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  • 51.
    Butt, Ali Azhar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Nicole
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Importance of systems approach for evaluating the life cycle environmental impacts of a road projectManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Aggregates from two different sources and the effect of using a warm mix asphalt additive(WMAA) in asphalt mixtures were investigated in the laboratory. Different pavement designalternatives were generated using the laboratory data and analysed using a road life cycleassessment (LCA) framework. It was concluded that the effects of WMAAs must beevaluated on a case by case basis since WMAA interaction with the aggregate surfacemineralogy appears to play a significant role. Asphalt production and material transportationwere found to be the most energy consuming processes having high greenhouse gasemissions. The results presented also showed that having actual pavement material propertiesas the key attributes in LCA enables a pavement focused assessment of environmental costsassociated with different design options.

  • 52.
    Butt, Ali Azhar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Mirzadeh, Iman
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Toller, Susanna
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Miljöstrategisk analys.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Bitumen Feedstock Energy and Electricity Production in Pavement LCA2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Asphalt production consumes considerable amount of fuel and electric energy as significant amount of materials (bitumen and aggregates) are blended together for the construction of flexible pavements. Bitumen is used in asphalt as a binder but can also be used as an alternate energy source. Feedstock energy of bitumen becomes relevant in the life cycle cost (LCC) study, as cost of the binder would be reflected in its alternative value as fuel. In this study, a method was suggested to calculate energy content of the bitumen. Importance of choosing electricity not produced in local diesel generators was also demonstrated. Replacing fuel with inefficiently produced electricity for heating the materials in the asphalt plant would result in high environmental impacts. The calculation of feedstock energy and the understanding of efficient energy production and use could be utilized in the life cycle assessment (LCA) of the roads.

  • 53.
    Butt, Ali Azhar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Mirzadeh, Iman
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Toller, Susanna
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Miljöstrategisk analys (fms).
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Life Cycle Assessment Framework for Asphalt Pavements: Methods to Calculate and Allocate Energy of Binder and Additives2014Ingår i: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, Vol. 15, nr 4, s. 290-302Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The construction, maintenance and disposal of asphalt pavements may lead to considerable environmental impacts, in terms of energy use and emissions during the life of the pavement. In order to enable quantification of the potential environmental impacts due to construction, maintenance and disposal of roads, an open life cycle assessment (LCA) framework for the asphalt pavements is presented in this paper. Emphasis was placed on the calculation and allocation of energy used for binder and additives at the project level. It was concluded from this study that when progressing from LCA to its corresponding life cycle cost, the feedstock energy of the binder becomes highly relevant as the cost of the binder will be reflected in its alternative value as fuel. Regarding additives like wax, a framework for energy allocation was suggested. The suggested project level LCA framework was demonstrated in a limited case study of a Swedish asphalt pavement. It was concluded that the asphalt production and transporting materials were the two most energy-consuming processes, emitting most greenhouse gases depending on the fuel type and electricity mix.

  • 54.
    Butt, Ali Azhar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Toller, Susanna
    Swedish Transport Administration (Trafikverket), Sweden .
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Life Cycle Assessment for the GreenProcurement of Roads: A Way Forward2015Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 90, s. 163-170Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Life cycle assessment (LCA) methodology can be used to assess the environmental impacts of a road system over its entire life time. However, it is very important to align the potentials and limitations of such tools with their intended purpose. For the LCA to be useful for the decision support in a procurement situation, it should therefore be important to have a clear understanding of the technical features (attributes) that build up the life cycle phases. In this paper, different types of decisions situations are outlined based on at what level of complexity (network or specific project) and at what stage within the planning process (early planning or late planning/design) the decision is to be made, and relevant methodological choices for these decision situations are discussed. Further, the attributes that are important to consider in an asphalt road LCA that seeks to serve as a decision support in a procurement situation are suggested and technical features for these attributes are outlined with focus on Energy and GreenHouse Gas emissions. It can be concluded that in order to aid the implementation of green procurement, it would help if the attributes of the system are defined in a transparent manner and consistently calculated. It is, however, also important that the attributes should mirror the material properties used in a pavement design and therefore be closely linked to the performance of the road in its life time. It is also recommended to report the feedstock energy in the road LCAs.

  • 55. Castelblanco, A.
    et al.
    Masad, Eyad
    Birgisson, Björn
    Moisture Damage as a Function of Air Void Size Distribution and Surface Energy2005Ingår i: Journal of Testing and Evaluation, ISSN 0090-3973, E-ISSN 1945-7553, Vol. 34, nr 1Artikel i tidskrift (Refereegranskat)
  • 56.
    Chen, Feng
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap.
    Taylor, Nathaniel
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Kringos, Nicole
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Bro- och stålbyggnad.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    A study on dielectric response of bitumen in the low-frequency range2015Ingår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 16, s. 153-169Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    From the current state of literature, the dielectric property of bitumen has not been understood extensively, nor its relation with other properties such as polarity and rheology. In this study, dielectric spectroscopy measurement in a low-frequency range (10−2–106 Hz) was performed on both pure bitumen in different grades and wax-modified bitumen (WMB). From the performed tests we found the following: (i) the dielectric response of base bitumen is strongly temperature and frequency dependent, which is also highly linked to the rheology of the system. (ii) No remarkable differences in the dielectric constant (Formula presented.) among different grades of bitumen from the same crude oil source can be seen. (iii) Regular changes of dielectric loss tangent (tan δ) among the different grades of bitumen can be observed, which can be a good indicator for the linkage between the dielectric and rheological responses. In addition, it can also be perceived that the dielectric spectroscopy may have the potential to become a new approach for the multi-scale characterisation of road infrastructure materials.

  • 57.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Balieu, Romain
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Arkitektur, Arkitekturteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    On the Oxidative Ageing Mechanism and Its Effect on Asphalt Mixtures Morphology2015Ingår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 48, nr 15, s. 3113-3127Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper investigates the influence of mixture morphologies and microstructures on oxidative ageing of asphalt mixtures. For this, an oxidative ageing mechanism based on a diffusion–reaction process was developed. Previously, most asphalt oxidative ageing modeling research focused on unidirectional diffusion of continuous oxygen flow through bitumen films, which is far from the actual boundary conditions in asphalt mixtures. For this reason in the current study, a finite element (FE) analysis has been conducted in which 3D mixture morphology was considered. Mixture morphology is the combination of mineral aggregate packing, porosity, air-void distribution and their interconnectivity. One dense and one open graded field asphalt mixture core were scanned with a computerized tomography X-ray scanner. In the analyses, the developed oxidative ageing model was implemented. The FE analysis showed that the effect of the air-void distribution, their interconnectivity and the mineral aggregate packing has a significant effect on the resulting age hardening of the overall mixture. Furthermore, from the microstructural investigation done in this research, strong indications were found that, depending on the bitumen and its conditioning, water soluble thin films are formed due to ageing. This means that ageing and moisture damage are strongly interlinked and this should thus be considered in the design of the asphaltic materials and the prediction of their long term performance. © 2014, RILEM.

  • 58.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Jelagin, Denis
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Investigation of the asphalt mixture morphology influence on its ageing susceptibility2015Ingår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 48, nr 4, s. 987-1000Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The main objective of this study is to investigate the influence that asphalt mixture morphology aspects have on its overall ageing behavior. Since mixture morphology is controllable, having insight into how the various morphological parameters influence the mixture’s long-term behavior can be of great value to optimize its design, regardless of the individual material properties. To do so, this study is utilizing a new framework to characterize the combined effect of aggregate packing, average air void size, porosity and level of compaction on ageing for a large set of data from different sources of field compacted and laboratory produced asphalt mixtures. The paper also hypothesizes about the mechanisms that lay behind the found influences and how thus mixture design improvements can be made. From all the investigated cases, it was found that the framework can be used to optimize the durability performance of asphalt mixtures. It was also observed that prediction of ageing behavior without considering the influence of mixture morphology may lead to erroneous conclusions and non-optimal mix design.

  • 59.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Jelagin, Denis
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Evaluation of the low temperature cracking performance of asphalt mixtures utilizing HMA fracture mechanics2013Ingår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 47, s. 594-600Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present study, the low temperature cracking performance of asphalt mixture has been investigated numerically and experimentally. To do so, the HMA thermal fracture model has extended by including fracture energy threshold and non-linear thermal contraction coefficient. This extended model is capable to predict thermally induced stress and fracture temperature, which is validated with experimental results obtained from three different types of asphalt mixtures. From the parametric study, it was observed that understanding the influence of thermal contraction coefficient, the cooling rate and the creep compliance parameters can make a significant contribution to the material's sustainability. From the analysis, it was found that this extended model can be utilized to evaluate the low temperature cracking performance of asphalt mixtures and capable to provide correct ranking. Interestingly, non-linear thermal contraction coefficient gave much better prediction than linear approach.

  • 60.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Jelagin, Denis
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Nicole
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Atomic Force Microscopy to Characterize the Healing Potential of Asphaltic Materials2012Ingår i: Atomic Force Microscopy - Imaging, Measuring and Manipulating Surfaces at the Atomic Scale / [ed] Victor Bellitto, InTech, 2012, s. 209-230Kapitel i bok, del av antologi (Refereegranskat)
  • 61.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Jelagin, Denis
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Micro-Mechanical Investigation of Low Temperature Fatigue Cracking Behaviour of Bitumen2012Ingår i: 7th RILEM International Conference on Cracking in Pavements: Mechanisms, Modeling, Testing, Detection and Prevention Case Histories / [ed] Scarpas, A.; Kringos, N.; Al-Qadi, I.; Loizos, A., Springer Netherlands, 2012, s. 1281-1290Konferensbidrag (Refereegranskat)
    Abstract [en]

    In an effort to understand the effect of low temperature fatigue cracking, atomic force microscopy (AFM) was used to characterize the morphology of bitumen. In addition, thermal analysis and chemical characterization was done using differential scanning calorimetry (DSC) and thin-layer chromatography/flame ionization detection (TLC/FID), respectively. The AFM topographic and phase contrast image confirmed the existence of bee-shaped microstructure and different phases. The bitumen samples were subjected to both environmental and mechanical loading and after loading, micro-cracks appeared in the interfaces of the bitumen surface, confirming bitumen itself may also crack. It was also found that the presence of wax and wax crystallization plays a vital role in low temperature cracking performance of bitumen.

  • 62.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Nicole
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Wallqvist, Viveca
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Micromechanical investigation ofphase separation in bitumen bycombining atomic force microscopywith differential scanning calorimetryresults2013Ingår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 14, nr S1, s. 25-37Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The thermo-rheological behaviour of bitumen depends largely on its chemical structure and intermolecular microstructures. Bitumen is a complex mixture of organic molecules of different sizes and polarities for which the micro-structural knowledge is still rather incomplete. Knowledge at that level can have great implications for behaviour at a larger scale and will help to optimise the bitumen in its production stage. The present study is focused on understanding the fundamental mechanisms behind the micro-structural phase appearance and the speed or mobility at which they change. To do so, atomic force microscopy was utilised at different temperatures to investigate the phase separation behaviour for four different types of bitumen and co-relate it with the differential scanning calorimetry measurements. Based on the experimental evidences, it was found that the observed phase separation is mainly due to the wax/paraffin fraction presence in bitumen and that the investigated bitumen behaves quite differently. Recommendations are made to continue this research into qualitative information to be used on the asphalt mix design level.

  • 63.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Micro-scale investigation of oxygen diffusion on bitumen surfaces2014Ingår i: Asphalt Pavements - Proceedings of the International Conference on Asphalt Pavements, ISAP 2014, CRC Press, 2014, Vol. 1, s. 935-942Konferensbidrag (Refereegranskat)
    Abstract [en]

    This study investigates the evolution of microstructures due to oxygen diffusion on bitumen surface and its effect on bulk properties utilizing Atomic Force Microscopy (AFM) and Differential Scanning Calorimetry (DSC). The bitumen specimens were conditioned in four different modes: both light and air, only air but no light, only light but no air and neither light nor air, for 15 and 30 days. From the AFM investigation after 15 and 30 days of conditioning period, it was found that the percentages of microstructure on the surface reduced with ageing. The DSC heating scan showed that the amount of wax remains constant even after the systematic conditioning. Interestingly, during the cooling cycle, crystallization of wax molecules started earlier for the oxidized specimens than the non-oxidized one. The analysis of the obtained results indicated that the oxidation created a thin film upon the exposed surface, which acts as a barrier and creates difficulty for the wax induced microstructures to float up at the surface. From the DSC analysis, it can be concluded that the oxidation product induced impurities in the bitumen matrix, which acts as a promoter in the crystallization process.

  • 64.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Microscale investigation of thin film surface ageing of bitumen2014Ingår i: Journal of Microscopy, ISSN 0022-2720, E-ISSN 1365-2818, Vol. 254, nr 2, s. 95-107Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper investigates the mechanism of bitumen surface ageing, which was validated utilizing the atomic force microscopy and the differential scanning calorimetry. To validate the surface ageing, three different types of bitumen with different natural wax content were conditioned in four different modes: both ultraviolet and air, only ultraviolet, only air and without any exposure, for 15 and 30 days. From the atomic force microscopy investigation after 15 and 30 days of conditioning period, it was found that regardless the bitumen type, the percentage of microstructure on the surface reduced with the degree of exposure and time. Comparing all the four different exposures, it was observed that ultraviolet radiation caused more surface ageing than the oxidation. It was also found that the combined effect was not simply a summation or multiplication of the individual effects. The differential scanning calorimetry investigation showed that the amount of crystalline fractions in bitumen remain constant even after the systematic conditioning. Interestingly, during the cooling cycle, crystallization of wax molecules started earlier for the exposed specimens than the without exposed one. The analysis of the obtained results indicated that the ageing created a thin film upon the exposed surface, which acts as a barrier and creates difficulty for the wax induced microstructures to float up at the surface. From the differential scanning calorimetry analysis, it can be concluded that the ageing product induced impurities in the bitumen matrix, which acts as a promoter in the crystallization process.

  • 65.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Numerical study on the effect of mixture morphology on long-term asphalt mixture ageing2015Ingår i: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, Vol. 16, nr 8, s. 710-720Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Asphalt mixtures with similar percentages of air voids can have different morphologies and can age differently. Prediction of ageing behaviour without considering the influence of mixture morphology may thus lead to erroneous conclusions and non-optimal mix design. This article investigates the long-term field ageing of asphalt mixtures by incorporating mixture morphology. For this, a computational analysis on diffusion-reaction process has been conducted by implementing fundamental mechanism of ageing and conducting a parametric sweep of the morphology. To investigate the ageing gradient along the depth of asphalt mixture, diffusion controlled oxidative ageing on one dense and one open-graded field core was investigated. The proposed model based on the mixture morphology information was able to predict the aged viscosity better than the existing model. As mixture morphology is controllable, having insight into how the morphology parameter influences the mixture's ageing susceptibility can be of great value to its design.

  • 66.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Towards a Multi-scale Framework to Optimize Ageing Resistance of Asphaltic Materials2013Ingår i: Multi-Scale Modeling and Characterization of Infrastructure Materials: Proceedings of the International RILEM Symposium Stockholm, June 2013 / [ed] Niki Kringos, Björn Birgisson, David Frost, Linbing Wang, Springer Netherlands, 2013, , s. 434s. 285-295Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper describes an ongoing research project that is aiming at developing a comprehensive multi-scale approach to optimize the ageing resistance of asphaltic mixtures. In this, ageing has been focused on oxidative ageing, but allows future extension to other ageing mechanisms. The developed framework considers three different scales: the nano, micro and meso-scale which are defined as the bitumen phase, the mastic phase and the mixture phase, respectively. In nano-scale, atomic force microscopy and calorimetry are coupled to each other to give insight into how bitumen phase separation evolves and the mobility of microstructure changes with temperature and ageing. On the micro-scale, the energy dissipation as a function of ageing is measured and coupled to the phase behavior information from the nano-scale. On the meso-scale a morphology framework is defined, capable of identifying the dominant mixture morphology parameters that control mixture performance under ageing conditions. By coupling the three scales, the dominant parameters that control ageing of asphaltic mixtures can be defined, modeled and analyzed and as such a tool is created that has the potential of enhancing the sustainability of asphaltic mixtures.

  • 67.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Tasdemir, Yuksel
    Bozok Univ, Yozgat, Turkey .
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Evaluation of fracture and moisture damage performance of wax modified asphalt mixtures2012Ingår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 13, nr 1, s. 142-155Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study the fracture and moisture damage characteristics of wax modified asphalt mixtures were evaluated. Two types of commercial waxes (FT-paraffin and Asphaltan B) were added to bitumen of penetration grade 70/100. Using this wax modified and unmodified bitumen; total 48 specimens were produced from two sources of aggregates and two levels of gradation. Bitumen properties were determined by conventional test methods, Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR) testing. Thermal Stress Restrained Specimen Test (TSRST) was used to evaluate low temperature cracking resistance and cracking behavior of asphalt mixture was investigated at 0 degrees C using Superpave Indirect Tensile Test (IDT). The influence of wax on the asphalt mixture resistance to cracking and moisture damage performance has been evaluated using Hot Mix Asphalt (HMA) fracture mechanics and Superpave IDT test results. The addition of FT-paraffin and Asphaltan B showed better cracking and moisture damage resistance of the asphalt mixture compared to unmodified mixture, but FT-paraffin showed the largest effect on cracking resistance while Asphaltan B showed highest resistance to moisture damage. In BBR test results, mixtures modified with FT-paraffin showed lower limit m value (LmT) which implies minor negative effect in stress relaxation. However, according to TSRST results, the mixtures with both waxes had nearly same fracture temperature as mixture with unmodified bitumen.

  • 68.
    Das, Prabir Kumar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Tasdemir, Yuksel
    Bozok University, Engineering and Architecture Faculty.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Low temperature cracking performance of WMA with the use of the Superpave indirect tensile test2012Ingår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 30, s. 643-649Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Low temperature cracking of wax modified bitumen and asphalt mixtures were studied using the Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR), Superpave IDT and Thermal Stress Restrained Specimens Test (TSRST). Two types of commercial waxes (FT-paraffin and Asphaltan-B) were added to 70/100 penetration grade bitumen. Hot Mix Asphalt (HMA) fracture mechanics was used to determine fracture parameters. Master curves obtained from DSR and BBR test results showed stiffening effect due to wax additive at low temperature. The analysis of covariance was performed using a General Linear Model (GLM) on the Superpave IDT test results for Energy Ratio (ER) by using SPSS (Statistical Program for Social Sciences). Statistical analysis of Superpave IDT results showed a minor negative effect of wax modification at lower temperatures. Statistical analysis also showed that fracture parameters are highly temperature dependent and the two types of aggregate used did not play any significant role in low temperature cracking performance. Results obtained from TSRST tests indicate wax modification has a minor negative effect in low temperature cracking performance of asphalt mixtures.

  • 69.
    Das, Prabir
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Tasdemir, Y.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    LOW TEMPERATURE CRACKING PERFORMANCE OF WAX MODIFIED BITUMEN AND MIXTURE2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    The road construction phase is one of the source of emissions (greenhouse gases), which causes climatic changes. To decrease this emission and energy consumption, asphalt industry is getting more aware of the warm mix asphalt (WMA) technology as it reduces the mixing and compaction temperature. There are several types of additives generally used for producing WMA such as: Fischer-Tropsch (FT) paraffin, Asphaltan B, Aspha-min, Evotherm etc. Fatigue and rutting resistance of asphalt mixtures could be increased by using WMA mixtures. On the other hand, the behavior of WMA mixtures in low temperature cracking is not completely clear yet. The main objective of this paper is to study the effect of commercial wax on low temperature cracking with the help of fracture mechanics.

    In this study, bitumen was modified with 4% Asphaltan B as a WMA additive. Bitumen properties were determined by conventional test methods, dynamic mechanical analysis and bending beam rheometer test whereas the mixture properties investigated by Superpave InDirect Tensile (IDT) test device and Thermal Stress Restrained Specimen Test (TSRST). The similar results were obtained from both Superpave IDT and TSRST. According to the test results, the addition of wax shows a minor negative effect. This minor difference between modified and unmodified mixture is very small, so it could be within the test repeatability limit.

  • 70.
    de Frias Lopez, Ricardo
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Silfwerbrand, Johan
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Betongbyggnad.
    Jelagin, Denis
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggnadsmaterial.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Vägtekniks laboratorium. School of Engineering and Applied Science, Aston University, Birmingham, UK.
    Force transmission and soil fabric of binary granular mixtures2016Ingår i: Geotechnique, ISSN 0016-8505, E-ISSN 1751-7656, Vol. 66, nr 7, s. 578-583Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of fines content on force transmission and fabric development of gap-graded mixtures under triaxial compression has been studied using the discrete-element method. Results were used to define load-bearing soil fabrics where the relative contributions of coarse and fine components are explicitly quantified in terms of force transmission. Comparison with previous findings suggests that lower particle size ratios result in higher interaction between components. A potential for instability was detected for underfilled fabrics in agreement with recent findings. It was also found that the threshold fines content provides an accurate macroscopic estimation of the transition between underfilled and overfilled fabrics.

  • 71. Dham, A.
    et al.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Boyd, A.J
    McGill University.
    The Determination of Bound Water in Waste Phosphatic Clay2009Ingår i: Research Letters in Materials Science, ISSN 1687-6822Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Phosphatic clay is a by-product of phosphate strip mining, particularly in Florida, USA. This waste material occupies about 100000 acres of land which could be utilized for other causes. Thus, its use as an alternating cementing material for the addition into the mixing matrix of cement paste and concrete to yield higher strength would be profitable for both materials involved. But the biggest drawback faced is that the phosphatic claypossesses high water holding capacity. The water is thus not available for mixing purposes when added to cement paste and concrete and is thus known as bound water. It is therefore essential to determine the amount of bound water to phosphatic clay which shall not be available for the hydration reaction of cement in cement paste and concrete.

  • 72. Dham, M.
    et al.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    The Evaluation of the Addition of Phosphatic Clay in Cement Paste and Concrete2011Ingår i: International Journal of Materials Engineering and Technology, ISSN 0975-0444, Vol. 5, nr 2, s. 101-114Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Phosphatic clay is a by-product of the phosphate strip mining industry, and disposal is particularly a problem in Florida, USA. This waste material occupies about 100,000 acres of land which could be utilized for other causes. Thus, its potential utilization as a supplementary cementing material added to the cement paste matrix of concrete to produce higher strength would be beneficial for both the mining and construction industries. The waste clay contains calcium montmorillonite, which should react pozzolanically with the calcium hydroxide produced from the hydration reactions to produce additional C-S-H, the building block of concrete systems, and thus enhancing the mechanical properties of cement paste and concrete. The effects of phosphatic clay addition on the bulk properties of cement paste and concrete are investigated, and it is shown that moderate additions (5% replacement of cement by mass) can indeed produce a significant increase in strength. The effect of the modified paste on the interfacial transition zone in concrete is also observed.

  • 73.
    Dinegdae, Yared H.
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Birgisson, Björn
    Aston University, UK.
    Design inputs variabilities influence on pavement performance reliability2016Ingår i: Functional Pavement Design / [ed] Erkens et al. (Eds), 2016, s. 741-750Konferensbidrag (Refereegranskat)
    Abstract [en]

    Pavement design is a probabilistic process as it involves many random variables.Through the incorporation of reliability, pavement design methods consider inputparameters variabilities effect on pavement performance. Load and Resistance Factor Design(LRFD) is a typical example of reliability-based design procedure. In LRFD, a set of partialsafety factors are developed by modelling input parameters variabilities with representativeaverage conditions. This paper evaluates the impact input parameters variabilities have onestimated target reliability in the case when actual variabilities are different from assumedconditions. This was achieved by evaluating a field pavement section with various combinationsof input parameters variabilities. The optimized section for a given target reliability wasachieved through the mechanics-based LRFD procedure and the actual reliabilities of thevarious cases were obtained using a methodology that uses response surface approach andfirst order reliability method (FORM). The results have shown that the level of input parametersvariabilities used affect the target reliability considerably.

  • 74.
    Dinegdae, Yared H.
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Birgisson, Björn
    Aston University, UK.
    Effects of truck traffic on top-down fatigue cracking performance of flexible pavements using a new mechanics-based analysis framework2016Ingår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mechanics-based analysis framework predicts top-down fatigue cracking initiation timein asphalt concrete pavements by utilising fracture mechanics and mixture morphology-basedproperty. To reduce the level of complexity involved, traffic data were characterised and incorporatedinto the framework using the equivalent single axle load (ESAL) approach. There isa concern that this kind of simplistic traffic characterisation might result in erroneous performancepredictions and pavement structural designs. This paper integrates axle load spectraand other traffic characterisation parameters into the mechanics-based analysis framework andstudies the impact these traffic characterisation parameters have on predicted fatigue crackingperformance. The traffic characterisation inputs studied are traffic growth rate, axle load spectra,lateral wheel wander and volume adjustment factors. For this purpose, a traffic integrationapproach which incorporates Monte Carlo simulation and representative traffic characterisationinputs was developed. The significance of these traffic characterisation parameters wasestablished by evaluating a number of field pavement sections. It is evident from the resultsthat all the traffic characterisation parameters except truck wheel wander have been observedto have significant influence on predicted top-down fatigue cracking performance.

  • 75.
    Dinegdae, Yared H.
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Onifade, Ibrahim
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Jelagin, Denis
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Mechanics-based Topdown Fatigue Cracking Initiation Prediction Framework for Asphaltic Pavements2015Ingår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 16, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, a new mechanics-based top-down fatigue cracking analysis framework is presented for asphalt pavements. A new mixture morphology-based set of material sub-models is presented for characterising key mixture properties and their change over time. Predicting the load induced top-down fatigue crack initiation (CI) time by utilising comprehensive mixture properties creates the possibility of optimising the mixture morphology while taking into account its subsequent effect on long-term pavement performance. The new framework was calibrated and subsequently validated against a number of field pavement sections with varying traffic levels that are representative for current practices and which have a wide range in material properties. The framework accounts the change in key mixture properties due to ageing and mixture-healing effect on damage accumulation while determining the overall effect of design inputs on cracking performance. Model calibration and validation were achieved based on the healing potential of the asphalt mixture. It was found out that the CI predictions for all the sections are in general agreement with the observed performance in the field, thus giving credibility for the framework.

  • 76.
    Dinegdae, Yared Hailegiorgis
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap.
    Reliability-based calibration for a mechanics-based fatigue cracking design procedure2016Ingår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 17, nr 3, s. 529-546Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    This paper presents a new reliability-based code calibration in load resistance factor design (LRFD) format for the mechanics-based fatigue cracking analysis framework. The pavement design procedure incorporates an appropriate failure criterion and design period. Moreover, it provides uniform performance at the desired level of reliability while considering the inherent variabilities and uncertainties involved. A number of field pavement sections with well documented performance histories and high quality field and laboratory data were used for this purpose. Moreover, a reliability computation methodology that incorporates a central composite design (CCD) response surface approach (RS) is proposed. Appropriate statistical characterization of the dominant design parameters was performed considering its key role in reliability analysis. A first order reliability method (FORM) was used to compute pavement performance reliability and to establish the partial safety factors of the design procedure. Illustrative examples based on the developed LRFD procedure have demonstrated clearly its capacity of delivering designs with uniform reliability.

  • 77. Drakos, C
    et al.
    Roque, R
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Effect of Measured Tire Contact Stresses on Near-Surface Rutting2001Ingår i: Transportation Research Record, Vol. 1764Artikel i tidskrift (Refereegranskat)
  • 78.
    Drakos, C
    et al.
    University of Florida, Gainesville.
    Roque, R
    University of Florida, Gainesville.
    Birgisson, Björn
    University of Florida, Gainesville.
    Novak, M
    University of Florida, Gainesville.
    Identification of a Physical Model to Evaluate Rutting Performance of Asphalt Mixtures2005Ingår i: Journal of ASTM International, ISSN 1546-962X, E-ISSN 1546-962X, Vol. 2, nr 3, s. 165-185Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The objective of this study is to identify a physical model that can provide reliable predictions about a mixture's ability to resist permanent deformation under realistic stress states. Key differences were identified between stress states under the existing Asphalt Pavement Analyzer (APA) loading device (hose) and stress states under radial truck tires, which may indicate potentially different rutting mechanisms. It was shown that the APA hose was not capturing the critical lateral stresses found to be detrimental to rutting and cracking of HMA pavements. A new loading device (rib) was designed and constructed for use in the APA that more closely represents stress states found under radial tires. Contact-stress measurements under the two loading devices - hose and rib - showed that the rib was able to reproduce the lateral stresses found under individual ribs on a radial-tire tread. Subsequent finite element modeling also showed that the rib appeared to generate similar shear stress patterns to those found under the modeled radial-tire load. A new method was developed to measure deformations on the surface of APA specimens, where a contour gauge was used to record and store the entire surface profile of the sample throughout the progress of the test. An area-change parameter, which reflects volume change, was introduced to calculate the volumetric changes in the specimen. The area-change parameter can be used to determine whether specimen rutting is primarily due to shear instability or consolidation. Two mixtures of known field performance - poor and good - were tested to evaluate the test's ability to predict performance with the new loading device and the new measurement and interpretation system. Results showed that the new system (loading strip and profile measurement method) appears to have greater potential of evaluating a mixture's potential for instability rutting than the original (hose and single rut-depth measurement) configuration.

  • 79.
    Drakos, Christos A.
    et al.
    University of Florida, Gainesville.
    Roque, Reynaldo
    University of Florida, Gainesville.
    Birgisson, Björn
    University of Florida, Gainesville.
    Novak, Marc
    University of Florida, Gainesville.
    Identification of a physical model to evaluate rutting performance of asphalt mixtures2006Ingår i: Performance Tests for Hot Mix Asphalt (HMA) Including Fundamental and Empirical Procedures, 2006, s. 156-176Konferensbidrag (Refereegranskat)
    Abstract [en]

    The objective of this study is to identify a physical model that can provide reliable predictions about a mixture's ability to resist permanent deformation under realistic stress states. Key differences were identified between stress states under the existing Asphalt Pavement Analyzer (APA) loading device (hose) and stress states under radial truck tires, which may indicate potentially different rutting mechanisms. It was shown that the APA hose was not capturing the critical lateral stresses found to be detrimental to rutting and cracking of HMA pavements. A new loading device (rib) was designed and constructed for use in the APA that more closely represents stress states found under radial tires. Contact-stress measurements under the two loading devices - hose and rib - showed that the rib was able to reproduce the lateral stresses found under individual ribs on a radial-tire tread. Subsequent finite element modeling also showed that the rib appeared to generate similar shear stress patterns to those found under the modeled radial-tire load. A new method was developed to measure deformations on the surface of APA specimens, where a contour gauge was used to record and store the entire surface profile of the sample throughout the progress of the test. An area-change parameter, which reflects volume change, was introduced to calculate the volumetric changes in the specimen. The area-change parameter can be used to determine whether specimen rutting is primarily due to shear instability or consolidation. Two mixtures of known field performance - poor and good - were tested to evaluate the test's ability to predict performance with the new loading device and the new measurement and interpretation system. Results showed that the new system (loading strip and profile measurement method) appears to have greater potential of evaluating a mixture's potential for instability rutting than the original (hose and single rut-depth measurement) configuration.

  • 80. Gopalakrishnan, Kasthurirangan
    et al.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Taylor, P.
    Attoh-Okine, Nii.
    Nanotechnology in Civil Infrastructure: A Paradigm Shift2011Bok (Refereegranskat)
  • 81. Grigoriu, M
    et al.
    Kulhawy, F
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Probabilistic estimation of the capacity of drilled shaft foundations1991Konferensbidrag (Refereegranskat)
  • 82.
    Guarin, Alvaro
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap.
    Khan, Abdullah
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap.
    Butt, Ali Azhar
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap. Aston University School of Engineering and Applied Science, Aston Triangle, Birmingham, United Kingdom.
    Kringos, Nicole
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap.
    An extensive laboratory investigation of the use of bio-oil modified bitumen in road construction2016Ingår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 106, s. 133-139Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several roads in Iceland with bio-oil modified surface dressings exhibited severe distresses such as bleeding, binder drain down, and eventually as surface dressing sticking to tires. Samples from six road sections were evaluated in the laboratory to determine the causes of the failure. Binders with and without bio-oil, rapeseed oil and fish oil, were evaluated through a comprehensive rheological and chemical characterization. Both oils, exhibited solubility issues with the bitumen; consequently, the oils covered the aggregates, preventing bonding between binder and stones. It appears that fish oil worked a little better than rapeseed oil for binder modification.

  • 83.
    Gudmarsson, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Ryden, N.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Application of Resonant Acoustic Spectoscopy to Beam Shaped Asphalt Concrete Samples2010Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 128, nr 4, s. 2453-2453Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamic modulus of asphalt concrete is a key parameter needed in modern pavement design and management. Traditional laboratory tests based on cyclic loading (0.1–25 Hz) at different testing temperatures are time consuming and require expensive equipment. There is therefore a need for more efficient non‐destructive methods to determine the dynamic modulus of asphalt concrete. This study applies resonant acoustic spectroscopy (RAS) to beam shaped asphalt concrete samples. Multiple modes of vibration are measured at each testing temperature using a miniature accelerometer and a small steel sphere as impact source. The complex modulus from each resonant frequency is calculated using the Rayleigh–Ritz method. The heterogeneous and viscoelastic nature of asphalt concrete presents challenges to the application of conventional RAS. The number of measurable modes decreases with increasing test temperature. In an attempt to extend the usable frequency and temperature range measured, transfer functions are inverted using the finite element method along with a frequency dependent complex modulus. Initial results indicate that RAS can be an efficient method for the prediction of the high‐frequency part of the asphalt concrete dynamic modulus mastercurve.

  • 84.
    Gudmarsson, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Rydén, N.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Determination of the frequency dependent dynamic modulus for asphalt concrete beams using resonant acoustic spectroscopy2012Ingår i: Nondestructive Testing of Materials and Structures, Springer Netherlands, 2012, s. 199-204Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    The objective of this paper is to study the application of resonant acoustic spectroscopy (RAS) to beam shaped asphalt concrete samples. Natural modes of vibration are generated by a small load impulse at different temperatures and an accelerom-eter measures the resulting acceleration through the specimen. By using the Fast Fourier Transform the obtained information is transformed to frequency domain from which the solid's damped natural frequencies can be determined. For each frequency and temperature the corresponding complex modulus is calculated using the approach of RAS. Results of the dynamic modulus from RAS are presented and compared with results of the dynamic modulus calculated according to ASTM E 1876-99 [1]. By using ASTM E 1876-99 only the fundamental frequency of each type of vibrational mode can be used. However, using RAS several resonance frequencies from the same temperature can be used in the evaluation. This opens the possibility of determining the high frequency (or the low temperature) part of the dynamic modulus mastercurve directly from RAS.

  • 85.
    Gudmarsson, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Rydén, Nils
    Lund Univ, Sweden.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Application of resonant acoustic spectroscopy to asphalt concrete beams for determination of the dynamic modulus2012Ingår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 45, nr 12, s. 1903-1913Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, a new application of resonant acoustic spectroscopy (RAS) is examined for constructing asphalt concrete mastercurves from seismic testing. The frequency-dependent material properties can be characterized from multiple modes of vibration through the use of RAS. Beam-shaped asphalt specimens are tested at multiple temperatures to determine the resonance frequencies of the specimens. The resonance frequencies are estimated by applying a small load impulse and measuring the resulting acceleration through the specimens. Using RAS, the material properties of the specimens are determined numerically using the measured resonance frequencies. The results presented show that the frequency-dependent dynamic modulus of the asphalt concrete specimens can be characterized using several modes of vibration at each testing temperature.

  • 86.
    Gudmarsson, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Rydén, Nils
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Characterizing the low strain complex modulus of asphalt concrete specimens through optimization of frequency response functions2012Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 132, nr 4, s. 2304-2312Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Measured and finite element simulated frequency response functions are used to characterize the low strain (similar to 10(-7)) complex moduli of an asphalt concrete specimen. The frequency response functions of the specimen are measured at different temperatures by using an instrumented hammer to apply a load and an accelerometer to measure the dynamic response. Theoretical frequency response functions are determined by modeling the specimen as a three-dimensional (3D) linear isotropic viscoelastic material in a finite element program. The complex moduli are characterized by optimizing the theoretical frequency response functions against the measured ones. The method is shown to provide a good fit between the frequency response functions, giving an estimation of the complex modulus between minimum 500 Hz and maximum 18 vertical bar 000 Hz depending on the temperature. Furthermore, the optimization method is shown to give a good estimation of the complex modulus master curve.

  • 87.
    Gudmarsson, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Rydén, Nils
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Non-Contact Excitation of Fundamental Resonance Frequencies of an Asphalt Concrete Specimen2015Ingår i: AIP Conference Proceedings, 2015, Vol. 1650, s. 1401-1408Konferensbidrag (Refereegranskat)
    Abstract [en]

    Impact hammer and non-contact speaker excitation were applied to an asphalt concrete, a PVC-U and a concrete specimen to measure the fundamental longitudinal resonance frequency at different strain levels. The impact and the non-contact excitation methods resulted in similar resonance frequencies for the undamaged asphalt concrete and for the PVC-U specimen. However, the two excitation approaches gave different results for the concrete specimen, which was shown to have a nonlinear response to increasing strain levels. A reduction and a following recovery of the resonance frequency of the asphalt concrete were shown after the specimen was exposed to a small amount of damage. However, no fast nonlinear dynamics were observed for the asphalt concrete through the speaker measurements.

  • 88.
    Gudmarsson, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Rydén, Nils
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Nondestructive evaluation of the complex modulus master curve of asphalt concrete specimens2013Ingår i: Review Of Progress In Quantitative Nondestructive Evaluation , Vols 32A And 32B / [ed] Donald O. Thompson, Dale E. Chimenti, American Institute of Physics (AIP), 2013, s. 1301-1308Konferensbidrag (Refereegranskat)
    Abstract [en]

    The dynamic Young's modulus of asphalt concrete is directly related to pavement quality and is used in thickness design of pavements. There is a need for a nondestructive laboratory method to evaluate the complex modulus, which can be linked to nondestructive field measurements. This study applies seismic measurements to an asphalt concrete beam where resonant acoustic spectroscopy and optimization of frequency response functions are used to estimate the complex moduli. A good estimation of the master curve is obtained.

  • 89.
    Gudmarsson, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Rydén, Nils
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Observed deviations from isotropic linear viscoelastic behavior of asphalt concrete through modal testing2014Ingår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 66, s. 63-71Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The complex Young's moduli, complex shear moduli and complex Poisson's ratio of a beam shaped asphalt concrete specimen have been characterized through low strain (similar to 10(-7)) frequency response function measurements. The assumption of isotropic linear viscoelastic behavior has been applied and investigated. The results indicate that the asphalt concrete specimen agree with the isotropic linear viscoelastic assumption at low temperatures and high frequencies (>10 kHz at 0 degrees C), but at higher temperatures and lower frequencies, discrepancies from isotropic linear behavior are shown. The dynamic shear moduli calculated from the estimated Young's moduli and Poisson's ratio of the asphalt concrete specimen are overestimated for frequencies and temperatures often applied to pavements.

  • 90.
    Gudmarsson, Anders
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Rydén, Nils
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Di Benedetto, Hervé
    University of Lyon/Ecole Nationale des Travaux Publics de l’Etat (ENTPE), France .
    Sauzéat, Cédric
    Tapsoba, Nouffou
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Comparing Linear Viscoelastic Properties of Asphalt Concrete Measured by Laboratory Seismic and Tension–Compression Tests2014Ingår i: Journal of nondestructive evaluation, ISSN 0195-9298, E-ISSN 1573-4862, Vol. 33, nr 4, s. 571-582Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Seismic measurements and conventional cyclic loading have been applied to a cylindrical asphalt concrete specimen to compare the complex modulus and complex Poisson’s ratio between the two testing methods. The seismic moduli and Poisson’s ratio have been characterized by optimizing finite element calculated frequency response functions to measurements performed at different temperatures. An impact hammer and an accelerometer were used to measure the frequency response functions of the specimen which was placed on soft foam for free boundary conditions. The cyclic loading was performed by applying both tension and compression to the specimen while measuring the displacements in the axial and radial direction. The Havriliak–Negami and the 2S2P1D model have been used to estimate master curves of the complex modulus and complex Poisson’s ratio from the seismic and the tension–compression tests. The seismic measurements performed at a lower strain level than the tension–compression test give a higher absolute value of the complex moduli (e.g.∼12% at 100 Hz) and a lower phase angle compared to the tension–compression results.

  • 91.
    Gullberg, David
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Jelagin, Denis
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Evaluation of a novel calibrated-mechanistic model to design against fracture under Swedish conditions2012Ingår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 13, nr 1, s. 49-66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sweden has initiated the development of a new calibrated-mechanistic pavement design procedure to replace the current mechanical-empirical pavement procedure entitled “PMS Objekt.” The first phase was focused on the implementation and calibration of the vi scoelastic fracture mechanics framework entitled “HMA Fracture Mechanics”, developed at the University of Florida. This paper outlines the implementation and calibration of a new pavement design module for Sweden that is based on the HMA fracture mechanics framework. Both the developed design module, as well as the reference model used for calibration (PMS Objekt) are presented in this paper. The results in thickness design after calibration of the design module indicate that the framework is clearly applicable for common Swedish conditions and design standards.

  • 92.
    Gullberg, David
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Jelagin, Denis
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Evaluation of the predictive models used in the new swedish mechanistic-empirical design module2012Ingår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 13, nr 2, s. 300-311Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to perform thickness design of flexible pavements based on the HMA fracture mechanics framework prior to construction, the tensile strength and creep power law parameters of the mixture has to be determined. As samples are normally not available in the design stage, these properties will have to be modelled rather than determined in a laboratory. This paper evaluates material models based on the relationship between dynamic (complex) modulus and creep compliance in order to predict tensile strength and creep power law parameters for a mixture. For this evaluation, fourteen field sections from the United States have been used for verification and the results indicate that the crack resistance of a mixture can indeed be estimated without a development of extensive empirical relations between mixture properties and crack-resistance.

  • 93.
    Hesami, Ebrahim
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Bidewell, Nathan
    Griffith School of Engineering .
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Evaluation of Environmental Susceptibility of Bituminous Mastic Viscosity as a Function of Mineral and Biomass Fillers: 2013Ingår i: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, nr 2371, s. 23-31Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bituminous mastics influence many other important asphalt mixture properties in addition to their own allowance for the load transfer in the aggregate skeleton. The influence of bituminous mastics extents to the overall stability of a mixture, air void distribution, bitumen draindown during transport, a mixture's workability during the laying process, and the overall in-time performance of the pavement. To understand the properties of asphalt mixtures and their resistance to environmentally induced failure mechanisms, it is paramount to study not only bitumen and the asphalt mixture but also the mastic itself. Current asphalt design procedures do not take mastic behavior into account, however; this omission leads to a significant flaw in the ability to design and predict asphalt concrete response. This paper presents the results of an ongoing research project to enhance the understanding of the mastic phase as well as to develop a new test protocol to characterize mastics. A description is given of the measurements of mastic viscosity for different types of mastics in which the bitumen source is kept as a constant but with varying fillers as well as concentrations. Environmental susceptibility was investigated by subjecting the samples to aging and moisture conditioning. Biomass fillers were included in some of the mastics, in addition to some of the traditional fillers, to show their impact on the viscosity under varying conditions. Results showed that the developed test protocol was able to identify clearly the impact of filler properties on the mastic viscosity. A critical filler concentration was identified beyond which the viscosity behavior became nonlinear. The results also showed that moisture and aging had significant effects on the viscosity of mastics.

  • 94.
    Hesami, Ebrahim
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Nicole
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap.
    Effect of mixing sequence on the workability and performance of asphalt mixtures2015Ingår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, s. 197-213Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In Sweden, during recent years, a new type of mixing protocol has been applied, in which the order of mixing is changed from the conventional method. Improved workability and diminished mixing and compaction energy needs have been important drivers for this. Considering that it is the mastic phase, which is modified by changing the mixing order, it provides an interesting case study for explaining the mechanisms of workability in connection with the mastic phase. To do so, an analytical viscosity framework was combined with a mixture morphology framework to upscale to the mixing level and tribology principles to explain the interaction between the mastic and the aggregates. From the mastic viscosity protocol, it was found that the mixing order significantly affects the resulting mastic viscosity. To analyse the effect of this on the workability and resulting mixture performance, X-ray computed tomography was used to analyse mixtures produced by the two different mixing sequences. Mechanical testing was utilised to determine the long-term mechanical performance. In this part of the study, mastic viscosity as a function of particle concentration and distribution was directly coupled to improved mixture workability and enhanced long-term performance.

  • 95.
    Hesami, Ebrahim
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    A new protocol for measuring bituminous mastic viscosity as a function of its filler concentration2014Ingår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 15, nr 2, s. 420-433Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this contribution the development and results of a new test protocol for measuring the viscosity of bituminous mastics are presented. The paper describes the various considerations that need to be taken into account when dealing with mastics, gives a detailed description of the sample preparation, the test set-up and the actual test performance. A demonstration of the use of the test procedure is given by developing three types of mastics in which different filler types, but a similar bitumen base, were used. From the results it can be seen that the developed protocol is sensitive enough to allow for detailed studies of the effect of filler shape, chemistry and size distribution. In continuation of this work, more types of mastics will be investigated and the test results will be linked to additional chemical and mechanical test results to further enhance the fundamental understanding of mastics.

  • 96.
    Hesami, Ebrahim
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Effect of mixing sequence on the workability and performance of asphalt mixturesIngår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402Artikel i tidskrift (Övrigt vetenskapligt)
  • 97.
    Hesami, Ebrahim
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Numerical and experimental evaluation of the influence of the filler-bitumen interface in mastics2014Ingår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 47, nr 8, s. 1325-1337Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The successful use of additives in modified asphalt mixtures, such as warm mix asphalt, depends largely on the effect such modification has on the mastic. Previous research indicated that such modifiers do not simply change the bitumen properties, but can also change the interaction between the filler and the bitumen matrix. Understanding the effect of the properties of the fillers, the bitumen and their interaction is thus important for future asphalt mix design. In order to investigate this and to define the dominant relationships, this paper combines a numerical and experimental approach. In the experiments, the viscosities of modified and unmodified mastics with different filler concentrations and types were systematically investigated utilizing a novel testing protocol. In the numerical analyses, the Finite Element Method was utilized for a micro-mechanical analysis, in which the shape and size of the filler particles were varied in the bitumen matrix. Combining the experimental and numerical results allowed for a detailed investigation of the effect of the interface properties, with and without modifiers. The research further indicated that the effect of the shape and size of the fillers varied, depending on the interface properties. From the research relationships were established between the overall mastic viscosity and the influence of the filler-bitumen interface, considering shape and size. The conclusion of this paper can thus be useful for the effective development of modified asphalt mixtures and gives strong indications towards future research directions.

  • 98.
    Hesami, Ebrahim
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Jelagin, Denis
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Nicole
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Towards a New Experimental and Numerical Protocol for Determining Mastic Viscosity2012Ingår i: 7th RILEM International Conference on Cracking in Pavements, 2012, s. 103-113Konferensbidrag (Refereegranskat)
    Abstract [en]

    The rheological characteristics of mastics, or filler-bitumen mixtures, as a component of asphalt mixtures have a significant effect on the overall in-time performance of asphalt pavements such as low temperature cracking, fatigue and rutting behaviour. Viscosity is one of the rheological characteristics which is influenced by the physico-chemical filler-bitumen interaction. In this study, after reviewing some of more often used theories for calculating the viscosity of suspensions, a framework for calculating the viscosity of mastics is presented. This framework aims at covering the entire range of filler concentrations that is found in mastics. Also, a procedure for measuring viscosity mastic from dilute to high concentration mastic using a vane rotor viscometer is introduced. The paper is presenting the first experimental results and discusses the effect of the shape of the investigated fillers on the measured viscosity of the mastics.

  • 99.
    Hesami, Ebrahim
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Jelagin, Denis
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Nicole
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    An empirical framework for determining asphalt mastic viscosity as a function of mineral filler concentration2012Ingår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 35, s. 23-29Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sufficient coating, easy paving and good compaction are desirable parameters, which are approachable with the optimum viscosity of the mastic. In many studies, models have been developed for calculating the viscosity for different types of suspensions at various particle-to-fluid ratios. Unfortunately, none of them are applicable to asphalt mastics, since this material has a much wider range of mineral filler concentration from dilute to very concentrate. To give an overview of the existing viscosity models and to evaluate their range of applicability to asphalt mastics, an extensive literature review was performed. A new empirical framework was developed that removes some of the stipulated limitations of the existing theories.

  • 100.
    Hesami, Ebrahim
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Nejad Ghafar, Ali
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.
    Birgisson, Björn
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Kringos, Niki
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Multi-Scale Characterization of Asphalt Mastic Rheology2013Ingår i: Multi-Scale Modeling and Charactrization of Infrastructure Materials: Proceedings of the International RILEM Symposium Stockholm, June 2013 / [ed] Niki Kringos, Björn Birgisson, David Frost and Linbing Wang, Springer, 2013, s. 45-61Konferensbidrag (Refereegranskat)
    Abstract [en]

    Understanding the influence of the fundamental parameters on asphalt mastic rheology is an important step towards improving the quality of asphalt mixtures. Due to the size of fillers and the sensitivity of the rheological behaviour of mastic, it is not always possible to study the effect of all parameters at one scale. Hence in this study, a theoretical framework is established for calculating the relative viscosity of asphalt mastics as a function of its filler concentration. Furthermore, a new test protocol is introduced for measuring the viscosity of asphalt mastic at higher temperatures and different filler concentrations.  To characterize the fillers and their agglomeration and distribution inside solid mastics, X-ray tomography, laser scattering, scanning electron microscopy, BET and Helium Pycnometery were utilized. To characterize the energy dissipation potential of the mastics under cyclic loads, as a function of their fillers, the dynamic mechanical analyzer was utilized. The research shown in this paper further investigated the various dominant parameters related to fillers and bitumen in mastics and relate them to the workability and resulting mechanical properties and developed an overall framework to connect different scales. The developed characterization protocols have the potential to allow the asphalt engineers to design their hot and warm asphalt mixtures on a more fundamental and thus sustainable basis.         

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