| 1. |
- Dinegdae, Yared H., et al.
(författare)
-
Design inputs variabilities influence on pavement performance reliability
- 2016
-
Ingår i: Functional Pavement Design. - : CRC Press. ; , s. 741-750
-
Konferensbidrag (refereegranskat)abstract
- Pavement design is a probabilistic process as it involves many random variables.Through the incorporation of reliability, pavement design methods consider inputparameters variabilities effect on pavement performance. Load and Resistance Factor Design(LRFD) is a typical example of reliability-based design procedure. In LRFD, a set of partialsafety factors are developed by modelling input parameters variabilities with representativeaverage conditions. This paper evaluates the impact input parameters variabilities have onestimated target reliability in the case when actual variabilities are different from assumedconditions. This was achieved by evaluating a field pavement section with various combinationsof input parameters variabilities. The optimized section for a given target reliability wasachieved through the mechanics-based LRFD procedure and the actual reliabilities of thevarious cases were obtained using a methodology that uses response surface approach andfirst order reliability method (FORM). The results have shown that the level of input parametersvariabilities used affect the target reliability considerably.
|
|
| 2. |
- Dinegdae, Yared H., et al.
(författare)
-
Effect of heavy traffic loading on predicted pavement fatigue life
- 2016
-
Ingår i: RILEM Bookseries. - Dordrecht : Springer Netherlands. ; , s. 389-395
-
Konferensbidrag (refereegranskat)abstract
- Fatigue cracking is one of the dominant failure modes of asphalt concrete pavements. There are a number of analysis and design methods that can be used to optimize pavement sections for this kind of distress. Most of these methods incorporate advanced material property predictive models. However, traffic loading, which has been identified as a primary contributing factor in causing fatigue cracking, is characterized relatively simplistically. There is a concern in light of recent advancement in traffic characterization, and tire inflation pressure surveys that existing methods might not be adequate. The objective of this paper is to evaluate and quantify the effects of truck traffic characterization in axle load spectra and high tire inflation pressure levels on predicted fatigue cracking performance. This was achieved by evaluating a number of pavement sections using the mechanics-based fatigue cracking analysis framework. The studied traffic characterization approaches are ESALs, axle load spectra with and without traffic seasonal variations and three levels of tire inflation pressures. It is evident from the result that higher tire inflation pressure and traffic characterization using axle load spectra induce more damage and subsequently early crack initiation time.
|
|
| 3. |
- Dinegdae, Yared H., et al.
(författare)
-
Effects of truck traffic on top-down fatigue cracking performance of flexible pavements using a new mechanics-based analysis framework
- 2018
-
Ingår i: International Journal on Road Materials and Pavement Design. - : Taylor & Francis. - 1468-0629 .- 2164-7402. ; 19:1, s. 182-200
-
Tidskriftsartikel (refereegranskat)abstract
- The mechanics-based analysis framework predicts top-down fatigue cracking initiation timein asphalt concrete pavements by utilising fracture mechanics and mixture morphology-basedproperty. To reduce the level of complexity involved, traffic data were characterised and incorporatedinto the framework using the equivalent single axle load (ESAL) approach. There isa concern that this kind of simplistic traffic characterisation might result in erroneous performancepredictions and pavement structural designs. This paper integrates axle load spectraand other traffic characterisation parameters into the mechanics-based analysis framework andstudies the impact these traffic characterisation parameters have on predicted fatigue crackingperformance. The traffic characterisation inputs studied are traffic growth rate, axle load spectra,lateral wheel wander and volume adjustment factors. For this purpose, a traffic integrationapproach which incorporates Monte Carlo simulation and representative traffic characterisationinputs was developed. The significance of these traffic characterisation parameters wasestablished by evaluating a number of field pavement sections. It is evident from the resultsthat all the traffic characterisation parameters except truck wheel wander have been observedto have significant influence on predicted top-down fatigue cracking performance.
|
|
| 4. |
- Dinegdae, Yared H.
(författare)
-
Mechanics-based Design Framework for Flexible Pavements
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Load induced top-down fatigue cracking has been recognized recently as a major distress phenomenon in asphalt pavements. This paper presents a mechanics-based design framework in load and resistance factor design (LRFD) format for the top-down fatigue cracking performance evaluation of flexible pavements. This was achieved by enhancing further the hot mix asphalt fracture mechanics (HMA-FM) model through the incorporation of mixture morphology influence on key fracture properties, and incorporating partial safety factors to account for variabilities and uncertainties. The analysis framework was calibrated and validated using pavement sections that have high quality laboratory data and well documented field performance histories. Moreover, as traffic volume was identified in having a dominant influence on predicted performance, a further investigation was performed to establish and evaluate truck traffic characterization parameters effect on predicted results.A two-component reliability analysis methodology, which uses central composite design (CCD) based response surface approach for surrogate model generation and the first order reliability method (FORM) for reliability estimation was used for the development of the LRFD mechanics-based design framework. The effectiveness of the design framework was investigated through design examples, and the results have shown that the formulated partial safety factors have accounted effectively the variabilities involved in the design process. Further investigation was performed to establish the influence design inputs variabilities have on target reliabilities through case studies that combine input variabilities in a systematic way. It was observed from the results that the coefficient of variation (COV) level of the variability irrespective of the distribution type used have a significant influence on estimated target reliability.
|
|
| 5. |
- Dinegdae, Yared H., et al.
(författare)
-
Mechanics-based Topdown Fatigue Cracking Initiation Prediction Framework for Asphaltic Pavements
- 2015
-
Ingår i: International Journal on Road Materials and Pavement Design. - : Taylor & Francis. - 1468-0629 .- 2164-7402. ; 16:4
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, a new mechanics-based top-down fatigue cracking analysis framework is presented for asphalt pavements. A new mixture morphology-based set of material sub-models is presented for characterising key mixture properties and their change over time. Predicting the load induced top-down fatigue crack initiation (CI) time by utilising comprehensive mixture properties creates the possibility of optimising the mixture morphology while taking into account its subsequent effect on long-term pavement performance. The new framework was calibrated and subsequently validated against a number of field pavement sections with varying traffic levels that are representative for current practices and which have a wide range in material properties. The framework accounts the change in key mixture properties due to ageing and mixture-healing effect on damage accumulation while determining the overall effect of design inputs on cracking performance. Model calibration and validation were achieved based on the healing potential of the asphalt mixture. It was found out that the CI predictions for all the sections are in general agreement with the observed performance in the field, thus giving credibility for the framework.
|
|
| 6. |
- Dinegdae, Yared H., 1981-
(författare)
-
Pavement inputs variability characterization : state of the art literature review
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The pavement analysis and design process, even if it is considered in most pavement performance evaluation tools as deterministic, is actually probabilistic. The probabilistic nature arises from uncertainties that originate from different sources. Even if all the sources contribute to the overall variance, each source impact can differ based on the failure mode and design approach under consideration. Moreover, some of these sources can be mitigated at a reasonable cost while those that are associated with model bias and inherent variability of future traffic and environmental inputs are difficult to quantify. This report aims to study and establish the variability associated with pavement inputs. This is achieved through a literature survey that encompasses a large body of literature among others published articles, reports, design guides and specifications. As it will not be economically feasible to model all the design inputs and parameters as random variable, a sensitivity survey is required to identify those inputs with significant influence. It is evident from the literature survey that pavement inputs variability can be described by a variety of distributions with a wide range of coefficient of variation (CV). Variability levels were shown to be dependent to a larger extent on data quality and testing method. Furthermore, factors such as functional class, material type, and design thickness were observed in creating their own variability cluster. For future variability characterization, a methodology that improves data quality while keeping the testing cost at a reasonable level should be pursued. In addition, emphasis should be given to factors that define and govern level of variability such as functional class as this would allow the data to be analysed in a manner that facilitate immediate utilization
|
|
| 7. |
- Dinegdae, Yared H., et al.
(författare)
-
Reliability-Based Design Procedure for Fatigue Cracking in Asphalt Pavements
- 2016
-
Ingår i: Transportation Research Record. - : NATL ACAD SCIENCES. - 0361-1981 .- 2169-4052. ; :2583, s. 127-133
-
Tidskriftsartikel (refereegranskat)abstract
- The need to account for the effect of design input variabilities on predicted performance has led to many design procedures that address reliability for pavement applications. The Florida cracking model uses empirically derived reliability for fatigue cracking design of asphalt pavements. A reliability approach, which is based on probabilistic uncertainty quantification, is necessary to account properly and effectively for the contribution of the variability in each parameter to the overall variance. This paper presents a load and resistance factor design (LRFD) procedure for the Florida cracking model. By delivering designs of uniform reliability, LRFD provides the basis for developing quality control and quality assurance standards. A first-order reliability method that incorporates a surrogate model based on central composite design was used to compute the reliability and formulate the partial safety factors. The reliability calibration was based on field pavement sections that had a wide range of design inputs and target reliability. Illustrative designs based on the developed LRFD procedure show the effectiveness of the partial safety factors and further confirm the credibility of the reliability analysis methodology.
|
|
| 8. |
- Onifade, Ibrahim, 1983-, et al.
(författare)
-
Hierarchical approach for fatigue cracking performance evaluation in asphalt pavements
- 2017
-
Ingår i: Frontiers of Structural and Civil Engineering. - : HIGHER EDUCATION PRESS. - 2095-2430 .- 2095-2449. ; 11:3, s. 257-269
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, a hierarchical approach is proposed for the evaluation of fatigue cracking in asphalt concrete pavements considering three different levels of complexities in the representation of the material behaviour, design parameters characterization and the determination of the pavement response as well as damage computation. Based on the developed hierarchical approach, three damage computation levels are identified and proposed. The levels of fatigue damage analysis provides pavement engineers a variety of tools that can be used for pavement analysis depending on the availability of data, required level of prediction accuracy and computational power at their disposal. The hierarchical approach also provides a systematic approach for the understanding of the fundamental mechanisms of pavement deterioration, the elimination of the empiricism associated with pavement design today and the transition towards the use of sound principles of mechanics in pavement analysis and design.
|
|
| 9. |
- Rahman, Mohammad Shafiqur, 1978-, et al.
(författare)
-
A model for the permanent deformation behavior of the unbound layers of pavements
- 2021
-
Ingår i: Proceedings Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields. - London : CRC Press. - 9781003222880 ; , s. 277-287
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This article presents a model for the permanent deformation (PD) behavior of unbound granular materials (UGMs) used in the base and subbase layers of pavement struc- tures. The model was developed based on multistage (MS) repeated load triaxial (RLT) test- ing. This is essentially a modified version of a previously developed model to better suit to field conditions in a simple and effective manner. The model was calibrated for eight com- monly used UGMs using MSRLT tests with a range of moisture contents. For validation, the calibrated models were used to predict the PD behavior of three of the UGMs in MSRLT tests with stress levels and moisture contents different from those used during the calibrations. This model showed better quality of fit when compared with another widely used PD model. The model was further tested successfully for field conditions by capturing the PD behavior of an instrumented pavement test section in a controlled environment using a heavy vehicle simu- lator (HVS) based accelerated pavement testing (APT). Inputs for calibrating the model were based on the readings from the instrumentations. The parameters of the model were adjusted to match the measured data with the predictions. Based on these results for various design conditions, some ranges of values of the material parameters of the model were suggested.
|
|
| 10. |
- Zhu, Jiqing, 1987-, et al.
(författare)
-
Experimental analysis and predictive modelling of linear viscoelastic response of asphalt mixture under dynamic shear loading
- 2022
-
Ingår i: Construction and Building Materials. - : Elsevier. - 0950-0618 .- 1879-0526. ; 328
-
Tidskriftsartikel (refereegranskat)abstract
- The use of predictive models can facilitate the inclusion of shear parameters in asphalt mixture evaluation and design processes. Unlike more extensively studied tension–compression models, the currently existing shear model, the Hirsch model, has unrealistic constants, particularly for the prediction of phase angle. Aiming at an improved predictive model in shear, this study employs a simple shear apparatus to experimentally analyse the linear viscoelastic properties of asphalt mixtures for road paving. Master curves were constructed and compared between different asphalt mixtures. Additionally, the test results were also analysed in the Black space and the Cole-Cole space. The dynamic shear response of asphalt mixtures was thereafter modelled on the basis of the Hirsch model. As the original model for phase angle prediction was found to be unrealistic, a particular focus in this study was put on identifying realistic empirical relationships for predicting the phase angle of asphalt mixtures in shear. More reliable shear test results of asphalt mixtures were used to calibrate the model, and extra test data were utilized to validate the calibrated model. It is indicated that the predictive model after calibration could deliver results of greatly improved accuracy, especially at the high-frequency and low-frequency ends. The analysis and modelling also leads to realistic empirical relationships for predicting the phase angle of asphalt mixtures in shear. The experimental verification confirms the good prediction accuracy of the calibrated model and proposed empirical relationships.
|
|
