Publications
Change search
Refine search result
1 - 23 of 23
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Ahmed, Abubeker
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Rahman, Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Iron sand as a frost protection layer: thickness design charts2022Report (Other academic)
    Abstract [en]

    Frost depths and frost heaving calculations were performed to prepare design charts and tables for the iron sand (järnsand) layer thickness design for roads typically used for residential area, parking lots and other low to medium traffic roads, and for ground insulation. 

    A segregation potential based frost design method was employed to generate the design charts and tables. The segregation potential method allows the prediction of both frost heaving and frost penetration depth of a pavement structure for a prescribed winter temperature profile or freezing index. Thus, the iron sand layer thickness design tables/charts for roads were prepared for different levels of maximum permitted heaving criteria of 50, 80, 100, and 120 mm. Whereas for ground insulation, a design chart/table was prepared to eliminate any frost action in the ground. In addition to the frost design calculations, two triaxial tests were conducted to evaluate the bearing capacity of the iron sand material. The limited test results indicated that, the bearing capacity of iron sand is similar to conventional sand both in terms of stiffness as well as permanent deformation behavior.

    Download full text (pdf)
    fulltext
  • 2.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Impact of longer and heavier vehicles on the performance of asphalt pavements: A laboratory study2018In: Bearing Capacity of Roads, Railways and Airfields - Proceedings of the 10th International Conference on the Bearing Capacity of Roads, Railways and Airfields, BCRRA 2017, CRC Press/Balkema , 2018, p. 483-490Conference paper (Refereed)
    Abstract [en]

    Historically, Longer and Heavier Vehicles (LHVs) have been permitted to operate in Sweden. Since 1996 and as of the beginning of 2015, the maximum gross vehicle weight of 60 tons and a length of up to 25.25 m have been permitted. The Swedish Transport Administration has decided to further increase the maximum gross vehicle weight to 74 tons and studies are undergoing to evaluate the impact of the proposed LHVs on existing transport infrastructure. To this end, repeated load triaxial tests and indirect tensile fatigue tests were conducted on selected conventional asphalt mixtures to investigate and quantify the impact of single, tandem and tridem axle configurations on permanent deformation and fatigue performances of conventional asphalt pavements. In addition, fatigue tests for selected LHV scenarios were conducted. This paper presents the results of the laboratory tests and simulations conducted. The test results have clearly demonstrated the impact of the different axle configurations on the rutting and fatigue performances of the mixture. Furthermore, such results can explain the significance of axle configuration on modelling the rutting and fatigue performances of asphalt pavements.

  • 3.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Impact of tire types and configurations on responses of a thin pavement structure2018In: Advances in Materials and Pavement Performance Prediction: Proceedings of the International AM3P Conference, 2018, London: CRC Press , 2018, p. 271-274Conference paper (Refereed)
    Abstract [en]

    The objective of this study was to assess the impact of tire and tire configurations on the responses of a thin asphalt pavement structure by means of full-scale tests using a Heavy Vehicle Simulator (HVS). A total of six different types of tires, four single and two dual tire configurations, were investigated. The structure was instrumented to measure tensile strains at the bottom of the asphalt layer and vertical stresses and strains in the unbound base, subbase and subgrade layers. The results indicated that, in general, single tire configurations produced higher tensile strain at the bottom of the asphalt layer and higher vertical stresses and strains in unbound base, subbase and subgrade layers.

  • 4.
    Dinegdae, Yared
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Ahmed, Abubeker W
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland, Iceland.
    Evaluation of ERAPave PP permanent deformation models using APT2023In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402Article in journal (Refereed)
    Abstract [en]

    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.

    Download full text (pdf)
    fulltext
  • 5.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. KTH.
    Evaluation of permanent deformation characteristics of unbound granular materials from multi-stage repeated load triaxial test2013In: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, no 2369, p. 17p. 11-19Article in journal (Refereed)
    Abstract [en]

    Rutting in flexible pavements is often associated with permanent deformation of the unbound granular layer. The current permanent deformation models are only applicable to a single stress path in repeated load triaxial (RLT) tests. In this paper, a simple approach using the time hardening concept was introduced to continuously model the permanent deformation of unbound granular materials (UGM) in multi-stage (MS) repeated load triaxial (RLT) tests. Three existing permanent deformation models were reconstructed to be implemented with this method and one model was slightly modified to better suit this approach. This approach was validated by calibrating these reconstructed models using data from MS RLT tests on three different UGM used in base layers of flexible pavement structures. The calibrations were done by optimizing the material parameters of the models using least square curve fitting method. The shakedown ranges were also calculated for each stress path of the MS RLT tests to compare these models in simulating these ranges. Generally, very good fits were obtained for these models where the modified model showed the best agreement.

  • 6.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Salour, Farhad
    Trafikverket.
    Characteristic of unbound granular materials and subgrades based on multi stage RLT testing2017In: Transportation Geotechnics, ISSN 2214-3912, Vol. 13, p. 28-42Article in journal (Refereed)
    Abstract [en]

    The unbound granular layers (UGM's) and the subgrade of a pavement structure provide a significant support for the structure as a whole. Hence the mechanical properties of these materials are important for the overall performance of the structure. These materials exhibit both non-linear stress dependency and their mechanical properties are highly affected by their moisture content. This paper describes two of the most important material properties of the unbound layers of the pavements, i.e. the resilient and the permanent deformation properties. The stress dependency of UGMs can be captured by the universal model or the enhanced model by Cary and Zapata (2011) for materials with high fine content. The Bishop's effective stress approach can be used for high fine content materials for estimating the effect of suction. UGMs and subgrade materials are further highly dependent on moisture content. Either the AASHTO sigmoidal model can be used to describe the moisture dependency or the simple exponential model described in this paper. The paper further discusses four models to characterize the accumulation of permanent deformation with the number of load repetitions in repeated load triaxial (RLT) testing. The models are all developed to fit single stage (SS) RLT test results but have been extended to fit multi-stage (MS) RLT test results with the aid of the time hardening scheme. The advantage of the MS RLT tests over the SS RLT tests is that it applies a range of stress paths on a single specimen, thus taking into account the effect of stress history and reducing the time and effort required to test a separate specimen for each stress path.

  • 7.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. Kungliga Tekniska Högskolan.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    A model for predicting permanent deformation of unbound granular materials2015In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 16, no 3, p. 653-673Article in journal (Refereed)
    Abstract [en]

    A simple model has been proposed to characterise the accumulation of permanent deformation (PD) in unbound granular materials (UGMs) under cyclic loading of variable magnitudes. The model was developed based on multi-stage (MS) repeated-load triaxial (RLT) tests. The material parameters of this model can be evaluated using an MS RLT test. The model was validated by calibrating it for a few UGMs with a range of grain size distributions, moisture contents and degrees of compaction.

    The calibrated model was further validated by predicting the PD behaviour of some of these UGMs for different stress conditions. Generally, quite satisfactory predictions were obtained with this model with the advantage of reduced effort required for its calibration compared to some existing models. Additionally, the sensitivity of the parameters of this model to moisture, degree of compaction and grain size distribution was investigated with the aim of incorporating them into the model in future.

  • 8.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Impact of introducing longer and heavier vehicles on the bearing capacity of pavement subgrades2021In: Proceedings Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields: Volume 1 / [ed] Inge Hoff, Helge Mork & Rabbira Saba, London: CRC Press, 2021, p. 239-249Conference paper (Other academic)
    Abstract [en]

    Increasing the maximum permissible gross weight of vehicles from 64 tons to 74 tons on Swedish highways may significantly increase deformation in subgrades requiring extensive and expensive measures for maintenance deep down in the structures. Even though the individual axle load remains the same, longer and heavier vehicles will contain higher pro- portions of tandem and tridem axles and the total load will be superposed on to the subgrade resulting in higher deformations. In this study, the relative impact of single, tandem and tridem axles on subgrade deformation was analyzed based on calculations in a pavement design software called ERAPave. Three structures with different layer thicknesses and varying material properties during the spring-thaw and summer period were analyzed. In general, it was observed that the relative impact is dependent on the thicknesses and material properties of the pavement structure and the subgrade. Weaker subgrade is more affected by the tridem axle followed by tandem and single axle. The tridem axle is more damaging to the sub-grade for thicker and stiffer structures. In certain cases, the single axle showed more impact on the top of the subgrade. The tridem axle showed more vertical deflection in all cases that may induce increased fatigue cracking of the asphalt concrete (AC) layer. Duration of loading was higher for the tridem axle which has more damage potential. Thus, for the whole vehicle, con- taining more tridem axles, the effects may be superposed resulting in greater damage. On the other hand, the higher load carrying capacity of the tandem and tridem axle configurations will reduce the number of trips required to carry the same amount of goods. This may compensate for the increased damage to the subgrade and the impact on the life cycle of the pavement.

    Download full text (pdf)
    fulltext
  • 9.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. Kungliga Tekniska Högskolan.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Influence of moisture on Resilient Deformation behaviour of Unbound Granular Materials2014In: Asphalt Pavements: Proceedings of the International Conference on Asphalt Pavements, ISAP 2014, 2014, p. 571-580Conference paper (Refereed)
    Abstract [en]

    This study investigated the influence of moisture on the Resilient Deformation (RD) properties of Unbound Granular Materials (UGMs). A typical UGM used in pavement constructions with three different grain size distributions were tested with a range of moisture contents using Repeated Load Triaxial tests (RLTTs). From the European standard, the procedure for the study of the RD behaviour was used where each stress path is applied for 100 cycles. Additionally, the Multi-Stage (MS) loading procedure for the study of the permanent deformation behaviour were used where each stress path is applied for 10,000 cycles, to compare the results using the two test procedures. Results showed that resilient modulus (MR) generally decreased with increase in moisture, where the finer grading was more affected. However, for the MS RLTTs, after a large number of load applications, some increase in MR with increasing moisture was observed. This happened when the moisture content increased up to close to the optimum; above the optimum, MR always decreased. This may be due to Post-Compaction (PC) aided by moisture in MS RLTTs where a large number of load cycles were applied.

  • 10.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Influence of post compaction on the moisture sensitive resilient modulus of unbound granular materials2016In: Procedia Engineering, Elsevier, 2016, p. 929-936Conference paper (Refereed)
    Abstract [en]

    The impact of moisture on the resilient modulus (MR) of unbound granular materials (UGMs) was investigated based on repeated load triaxial (RLT) tests and considering the effect of post compaction (PC) from cyclic loading. Results showed that although MR decreases with increased moisture, it may appear to increase with increased moisture if the PC process is aided by moisture for a relatively large number of load applications. When limited PC was involved, the parameter k1 of the k-θ model decreased with increased moisture while the parameter k2 was unaffected. On the other hand, when significant amount of PC took place, k2 increased with increased moisture.

    The mechanistic-empirical pavement design guide (MEPDG) model worked well to capture the influence of moisture on the stiffness when MR decreased with increased moisture. However, it did not work when MR increased with increased moisture due to the PC effect. On the other hand, an alternative approach expressing k1 and k2 as functions of moisture worked well for both situations. Generally, this study suggested that the effect of PC should be considered in modelling the impact of moisture on MR for better accuracy.

  • 11.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Modelling the moisture dependent permanent deformation behavior of unbound granular materials2016In: Procedia Engineering, Elsevier, 2016, p. 921-928Conference paper (Refereed)
    Abstract [en]

    The impact of moisture on the permanent deformation (PD) behavior of unbound granular materials (UGMs) was investigated based on multistage (MS) repeated load triaxial (RLT) tests. Two UGMs with different particle size distributions were tested for a range of moisture contents and the accumulation of permanent strains for the different moisture contents were modelled using a simple predictive model.

    Moisture was found to increase the accumulation of PD in the materials. Analyses of the variation of the parameters of the model with respect to moisture showed that it is possible to capture the moisture dependent PD behavior of the materials assuming a simple linear relationship between one of the parameters of the model and the moisture content.

  • 12.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. Kungliga Tekniska Högskolan.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Moisture influence on the resilient deformation behaviour of unbound granular materials2015In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268XArticle in journal (Refereed)
    Abstract [en]

    The influence of moisture on the resilient deformation properties of unbound granular materials was investigated based on repeated load triaxial tests. Results showed that the resilient modulus (MR) decreased with increasing moisture for a relatively low number of load cycles (N) where the deformation behaviour was mostly resilient with a negligible amount of associated accumulated permanent deformation (PD). Modelling attempts on this behaviour were quite satisfactory.

    Furthermore, the MR showed an increasing trend with increasing moisture, up to the optimum, when the N was relatively large with a significant amount of accumulated PD. Above the optimum, the MR generally decreased. Further investigation suggested that moisture aided the post-compaction (PC) and possible particle rearrangement that resulted in the increased PD and increased MR. The existing model did not work in this case indicating that the effect of PC on MR should be considered in modelling.

  • 13.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland, Iceland.
    Monitoring and Simulating the Responses of Four Flexible Pavement Test Sections under Heavy Vehicle Loading2022In: Journal of Testing and Evaluation, ISSN 0090-3973, E-ISSN 1945-7553, Vol. 51, no 4Article in journal (Refereed)
    Abstract [en]

    For mechanistic-empirical design of pavements, it is essential to accurately predict the responses of the structure that are caused by the design traffic loading. The aim of this study was to compare the simulated responses of pavements with real measurements under heavy vehicle loading. With this objective, four instrumented test sections were built in northern Sweden-about 100 km north of the Arctic Circle. These test sections differed in material quality of the various layers. Each test section was instrumented with pressure cells and strain sensors that measured the pavement response to external loading. Climatic variables were monitored through a weather station as well as temperature and moisture sensors installed in the road structures. Response measurements were carried out using 25-m-long 10-axle vehicles with gross weight of 90 tons. For the simulations of the responses of these test structures under the same vehicular loading, a multilayer elastic theory-based program called ERAPave was used. The required material properties for the simulations were based on laboratory testing of core-drilled samples from the sites. For the simulations, three combinations of material characterizations were considered: (a) linear elastic (LE) all layers, (b) nonlinear (NL) unbound layers, and (c) viscoelastic (VE) asphalt layers. Acceptable agreement between the simulations and measured responses were observed. Generally, the responses calculated based on LE and NL analyses were indistinguishable, whereas the VE analyses showed somewhat lower amplitude peaks.

  • 14.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. Kungliga Tekniska Högskolan.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Predicting permanent deformation behaviour of unbound granular materials2015In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, Vol. 16, no 7, p. 587-601Article in journal (Refereed)
    Abstract [en]

    To reliably predict the permanent deformation behaviour of unbound granular materials (UGM) in a pavement structure, the material parameters of the constitutive models used in design should be evaluated using a multi-stage (MS) loading approach. This paper investigated the prediction of the accumulation of permanent strain in UGM using some current models, extended applying the time-hardening approach, based on MS repeated load triaxial tests (RLTTs).

    The material parameters of these models were optimised for five different UGM used in pavement construction using the MS RLTT data with a specific set of stress levels. With these models, the accumulations of permanent strain in the same materials for MS RLTTs with a different set of stress levels were predicted. Using this approach, three out of the four models performed very well, which may be further developed for field conditions for better prediction of rutting.

  • 15.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland, Iceland.
    Ahmed, Abubeker W
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Modelling the permanent deformation of unbound granular materials in pavements2022In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402Article in journal (Refereed)
    Abstract [en]

    An existing permanent deformation (PD) model for the unbound granular materials (UGMs) in pavements, developed based on multistage (MS) repeated load triaxial (RLT) tests, was modified to better suit to field conditions and software applications. The model was calibrated for a few UGMs with a series of moisture contents (w) using MS (to include the stress-history effect) RLT tests and was validated by predicting the PD under different sets of stress levels and w's. Generally, it exhibited improved predictions over the Mechanistic-Empirical Pavement Design Guide (MEPDG) model. The model was further applied for field conditions and was implemented in a pavement design software entitled ERAPave PP, using data from accelerated testing of three structures employing a heavy vehicle simulator (HVS). Based on additional MS RLT tests, a guideline for the ranges of the material parameters for different types of UGMs was presented.

    Download full text (pdf)
    fulltext
  • 16.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Ahmed, Abubeker W
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Dinegdae, Yared H.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    A model for the permanent deformation behavior of the unbound layers of pavements2021In: Proceedings Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields: Volume 1 / [ed] Inge Hoff, Helge Mork & Rabbira Saba, London: CRC Press, 2021, Vol. 1, p. 277-287Conference paper (Other academic)
    Abstract [en]

    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.

    Download full text (pdf)
    fulltext
  • 17.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Hellman, Fredrik
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Stiffness and permanent deformation characteristics of open-graded unbound granular materials2018In: Bearing Capacity of Roads, Railways and Airfields - Proceedings of the 10th International Conference on the Bearing Capacity of Roads, Railways and Airfields, BCRRA 2017, CRC Press/Balkema , 2018, p. 151-157Conference paper (Refereed)
    Abstract [en]

    This paper presents the investigation of the deformation characteristics of two Open-Graded (OG) Unbound Granular Materials (UGMs) that are generally used in permeable pavement structures. Based on multistage Repeated-Load Triaxial (RLT) tests, the stiffness and resistance against Permanent Deformation (PD) of these materials were compared to their well graded (standard) counterparts. The OG UGMs showed similar stiffness characteristics as standard UGMs. On the other hand, the resistance against PD was slightly worse than the standard UGMs in a relatively dry state. However, the OG UGMs showed less sensitivity to moisture variation, yielding similar performance to that of standard materials at higher moisture content. The parameters of a stiffness model and a PD model were evaluated for these materials which may be used for prediction of rutting, estimating bearing capacity and for layer thickness design, using any suitable pavement design software.

  • 18.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Hellman, Fredrik
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Investigation of the permanent deformation properties of open-graded permeable unbound granular materials2019In: Pavement and Asset Management - Proceedings of the World Conference on Pavement and Asset Management, WCPAM 2017, CRC Press/Balkema , 2019, p. 105-114Conference paper (Refereed)
    Abstract [en]

    Open-Graded (OG) Unbound Granular Materials (UGMs) are generally used in permeable pavement constructions. In this study, the Permanent Deformation (PD) characteristics of two OG UGMs were investigated by means of Multistage (MS) Repeated- Load Triaxial (RLT) tests. The influence of moisture on the PD behavior was also investigated. Compared to a few standard UGMs, these OG UMGs exhibited slightly lower resistance against PD in relatively dry state. On the other hand, these materials were less sensitive to moisture. Therefore, at higher moisture content, the OG UGMs and the standard UGMs showed identical PD behavior. Furthermore, the accumulation of PD was modelled using a simple model which may be used for prediction of rutting, estimating bearing capacity, and for layer thickness design, using a suitable pavement design software.

  • 19.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Kharrazi, Sogol
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle Systems and Driving Simulation.. Department of Electrical Engineering, Linköping University, Sweden.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    High-capacity transport in cities and the impact on the roads2024In: Technology Convergence 2023: Setting the Wheels In Motion: Reimagining the future of heavy vehicles, roads and freight, International Forum for Heavy Vehicle Transport & Technology; The International Society for Weigh-In-Motion , 2024, article id 8555Conference paper (Other academic)
    Abstract [en]

    This paper presents the evaluation of the relative pavement damage caused by a high-capacity transport (HCT) 5 axle truck with respect to three other reference trucks consisting of 4, 3 and 2 axles. The analysis was conducted by simulating the responses of three pavement structures using the pavement analysis tool ERAPave. Two damage criteria of the pavement structures were evaluated: fatigue cracking of the asphalt concrete (AC) layer and permanent deformation of the subgrade. The relative damage caused by the different vehicles were estimated by calculating a damage factor (Dr) following the Asphalt Institute Method. Three loading scenarios of the trucks were analyzed: (a) one way trip with fully loaded trucks, (b) round trip where the return trip consisted of the empty vehicles with lifted axles and (c) round trip where the return trip consisted of the empty vehicles without lifting any axles. The damage factors were calculated for per ton of carried load and were normalized with respect to the 2-axle truck. Results indicate that the relative impacts of the vehicles depend on the structure type and seasons. Generally, the 4-axle truck appeared to be the least damaging one. The HCT 5-axle truck is more damaging than the 4-axle truck, but less damaging than the other two.

    Download full text (pdf)
    fulltext
  • 20.
    Rahman, Mohammad Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Simonsen, Erik
    Cementa AB.
    Hellman, F.
    Ahmed, Abubeker W
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Structural performance evaluation of block pavements using heavy vehicle simulator2020In: Lecture Notes in Civil Engineering, Springer , 2020, Vol. 96, p. 280-288Conference paper (Refereed)
    Abstract [en]

    Block pavements (BPs) can be of different types depending on applications and provide certain advantages in many instances. Among BPs, permeable concrete block pavements (PCBPs) play a vital role in sustainable drainage system and help the growth of trees and vegetations in urban environment. With the expansion of the usage of BPs from parking lots to heavier trafficked areas and owing to changing climatic conditions, it is necessary to develop guidelines for their designs and constructions. With this objective, ten different types of BPs were investigated in an accelerated pavement testing facility using a heavy vehicle simulator (HVS). The surface rutting developed during the load applications were measured. The impact of moisture was also investigated by raising the ground water table during the tests. By comparing the rutting performances of the BPs to a reference BP structure, the layer thicknesses of these BPs were adjusted using a pavement design software to attain the same rutting performance as the reference structure. Based on these analyses, design tables for BPs for Swedish conditions were developed. In this paper, the results from the HVS tests and the methodology used for the development of the design tables are summarized.

  • 21.
    Rahman, Shafiqur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Waldemarson, Andreas
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Ahmed, Abubeker
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Evaluation of conditioning methods for the determination of water sensitivity of asphalt concrete mixtures: comparison of MIST, SS-EN 12697-12:2018 (Method A) and TDOK 2017:06502022Report (Other academic)
    Abstract [en]

    Water or moisture in different physical states is a major factor that contributes to various forms of damages in asphalt concrete (AC) pavements. For pavement design and maintenance, it is essential to evaluate the AC mixtures with respect to water/ moisture damage susceptibility. In Sweden, this is currently done according to the Swedish standard (TDOK 2017:0650) or alternatively can be done according to the European standard (SS-EN 12697-12). However, these methods are time consuming, and they do not simulate the pumping action of water due to passing wheels. On the other hand, the Moisture Induced Sensitivity Test (MIST) is intended to be a quick method that applies cyclic pore pressure to simulate the repeated pumping action of water. However, it is a relatively new approach that has not yet been properly studied for Swedish conditions and yet to be standardized in Europe. 

    In this project, the MIST, TDOK and the EN methods were evaluated using five different AC mixes. Results showed that the MIST with 12,000 cycles and the TDOK method have comparable and the strongest effect on the stiffness properties. MIST with 3,500 and 7,000 cycles and the EN method showed identical and relatively weak impact of water. MIST also indicated the changes of the indirect tensile strengths of the specimens. However, compared to the TDOK or EN methods, the changes in the indirect tensile strengths due to MIST conditioning were smaller. Overall, MIST was concluded to be a quicker, more convenient and a more realistic alternative. Comparing the various mixes with respect to moisture sensitivity, binder content and air voids showed great influences. The specimens with cut surfaces were less affected by moisture conditioning. The addition of amine additives significantly improved the resistance to moisture damage of the mixes. Generally, the results of this study formed the basis for further development of the EN and TDOK method as well as standardizing the MIST conditioning method in Europe.

    Download full text (pdf)
    fulltext
  • 22.
    Said, Safwat
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Lundberg, Thomas
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Rahman, Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    McGarvey, Terence
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Ahmed, Abubeker
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Enocksson, Carl-Gösta
    Trafikverket.
    Utförandets inverkan på hållbarhet för beläggningslager2019Report (Other academic)
    Abstract [en]

    Non-destructive testing in quantifying the asphalt pavement layers homogeneity can be used for the quality assurance in paving contracts. This paper summarizes the findings from a field study on segregation in bituminous pavement mixes that relates pavement layer surface texture to the homogeneity of the paved bituminous layer by distinguishing mix segregated area. The mean profile depth (MPD) values of paved layer were measured. Based on these values three locations on the road were identified having low, intermediate and high MPD values. Thereafter, cored samples were tested for stiffness modulus before and after moisture conditioning by performing the moisture induced sensitivity test (MIST). Results clearly showed that the samples from the locations with high MPD values were mostly affected by the moisture conditioning for which the stiffness moduli were significantly reduced. The samples with high MPD values had the highest air voids as well. Thus, this study demonstrated that construction quality described by segregation in the paved asphalt mix has a significant impact on the moisture sensitive performance of pavements. A limited number of falling weight deflectometer (FWD) measurements were performed at positions with different degree of separation in the road base layer. There was a tendency for the effect of separation in the road base layer on FWD even though there was a variation in data. The strong correlation between the MPD values and change in stiffness modulus also suggests that the measurements of the MPD values can be a reliable and non-destructive method for evaluating the construction quality of a pavement and in developing the quality assurance criteria based on pavement performance that can be used in paving contracts.

    Download full text (pdf)
    fulltext
  • 23.
    Salour, Farhad
    et al.
    Trafikverket.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Characterizing Permanent Deformation of Silty Sand Subgrades by Using a Model Based on Multistage Repeated-Load Triaxial Testing2016In: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, no 2578, p. 47-57Article in journal (Refereed)
    Abstract [en]

    A simple model for the prediction of permanent deformation of unbound pavement material was used to characterize the accumulation of permanent deformation of unsaturated silty subgrade soils from multistage repeated-load triaxial (RLT) tests. The model incorporated the time hardening concept; data obtained from RLT tests with cyclic loading of variable magnitudes, conducted on a single specimen, could be used to calibrate the material model parameters. This feature of the model allowed for characterizing the accumulation of permanent deformation of the material under a wide range of stress conditions.

    The tests were carried out on two silty sand subgrades and at different moisture contents with pore suction measurements (matric suction) incorporated into the stress state calculations used in the modeling. The shakedown ranges for the permanent deformations for each stress path were calculated, and the material parameters of the predictive models were optimized with the RLT test data. In general, the models performed satisfactorily in capturing the permanent deformation behavior of the selected subgrade materials.

    The model includes fewer parameters as compared with some existing permanent deformation models and requires reduced testing effort because it is based on results from a multistage RLT test with a single specimen. It can be concluded that the model and the approach have great potential for characterizing and modeling the permanent deformation of subgrade soils.

1 - 23 of 23
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf