lnu.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Johannesson, Björn
Publications (10 of 82) Show all publications
Wu, M., Fridh, K., Johannesson, B. & Geiker, M. (2018). Impact of sample crushing on porosity characterization of hardened cement pastes by low temperature calorimetry: Comparison of powder and cylinder samples. Thermochimica Acta, 665, 11-19
Open this publication in new window or tab >>Impact of sample crushing on porosity characterization of hardened cement pastes by low temperature calorimetry: Comparison of powder and cylinder samples
2018 (English)In: Thermochimica Acta, ISSN 0040-6031, E-ISSN 1872-762X, Vol. 665, p. 11-19Article in journal (Refereed) Published
Abstract [en]

Theimpact of sample crushing on the detected porosity of hardened cement pastes bylow temperature calorimetry (LTC) was studied using powder and cylindersamples. Two types of cements, CEM I and CEM III were used to prepare thepastes. A model porous material, MCM-41, was also used in order to investigatesome aspects of the measurement and the evaluation approach. The powder andcylinder samples of the cement pastes were compared in terms of the calculatedice content curves, total pore volumes and pore size distribution curves. For thetwo studied cement pastes, the calculated ice content curves of freezing of thepowder sample differed from that of the cylinder samples, especially for thepaste CEM III. The results indicate that sample crushing changed the poreconnectivity as compared to non-crushed samples. One important differencebetween the powder sample and the cylinder samples of the paste CEM III wasthat the determined maximum ice content in the powder sample was much higherthan that in the cylinder samples, the relatively difference being about 40–50%.However, this kind of marked difference was not found in the paste CEM I. Theobserved difference between the calculated pore volume of the powder and thecylinder samples of the paste CEM III is possibly due to some of the “isolated”pores which, presumably, cannot be fully filled with water in the preparationof the cylinder samples. However, sample crushing makes it possible to saturatethe pores to a greater extent if the crushing contributes to open up the“isolated” pores. Consequently, more pores are detected in the powder samples.The argument that the “isolated” pores have a tendency to be opened up by thecrushing process is supported by results using gravimetric measurements and“dynamic (water) vapor sorption” measurements on powder samples.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Other Materials Engineering Construction Management
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-74363 (URN)10.1016/j.tca.2018.05.002 (DOI)000437372400002 ()
Available from: 2018-05-15 Created: 2018-05-15 Last updated: 2018-07-27Bibliographically approved
Addassi, M., Johannesson, B. & Wadsö, L. (2018). Inverse analyses of effective diffusion parameters relevant for a two-phase moisture model of cementitious materials. Cement and Concrete Research, 106, 117-129
Open this publication in new window or tab >>Inverse analyses of effective diffusion parameters relevant for a two-phase moisture model of cementitious materials
2018 (English)In: Cement and Concrete Research, ISSN 0008-8846, E-ISSN 1873-3948, Vol. 106, p. 117-129Article in journal (Refereed) Published
Abstract [en]

Here we present an inverse analyses approach to determining the two-phase moisture transport properties re-levant to concrete durability modeling. The purposed moisture transport model was based on a continuumapproach with two truly separate equations for the liquid and gas phase being connected by the sorption ki-netics. The moisture properties of ten binder-systems containingfly ash, calcined clay, burnt shale and graymicro-filler, were investigated experimentally. The experiments used were, (i) sorption test (moisturefixation),(ii) cup test in two different relative humidity intervals, (iii) drying test, and, (iv) capillary suction test. Masschange over time, as obtained from the drying test, the two different cup test intervals and the capillary suctiontest, was used to obtain the effective diffusion parameters using the proposed inverse analyses approach. Themoisture properties obtained with the proposed inverse analyses method provide a good description of the testperiod for the ten different binder-systems.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Construction Management Other Materials Engineering
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-71491 (URN)10.1016/j.cemconres.2018.01.011 (DOI)000429762800012 ()
Available from: 2018-03-12 Created: 2018-03-12 Last updated: 2018-07-10Bibliographically approved
Geiker, M. R., De Weerdt, K., Garzon, S. F., Jensen, M. M., Johannesson, B. & Michel, A. (2017). Screening of Low Clinker Binders, Compressive Strength and Chloride Ingress. Nordic Concrete Research, 57(2), 23-38
Open this publication in new window or tab >>Screening of Low Clinker Binders, Compressive Strength and Chloride Ingress
Show others...
2017 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 57, no 2, p. 23-38Article in journal (Refereed) Published
Abstract [en]

This paper reports an initial screening of potential new binders for concrete with reduced CO2-emission. Mortars cured saturated for 90 days are compared with regard to a) compressive strength of mortars with similar water-to-binder ratio, and b) chloride ingress in similar design strength mortars exposed to seawater. The reference used was a binder composition typical for a Danish ready mixed concrete for aggressive environments and strength class C35/45. Based on the present investigation and assumptions up to around 15% reduction in CO2 emission from binder production might be obtained without compromising the 90 days compressive strength and resistance to chloride ingress in marine exposure by using selected alternative binders.

Keywords
Cement, chlorides, CO2-emission, supplementary cementitious materials (SCM)
National Category
Civil Engineering
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-72108 (URN)000425406800004 ()
Available from: 2018-04-04 Created: 2018-04-04 Last updated: 2018-04-04Bibliographically approved
Addassi, M., Schreyer, L., Johannesson, B. & Lin, H. (2016). Pore-scale modeling of vapor transport in partially saturated capillary tube with variable area using chemical potential. Water resources research, 52(9), 7023-7035
Open this publication in new window or tab >>Pore-scale modeling of vapor transport in partially saturated capillary tube with variable area using chemical potential
2016 (English)In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 52, no 9, p. 7023-7035Article in journal (Refereed) Published
Abstract [en]

Here we illustrate the usefulness of using the chemical potential as the primary unknown by modeling isothermal vapor transport through a partially saturated cylindrically symmetric capillary tube of variable cross-sectional area using a single equation. There are no fitting parameters and the numerical solutions to the equation are compared with experimental results with excellent agreement. We demonstrate that isothermal vapor transport can be accurately modeled without modeling the details of the contact angle, microscale temperature fluctuations, or pressure fluctuations using a modification of the Fick-Jacobs equation. We thus conclude that for a single, axisymmetric pore, the enhancement factor depends upon relative humidity boundary conditions at the liquid bridge interfaces, distance between liquid bridges, and bridge lengths.

Place, publisher, year, edition, pages
AGU Publications, 2016
National Category
Oceanography, Hydrology and Water Resources
Research subject
Technology (byts ev till Engineering)
Identifiers
urn:nbn:se:lnu:diva-56688 (URN)10.1002/2016WR019165 (DOI)000386977900018 ()2-s2.0-84988489832 (Scopus ID)
Available from: 2016-09-23 Created: 2016-09-23 Last updated: 2018-01-10Bibliographically approved
Jensen, M. M., Johannesson, B. & Geiker, M. R. (2015). A Numerical Comparison of Ionic Multi-Species Diffusion with and without Sorption Hysteresis for Cement-Based Materials. Transport in Porous Media, 107(1), 27-47
Open this publication in new window or tab >>A Numerical Comparison of Ionic Multi-Species Diffusion with and without Sorption Hysteresis for Cement-Based Materials
2015 (English)In: Transport in Porous Media, ISSN 0169-3913, E-ISSN 1573-1634, Vol. 107, no 1, p. 27-47Article in journal (Refereed) Published
Abstract [en]

A finite element solution for a mass transport model for porous materials accounting for sorption hysteresis is presented in this paper. The model is prepared for modeling of concrete durability, but the general presentation makes it suitable for other porous materials like soil and tissues. The model is an extended version of the Poisson–Nernst–Planck (PNP) system of equations. The PNP extension includes a two-phase vapor and liquid model coupled by a sorption hysteresis function and a chemical equilibrium term. The strong and weak solutions for the equation system are shown, and a finite element formulation is established by Galerkin’s method. A single-parameter implicit time integration scheme is used for solving the transient response, and the out-of-balance solution is minimized by using a modified Newton–Raphson scheme in which the tangential stiffness is not computed exactly. The sorption hysteresis is added to the solution procedure by a rate function. The hysteresis effect is described by scanning curves defined between two boundary sorption isotherms. A numerical example was constructed to show the applicability and compare a simple approach and a extended approach within the sorption hysteresis model. The examples illustrate the impact of changing relative humidity at the mass transport boundary on the adsorption and desorption stages of a cement-based material. Changes in the pore solution ion concentrations are a result of the changing moisture content, which are shown by the example. Comparing the two approaches showed significant deviations in the liquid content and ion concentrations, in parts of the domain considered.

Keywords
Mass transport, Sorption hysteresis, Finite element method, Cement-based materials
National Category
Construction Management
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-48686 (URN)10.1007/s11242-014-0423-3 (DOI)
Available from: 2016-01-12 Created: 2016-01-12 Last updated: 2017-11-30Bibliographically approved
Latini, C., Zania, V. & Johannesson, B. (2015). Dynamic stiffness and damping of foundations for jacket structures. In: The proceedings of the 6th International conference on earthquake geotechnical engineering: . Paper presented at 6th International Conference on Earthquake Geotechnical Engineering 1-4 November 2015 Christchurch New Zealand.
Open this publication in new window or tab >>Dynamic stiffness and damping of foundations for jacket structures
2015 (English)In: The proceedings of the 6th International conference on earthquake geotechnical engineering, 2015Conference paper, Published paper (Refereed)
Abstract [en]

Foundation for offshore jacket structures may comprise of long floating piles. The dynamic response of floating piles to horizontal load is herein investigated. The analytical solution of horizontally vibrating end bearing piles by Novak & Nogami (1977) has been modified. At first the soil resistance as defined by Nogami & Novak (1977) is determined, considering 3D wave propagation within linear soil layer with hysteretic damping. Thereafter, the dynamic response of the pile is estimated assuming soil pressure equal to the soil resistance and imposing displacement compatibility. A parametric study clarifies the role of the parameters involved i.e. the depth of the soil layer, the pile diameter and the soil layer shear wave velocity. Results are presented in terms of dimensionless graphs which highlight the frequency dependency of the dynamic stiffness and damping.

National Category
Construction Management
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-48687 (URN)
Conference
6th International Conference on Earthquake Geotechnical Engineering 1-4 November 2015 Christchurch New Zealand
Available from: 2016-01-12 Created: 2016-01-12 Last updated: 2016-01-18Bibliographically approved
Wu, M., Fridh, K., Johannesson, B. & Geiker, M. R. (2015). Influence of frost damage and sample preconditioning on the porosity characterization of cement based materials using low temperature calorimetry. Thermochimica Acta, 607, 30-38
Open this publication in new window or tab >>Influence of frost damage and sample preconditioning on the porosity characterization of cement based materials using low temperature calorimetry
2015 (English)In: Thermochimica Acta, ISSN 0040-6031, E-ISSN 1872-762X, Vol. 607, p. 30-38Article in journal (Refereed) Published
Abstract [en]

Low temperature calorimetry (LTC) can be used to study the meso-porosity of cement based materials. The influence of frost damage on the meso-porosity determination by LTC was explored on a model material MCM-41 and two cement pastes by conducting repeated cycles of freezing and melting measurements. The results indicate that the pressure generated during freezing and melting measurements has little impact on the pore structure of the powder MCM-41 samples. As for the studied cylinder samples of cement pastes, frost damage probably took place and it changed the pore connectivity while it had limited effect on changing the interior size distribution of the meso-pores. The analysis of the freezing and melting behavior of the pore liquid of cement based materials is complicated by the presence of ions. The freezing and melting behavior of the pore solution of cement paste samples preconditioned in either a small amount or a big amount of saturated limewater was compared. The results suggest that either the preconditioning in a big amount of limewater does not change the ionic concentration of the pore solution very much or the possible leaching of ions from cement hydrates during the preconditioning has limited influence on the freezing and melting behavior of the pore solution in the studied cement paste samples.

Keywords
Calorimetry, Cement paste, Cryoporometry, Freezing and thawing, Frost damage, Thermoporometry, Calorimeters, Characterization, Freezing, Hydrated lime, Hydrates, Melting, Porosity, Temperature, Cements
National Category
Construction Management
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-48688 (URN)10.1016/j.tca.2015.03.005 (DOI)000354139300004 ()
Available from: 2016-01-12 Created: 2016-01-12 Last updated: 2017-11-30Bibliographically approved
Madsen, S. S., Krenk, S. & Johannesson, B. (2015). Relaxation modeling of asphalt behavior under moving load. In: 5th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering: . Paper presented at 5th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering. Crete Island: Technical University of Crete Chania Crete Greece
Open this publication in new window or tab >>Relaxation modeling of asphalt behavior under moving load
2015 (English)In: 5th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Crete Island: Technical University of Crete Chania Crete Greece, 2015Conference paper, Oral presentation only (Refereed)
Abstract [en]

In relation to the development of a Rolling Wheel Deflectometer (RWD), which is a non-destructive testing device for measuring pavement deflections, a finite element model for obtaining the soil/pavement response has been developed [1]. The RWD is operating at traffic speeds and the soil model is therefore subjected to a moving transient dynamic load. Perfectly Matched Layer (PML) [2] is used as absorbing boundary conditions in order to prevent reflections of the waves propagating through the soils due to the dynamic loading. As the load is moving with high speed, the formulation is in the moving frame of reference [3].

To accurately predict pavement response, proper material characterization is needed. Flexible pavements are commonly modeled as multilayer linear elastic systems. However, asphalt behaves as a viscoelastic material because its response to induced loading depends on temperature and load frequency and can be modeled in different ways. A finite element model can quickly reach high computational cost, thus a simple, time-efficient viscoelastic model is preferable.

The viscoelastic behavior of asphalt can be described by a relaxation format of the constitutive relation with four parameters; two elastic moduli defining the minimum and maximum stiffnesses of asphalt in relation to frequency, a time scale parameter controlling the relaxation time and a differential fractional order characterizing the interpolation between low and high frequency regimes [4]. Assuming the most common interpolation shape by setting the fractional order equal to one, the system is reduced to only 3 parameters and the formulation can be implemented in the finite element model without increasing the computational cost significantly.

In this paper a formulation of the relaxation format of viscoelastic behavior is developed in translated coordinates with efficiently absorbing boundary conditions (PML). The viscoelastic properties of the formulation are illustrated through numerical examples.          

 

References

[1] S. Madsen, S. Krenk and O. Hededal, Perfectly Matched Layer (PML) for transient wave propagation in a moving frame of reference. Proceedings of the Fourth International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, COMPDYN 2013, pp. 4379-4388. Kos, 2013.

[2]  R. Matzen, An efficient finite element time-domain formulation for the elastic second-order wave equation: A non-split complex frequency shifted convolutional PML. International Journal for  Numerical Methods in Engineering, 88, 951-973, 2011.

[3] S. Krenk, L. Kellezi, S.R.K. Nielsen and P.H. Kirkegaard, Finite elements and transmitting boundary conditions for moving loads, in Proceedings of the Fourth European Conference on Structural Dynamics, EURODYN’99, Vol. 1, 447-452. Balkema, Rotterdam, 1999.

 [4] S. Krenk, Damping mechanisms and models in structural dynamics. Proceedings of the Fourth International Conference on Structural Dynamics, EURODYN 2002, Vol 2, Munich, Germany, 2002.

Place, publisher, year, edition, pages
Crete Island: Technical University of Crete Chania Crete Greece, 2015
National Category
Building Technologies
Research subject
Technology (byts ev till Engineering)
Identifiers
urn:nbn:se:lnu:diva-49052 (URN)
Conference
5th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering
Available from: 2016-01-20 Created: 2016-01-20 Last updated: 2016-04-25Bibliographically approved
Jensen, M. M., De Weerdt, K., Johannesson, B. & Geiker, M. R. (2015). Use of a multi-species reactive transport model to simulate chloride ingress in mortar exposed to NaCl solution or sea-water. Computational materials science, 105, 75-82
Open this publication in new window or tab >>Use of a multi-species reactive transport model to simulate chloride ingress in mortar exposed to NaCl solution or sea-water
2015 (English)In: Computational materials science, ISSN 0927-0256, E-ISSN 1879-0801, Vol. 105, p. 75-82Article in journal (Refereed) Published
Abstract [en]

Simulations of ion ingress in Portland cement mortar using a multi-species reactive mass transport model are compared with experimental test results. The model is an extended version of the Poisson–Nernst–Planck equations, accounting for chemical equilibrium. Saturated mortar samples were exposed after 8 days of hydration to a NaCl-solution or natural sea-water in a laboratory controlled environment for the experimental part. The samples were analyzed for the total chloride content after 21, 90 and 180 days of exposure, at varying depths from the exposed surface. The applicability of the reactive mass transport model is shown by comparing the simulation and experimental results. The tortuosity factor used in the simulations is adjusted to obtain the best reproduction of the experimental results. The model predicts the total chloride content satisfactorily, despite assumptions in the simulation like fixed hydration degree over time. Improvements and suggestions for further development of the model are discussed, e.g. extended hydration description, improved overall chemical description and a more strict use of the tortuosity factor.

Keywords
Numerical modeling, Cement, Ion ingress
National Category
Construction Management
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-48689 (URN)10.1016/j.commatsci.2015.04.023 (DOI)
Available from: 2016-01-12 Created: 2016-01-12 Last updated: 2017-11-30Bibliographically approved
Wu, M., Johannesson, B. & Geiker, M. (2014). A preliminary study of the influence of ions in the pore solution of hardened cement pastes on the porosity determination by low temperature calorimetry. Thermochimica Acta, 589, 215-225
Open this publication in new window or tab >>A preliminary study of the influence of ions in the pore solution of hardened cement pastes on the porosity determination by low temperature calorimetry
2014 (English)In: Thermochimica Acta, ISSN 0040-6031, E-ISSN 1872-762X, Vol. 589, p. 215-225Article in journal (Refereed) Published
Abstract [en]

Thermodynamic modeling was used to predict the ionic concentrations in the pore solution of cement pastes at different temperatures during a freezing and melting measurement in low temperature calorimetry (LTC) studies. By using the predicted ionic concentrations, the temperature depressions caused by the ions presented in the pore solution were determined. The influence of the freezing/melting point depression caused by the ions on the determined pore size distribution by LTC was demonstrated. Thermodynamic modeling using the program PHREEQC was performed on the cylinder and powder samples of cement pastes prepared by two types of cements, i.e., CEM 132.5 R and CEM III/B 42.5 N. Using the modeled ionic concentrations, the calculated differential pore size distributions for the studied samples with and without considering the temperature depression caused by the ions in the pore solution were compared. The results indicate that for the studied cement paste samples, the influence of the temperature depression caused by the presence of the ions in the pore solution on the determination of the pore size distribution by LTC is limited. (C) 2014 Elsevier B.V. All rights reserved.

Keywords
Cement paste, Low temperature calorimetry, PHREEQC, Ionic strength, Pore size distribution, Thermoporometry
National Category
Construction Management
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-48692 (URN)10.1016/j.tca.2014.05.027 (DOI)000340320400027 ()
Available from: 2016-01-12 Created: 2016-01-12 Last updated: 2017-11-30Bibliographically approved
Organisations

Search in DiVA

Show all publications