| 1. |
- Ekblad, Jonas, et al.
(författare)
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Impact on rutting from introduction of increased axle loads in Finland
- 2020
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Ingår i: The international journal of pavement engineering. - : Taylor and Francis Ltd.. - 1029-8436 .- 1477-268X.
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Tidskriftsartikel (refereegranskat)abstract
- In 2013, Finland introduced legislation increasing gross vehicle weights (GVW) on a number of trucks. Since the actual impact on road damage is nearly impossible to quantify in advance, the present analysis of road surface measurements is intended to provide knowledge regarding the impact on road damage. Rutting is influenced by many conflated phenomena. To indicate and capture the effect on road damage due to the new maximum GVW for certain truck- and trailer combinations, the analysis follows two different but mutually supporting lines of reasoning, empirical and theoretical, respectively. Analysis of measured rut depth is supported by theoretical calculations. Theoretical findings clearly indicate that the relative increase in road damage induced by higher GVW is larger than the increase in relative payload capacity. There was a rapid fleet shift towards heavier trucks after 2013, and statistical (empirical) analysis of road surface measurements shows an increase in rutting after this introduction.
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| 2. |
- Etikan, M. Kaan, et al.
(författare)
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Experimental and numerical analyses of crushing resistance of unbound road materials
- 2024
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Ingår i: The international journal of pavement engineering. - : Taylor & Francis. - 1029-8436 .- 1477-268X. ; 25:1
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Tidskriftsartikel (refereegranskat)abstract
- Aggregate breakage in unbound pavement layers can lead to pavement distresses that affect their functionality and service life. Thus understanding the mechanics and clarifying the factors affecting materials breakage resistance are important for ensuring adequate performance of these layers. In this study, aggregate breakage in unbound granular materials (UGM) is investigated experimentally and numerically. Experimentally, aggregate breakage under uniaxial compression is examined for two UGMs prepared with the same aggregate type but different gradations. To capture the experimentally observed influence of gradation and load magnitude on aggregate breakage, a Discrete Element Method (DEM) model was developed, based on granular mechanics particle contact and failure laws. A simple procedure to identify the contact and failure law parameters from experiments is proposed. With those parameters, the model’s capability of capturing the effect of gradation and loading on the aggregate breakage in UGM is evaluated. Based on comparison with experimental findings, it is shown that the model can capture macro-scale properties of UGM, such as its deformation response under uniaxial compression, as well as the amount of aggregate breakage in the material.
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| 3. |
- Larsson, Martin, et al.
(författare)
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Condition assessment of cycle path texture and evenness using a bicycle measurement trailer
- 2023
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Ingår i: The international journal of pavement engineering. - : Informa UK Limited. - 1029-8436 .- 1477-268X. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Cyclists' riding comfort, related to pavement texture and unevenness, has not been thourougly investigated, partly due to the lack of condition assessment methods specifically adapted to the speed and space limits on cycle paths. Metrics that better describe the perceived comfort of cyclists, rather than that of car users, are needed. In this paper a novel method, the Bicycle Measurement Trailer (BMT), is proposed to bridge this gap. Eight different cycle path surface types have been assessed with regards to pavement texture and for four of these surfaces the longitudinal evenness was assessed. The accuracy and repeatability of the BMT were evaluated. Finally, five different metrics (Dynamic Comfort Index, Evenness Coefficient, 0.5 m Straight Edge, International Roughness Index and Root Mean Square), were calculated from the collected data and assessed. The main findings suggest that the BMT has a high accuracy at normal and high cycling speeds and a high level of repeatability at normal cycling speed. The surfaces could be ranked according to texture, and the evenness was successfully analysed. In conclusion, the BMT could be a valuable tool to assess the cycle path surface condition in relation to bicycle riding comfort.
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| 4. |
- Lindelöf, Peter, et al.
(författare)
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Influences of bus traffic loading on asphalt concrete rutting
- 2023
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Ingår i: International Journal of Pavement Engineering. - : Informa UK Limited. - 1029-8436 .- 1477-268X. ; 24:2
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Tidskriftsartikel (refereegranskat)abstract
- Permanent deformation is the primary failure mode for the asphalt concrete (AC) pavement in urban environment. It is mainly caused by a combination of heavy traffic load, low vehicle speed and channelised traffic. A rut prediction model would therefore be a valuable tool for planning maintenance scheduling and selecting an appropriate asphalt material. This study uses the PEDRO (Permanent deformation in asphalt concrete layers for roads) model to evaluate the rutting performance of flexible pavements in dedicated bus lanes and intersections in urban areas. For this purpose, three road sections along a bus lane in Malmö, Sweden, were selected. To achieve this, AC cores from the road sections were tested using a Shear Box Tester to characterise the asphalt mixtures. Traffic data such as axle load, tyre configuration, speed, and lateral wander distribution of vehicles, and climate data were measured for the selected sections. Field measurements were carried out to assess the structural conditions of the pavements and to measure transverse profiles. This study introduced a procedure for the evaluation and local calibration of the PEDRO rutting model. The results revealed that the prediction of the transverse profiles are generally in good agreement with the rut measurements.
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| 5. |
- Lundberg, Joacim, 1991-, et al.
(författare)
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Calibration of the Swedish studded tyre abrasion wear prediction model with implication for the NORTRIP road dust emission model
- 2021
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Ingår i: The international journal of pavement engineering. - : Taylor and Francis Ltd.. - 1029-8436 .- 1477-268X. ; 22:4, s. 432-446
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Tidskriftsartikel (refereegranskat)abstract
- An experimentally based prediction model of road abrasion wear due to studded tyres is available in Sweden and has been found to work well. However, it has not been validated since 2007, and since then road surfaces and tyre design have developed, and the question has arisen regarding the model’s current validity. The abrasion wear model is used in the NORTRIP emission model (NOn-exhaust Road Traffic Induced Particle emission modelling), and the effect of a recalibrated abrasion wear model on the emission model is shown. In this paper, the abrasion wear model is compared to full-scale field measurements at several recently constructed roads in Sweden to investigate its validity, while also proposing changes to allow for continued use. It is concluded that the model overestimates the wear and an update is suggested. In addition, the impact on NORTRIP emission predictions is briefly investigated. There were also indications that NORTRIP is affected by the abrasion model overestimating the contribution of pavement wear to the particle emissions.
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| 6. |
- Lövqvist, Lisa, 1992-, et al.
(författare)
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Multiscale model for predicting freeze-thaw damage in asphalt mixtures
- 2021
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Ingår i: The international journal of pavement engineering. - : Informa UK Limited. - 1029-8436 .- 1477-268X. ; , s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- Freeze-thaw cycles in combination with long-term moisture exposure and traffic is a major threat to the performance of asphalt pavements. To enable characterisation and understanding of the damage process, this paper presents a new thermodynamics-based multiscale model of freeze-thaw damage in asphalt mixtures which also accounts for the damage due to moisture and traffic. The developed model consists of a microscale and a macroscale and is thereby able to account for the effect of the different microscale material components on the homogenous macroscale damage development. Additionally, the model is able to account for the acceleration of freeze-thaw damage which occurs when moisture infiltrates a damaged pavement with an increased effective air void content between freeze-thaw cycles. The novelty of the model lies in the ability to simulate the in-time acceleration of damage, the combined deteriorating effect of freeze-thaw cycles, moisture and traffic, as well as the coupling of the two scales to enable accurate predictions and understanding of the damage evolution. These features are demonstrated through a set of parametric examples which demonstrate the importance of including the effect of long-term moisture exposure and freeze-thaw cycles as well as the coupling between the different damage modes.
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| 7. |
- Saeed, Nausheen, et al.
(författare)
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Gravel road classification based on loose gravel using transfer learning
- 2022
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Ingår i: The international journal of pavement engineering. - : Taylor & Francis. - 1029-8436 .- 1477-268X. ; , s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Road maintenance agencies subjectively assess loose gravel as one of the parameters for determininggravel road conditions. This study aims to evaluate the performance of deep learning-based pretrainednetworks in rating gravel road images according to classical methods as done by humanexperts. The dataset consists of images of gravel roads extracted from self-recorded videos andimages extracted from Google Street View. The images were labelled manually, referring to thestandard images as ground truth defined by the Road Maintenance Agency in Sweden (Trafikverket).The dataset was then partitioned in a ratio of 60:40 for training and testing. Various pre-trainedmodels for computer vision tasks, namely Resnet18, Resnet50, Alexnet, DenseNet121, DenseNet201,and VGG-16, were used in the present study. The last few layers of these models were replaced toaccommodate new image categories for our application. All the models performed well, with anaccuracy of over 92%. The results reveal that the pre-trained VGG-16 with transfer learning exhibitedthe best performance in terms of accuracy and F1-score compared to other proposed models.
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| 8. |
- Saliko, Denis, et al.
(författare)
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Evaluation of the structural response of two in-service thin flexible pavements under heavy vehicle loading during different seasons by built-in sensors
- 2023
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Ingår i: The international journal of pavement engineering. - : Taylor & Francis. - 1029-8436 .- 1477-268X. ; 24:2
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Tidskriftsartikel (refereegranskat)abstract
- Long Heavy Vehicles (LHV) are considered more efficient and environmentally friendly transportation of goods compared to conventional trucks. Thus, the maximum allowable gross vehicle weight (GVW) in Sweden was increased on part of the road network from 64 to 74 tons in 2018 by increasing the vehicles' length and the number of axle groups per vehicle but not the axle load limits. This change in loading conditions is expected to lead to changes in the structural response and degradation rate of thin pavements on the low-volume road network. To improve our understanding of thin pavements behaviour exposed to multiple axle loadings two thin pavement structures located in the north of Sweden were instrumented with road response and climate sensors. Four measurement campaigns were carried out within one year by in-situ stress and strain measurements from the built-in sensors as LHV passes over at normal speed. The recorded response was compared with numerical calculations based on multilayer elastic theory (MLET). Values of stresses and strains showed a generally good agreement with high values of coefficient of determination R-2 during different seasons when the asphalt stiffness values were adjusted based on temperature and granular layer stiffness values based on moisture.
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| 9. |
- Sulejmani, Pajtim, et al.
(författare)
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Impact of temperature and moisture on the tensile strain of asphalt concrete layers
- 2021
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Ingår i: International Journal of Pavement Engineering. - : Informa UK Limited. - 1029-8436 .- 1477-268X. ; 22:13, s. 1711-1719
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Tidskriftsartikel (refereegranskat)abstract
- Moisture in unbound layers and temperature in asphalt layers affect the structural response of pavements, such as the tensile strain at the bottom of asphalt concrete layers. Previous studies have proposed relationships for estimating tensile strain at the bottom of an asphalt layer from Falling Weight Deflectometer (FWD) surface deflection measurements. These relationships have been developed based on theoretical calculations of strains and surface deflections. The main objective of this study was to evaluate these relationships using measured FWD deflections and tensile strains at the bottom of asphalt concrete layers. Three instrumented test structures were considered in the study. FWD and strain measurements were conducted at varying groundwater levels in the subgrade and temperatures in the asphalt concrete layers. The results revealed that the relationships have poor agreement with measured strains. A new relationship is proposed that incorporates the volumetric water content in the subgrade and the temperature in the asphalt layers in addition to the surface FWD deflections.
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| 10. |
- Tan, Zhifei, et al.
(författare)
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Constitutive modelling and systematic evaluation of asphalt concrete’s viscoelastic tension-compression asymmetry effect on pavement performance
- 2024
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Ingår i: The international journal of pavement engineering. - : Informa UK Limited. - 1029-8436 .- 1477-268X. ; 25:1
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Tidskriftsartikel (refereegranskat)abstract
- Asphalt concrete (AC) exhibits significant tension-compression (TC) asymmetry, which is currently not considered in pavement design. This study develops a novel temperature-dependent dual viscoelastic model to quantitatively capture the viscoelastic behaviour of AC. Unlike the conventional viscoelastic constitutive model, the proposed model decomposes strain into tensile and compressive components to characterise AC’s TC asymmetry. Additionally, a systematic modelling framework with intrinsic TC asymmetry is developed for the first time to predict the response of pavement under moving tire load. The results illustrate that implementing the proposed dual viscoelastic model enlarges both the vertical deformation of pavements and the tensile and shear strains in the AC layers, bringing it closer to the realistic scenario compared to the conventional model that only considers compression properties. Furthermore, high temperatures and low vehicular speeds exacerbate the substantial effects of AC’s TC asymmetry on asphalt pavement. This study provides a valuable method to capture AC’s TC asymmetry and predict pavement response more accurately, giving better insight into pavement response and enhancing pavement design and maintenance.
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