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  • 1.
    Laurell Lyne, Åsa
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    A Fundamental Adhesion Model for Asphalt2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One of the mechanisms for the deterioration of asphalt is debonding. This is often referred to as stripping. Most losses of adhesion at the bitumen-aggregate interface are attributed to the action of water leading to a reduction in properties such as tensile strength, tensile stiffness and wear resistance. If we move to more accurate models for predicting bitumen-aggregate adhesion based on material properties, then we can be much more effective in building roads that are stable and resist hardening, crack-building, and stripping more effectively.

    The main aim of this doctoral thesis was to propose a hypothesis for what makes bitumen binders stay adhered to aggregates (or filler particles such as Portland cement) and to provide a fundamental understanding for the development of a new test method for bitumen-aggregate adhesion.

    The Hamaker constant was used to estimate van der Waals interactions. Hamaker’s constant is composed of two parts. The first part describes the Keesom and Debye contribution, which represents the attraction energy at zero-frequency, and the second part the London dispersive (electronic) contribution, which represents the attraction energy in the optical/UV spectrum. Calculations of Hamaker’s constant require accurate dielectric data, i.e. the dielectric constant and the refractive index of the interacting materials and the intervening medium.

    Paper I: Hamaker’s constant was introduced to describe and calculate the van der Waals interaction and to determine its relationship to resistance to stripping.

    Paper II: The dispersive component of minerals was calculated from their refractive indices using data from mineral data sheets.

    Paper III: The dispersive component of un-aged bitumen and aggregates was calculated from their refractive indices, determined by ellipsometery measurements.

    Paper IV: The surface force mapping technique, AFM QNM, was used to measure parameters such as topography, adhesion and elastic modulus simultaneously on un-aged 70/100 penetration grade bitumen binders. The result was presented as images representing individual and overlaid parameters, e.g. topographic images with an adhesion overlay and topographic images with a modulus overlay. The adhesion forces measured in the region surrounding (peri phase) the ‘bees’ (catana phase) and the region in the ‘bee’ areas are lower than the adhesion force measured in the smooth matrix (para phase). Likewise it can be observed that Young’s moduli in the region surrounding (peri phase) the ‘bees’ (catana phase) and in the ‘bees’ are higher than Young’s modulus of the smooth matrix (para phase).

    Paper V: The mechanism for bee formation was investigated via AFM.

    Paper VI: The bitumen components that are expected to migrate to the air interface and to the surface of laboratory glass slides (or to the surface of aggregates), were investigated based on the relative dielectric spectroscopic response of the material components, as determined by their dielectric constants and refractive indices.

    The total polarizability can be determined from the dielectric constant. The non-polar London dispersive (electronic) polarizability can be determined from refractive index measurements. In materials with higher permittivity at zero frequency the Keesom and Debye attraction energies will be responsible for a significant part of the polarization. Bitumen as a whole has a low degree of total polarizability. Bitumen contains a small fraction of n-heptane insoluble molecules that have a somewhat higher total polarizability and therefore may contribute to Debye and Keesom interactions. Bitumen as a whole is highly London dispersive (electronic) polarizable and the asphaltene (or n-heptane insoluble) fraction is even higher London dispersive (electronic) polarizable. The degree of non-polar London dispersion polarizability increases with increasing molecular size and with increasing aromaticity.

    Paper VII: Adhesion properties of un-aged 70/100 penetration grade bitumen binders were probed by means of permittivity analysis.

    The initial adhesion of non-aged bitumen binders to pure quartz aggregates is primarily London dispersive due to low total polarizability of the components.

    The higher surface coverage with the addition of the Portland cement to the surface of the aggregates can be explained by the addition of components with higher London dispersive polarizability and higher total polarizability of CaO, MgO and ironoxides. Portland cement is a material contributing to Debye and Keesom interactions. Portland cement could also have chemical influence on its bonding to aggregates.

    A strong correlation was identified between the average tangent of the dielectric loss angle in the frequency region of 0.01 to 1 Hz and surface coverage (a common method to indicate suitability of bitumen for use in roads). Surface coverage is higher for bitumen binders having a larger average loss tangent.

    It is suggested that the average tangent of the dielectric loss angle in the frequency range of 0.01 to 1 Hz, could be used as an indicator for predicting polarizability and thereby, adhesion potential of bitumen binders.

  • 2.
    Laurell Lyne, Åsa
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Highway and Railway Engineering (closed 20110301).
    Minerals and their dispersive interaction with bitumen2011Licentiate thesis, comprehensive summary (Other academic)
  • 3.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Highway and Railway Engineering (closed 20110301).
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Highway and Railway Engineering (closed 20110301).
    Redelius, Per
    Nynas Bitumen, Nynäs AB, Nynäshamn, Sweden.
    Interaction forces between mineral aggregates and bitumen Calculated using the Hamaker constant2010In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 11, p. 305-323Article in journal (Refereed)
    Abstract [en]

    Moisture damages to bituminous pavements leads to costly repairs. The most serious outcome of the influence of water is the loss of adhesion between binders and aggregates. This is often described as stripping. Adhesion is the ability at a molecular level of materials to stick steadfastly to one another. An alternative way of explaining the adhesion of bitumen to aggregates is presented in this paper using the Hamaker constant, a measure of the van der Waals attraction forces between two materials. The Hamaker constant is significantly lower for water as the intervening medium than for air. For the aggregates and minerals studied, the Lifshitz-van der Waals interactions contribute 65-78 percent of the 'work of adhesion' calculated by the acid-base method. The performance of the aggregates and minerals correlates well to A(total) where resistance to stripping data is available.

  • 4.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Chatterjee, S
    Ramarao, B
    Domain theory applied to the hygroexpansion hysteresis of isotropic restraint dried bleached kraft1998Report (Other academic)
  • 5.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Collin, Måns
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Obstacles to Measuring Bitumen Surface Energy as it Pertains to Adhesion in AsphaltManuscript (preprint) (Other academic)
  • 6.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Fellers, C
    Kolseth, P
    The effect of filler on hygroexpansivity1996In: Nordic Pulp and Paper Research Journal, Vol. 11, no 3Article in journal (Refereed)
  • 7.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Fellers, C
    Kolseth, P
    Three dimensional hygroexpansivity of unfilled and filled laboratory made fine papers1994In: Appita, Vol. 47, no 5Article in journal (Refereed)
  • 8.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Krivosheeva, Olga
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Adhesion between bitumen and aggregate: implementation of spectroscopic ellipsometry characterisation and estimation of Hamaker's constant2013In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 46, no 10, p. 1737-1745Article in journal (Refereed)
    Abstract [en]

    Refractive indices of seven bitumen samples and three aggregates (typical components in flexible asphalt pavement) were determined by ellipsometry in order to predict bitumen-aggregate adhesion and bitumen-bitumen cohesion using Hamaker’s constant.

    Hamaker’s constant according to Lifshitz was introduced to the asphalt field by two of the authors to describe and estimate van der Waal’s interaction and bitumen–aggregate adhesion. Lifshitz used the refractive index to estimate the dispersive non-polar van der Waal’s interaction component of adhesion, the predominant component in adhesion between minerals and bituminous binder. The impact of an intervening thin medium such as air or water on the adhesion can be estimated using Hamaker’s coefficient, which in turn can be related to stripping potential.

    The bitumen binders studied were delivered as a paving grade 70/100 according to EN 12591:2009 and came from different bitumen suppliers. The three aggregates studied were two types of granite and one diabase.

    It is concluded from the measurement of refractive indices and calculations of the Hamaker’s constant that there was a larger spread in refractive index among the three aggregate samples studied than among the seven bitumen samples.

  • 9.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Luner, P
    Properties of papers crosslinked with butanetetracarboxylic acid (BTCA).1995Report (Other academic)
  • 10.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Luner, P
    The influence of BTCA on hygroexpansion and hysteresis of isotropic handsheets1998Report (Other academic)
  • 11.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Redelius, Per
    Nynas AB, Stockholm, Sweden.
    Collin, Måns
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Characterization of stripping properties of stone material in asphalt2013In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 46, no 1-2, p. 47-61Article in journal (Refereed)
    Abstract [en]

    Aggregates and bitumen together form a composite called asphalt concrete pavement. Moisture damage to asphalt concrete pavement can occur as stripping, and is a common problem that can lead to costly repairs. There is therefore a need to understand which stone aggregates adhere best to bituminous binder and result in a minimum of stripping. Lifshitz used the refractive index to estimate the dispersive non-polar van der Waal's interaction component of adhesion, the predominant component in adhesion between minerals and bituminous binder. The impact of an intervening thin medium such as air or water on the adhesion can be estimated using Hamaker's coefficient, which in turn can be related to stripping potential. Aggregates consist of minerals and minerals consist of different elements. The objective of this study was to investigate variation in the dispersive component of minerals via their refractive indices using data from mineral data sheets. The influence of the position of elements in the periodic table and chemical composition on refractive index of minerals was examined in order to classify mineral aggregates for asphalt road building with regard to dispersive adhesive properties and expected resistance to stripping. It is clear from this study that the elemental composition of a mineral will affect its refractive index and hence its dispersive adhesion to bitumen. Aggregates and minerals have been classified according to degree of stripping in the literature. In this study it was shown that aggregates and minerals that have a refractive index higher than approximately 1.6 are expected to be less susceptible to stripping. Also, minerals containing alkali metals are sensitive to stripping since they are partially soluble in water.

  • 12.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Highway and Railway Engineering (closed 20110301).
    Redelius, Per
    Nynas Bitumen, Nynäs AB, Nynäshamn, Sweden.
    Collin, Måns
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Highway and Railway Engineering (closed 20110301).
    The mechanism of adhesion between aggregates and bitumen in asphaltIn: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873Article in journal (Refereed)
  • 13.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Jäverberg, Nadejda
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Edin, Hans
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Low Frequency Dielectric Spectroscopy of Bitumen Binders.Manuscript (preprint) (Other academic)
  • 14.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Wallqvist, V.
    Rutland, Mark
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Surface wrinkling: The phenomenon causing bees in bitumen2013In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 48, no 20, p. 6970-6976Article in journal (Refereed)
    Abstract [en]

    The so called "bee phenomenon" in bitumen has been investigated by means of AFM quantitative nanomechanical property mapping. Bees are a phenomenon that can be observed by topography measurements using AFM. The characteristic "bee" appearance comes from regions with alternating higher and lower bands in the surface topography of bitumen, which are surrounded by a flat area. The proposed mechanism for bee formation is phase separation and differential contraction during cooling from melt temperatures leading to wrinkling due to differences in the elastic modulus of the material phases. Using a laminate wrinkling model, the thickness of the bee laminate was calculated from the wavelengths and Young's moduli of the bee laminate and the matrix. It was found to vary between 70 and 140 nm for the five bitumen samples that contained significant amounts of wax.

  • 15.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Wallqvist, Viveca
    SP Technical Research Institute of Sweden, Box 5607, SE-114 86 Stockholm, Sweden .
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Adhesive surface characteristics of bitumen binders investigated by Atomic Force Microscopy2013In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 113, p. 248-256Article in journal (Refereed)
    Abstract [en]

    Bitumen is a complex hydrocarbon whose composition-structure-property relationship is not well-understood. In this paper, microphase-separated topographic morphologies of unaged penetration grade 70/100 bitumen binders have been visualized by means of AFM QNM, and the relationship to local mechanical properties has been demonstrated. AFM QNM is a surface force mapping technique which measures parameters such as topography, adhesion and elastic modulus simultaneously. The resulting data can then be presented as images representing individual or overlaid parameters, e. g. topographic images with an adhesion overlay or topographic images with a modulus overlay. AFM QNM results show that the adhesive forces measured in the region surrounding (peri phase) the periodic topographic features resembling 'bees' (catana phase) and the region in the 'bee' areas are lower than the adhesive force measured in the smooth matrix (para phase). Likewise it was observed that Young's moduli in the region surrounding (peri phase) the 'bees' (catana phase) and in the 'bees' are higher than Young's modulus of the smooth matrix (para phase).

  • 16. Lavrykov, S.
    et al.
    Ramarao, B.
    Laurell Lyne, Åsa
    International Paper CRC.
    The planar transient hygroexpansion of copy paper: Experiments and analysis2004In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 19, no 2, p. 183-190Article in journal (Refereed)
    Abstract [en]

    Experimental results for transient hygroexpansion of copy paper sheets subjected to step changes in RH were obtained. MD transient hygroexpansion strain rates (expressed in normalized forms) during adsorption were higher than the corresponding CD rates for every cycle tested. CD hygroexpansion strains were observed to be linear in the average moisture content of the sheets. MD strains however showed significantly non-linear behavior. A mathematical model for transient hygroexpansion of paper sheets was developed based on the twin mechanisms of moisture diffusion through the pore and fiber spaces. The model incorporates the effects of surface boundary layers also. Assuming the hygroexpansion to be "quasi-static" (i.e. local hygroexpansion coefficients are equivalent to the equilibrium values), traditional theory for linear thermal elasticity was applied to estimate hygroexpansion strains. The model describes different hygroexpansion strain rates in CD and MD.

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