1. |
- Dinegdae, Yared, 1981-, et al.
(author)
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Calibrating ERAPave PP with field performance data
- 2024
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Conference paper (other academic/artistic)abstract
- The conventional pavement design approach considers various parameters for the optimization of pavements for the prevailing traffic and environmental conditions. Demands related to technological developments, climate adaptation and infrastructure resilience are expected to influence the way pavements are designed and constructed. For this, better and improved flexible pavement design tools are required. ERAPave performance prediction (PP) which is a mechanistic-empirical (M-E) pavement design tool is currently under development with the goal of addressing the several challenges facing the pavement industry. This paper calibrates the permanent deformation prediction approach in ERAPave PP using pavement performance data from actual field pavements. As traffic volume is observed to have a significant influence on predicted results, separate calibration was performed for medium-to-high-volume and low-volume traffic categories. A global calibration factor is used for this purpose, significantly improving the accuracy of the prediction for both categories. Prediction accuracy can be improved further through the consideration of observed rut depth variability.
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2. |
- Dinegdae, Yared, 1981-, et al.
(author)
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ERAPave PP calibration using field pavement sections
- 2024
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In: Sammanställning av postrar från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut.
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Conference paper (other academic/artistic)abstract
- Introduction - ERAPave PPMechanistic-empirical (M-E) pavement performance evaluation toolEmploys enhanced approaches for inputs characterization, pavement response modeling and performance evaluationPredicts distresses such as permanent deformation, fatigue cracking, frost heave and studded tire wearUnder consideration by the Swedish and Norwegian Transport Administration as a possible successor to existing methods
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3. |
- Dinegdae, Yared, 1981-, et al.
(author)
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Evaluation of ERAPave PP permanent deformation models using APT
- 2023
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In: International Journal on Road Materials and Pavement Design. - : Taylor & Francis. - 1468-0629 .- 2164-7402. ; 25:sup1, s. 95-111
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Journal article (peer-reviewed)abstract
- Permanent deformation is one of the failure modes considered in the analysis and design of flexible pavements. ERAPave performance prediction (PP) which is a mechanistic empirical (ME) pavement design tool utilises two distinct models for the prediction of permanent deformation in the bound and unbound granular layers including subgrade. This paper aims to calibrate these models using pavement response and performance data from accelerated pavement testing (APT) structures. Material properties such as layer modulus were established through an optimisation that involves both falling weight deflectometer (FWD) and pavement response measurements. Based on the predicted performance results, a separate set of calibration was performed for permanent deformation development in moist and wet moisture conditions. The calibrated models have resulted in predictions that are in good agreement with observed performances. Furthermore, the model parameters successfully captured the initial densification behaviour and the associated sensitivity with axle load level.
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4. |
- Dinegdae, Yared, 1981-, et al.
(author)
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Implementation of energy-based models for pavement performance evaluation : Summary of results
- 2023
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Reports (other academic/artistic)abstract
- Currently operational pavement design systems utilize empirical relationships to predict the long-term performance of pavement structures. These weak empirical couplings define the pavement response to environmental and traffic loads. The Swedish Transport Administration in close collaboration with the pavement industry has initiated a multi-year program with the aim of developing and implementing advanced models for Swedish conditions. The implementation of the program was carried out in phases and during these phases different activities were executed. This report presents and summarizes the main findings of the implementation project. The summary includes the development and enhancement of advanced material models and the incorporation of these models into a windows-based pavement analysis tool. Material models that are developed on the basis of micromechanics and mixture morphology are utilized for the prediction of asphalt mixture properties such as viscosity, shear modulus, phase angle, scalar modulus, creep rate and dynamic modulus. These material models account for factors such as temperature and rate of loading and are verified for a number of Swedish mixtures. The windows-based pavement analysis tool was developed using an interactive and dynamic Python programming language and incorporates energy-based methods for the prediction of rutting and cracking. The tool incorporates features for the prediction of pavement temperature profile and the integration of axle load spectra (ALS). The developed and enhanced material models have been observed to provide reasonable and acceptable predictions while the Windows-based pavement analysis tool is observed to be stable andefficient. The analysis of different scenarios has shown that the linear elastic analysis (LEA) based cracking model provides predictions that are reasonable. The finite element method (FEM) based cracking and rutting models, on the other hand, are observed to deliver results that are over exaggerated and unacceptable. To improve further the accuracy of predicted results, it is strongly recommended that both the rutting and cracking predictive models should be verified, calibrated and validated for Swedish conditions.
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5. |
- Dinegdae, Yared, 1981-, et al.
(author)
-
Structural response analysis of concrete pavement
- 2024
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Reports (other academic/artistic)abstract
- Cement concrete or concrete pavements are an integral part of the road network in many countries. In the United States, concrete pavements comprise approximately 45% of the road network. In comparison, the share in Sweden is almost negligible. In 2007, the Swedish Transport Administration (Trafikverket) initiated in close collaboration with the paving industry a field project with the aim of building knowledge and understanding on the structural response of concrete pavements.This report aims to characterize the structural response of a concrete pavement under varying traffic and environmental conditions. This is achieved by utilizing in-situ strains, stresses and deflections measured over an extended period of time from a concrete test slab. The structural responses and environmental conditions were measured using strain gauges, geophones, soil pressure cells and temperature measuring sensors. These instruments were installed at different locations of interest within the concrete slab. Loading was applied using dynamic falling weights and heavy trucks that travel at different speed levels. The strain measurements from the heavy truck were used to establish a relationship between applied axle load level and induced strain at various location of the slab. The analyses have shown that the structural response of concrete pavements is highly dependent on both environmental and traffic loadings. It has also been observed that strain levels are speed dependent, slow-moving trucks inducing a higher magnitude of longitudinal and transverse strainsunder the wheel at the bottom of the slab. Increase in truck axle load level is also observed to increase the amount of induced strain for all the locations considered. It is important to further validate the experimental results with a numerical analysis that involve multi layered linear elastic analysis (MLEA) and finite element method (FEM). This allows to enhance the predictive models of the existing Swedish concrete pavement design method.
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6. |
- Dinegdae, Yared, 1981-, et al.
(author)
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Toward a Comprehensive Pavement Reliability Analysis Approach
- 2023
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In: Transportation Research Record. - : Sage Publications. - 0361-1981 .- 2169-4052. ; 2677:7, s. 680-692
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Journal article (peer-reviewed)abstract
- Reliability has been incorporated in pavement design tools to account for input variability influence on predicted performance. As they are not based on a probabilistic method of uncertainty propagation, the reliability analysis methodologies that are currently implemented in pavement performance tools lack rigor and robustness. This paper investigates the potential of three reliability analysis methodologies for pavement application: the Pavement ME reliability analysis methodology, Monte Carlo simulation (MCS), and the first-order reliability method (FORM). The MCS and FORM involve a response surface method for the generation of a second-order surrogate model. The investigation was performed using inputs and performance data from accelerated pavement testing structures. Inputs that were identified as significant were characterized as random variables and their associated variability was established using measured structural and material properties. Pavement performance with respect to rutting was predicted using the ERAPave performance prediction tool, while MCS was used to generate the actual variability of the distress. The reliability analysis results have shown that a comprehensive reliability analysis methodology is required that effectively captures input variabilities and the error associated with surrogate models.
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7. |
- Rahman, Mohammad Shafiqur, 1978-, et al.
(author)
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A model for the permanent deformation behavior of the unbound layers of pavements
- 2021
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In: Proceedings Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields. - London : CRC Press. - 9781003222880 ; , s. 277-287
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Conference paper (other academic/artistic)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.
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8. |
- Zhu, Jiqing, 1987-, et al.
(author)
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Bitumen properties and the shear resistance of asphalt mixtures : towards a tool for bitumen selection
- 2021
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Reports (other academic/artistic)abstract
- The shear resistance of asphalt mixtures is a crucial material property to ensure the pavement quality and minimize shear-related distresses. For a high shear resistance, proper protocols to select suitable raw materials for asphalt mixtures, mainly bitumen and mineral aggregates, are of great importance. The study presented in this report focuses on the selection of bitumen for asphalt mixtures. Towards a tool for bitumen selection, this study aims to understand the relationship between asphalt mixture shear properties and bitumen. The research objective is to identify the correlation between them. Following this direction, this report presents an experimental investigation on the dynamic shear properties of asphalt mixtures and their relationships with the bitumen properties. The influence of binder content is also considered. Six bituminous binders, two of which were polymer-modified, were used to prepare asphalt mixtures in laboratory. The binders were tested with various methods, while their asphalt mixtures were characterized by the dynamic shear test. With the test results, the correlation between them was analysed. It is indicated that the iso-modulus temperatures of bitumen after short-term ageing by dynamic shear rheometer testing at 10 rad/s have very strong correlations with the asphalt mixture viscosity at the maximum phase angle. This was valid for both the studied neat (unmodified) bitumen and polymer-modified bitumen (PMB), although the number of studied PMB samples was limited in this study.
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9. |
- Zhu, Jiqing, 1987-, et al.
(author)
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Durability assessment of bio-extended bituminous binders by rheological characterisation after long-term ageing
- 2024
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In: 8th E&E (Eurasphalt & Eurobitume) Congress, Budapest, Hungary, 19-12 June, 2024.
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Conference paper (other academic/artistic)abstract
- The pursuit of sustainable road infrastructure is prompting extensive research into the utilization of bio-extended bituminous binders. This paper investigates the durability of bio-extended bituminous binders (both unmodified and polymer-modified) containing a plant-based bio-oil, aiming to assess their long-term performance. The research employed laboratory-scale tests and advanced rheological techniques to evaluate viscoelastic properties of the binders after long-term ageing. Accelerated ageing protocols were used to simulate prolonged exposure to environmental factors, including the Rolling Thin Film Oven Test (RTFOT) and Pressure Ageing Vessel (PAV) test. Dynamic Shear Rheometer (DSR) tests measured the shear modulus and phase angle of the binders under various conditions while Bending Beam Rheometer (BBR) tests measured the flexural creep stiffness at different low temperatures. Various performance indicators and specification parameters were analysed for the investigated binders regarding their resistance to both fatigue cracking at intermediate temperatures and thermal cracking at low temperatures.The results indicate that the bio-extended binders passed all the analysed criteria after RTFOT+PAV ageing. Using the investigated bio-oil in bituminous binders had largely a positive effect on the ΔTc and did not affect the standard performance low-temperature grade significantly. The bio-extended binders followed the same relationships between several durability-related performance indicators as the reference binders did. Certain slight negative effects could be noticed at low temperatures when the bio-oil content was high, but a further verification on the asphalt mixture scale will be necessary to assess if these effects are significant enough to impact the asphalt mixture performance in practical applications.
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10. |
- Zhu, Jiqing, 1987-, et al.
(author)
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Experimental analysis and predictive modelling of linear viscoelastic response of asphalt mixture under dynamic shear loading
- 2022
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In: Construction and Building Materials. - : Elsevier. - 0950-0618 .- 1879-0526. ; 328
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Journal article (peer-reviewed)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.
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