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  • 1.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Said, Safwat F.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Lu, Xiaohu
    Nynäs AB.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Pavement performance follow-up and evaluation of polymer-modified test sections2018In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, p. 1-14Article in journal (Refereed)
    Abstract [en]

    Between 2003 and 2006, a test road consisting of several conventional and polymer-modified structures was built on a motorway. Different combinations of styrene–butadiene–styrene (SBS) and ethyl vinyl acetate (EVA) polymer-modified binders were used. The test structures have been in service since then and have been monitored for over 9 years. The resistance of the different types of asphalt concrete mixes to rutting and cracking was measured and predicted. The impact of ageing on the mixes was also evaluated. Although all the sections are in good condition after 9 years of traffic, the predicted differences between the test sections based on the PEDRO (Permanent Deformation of asphalt concrete layers for Roads) approach and laboratory evaluations are noticeable. Lateral wander and transverse profile measurements indicated that studded winter tyre wear contributed to most of the rutting compared to permanent deformation due to heavy traffic. The unmodified mixes exhibited considerable ageing and the SBS-modified mixes were least affected by ageing. Furthermore, the SBS-modified base mix produced significantly better fatigue resistance than the conventional base mix. However, further investigations of the relationships between bitumen and mix properties and further follow-ups of the test sections are recommended to validate the findings.

  • 2.
    Berglund, Liliane
    et al.
    Swedish National Road and Transport Research Institute.
    Höbeda, Peet
    Swedish National Road and Transport Research Institute.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Ohlsson, P-O
    Reseberättelse från resa till Helsingfors 19-20 april för studie av ASTO 1987-1992 "The Asphalt Pavement Research Program"1989Report (Other academic)
  • 3.
    Djärf, Lennart
    et al.
    Swedish National Road and Transport Research Institute.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Laboratory fatigue properties compared with field performance1993Report (Other academic)
  • 4.
    Edwards, Ylva
    et al.
    Swedish National Road and Transport Research Institute.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Höbeda, Peet
    Swedish National Road and Transport Research Institute.
    Viman, Leif
    Swedish National Road and Transport Research Institute.
    Polymermodifierade slitlagerbeläggningar på Arlanda Ramp Rudolf: en jämförande laboratorieundersökning1999Report (Other academic)
    Abstract [sv]

    Ett provläggningsförsök har utförts i anslutning till ordinarie beläggningsarbete på Arlandas Ramp Rudolf. Avsikten har varit att prova och utvärdera ett antal slitlagertyper med olika polymermodifierade bindemedel för att få underlag till en framtida kravspecifikation vad gäller flygfältsbeläggningar.

  • 5.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Said, Safwat
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    McGarvey, Terry
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Influence of heavy traffic lateral wander on pavement deterioration2012In: EPAM 2012: Malmö, Sweden, 5–7 September : 4th European pavement and asset management conference, Linköping: Statens väg- och transportforskningsinstitut, 2012, , p. 11Conference paper (Other academic)
    Abstract [en]

    Lateral wander of the traffic has an impact on the degradation development of pavements. This is usually not accounted for in the structural design process. Facilities with wide carriageways and broad shoulders tends to have relatively large lateral spreading while narrow road facilities lacking any shoulders can have highly channelized traffic pattern. In this research lateral wander characteristics have been measured for different road facilities. They can be assumed follow a normal distribution where the standard deviation describes their lateral spreading. Rut depth has thereafter been estimated according to two new rutting calculation scheme where lateral wander characteristics has been taken into account. The first approach is based on a two step mechanistic empirical (M-E) evaluation of the permanent strain in all layer of the structure and using a time hardening approach to sum up for all wander locations. This has thereafter been used to estimate the difference in rutting development as a function of the standard deviation. The second approach concentrates on calculating the permanent strain visco-elastically in the bound layers of the structure. Both procedures can be used to estimate the rate of relative deterioration for different road facilities. Based on the same structure the first approach give around 6 % increase in the surface rut as the standard deviation of the lateral wander increases from 10 to 20 cm. The second approach estimates this difference to be around 20 %. The difference between the two approaches are partly explained due to that the first approach estimates the rut based on all layers but the second approach from the bound layers only.

  • 6.
    Hakim, Hassan
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Nilsson, Richard
    Skanska Sverige AB.
    Said, Safwat
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Utveckling av provningsmetod för bestämning av styvhetsmodul2010Report (Other academic)
    Abstract [sv]

    There is a great variation between the laboratories when determining the stiffness modulus of bituminous pavements. This is a problem in connection with the evaluation and control of the stiffness modulus of bituminous pavements performed by different laboratories. It is also an obstacle with reference to the stiffness modulus of bituminous pavements in connection with performance based contracts. Stiffness modulus is also an important parameter when designing road structures. Inaccuracy about the measured stiffness modulus can lead to unreasonable thicknesses of pavement layers. In an earlier study concerning the determination of stiffness modulus, it was stated that the comparative tests showed that there is a great variation both within and in-between the results of different laboratories. The aim is to refine the test method for determining the stiffness modulus in a way that partly leads to less variation between stiffness modulus measurements performed by different laboratories, partly to increased knowledge of different apparatuses used in Sweden. This is done by controlling and comparing the load pulse and the resulting deformation pulse when using variable loading. Force and deformation were registered by different systems (additional stress and strain gauges). Dummy specimens, with more stable characteristics than bituminous test specimens, were used as a completion to the calibration and for the analysis of stress, deformation, loading time and pulse of different apparatuses.

  • 7.
    Hakim, Hassan
    et al.
    Swedish National Road and Transport Research Institute.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Glimmer i bitumenbundna beläggningar: inverkan av fina, fria glimmerkorn2002Report (Other academic)
    Abstract [sv]

    På senare tid har man på sina håll observerat en del skador på vägarna vilket

    man tror beror på ökad halt av glimmer i finandelen. Mot den bakgrunden har

    VTI på uppdrag av Vägverket undersökt effekten av glimmerhalt i en massa

    under simulerade vinterförhållande. Syftet med det här arbetet är att belysa

    effekten av förekomst av fina glimmerkorn i bergkrossmaterial på

    massabeläggningars egenskaper och eventuellt också ta fram rekommendationer

    för gränsvärden på glimmerhalt hos asfaltmassor. Fyra serier av asfaltprov

    har tillverkats innehållande varierande halter av glimmerkorn. Serierna

    undersöks och utvärderas med hänsyn till styvhetsmodul, svällning och ev.

    indirekt draghållfasthet. Proverna har konditionerats under inverkan av

    saltlösning och vatten samt frys-töcykler. Rena glimmerpartiklar som

    marknadsförs kommersiellt används i massan för att få bättre kontroll av

    glimmerhalten tillsammans med en bergart som icke är särskilt känslig för

    dålig vidhäftning.

  • 8.
    Höbeda, Peet
    et al.
    Swedish National Road and Transport Research Institute.
    Djärf, Lennart
    Swedish National Road and Transport Research Institute.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Viman, Leif
    Swedish National Road and Transport Research Institute.
    Provningar av obundna material genom cykliska triaxialförsök och andra undersökningar1987Report (Other academic)
  • 9.
    Höbeda, Peet
    et al.
    Swedish National Road and Transport Research Institute.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Funktionsegenskaper hos dränbeläggning: Undersökning av borrkärnor från väg E20 vid Skara1994Report (Other academic)
    Abstract [sv]

    En vägsträcka, 4600 meter lång, bestående av dränbeläggning på väg E20 är objekt för rehabilitering. Frågan är om man kan lägga ett nytt slitlager på den befintliga dränbeläggningen utan störrerisk för allt för tidiga deformationer i lagren. Alternativt finns det möjlighet för remixing av denbefintliga dränbeläggningen.Vid påläggning av nytt slitlager kommer det dränerade lagret att vara mellan två täta beläggningaroch några centimeter under vägytan. Risken för vattenansamling och plastiska deformationerökar i dränbeläggningen, varför vattenkänslighet och stabilitetsegenskaper har undersöktshos borrkämor från dränbeläggningen. Slutsatsen är att aktuell beläggning inte bör byggas inmellan täta asfaltlager p g a potentiell vattenkänslighet och därefter ökad risk för deformationer.Remixing av beläggningen har visat sig vara ett bra alternativ i det här fallet.

  • 10.
    Jacobson, Torbjörn
    et al.
    Swedish National Road and Transport Research Institute.
    Hakim, Hassan
    Swedish National Road and Transport Research Institute.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Undersökning av mekaniska egenskaper hos tunna beläggningar av MJAB: etapp 12006Report (Other academic)
    Abstract [sv]

    Tunna asfaltbeläggningar har använts till lågtrafikerade vägar i många år. I delar av Norrland har mjukgjord asfaltbetong och mjukbitumenbundet grus (MJAB och MJOG) ersatt oljegruset under senare år. Beläggningar med god flexibilitet och mjuka bindemedel är en förutsättning för att vägarna i denna del av landet skall klara ojämna tjällyftningar, svag bärighet eller låga temperaturer utan att spricka sönder. Beläggningen måste samtidigt vara tillräckligt stabil för att klara påkänningarna från den tunga trafiken (timmerbilar) under sommaren utan att deformationer uppstår. I ATB VÄG saknas funktionskrav på tunna eller mjukgjorda beläggningar. Därför har VTI på uppdrag av Vägverket undersökt ett antal borrkärnor från några vägobjekt i norra Norrland. Beläggningstyperna bestod av MJAB- och MJOG-massorna. Proven har undersökts med avseende på funktionsegenskaper och parametrar som behövs vid dimensionering av överbyggnader. Ett begränsat antal prover undersöktes med avseende på sammansättning för helhetsbedömning och verifiering av analysresultat.

  • 11.
    Jacobson, Torbjörn
    et al.
    Swedish National Road and Transport Research Institute.
    Hornwall, Fredrik
    Swedish National Road and Transport Research Institute.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Stabilitetsundersökningar i VTI:s provvägsmaskin: undersökning av bitumenbundna lager1999Report (Other academic)
  • 12.
    Jansson, Håkan
    et al.
    Swedish National Road and Transport Research Institute.
    Bäckman, Lars
    Swedish National Road and Transport Research Institute.
    Djärf, Lennart
    Swedish National Road and Transport Research Institute.
    Hermansson, Åke
    Swedish National Road and Transport Research Institute.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Stenberg, Lars
    Swedish National Road and Transport Research Institute.
    Wågberg, Lars-Göran
    Swedish National Road and Transport Research Institute.
    Ydrevik, Krister
    Swedish National Road and Transport Research Institute.
    Värdering av vägobjekt och beräkning av förbättrings-/förstärkningsbehov. Delrapport 11998Report (Other academic)
  • 13.
    Jansson, Håkan
    et al.
    Swedish National Road and Transport Research Institute.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Töjningskriterier tunna beläggningar2001Report (Other academic)
    Abstract [sv]

    Beläggningens utmattningsegenskaper är avgörande för uppkomsten av sprickor. Hur dessa egenskaper uttrycks i form av dimensioneringskriterier är också avgörande för den trafikbelastning som en konstruktion beräknas klara. Det kriterium som återfinns i VÄG 94 är grundat på erfarenheter från vägar med bärlager av typ AG med bindemedel av typ B 180. Kriteriet anges gälla enbart för denna typ av material och för vägöverbyggnad med en sammanlagd nominell tjocklek på bitumenbundna lager på minst 75 mm. Vid beräkning av horisontell dragtöjning i underkant av en tunnare beläggning kan för en given last och konstruktion töjningen öka med ökad beläggningstjocklek upp till en viss gräns, varefter töjningen minskar med ökad tjocklek. Fenomenet med ökad töjning med ökad beläggningstjocklek kan med nuvarande standardaxel inträffa under perioder med hög temperatur i beläggningen, då beläggningen har låg styvhet. Perioder med hög temperatur i beläggningen är dock inte kritiska med det angivna kriteriet. Ett förslag är att begränsningen i tjocklek vid användning av kriteriet slopas. Vid en beläggningstjocklek understigande 75 mm (>40 mm) görs en kontroll av att detta inte leder till oönskade konsekvenser i form av att en alltför tunn beläggning kan beräknas klara en trafik som överstiger den som motsvarande konstruktion med en tjockare beläggning kan klara. Då endast en tunn beläggning behövs kan det bundna bärlagret slopas och enbart slitlager läggas. Om ett sådant ska dimensioneras saknas sålunda ett kriterium för detta.

    Ett alternativt kriterium har tagits fram baserat på fältstudier av nybyggda svenska vägar. Även detta förutsätter ett bundet bärlagret av typ AG, men skiljer sig i några avseenden från kriteriet i VÄG 94. Massans sammansättning påverkar såväl styvhet som utmattningsegenskaper och bör beaktas vid dimensionering av en flexibel vägkonstruktion. Formler för beräkning av beläggningens styvhet utifrån massans sammansättning presenteras liksom laboratoriebaserade utmattningssamband.

  • 14.
    Jelagin, Denis
    et al.
    KTH.
    Ahmed, Abubeker W
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Lu, Xiaohu
    Nynäs AB.
    Said, Safwat F.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Asphalt layer rutting performance prediction tools2018Report (Other academic)
    Abstract [en]

    Flexible pavement rutting due to permanent deformation accumulation in asphalt layers is one of the most common modes of road failures. In addition to creating high maintenance costs, rutting is a major concern for traffic safety, as the rut development increases the risk of hydroplaning and introduce difficulties in vehicle steering. In this context, accurate methodologies for pavement rutting performance prediction are crucial for decision support in pavement design and rehabilitation. In particular, better rutting performance models are needed to evaluate, new asphalt materials as well as to evaluate the impact of different vehicle types on roads’ service life.

    The main goal of this report is to present a summary of the existing asphalt rutting performance prediction tools. The present review is limited to available and/or frequently referred to tests and models with an established link to field rutting performance. Accordingly, models focusing solely on permanent deformation on the material level are beyond the framework of the present study.

    Road structure and its materials, heavy vehicle parameters and climate affecting rutting accumulation in the field are identified. Their significance has been evaluated based on the experimental and numerical findings reported in the literature. Several rutting performance prediction models recently proposed in the literature are summarized along with the material characterization tests used in the models. The reviewed models’ capability to quantify the influence of various structural, material and traffic parameters on the pavement’s rutting performance is examined.

    It is concluded that implementation of rutting performance models incorporating experimentally measured viscoelastic and permanent deformation properties of asphalt mixtures is a promising way to improve the accuracy of pavement performance predictions. In particular since they allow the effect of novel materials, e.g. polymer-modified, on the pavement’s rutting performance to be quantified.

  • 15.
    Kalman, Björn
    et al.
    Swedish National Road and Transport Research Institute.
    Hakim, Hassan
    Swedish National Road and Transport Research Institute.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Waldemarsson, Andreas
    Swedish National Road and Transport Research Institute.
    Beständighet hos asfaltbeläggningar: utmattning av asfaltlager som utsätts för upprepade belastningar i närvaro av vatten2005Report (Other academic)
    Abstract [sv]

    Brister i asfaltlagers beständighet kan antas orsaka stora kostnader för

    samhället. För att förbättra beständigheten på asfaltbeläggningar har

    vattenkänsligheten undersökts på bitumenbundet bärlager. Av speciell

    betydelse för bärlager är dess förmåga att motstå utmattning. Samband mellan

    töjningsnivån i underkant av bärlagret och förmågan att motstå utmattning är

    av vikt vid dimensionering av bitumenbundna lager. Hur vatten påverkar dessa

    samband är därför av stor betydelse för att kunna göra en lägesspecifik

    dimensionering eftersom olika vägkonstruktioner i olika klimat utsätts för

    mer eller mindre vatten. Två bärlagerbeläggningar, AG16, undersöktes med en

    speciell försöksuppställning i VTI:s wheeltracking-utrustning, med syftet att

    studera sprickinitiering och sprickpropagering i konstruktionerna under torra

    respektive våta förhållanden. De två beläggningarnas styvhetsmoduler och hur

    dessa påverkades av s.k. vinterkonditionering studerades parallellt med

    utmattningsprovningen. Sambandet mellan töjningsnivån i utmattningsförsöken

    och antalet belastningar till sprickinitiering var likvärdigt för de två

    bärlagren samt relativt oberoende av om bärlagren testades under torra eller

    våta förhållanden. Likaså var sprickpropageringen, dvs. antalet belastningar

    mellan det att en spricka bildats i underkanten i beläggningen och till dess

    sprickan är genomgående, likvärdiga för de två beläggningarna under torra

    förhållanden. Undersökningarna visar däremot att sprickpropageringen gick

    markant snabbare för ett av materialen vid närvaro av vatten. Detta material

    uppvisade också större sänkning av styvhetsmodulen vid vinterkonditionering.

  • 16.
    Kuttah, Dina K
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Said, Safwat H
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Hakim, Hassan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Effect of Aggregate Composition and Freeze-Thaw Cycles on the Stiffness Modulus of Asphalt Concrete Mix2013Conference paper (Refereed)
  • 17.
    Lindelöf, Peter
    et al.
    Lunds Universitet.
    Said, Safwat F.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Ahmed, Abubeker W
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Poisson’s Ratio of Asphalt Concrete Mixes Using Indirect Tensile Test2019In: Journal of Testing and Evaluation, ISSN 0090-3973, E-ISSN 1945-7553, Vol. 47, no 1Article in journal (Refereed)
    Abstract [en]

    Increased interest in mechanistic evaluation of flexible pavement structures has brought a demand for accurate and practical methods, models, or both to estimate the mechanical properties of asphalt concrete mixtures. One of these properties is the Poisson’s ratio (ν) of asphalt concrete mixtures, which is often assumed to have a constant value of 0.35 in asphalt concrete evaluations. However, investigations have reported that mixture type, air void content, and temperature produce considerable variation in measured ν-values that could have a significant effect on evaluations of asphalt concrete mixes. The objective of this study was to evaluate the effect of air voids, binder type, and testing conditions on the measured ν-values. Indirect tensile (IDT) tests were conducted to measure ν-values. The study indicated that the Poisson’s ratio of the asphalt concrete mixes, on average, attained a maximum value at a particular level of air void content. Furthermore, when comparing the Poisson’s ratio values in relation to the dynamic modulus, calculated using the Mechanistic Empirical Pavement Design Guide (MEPDG) equation, higher ν-values were attained. This demonstrates the importance of measuring the Poisson’s ratio of a mix type.

  • 18.
    Lu, Xiaohu
    et al.
    Nynäs AB.
    Said, Safwat
    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.
    Soenen, Hilde
    Nynas NV.
    Heyrman, Serge
    Nynas NV.
    Redelius, Per
    Nynäs AB.
    Performance Evaluation of Polymer Modified Bitumens on a Heavily Trafficked Test Road2014In: International Journal of Pavement Research and Technology, ISSN 1997-1400, Vol. 7, no 6, p. 381-388Article in journal (Refereed)
    Abstract [en]

    In asphalt paving, polymer modified bitumens (PMBs) have more potential for use and can clearly demonstrate the value of their initial higher cost. To further assess the sustainable benefits of using PMBs, a test road was constructed on a highway in Sweden. In this paper, the asphalt binders used were investigated extensively using rheological and chemical methods, and asphalt field cores characterized with respect to permanent deformation and fatigue. It was found that the modified binders, particularly with SBS polymers, retain better rheological properties in comparison with conventional ones, even after several years in the field; these include higher strain recovery and lower non-recoverable compliance at high temperatures, and lower stiffness at low temperatures. The SBS modified binders also demonstrate good aging resistance, shown by both laboratory aging tests and field aging. the high resistance to aging for the SBS modified binders was also evident in the stiffness measurement made on asphalt field cores. Moreover, the modified binders with SBS polymers significantly enhance fatigue behaviour.

  • 19.
    Lu, Xiaohu
    et al.
    Nynas AB.
    Said, Safwat F.
    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.
    Soenen, Hilde
    Nynas NV.
    Heyrman, Serge
    Nynas NV.
    Redelius, Per
    Nynas AB.
    Evaluation of test sections with Polymer Modified Bitumens2014In: Asphalt Pavements: Proceedings of the International Conference on Asphalt Pavements, ISAP 2014, 2014, p. 287-296Conference paper (Refereed)
    Abstract [en]

    It has been recognized that Polymer Modified Bitumens (PMB) have more potential for use in asphalt paving and can clearly demonstrate the value of their initial higher cost. To further assess sustainable benefits on heavy trafficked roads, test sections using various PMBs were built on highway E6 in Sweden during 2003-2006. The main objective of this paper is to study the aging and rheological properties of the binders used. A large number of cores were drilled and characterized with respect to stiffness, fatigue and permanent deformation. The binders (original, lab aged and recovered) were investigated extensively with rheological and chemical methods. It was found that PMBs, particularly SBS modified, demonstrate better rheological properties as compared to unmodified bitumens, even after several years in the field. These include higher strain recovery and lower non-recoverable compliance at high temperatures, and lower stiffness at low temperatures. For the SBS modified binders, good aging resistance was observed. The high resistance to aging for the SBS modified binders was also evident in the stiffness measurement made on asphalt field cores. Although significant differences have not yet been seen between the test sections (all the sections are in good condition after six years of traffic), the observed improvements for the modified binders are expected to be confirmed by a longer follow-up of the test road.

  • 20.
    Oscarsson, Erik
    et al.
    Lunds universitet.
    Said, Safwat
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Assessment of zero shear rate viscosity in asphalt concrete using shear frequency sweep testing2011Manuscript (preprint) (Other academic)
  • 21.
    Oscarsson, Erik
    et al.
    Lunds universitet.
    Said, Safwat
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Modelling permanent deformations in asphalt concrete layers using the PEDRO model2011Manuscript (preprint) (Other academic)
  • 22.
    Porot, Laurent
    et al.
    Kraton Chemical.
    Soenen, Hilde
    Nynas, Machelen.
    Besamusca, Jeroen
    Kuwait Petroleum.
    Apeagyei, Alex
    University of Nottingham.
    Grenfell, James
    University of Nottingham.
    Vansteenkiste, Stefan
    Belgium Road Research Center.
    Chailleux, Emmanuel
    LUNAM Université, IFSTTAR.
    Gaudefroy, Vincent
    LUNAM Université, IFSTTAR.
    Chaturabong, Preeda
    Wisconsin University.
    Tozzo, Cristina
    University Roma La Sapienza.
    Artamendi, Ignacio
    Aggregates Industries.
    Sybilski, Darius
    Road & Bridge Research Institute.
    Martinez, Francisco Barcelo
    Repsol.
    Said, Safwat F.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Partl, Manfred N.
    EMPA.
    Canestrari, Francesco
    Universita Politecnica Delle Marche.
    Hauser, Elisabeth
    ISBS Braunschweig University.
    Wistuba, Michael
    ISBS Braunschweig University.
    Bituminous binder2018In: Testing and Characterization of Sustainable Innovative Bituminous Materials and Systems: State-of-the-Art Report of the RILEM Technical Committee 237-SIB / [ed] Manfred N. Partl, Laurent Porot, Hervé Di Benedetto, Francesco Canestrari, Paul Marsac, Gabriele Tebaldi, Springer Netherlands , 2018, p. 15-74Chapter in book (Refereed)
    Abstract [en]

    One of the most important aspects of asphalt pavement deterioration is the ingress of water in pavement which leads to loss of the material characteristics, even material integrity with loss of aggregates. Thus the behaviour of asphalt mixture under moisture conditions is one of the key parameter for specifications. It’s a complex phenomenon which is influenced amongst other things by materials properties with wetting, cohesion and adhesion of bituminous binder and by environmental conditions with temperature, moisture, loading and layer type. It has been a research subject for a very long time and still not precisely described. A large number of test methods is available to estimate the affinity between aggregates and bituminous binders. These test methods can be subdivided in different ways; a first distinction can be based on the presence or absence of water during the test procedure. If water is present, the evaluation is in fact referred to as water sensitivity or moisture damage testing. Another distinction can be based on the type of sample that is evaluated. The test sample can be loose aggregates coated with a bituminous binder or a compacted asphalt mix sample. Lastly the individual components, bitumen and aggregate, can be tested separately through intrinsic properties. Furthermore, test results can also be based on the quantification of the test results, whether this is based on a qualitative or a quantitative evaluation. In RILEM TC 237 SIB, TG1 the main purpose was to evaluate common test methods, used to assess the affinity of bitumen to aggregate surfaces, to determine, if possible, the repeatability and reproducibility and to give recommendations for improvement. In this study both binders and aggregates have been considered. Three bituminous binders, two unmodified from different sources, one polymer modified binder, and four aggregate types, with different mineralogy, have been selected. The test methods considered in the study include the rolling bottle test, the boiling water stripping test and the bitumen bond strength test; also surface energy was investigated. This chapter presents the results of these tests and their accuracy.

  • 23.
    Prapoorna Biligiri, Krishna
    et al.
    Indian Institute of Technology Kharagpur.
    Said, Safwat H
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Prediction of the Remaining Fatigue Life of Flexible Pavements Using Laboratory and Field Correlations2014In: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533Article in journal (Refereed)
    Abstract [en]

    The main objective of this study was to develop comprehensive criteria to evaluate the remaining service life of existing roads as regards their field fatigue cracking characteristics using fracture mechanics principles and associated laboratory performance tests. Two basecourse layers were investigated for their residual fatigue lives: reference and modified stone mastic asphalt mixes. The two pavement systems’material characteristics using the actual field cores were estimated in the laboratory, including moduli, fatigue relationships, and crack propagation parameters. Additionally, field measurements encompassed collection of falling weight deflectometer deflections, temperature variations, and traffic counts. Fatigue lives of the two base course layers were predicted using the developed laboratory-based fatigue and crack propagation parametric relationships during one climatic period. The modified structure presented significantly longer fatigue life than the reference mix. This was indicative of the findings that the laboratory procedure(s) based on asphalt mixture properties’ fracture and fatigue mechanics such as crack initiation, and propagation modeling and relationships are useful for evaluating the pavement mix’s performance in the field as well. Overall, laboratory tests provided reliable information regarding residual life predictions in case it is difficult to actually perform field measurements and estimate the residual life of a pavement system. The criteria developed in this study should serve as guidelines for agencies to comprehend and understand a substantial amount of information regarding asphalt materials’ fatigue characterization so that it can be implemented as one of the quality control tests to assess the pavement design life.

  • 24.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Fundamentala egenskaper hos skelettbeläggningar: serie H1, H2 och H31997Report (Other academic)
  • 25.
    Said, Safwat
    Swedish National Road and Transport Research Institute.
    Funktionsegenskaper hos asfaltbeläggningar: flygfältsbanor vid F211996Report (Other academic)
    Abstract [sv]

    Denna undersökning har till syfte att dels belysa betydelsen av funktionsegenskaper vid utvärdering av asfaltbeläggningars kvalité och dels komma med förslag till reparationsåtgärder hos asfaltbanor vid F21. Framför allt har spårbildning studerats i det här arbetet. Borrkämor från befintliga beläggningar har utsatts för dynamiskt krypförsök. Stensläpp från rullbanan har undersökts genom vidhäftningsbestämningar hos borrkämor. Styvhetsmoduler har också bestämts hos några provkroppar samt att även sammansättning och hålrumshalt bestämdes hos de flesta borrkämoma för identifiering av massan.

  • 26.
    Said, Safwat
    et al.
    Swedish National Road and Transport Research Institute.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute.
    Alternativa bitumenbundna bärlager - provsträckor på E18 Köping: lägesrapport1999Report (Other academic)
    Abstract [sv]

    Nya bitumenbundna bärlagertyper som alternativ till konventionella AG-beläggningar har börjat användas sedan några år. Åtta provsträckor, där 4 olika typer av bitumenbundna bärlager ingår, på E18 Köping har följts upp under ett antal år. Den här lägesrapporten behandlar laboratorieresultat hos borrkärnoroch fältmätningar sedan vägens öppnande 1995.

  • 27.
    Said, Safwat
    et al.
    Swedish National Road and Transport Research Institute.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute.
    Johansson, Svante
    Swedish National Road and Transport Research Institute.
    Stålarmering av väg E6 Ljungskile, Bratteforsån-Lyckorna2003Report (Other academic)
    Abstract [sv]

    En sträcka på 800 m av motorvägen E6 söder om Ljungskile

    (Bratteforsån-Lyckorna), öppnad för trafik 1991, uppvisade skador i form av

    längsgående sprickor i hjulspåren redan efter ca 5 års trafikering. En

    skadeutredning utfördes under 1996 och vägsträckan underhölls genom en

    försegling av vägytan på de skadade avsnitten. Det var dock klarlagt redan då

    att det fanns ett förstärkningsbehov. Under år 2000 hade vägen omfattande

    längs- och tvärgående sprickbildning samt visade en omfattande spårbildning

    med ojämnheter. Under år 2000 förstärktes sträckan genom fräsning och

    påbyggnad inklusive armering med stålnät. Inom vägavsnittet anlades tre

    provsträckor för undersökning av stålnätsarmeringens betydelse för upphöjning

    och förbättring av bärigheten och motståndet mot sprickor och spår. Denna

    rapport beskriver dessa sträckor samt redovisar resultat från uppföljning

    under tre år. Det här är det första svenska försöket med stålarmerad väg där

    uppföljningen skett med töjningsgivare i vägkonstruktionen. Syftet med

    projektet i Ljungskile är att studera stålnätets förmåga att ge ökad bärighet

    i vägkroppen och motverka sprickor och spårbildning i beläggningsytan.

    Uppföljning med fallviktsmätningar visar inga nämnbara skillnader mellan

    provsträckorna. Resultaten från töjningsgivarna i asfaltbeläggningen däremot

    gav stora skillnader i töjningsnivå mellan provsträckorna. De största

    töjningarna uppmättes på referenssträckan. Armerade sträckor uppvisade

    betydligt lägre töjningar. Spårdjupsmätningarna med Primal visade hittills på

    liten spårbildning och inga tydliga skillnader mellan provsträckorna. Om

    tendensen till spårutveckling fortsätter kommer de båda stålarmerade

    konstruktionerna uppvisa en något lägre spårbildning än referenssträckan.

    Vägen har ännu bara trafikerats två år efter förstärkningsåtgärden och den

    fortsatta utvecklingen är av största intresse att följa!

  • 28.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Bestämning av fasvinkel och dynamisk modul hos asfaltbetong1994Report (Other academic)
  • 29.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Bestämning av styvhetsmodul hos asfaltbetong genom pressdragprovet1995Report (Other academic)
  • 30.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Bestämning av utmattningshållfasthet hos asfaltbetong genom pulserande pressdragprovning1995Report (Other academic)
  • 31.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Bituminösa beläggningar: Att bygga broar mellan teori och verklighet1995Report (Other academic)
  • 32.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Fatigue and stiffness properties of roadbase layer using indirect tensile test1996Report (Other academic)
  • 33.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Fatigue characteristics of asphalt concrete mixtures1988Report (Other academic)
    Abstract [sv]

    This report presents the state of the art in investigating fatigue cracking of asphalt mixtures, due to repeated load applications in the laboratory. A review of research relating to bitumen content and type, aggregate, filler, void content, mix stiffness, temperature, and moisture content is presented. The effect of test conditions such as controlied-stress or controlled-strain mode, rest period, and simple or compound loading upon the fatigue response of asphalt concrete is illustrated. Fatigue test apparatus such as two-, three-, and four- point bending test, wheel tracking machine, indirect tensile test, triaxial, direct tension, and push-pull test are reviewed.

    It is concluded from the comparisons between different apparatus that the test apparatus has a minor effect on fatigue results. Therefore it is reasonable to use the apparatus which is most economical and practical.

    An acceleration in fatigue testing (for example, testing at high loading speed with large stresses and/or without rest periods) could give unreliable fatigue results if the effect of such variables is not already known. Therefore the test conditions must be chosen with care.

    Neither the controlled-stress test nor the controlled-strain test can simulate the actual compound loading conditions that occur in the field. Nevertheless, the controlied-stress test is more reliable and practical

    than the controlled-strain test.

    More attention is desirable concerning the superposition effect of the variables influencing the fatigue resistance of the asphalt materials, which could induce a dramatic change in fatigue life.

  • 34.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Fatigue characteristics of asphalt concrete mixtures1988Report (Other academic)
  • 35.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Krypbenägenhet hos asfaltprov: testparametrar1995Report (Other academic)
  • 36.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Mechanical properties of bitumen roadbase mixes1997Report (Other academic)
  • 37.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Plastiska deformationer på väg E4 mellan Tvärbacken- Skillingaryd1991Report (Other academic)
  • 38.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Provtagning av asfaltmaterial1992Report (Other academic)
  • 39.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Resilient modulus by indirect tensile test1990Report (Other academic)
  • 40.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Skiftfaktor1996Report (Other (popular science, discussion, etc.))
  • 41.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Spårbildning: Vägsträcka Sörmon-Skutberget, E18 - Karlstad1992Report (Other academic)
  • 42.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Test and design parameters of elastic stiffness and permanent deformation1995Report (Other academic)
  • 43.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Undersökningen av KGO-blandad massa1993Report (Other academic)
  • 44.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Utmattningsresistens hos bärlagerbeläggningar: en jämförelse mellan laboratorieundersökningar och accelererad provning i Nestes provvägsmaskin1996Report (Other (popular science, discussion, etc.))
  • 45.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Validation of indirect tensile test for fatigue testing of bituminous mixes1998Report (Other academic)
  • 46.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Variability in roadbase layer properties conducting indirect tensile test1997Report (Other academic)
  • 47.
    Said, Safwat F
    Swedish National Road and Transport Research Institute.
    Återanvändning av asfaltmaterial: Proportionering1992Report (Other academic)
  • 48.
    Said, Safwat F.
    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.
    Prediction of heavy vehicle impact on rut development using pedro model2018In: 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. 1359-1366Conference paper (Refereed)
    Abstract [en]

    Permanent deformation or flow rutting in bituminous layers is a common distress mode in flexible pavements that is exhibited as an excessive deformation of bituminous material in the wheel paths. Rutting gradually increases with repeated loading of heavy vehicles. To predict surface rutting, it is therefore essential to include the influence of heavy vehicle parameters such as the number of passages of wheel loads, axle load configuration (single or dual wheel), tire type, inflation pressure, vehicle speed and lateral wandering of the traffic in addition to variation in mixture properties at ambient temperatures over elapsed time. The linear viscoelastic permanent deformation model for a bituminous layer of roads, PEDRO, has been adopted in this work to analyse the vertical strain distribution in a flexible pavement and prediction of rutting under various combination of heavy vehicle parameters. The effects of heavy vehicles with different axle load configurations are evaluated with support of field measurements over a 14-year period.

  • 49.
    Said, Safwat F
    et al.
    Swedish National Road and Transport Research Institute.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute.
    Samband mellan fält- och laboratoriemoduler1995Report (Other academic)
  • 50.
    Said, Safwat F
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Hakim, Hassan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Förstärkning av vägkonstruktion med stålnätsarmering: 12 års uppföljning av väg E6 Ljungskile2014Report (Other academic)
    Abstract [en]

    A motorway road section of 800 metre long of the road E6 south of Ljungskile in the Southwest of Sweden was seriously damaged due to low bearing capacity. Longitudinal and transversal cracks were frequently observed after about five year’s traffic. The road section was rehabilitated by milling away 80 millimetre and paving with new bituminous layers. Three full-scale, 100-metre test sections were built. Two test sections were reinforced with steel fabrics and one section without reinforcement as a reference section. These sections are instrumented with strain gauges. The section’s performance have been tested by deflection, strain and rut measurements and manual distress surveys. Degradation behavior of the test sections were numerically analyzed. This report presents pavement performance of the test sections after 12 years in-service. The reference section has shown extensive longitudinal cracks in the wheel paths. However, almost no cracks in the reinforced sections. It is concluded that the reinforcement had a significant influence (10–15%) in increasing the resistance of the test sections against fatigue cracking and in limitation of the rutting in pavement surface related to repeated-loading of the heavy vehicles.

12 1 - 50 of 75
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