stability reasons it was necessary to assess the quality of the sand densification due to compaction at greater depth. So addditionally cone penetration tests and non-destructive seismic testing were used to evaluate stiffness profiles within the sand embankment. Both the CPT and SASW results showed good agreement. This paper focuses on the in situ assessment of the stiffness of the sand out of the PLT, CPT and SASW measurements. Correlations will be formulated between plate load moduli, dynamic shear moduli and point resistances for the compacted sand material. Finally the feasibility of the SASW method to determine the compaction quality at depth in a fast and economical way is discussed. For the covering abstract see ITRD E118503.","PeriodicalId":11581,"journal":{"name":"Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1","volume":"110 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72779561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-20DOI: 10.1201/9781003078814-45
P. Ekdahl
Deterioration models are largely dependent on the input data. Data is collected with a varying degree of accuracy, and different variables affect the pavement deterioration to varying degrees. The effect of variation from eleven input variables, with their distribution functions, has been tested in two deterioration models. This sensitivity analysis consists of individual variation and simultaneous variation of input data. The analysis is made with two deterioration models, HDM-4 and MMOPP with two different pavement types. HDM-4 is generally less sensitive to changes in input data than MMOPP. Generally, layer properties, such as thickness and modulus, have the greatest influence on service life in both models. By concentrating the effort on determining those variables that affect pavement performance the most with the highest accuracy, the precision in calculated pavement performance may probably increase considerably. The paper is based on a licentiate thesis (Ekdahl, 1999). For the covering abstract see ITRD E118503.
{"title":"Variation in Calculated Pavement Performance Due to Variation in Input Data","authors":"P. Ekdahl","doi":"10.1201/9781003078814-45","DOIUrl":"https://doi.org/10.1201/9781003078814-45","url":null,"abstract":"Deterioration models are largely dependent on the input data. Data is collected with a varying degree of accuracy, and different variables affect the pavement deterioration to varying degrees. The effect of variation from eleven input variables, with their distribution functions, has been tested in two deterioration models. This sensitivity analysis consists of individual variation and simultaneous variation of input data. The analysis is made with two deterioration models, HDM-4 and MMOPP with two different pavement types. HDM-4 is generally less sensitive to changes in input data than MMOPP. Generally, layer properties, such as thickness and modulus, have the greatest influence on service life in both models. By concentrating the effort on determining those variables that affect pavement performance the most with the highest accuracy, the precision in calculated pavement performance may probably increase considerably. The paper is based on a licentiate thesis (Ekdahl, 1999). For the covering abstract see ITRD E118503.","PeriodicalId":11581,"journal":{"name":"Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73389006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-20DOI: 10.1201/9781003078814-66
M. Graczyk, T. Mechowski, J. Sudyka, M. Chomicki, J. Rafa
This paper presents an original method of estimating physical features of pavement layers with the use of the effects of wave influence, originating in pavement during the dynamic loading caused by moving vehicles. This method making use of the FWD device affords possibilities for an increase in precision of estimating module value in comparison with other methods. Conducting these quasi-static tests affords possibilities for estimation of the modulus value and Poisson's coefficient and for reaching a higher level of precision for non-typical configuration of layers and back structure. This method possible renders calculation of bearing capacity according to own procedures and evaluation of influence of physical features on bearing capacity during the operation process of a road pavement. For the covering abstract see ITRD E118503.
{"title":"Method of Estimation of Bearing Capacity of Multi-layer Pavements with Application of Quasi-static Tests","authors":"M. Graczyk, T. Mechowski, J. Sudyka, M. Chomicki, J. Rafa","doi":"10.1201/9781003078814-66","DOIUrl":"https://doi.org/10.1201/9781003078814-66","url":null,"abstract":"This paper presents an original method of estimating physical features of pavement layers with the use of the effects of wave influence, originating in pavement during the dynamic loading caused by moving vehicles. This method making use of the FWD device affords possibilities for an increase in precision of estimating module value in comparison with other methods. Conducting these quasi-static tests affords possibilities for estimation of the modulus value and Poisson's coefficient and for reaching a higher level of precision for non-typical configuration of layers and back structure. This method possible renders calculation of bearing capacity according to own procedures and evaluation of influence of physical features on bearing capacity during the operation process of a road pavement. For the covering abstract see ITRD E118503.","PeriodicalId":11581,"journal":{"name":"Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1","volume":"100 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79324988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-20DOI: 10.1201/9781003078814-17
G. Eiksund, I. Hoff, G. Svano, A. Watn, E. Cuelho, S. Perkins, B. Christopher, C. Schwartz
Reinforcement products used in flexible pavement systems have previously been shown to provide a significant structural contribution for certain pavement design configurations. The prediction of structural response of reinforced pavements through the use of mechanistic response models is dependent on the material models used for the unbound aggregate and the manner in which the reinforcement is numerically modeled. This paper examines the use of six different constitutive models for the unbound aggregate and three different methods of modeling the reinforcement inclusion. For similar property set values, the material and numerical model sets are seen to influence the degree of structural benefit provided by the reinforcement. For the covering abstract see ITRD E118503.
{"title":"Material Models for Reinforced Unbound Aggregate","authors":"G. Eiksund, I. Hoff, G. Svano, A. Watn, E. Cuelho, S. Perkins, B. Christopher, C. Schwartz","doi":"10.1201/9781003078814-17","DOIUrl":"https://doi.org/10.1201/9781003078814-17","url":null,"abstract":"Reinforcement products used in flexible pavement systems have previously been shown to provide a significant structural contribution for certain pavement design configurations. The prediction of structural response of reinforced pavements through the use of mechanistic response models is dependent on the material models used for the unbound aggregate and the manner in which the reinforcement is numerically modeled. This paper examines the use of six different constitutive models for the unbound aggregate and three different methods of modeling the reinforcement inclusion. For similar property set values, the material and numerical model sets are seen to influence the degree of structural benefit provided by the reinforcement. For the covering abstract see ITRD E118503.","PeriodicalId":11581,"journal":{"name":"Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82160031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-20DOI: 10.1201/9781003078814-79
N.H. Thom, P.R. Fleming
{"title":"Experimental and Theoretical Comparison of Dynamic Plate Testing Methods","authors":"N.H. Thom, P.R. Fleming","doi":"10.1201/9781003078814-79","DOIUrl":"https://doi.org/10.1201/9781003078814-79","url":null,"abstract":"","PeriodicalId":11581,"journal":{"name":"Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89795140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-20DOI: 10.1201/9781003078814-12
Jjcb Veloso, F. Branco
A basic tool for airfield pavement management is the Pavement Condition Index (PCI), a numerical indicator that notes the surface condition of the pavement through the visual analysis of the frequency and severity of pavement distresses, on a set of samples criteriously selected. The U.S. Army Corps of Engineers developed the PCI for airport pavements and its determination has become an ASTM Standard Test Method (ASTM D 5340-98). Furthermore, the PCI has become a mandatory airfield condition index by the Federal Aviation Administration (FAA) of the USA. It provides an objective basis for determining maintenance and repair needs and priorities. In order to contribute to the implementation of an airfield pavement management system in Portugal, an application of this tool has been made on the pavement condition evaluation of a military airfield in this country. This paper describes the survey procedures, the obtained results and their validation by non-destructive testing (Mu-Meter and FWD). For the covering abstract see ITRD E118503.
机场路面管理的一个基本工具是路面状况指数(PCI)，这是一个数字指标，通过对一组标准选择的样本的路面损坏频率和严重程度的可视化分析来记录路面的表面状况。美国陆军工程兵团开发了机场路面PCI，其测定已成为ASTM标准测试方法(ASTM D 5340-98)。此外，PCI已成为美国联邦航空管理局(FAA)的强制性机场状况指数。它为确定维护和修理的需要和优先次序提供了客观的基础。为了促进葡萄牙机场路面管理系统的实施，已将该工具应用于该国一个军用机场的路面状况评估。本文介绍了测量过程、所得结果及其无损检测(Mu-Meter和FWD)的验证。相关摘要见ITRD E118503。
{"title":"Validation of Pavement Condition Index – PCI: A Portuguese Case Study","authors":"Jjcb Veloso, F. Branco","doi":"10.1201/9781003078814-12","DOIUrl":"https://doi.org/10.1201/9781003078814-12","url":null,"abstract":"A basic tool for airfield pavement management is the Pavement Condition Index (PCI), a numerical indicator that notes the surface condition of the pavement through the visual analysis of the frequency and severity of pavement distresses, on a set of samples criteriously selected. The U.S. Army Corps of Engineers developed the PCI for airport pavements and its determination has become an ASTM Standard Test Method (ASTM D 5340-98). Furthermore, the PCI has become a mandatory airfield condition index by the Federal Aviation Administration (FAA) of the USA. It provides an objective basis for determining maintenance and repair needs and priorities. In order to contribute to the implementation of an airfield pavement management system in Portugal, an application of this tool has been made on the pavement condition evaluation of a military airfield in this country. This paper describes the survey procedures, the obtained results and their validation by non-destructive testing (Mu-Meter and FWD). For the covering abstract see ITRD E118503.","PeriodicalId":11581,"journal":{"name":"Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1","volume":"116 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90978187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-20DOI: 10.1201/9781003078814-33
F. Bayomy, Mah Abo-Hashema
The Seasonal Adjustment Factor (SAF) is a key input in the mechanistic-empirical overlay design system for flexible pavements. The SAF accounts for the environmental changes on the pavement layer properties. It adjusts the elastic modulus of an unbound layer from one season (e.g. reference normal season) to another. A sensitivity analysis was conducted to study the effect of variation of the SAF values on the flexible overlay design thickness. The study was performed using the WINFLEX 2000 overlay design software. The analysis of the results indicates that the overlay thickness is more sensitive to changes in the moduli values during the spring thaw. The overlay thickness may increase by about 21% if 80% reduction in the moduli values were obtained in the subgrade and base layers, which could be the worst-case scenario during the spring thaw. Winter freeze was found to have little or no effect on the overlay thickness. For the covering abstract see ITRD E118503.
{"title":"Effect of the Variability of Seasonal Moduli Adjustment Factors on the Mechanistic-Empirical Overlay Design","authors":"F. Bayomy, Mah Abo-Hashema","doi":"10.1201/9781003078814-33","DOIUrl":"https://doi.org/10.1201/9781003078814-33","url":null,"abstract":"The Seasonal Adjustment Factor (SAF) is a key input in the mechanistic-empirical overlay design system for flexible pavements. The SAF accounts for the environmental changes on the pavement layer properties. It adjusts the elastic modulus of an unbound layer from one season (e.g. reference normal season) to another. A sensitivity analysis was conducted to study the effect of variation of the SAF values on the flexible overlay design thickness. The study was performed using the WINFLEX 2000 overlay design software. The analysis of the results indicates that the overlay thickness is more sensitive to changes in the moduli values during the spring thaw. The overlay thickness may increase by about 21% if 80% reduction in the moduli values were obtained in the subgrade and base layers, which could be the worst-case scenario during the spring thaw. Winter freeze was found to have little or no effect on the overlay thickness. For the covering abstract see ITRD E118503.","PeriodicalId":11581,"journal":{"name":"Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1","volume":"129 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85746365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-20DOI: 10.1201/9781003078814-48
Y. Hachiya, Y. Tsubokawa, O. Takahashi
A nondestructive structural evaluation system was developed for evaluating airport asphalt pavements by using a Falling Weight Deflectometer (FWD). The method includes estimating the modulus of elasticity for each layer, calculating the strains for the design load, and then comparing the results to the strain criteria. Next, an allowable number of load repetitions is estimated, and finally the thickness of any required overlay is determined. A simplified method was developed that is based on the FWD maximum deflection because of its convenience for in situ evaluations. Subgrade property corrections and residual life estimation were considered for practical applications. This evaluation system was used for many actual structural evaluations of airport asphalt pavements. The results verified the validity of this method. For the covering abstract see ITRD E118503.
{"title":"Implementation of Nondestructive Structural Evaluation for Airport Asphalt Pavements","authors":"Y. Hachiya, Y. Tsubokawa, O. Takahashi","doi":"10.1201/9781003078814-48","DOIUrl":"https://doi.org/10.1201/9781003078814-48","url":null,"abstract":"A nondestructive structural evaluation system was developed for evaluating airport asphalt pavements by using a Falling Weight Deflectometer (FWD). The method includes estimating the modulus of elasticity for each layer, calculating the strains for the design load, and then comparing the results to the strain criteria. Next, an allowable number of load repetitions is estimated, and finally the thickness of any required overlay is determined. A simplified method was developed that is based on the FWD maximum deflection because of its convenience for in situ evaluations. Subgrade property corrections and residual life estimation were considered for practical applications. This evaluation system was used for many actual structural evaluations of airport asphalt pavements. The results verified the validity of this method. For the covering abstract see ITRD E118503.","PeriodicalId":11581,"journal":{"name":"Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84017685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-20DOI: 10.1201/9781003078814-74
W. P. Núñez, J. Ceratti, W. Gehling, J. Oliviera
This paper analyses the elastic behaviour of thin pavements built with densely graded sound rock and weathered basalts (alternative materials) dry-bound macadam. Four surface treated test sections were built on lateritic soil subgrade and loaded by a linear traffic simulator. More than 1,300,000 equivalent single axle loads were applied and more than 2,000 deflections measured during traffic. Pavement and subgrade moduli were back calculated, and cyclic triaxial tests were carried out on the subgrade soil. The investigation results make clear that thin surfaced unbound granular pavements, built on lateritic clay subgrades, may present a quite high bearing capacity. The contribution of lateritic subgrades to the bearing capacity of thin pavements and the influence of permeability on the elastic response of unbound aggregate bases are also evidenced. For the covering abstract see ITRD E118503.
{"title":"Elastic Analysis of Thin Pavements and Subgrade Soil Based on Field and Laboratory Tests","authors":"W. P. Núñez, J. Ceratti, W. Gehling, J. Oliviera","doi":"10.1201/9781003078814-74","DOIUrl":"https://doi.org/10.1201/9781003078814-74","url":null,"abstract":"This paper analyses the elastic behaviour of thin pavements built with densely graded sound rock and weathered basalts (alternative materials) dry-bound macadam. Four surface treated test sections were built on lateritic soil subgrade and loaded by a linear traffic simulator. More than 1,300,000 equivalent single axle loads were applied and more than 2,000 deflections measured during traffic. Pavement and subgrade moduli were back calculated, and cyclic triaxial tests were carried out on the subgrade soil. The investigation results make clear that thin surfaced unbound granular pavements, built on lateritic clay subgrades, may present a quite high bearing capacity. The contribution of lateritic subgrades to the bearing capacity of thin pavements and the influence of permeability on the elastic response of unbound aggregate bases are also evidenced. For the covering abstract see ITRD E118503.","PeriodicalId":11581,"journal":{"name":"Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88218533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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