Further Evaluation of Limiting Strain Criteria for Perpetual Asphalt Pavement Design

2017 ◽  
Vol 2640 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Alfredo J. Castro ◽  
Nam Tran ◽  
Mary Robbins ◽  
David H. Timm ◽  
Chris Wagner
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Pavement ◽  
Fatigue Cracking ◽  
Pavement Design ◽  
Threshold Values ◽  
Bottom Up ◽  
Test Track ◽  
Climatic Regions ◽  
Concrete Layer ◽  
Perpetual Pavement

Perpetual asphalt pavements have been designed with single threshold values for the horizontal strains at the bottom of the asphalt concrete layer and for vertical strains on top of the subgrade to prevent the occurrence of bottom-up fatigue cracking and subgrade rutting. Several thresholds have been utilized for design based on laboratory and field test results. Limiting strain distributions were recently proposed for perpetual pavement design instead of single threshold values for controlling the horizontal and vertical strains. These design criteria were developed with data collected from test sections at the National Center for Asphalt Technology pavement test track. The objective of this study was to conduct additional analyses of eight perpetual pavement sections located in different climatic regions, to support the proposed limiting strain criteria. These sections were simulated in the PerRoad perpetual pavement design software to determine the horizontal strains at the bottom of the asphalt concrete layer and the vertical strains on top of the subgrade. The strains were then analyzed to evaluate the proposed limiting strain criteria. Based on the simulations, the limiting horizontal strain distribution above the 60th percentile can effectively differentiate the calculated strain distributions of the eight perpetual pavement sections from those of the test sections that failed due to bottom-up fatigue cracking on the test track. In addition, the calculated vertical strains on top of the subgrade at the 50th percentile were lower than the proposed 200-microstrain limit. These results provide additional support for utilizing the proposed strain criteria in perpetual asphalt pavement design.

scholarly journals Classification of Surface Pavement Cracks as Top-down, Bottom-up, and Cement-Treated Reflective Cracking Based on Deep Learning Methods

2021 ◽  
Author(s):  
Nirmal Dhakal ◽  
Mostafa A. Elseifi ◽  
Zia U. Zihan ◽  
Zhongjie Zhang ◽  
Christophe N. Fillastre ◽  
...  
Keyword(s):  
Neural Network ◽  
Deep Learning ◽  
Asphalt Concrete ◽  
Fatigue Cracking ◽  
Ann Model ◽  
Reflective Cracking ◽  
Top Down ◽  
Bottom Up ◽  
Concrete Layer ◽  
Artificial Neural Network Ann

The treatment and repair strategies of reflective and fatigue cracking that initiate at the pavement surface (i.e. top-down cracking) and at the bottom of the asphalt concrete layer (i.e. bottom-up cracking) are noticeably different. However, pavement engineers are facing difficulties in identifying these cracks in the field as they usually appear in visually identical patterns. The objective of this study was to develop Artificial Neural Network (ANN) and Convolutional Neural Network (CNN) applications to differentiate and classify top-down, bottom-up, and cement-treated reflective cracking in in-service pavements using deep-learning models. The developed CNN model achieved an accuracy of 93.8% in the testing and 91% in the validation phases and the ANN model showed an overall accuracy of 92%. The ANN classification tool was developed based on variables related to pavement and crack characteristics including age, Average Daily Traffic , thickness of Asphalt Concrete layer, type of base, crack orientation and location.

Incorporation of Endurance Limit in the Mechanistic-Empirical Flexible Perpetual Pavement Design

2018 ◽  
Vol 2672 (40) ◽  
pp. 108-121 ◽  
Author(s):  
Sheng Hu ◽  
Sang-Ick Lee ◽  
Lubinda F. Walubita ◽  
Fujie Zhou ◽  
Tom Scullion
Keyword(s):  
Endurance Limit ◽  
Design Method ◽  
Field Performance ◽  
Fatigue Cracking ◽  
Climatic Conditions ◽  
Influential Factors ◽  
Pavement Design ◽  
Design System ◽  
Viscoelastic Continuum Damage ◽  
Perpetual Pavement

In recent years, there has been a push toward designing long-lasting thick hot mix asphalt (HMA) pavements, commonly referred to as a perpetual pavements (PP). For these pavements, it is expected that bottom-up fatigue cracking does not occur if the strain level is below a certain limit that is called the HMA fatigue endurance limit (EL). This paper proposed a mechanistic-empirical PP design method based on this EL concept. The ELs of 12 HMA mixtures were determined using simplified viscoelastic continuum damage testing and the influential factors were comparatively investigated. It was found that HMA mixtures seem to have different EL values based on mix type and test temperatures. There is not just a single EL value that can be used for all mixtures. Thus, default EL criteria for different mixtures under different climatic conditions were developed and incorporated into the Texas Mechanistic-Empirical Flexible Pavement Design System (TxME). As a demonstration and case study, one Texas PP test section with weigh-in-motion traffic data was simulated by TxME. The corresponding TxME inputs/outputs in terms of the PP structure, material properties, traffic loading, environmental conditions, and ELs were demonstrated. The corresponding TxME modeling results were consistent with the actual observed field performance of the in-service PP section.

The Study on the Asphalt Pavement with Composite Base

2012 ◽  
Vol 505 ◽  
pp. 468-473
Author(s):  
Jing Song Shan ◽  
Ning Zhang ◽  
He Xue Fan
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Pavement ◽  
Elastic Theory ◽  
Rigid Base ◽  
Internal Stresses ◽  
Heavy Load ◽  
Concrete Layer ◽  
Rigid Layer ◽  
Suitable Structure ◽  
Treated Layer

Semi-rigid layer is widely used as the base in China. However, the structure has resulted in many premature distresses in asphalt concrete layer. In order to overcome the problem, the composite base is introduced which is composed by both flexible and chemically stabilized material. The internal stresses are calculated by linear multilayer elastic theory and then, a comparison of the stresses of asphalt pavement with semi-rigid base and composite base is provided. The result shows that the composite base composed by all, consisting of the asphalt treated layer, graded crushed stone and cement treated layer is more suitable structure to resist cracking and the structure also has good adaptability to heavy load.

scholarly journals Influence of Polypropylene Length on Stability and Flow of Fiber-reinforced Asphalt Mixtures

2016 ◽  
Vol 2 (10) ◽  
pp. 538-545 ◽  
Author(s):  
Ramin Bayat ◽  
Siamak Talatahari
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Pavement ◽  
Flexible Pavements ◽  
Asphalt Mixture ◽  
Fatigue Cracking ◽  
Asphalt Mixtures ◽  
Concrete Mixture ◽  
Fiber Reinforced ◽  
Surface Distress ◽  
Marshall Stability

Engineers are constantly trying to improve the performance of the flexible pavements. The main surface distress types which cause maintenance and disruption are rutting and fatigue cracking. For solving these problems, many studies have been carried out until now, ranged from changing gradation to adding polymers and fibers to asphalt mixture. In this study, polypropylene additive was selected as fiber additive because of low costing and having good correlation with asphalt pavement. Three type of polypropylene additive in the length 6, 12 and 19 mm were selected and used at five different percentages in the asphalt concrete mixture. Asphalt specimens were analysed by Marshall Analysis and finally tested by Marshall Stability apparatus. Adding polypropylene increased Marshall Stability (38%), and decreased Flow (39%). These results show that polypropylene can be helpful for increasing pavement life.

Field Calibration of Fatigue Models of Cementitiously Stabilized Pavement Materials for Use in the Mechanistic-Empirical Pavement Design Guide

2019 ◽  
Vol 2673 (2) ◽  
pp. 427-435
Author(s):  
Xiaojun Li ◽  
Jingan Wang ◽  
Haifang Wen ◽  
Balasingam Muhunthan
Keyword(s):  
Field Performance ◽  
Fatigue Cracking ◽  
Pavement Design ◽  
Fatigue Properties ◽  
Bottom Up ◽  
Freeze Thaw ◽  
State Highway ◽  
Design Guide ◽  
Fatigue Model ◽  
Pavement Structures

The use of cementitiously stabilized materials (CSM), such as lean concrete, cement-stabilized aggregate, and soil stabilized with cement, lime, fly ash, or combinations thereof in the subgrade, sub-base, and base layers of flexible and rigid pavement structures, is a widely accepted practice by many state highway agencies. However, the bottom-up fatigue cracking models of cementitiously stabilized layers (CSL) described in the AASHTO Interim Mechanistic-Empirical Pavement Design Guide Manual of Practice (referred to as the MEPDG) have not been calibrated for CSM based on their field performance. In addition, top-compression fatigue as well as the effects of increases in the modulus and strength values of CSM over time, erosion, and freeze–thaw and wet–dry cycles on the fatigue properties of CSM are not considered in the MPEDG. To address these deficiencies, this research calibrated the bottom-up fatigue model, and developed and calibrated the top-compression fatigue model, with consideration of modulus and strength growth, erosion, and freeze–thaw and wet–dry cycles. Reasonable correlations between the predicted modulus values and measured modulus values are found for CSL. Further study is needed to refine the calibration and validate the models based on a larger population of field data that covers different material types, climatic zones, and traffic conditions.

Research on anti-fatigue ability of Sisal Fiber Asphalt Mixture Pavement

2013 ◽  
Vol 405-408 ◽  
pp. 1782-1785
Author(s):  
Zi Ye He ◽  
Fu Xue Liu
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Fatigue Cracking ◽  
Concrete Pavement ◽  
Pavement Performance ◽  
Sisal Fiber ◽  
Viscoelastic Parameters ◽  
Cracking Performance ◽  
Asphalt Concrete Pavement

Fatigue crack is one of the main road damage forms of asphalt pavement structure, and serious impact the asphalt pavement performance and service life. Asphalt mixture has typical viscoelastic,and can get Burgers model and viscoelastic parameters form creep test. Using finite element method of fracture mechanics, simulation under dynamic loading, research crack extending behavior of common asphalt concrete pavement and mixed with 0.2% of sisal fiber asphalt concrete pavement. From the results, it can find out that when mixed with sisal fiber, the anti-fatigue cracking performance is obvious enhancement.

scholarly journals Dynamic Modulus and Field Performance of Cold-in-Place Recycled Asphalt Pavement

2019 ◽  
Vol 6 (2) ◽  
pp. b1-b7
Author(s):  
M. R. Islam ◽  
S. A. Kalevela ◽  
J. A. Rivera ◽  
T. B. Rashid
Keyword(s):  
Dynamic Modulus ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Field Performance ◽  
Fatigue Cracking ◽  
Threshold Values ◽  
Recycled Asphalt ◽  
Transverse Cracking ◽  
Service Period ◽  
Dynamic Modulus Test

This study investigates the dynamic modulus of cold-in-place recycling (CIR) asphalt material and its performance using pavement performance data and laboratory dynamic modulus testing. Colorado Department of Transportation (CDOT) has 37 projects with over 8 million square yards using CIR materials. Sites from ten projects were selected to monitor the performances and collect samples for laboratory testing. Dynamic modulus testing on the CIR cores was conducted by the CDOT. Results show measured distresses of CIR rehabilitation techniques are mostly below the threshold values during the service period. International Roughness Index, rutting, and transverse cracking never exceeded the threshold values during the studied period. Only two CIR pavements exceeded the threshold values for fatigue cracking after 8-10 years of service. Measured distresses of CIR rehabilitation techniques are similar to conventional pavements based on engineering judgment. The laboratory dynamic modulus test results show CIR has about 50 % less dynamic modulus compared to the traditional asphalt mixture. Keywords: asphalt pavement, cold-in-place recycling, dynamic modulus, fatigue cracking, transverse cracking.

Load Spectra–Incorporated Fatigue Cracking Model Implementation and Case Study

2017 ◽  
Vol 2640 (1) ◽  
pp. 1-10
Author(s):  
Sheng Hu ◽  
Fujie Zhou ◽  
Tom Scullion
Keyword(s):  
Asphalt Concrete ◽  
Fatigue Cracking ◽  
Pavement Design ◽  
Design System ◽  
Key Factors ◽  
Spectra Analysis ◽  
Traffic Loading ◽  
Load Spectra ◽  
Comparison Results ◽  
Asphalt Concrete Pavement

Traffic loading is one of the key factors that may cause asphalt concrete pavement fatigue cracking. Axle load spectra input provides an opportunity for evaluating the pavement response under real traffic loads throughout the pavement design life. This paper describes the methodology of incorporating axle load spectra into the mechanistic–empirical fatigue cracking model that uses a fracture mechanics method to determine crack propagation. The paper also presents the incorporation of the method into the Texas mechanistic–empirical flexible pavement design system. Several load spectra cases were studied, and the percentages of the corresponding fatigue cracking areas were predicted and compared. The comparison results confirmed the necessity of load spectra analysis. Overall, the implemented load spectra–incorporated asphalt concrete fatigue cracking model generated rational results. Further research is continuing on field validation and calibration.

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