Change search
Link to record
Permanent link

Direct link
BETA
Habermehl-Cwirzen, KarinORCID iD iconorcid.org/0000-0001-7279-6528
Alternative names
Publications (10 of 35) Show all publications
Rajczakowska, M., Habermehl-Cwirzen, K., Hedlund, H. & Cwirzen, A. (2019). Autogenous Self-Healing: A Better Solution for Concrete. Journal of materials in civil engineering, 31(9), Article ID 3119001.
Open this publication in new window or tab >>Autogenous Self-Healing: A Better Solution for Concrete
2019 (English)In: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 31, no 9, article id 3119001Article in journal (Refereed) Published
Abstract [en]

Self-healing can be defined as the ability of a material to repair inner damage without any external intervention. In the case of concrete, the process can be autogenous, based on optimized mix composition, or autonomous, when using additionally incorporated capsules containing a healing agent and/or bacteria spores. The first process uses unhydrated cement particles as the healing material while the other utilizes a synthetic material or bacteria released into the crack from a broken capsule or activated through access of water and oxygen. The critical reviewing of both methods indicates that the autogenous self-healing is more efficient, more cost effective, safer, and easier to implement in full-scale applications. Nevertheless, a better understanding of the mechanism and factors affecting the effectiveness of the process is needed. The main weaknesses of the autonomous method were identified as loss of workability, worsened mechanical properties, low efficiency and low probability of the healing to occur, low survivability of the capsules and bacteria in harsh concrete environment, very high price, and lack of full-scale evaluation.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2019
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-75206 (URN)10.1061/(ASCE)MT.1943-5533.0002764 (DOI)000475694700023 ()2-s2.0-85067520596 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-07-03 (svasva)

Available from: 2019-07-03 Created: 2019-07-03 Last updated: 2019-10-28Bibliographically approved
Rajczakowska, M., Nilsson, L., Habermehl-Cwirzen, K., Hedlund, H. & Cwirzen, A. (2019). Does a High Amount of Unhydrated Portland Cement Ensure an Effective Autogenous Self-Healing of Mortar?. Materials, 12(20), Article ID 3298.
Open this publication in new window or tab >>Does a High Amount of Unhydrated Portland Cement Ensure an Effective Autogenous Self-Healing of Mortar?
Show others...
2019 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 20, article id 3298Article in journal (Refereed) Published
Abstract [en]

It is commonly accepted that the autogenous self-healing of concrete is mainly controlled by the hydration of Portland cement and its extent depends on the availability of anhydrous particles. High-performance (HPCs) and ultra-high performance concretes (UHPCs) incorporating very high amounts of cement and having a low water-to-cement ratio reach the hydration degree of only 70–50%. Consequently, the presence of a large amount of unhydrated cement should result in excellent autogenous self-healing. The main aim of this study was to examine whether this commonly accepted hypothesis was correct. The study included tests performed on UHPC and mortars with a low water-to-cement ratio and high cement content. Additionally, aging effects were verified on 12-month-old UHPC samples. Analysis was conducted on the crack surfaces and inside of the cracks. The results strongly indicated that the formation of a dense microstructure and rapidly hydrating, freshly exposed anhydrous cement particles could significantly limit or even hinder the self-healing process. The availability of anhydrous cement appeared not to guarantee development of a highly effective healing process.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
continued hydration, ultra-high performance concrete, cracking, microstructure, calcite
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-76510 (URN)10.3390/ma12203298 (DOI)
Note

Validerad;2019;Nivå 2;2019-10-28 (johcin)

Available from: 2019-10-25 Created: 2019-10-25 Last updated: 2019-11-20Bibliographically approved
Humad, A., Habermehl-Cwirzen, K. & Cwirzen, A. (2019). Effects of fineness and chemical composition of blast furnace slag on properties of alkali-activated binder. Materials, 12(20), Article ID 3447.
Open this publication in new window or tab >>Effects of fineness and chemical composition of blast furnace slag on properties of alkali-activated binder
2019 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 20, article id 3447Article in journal (Refereed) Published
Abstract [en]

Abstract: The effects of fines and chemical composition of three types of ground granulated blast furnace slag (GGBFS) on various concrete properties were studied. Those studied were alkali activated by liquid sodium silicate (SS) and sodium carbonate (SC). Flowability, setting times, compressive strength, efflorescence, and carbonation resistance and shrinkage were tested. The chemical composition and microstructure of the solidified matrixes were studied by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) coupled with EDX analyser. The results showed that the particle size distribution of the slags and the activator type had significantly stronger effects on all measured properties than their chemical composition. The highest compressive strength values were obtained for the finest slag, which having also the lowest MgO content. SC-activated mortar produced nearly the same compressive strength values independently of the used slag. The most intensive efflorescence and the lowest carbonation resistance developed on mortars based on slag containing 12% of MgO and the lowest fineness. The slag with the highest specific surface area and the lowest MgO content developed a homogenous microstructure, highest reaction temperature and lowest drying shrinkage. Thermogravimetric analysis indicated the presence of C-(A)-S-H, hydrotalcite HT, and carbonate like-phases in all studied mortars.

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI, 2019
Keywords
alkali-activated slag GBFS, strength, microstructure of AAS, hydration products, shrinkage
National Category
Engineering and Technology Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-76497 (URN)10.3390/ma12203447 (DOI)31640292 (PubMedID)2-s2.0-85074230932 (Scopus ID)
Funder
Luleå University of Technology, 143103
Note

Validerad;2019;Nivå 2;2019-10-28 (johcin)

Available from: 2019-10-24 Created: 2019-10-24 Last updated: 2019-11-20Bibliographically approved
Tole, I., Habermehl-Cwirzen, K. & Cwirzen, A. (2019). Mechanochemical activation of natural clay minerals: an alternative to produce sustainable cementitious binders – review. Mineralogy and Petrology, 113(4), 449-462
Open this publication in new window or tab >>Mechanochemical activation of natural clay minerals: an alternative to produce sustainable cementitious binders – review
2019 (English)In: Mineralogy and Petrology, ISSN 0930-0708, E-ISSN 1438-1168, Vol. 113, no 4, p. 449-462Article in journal (Refereed) Published
Abstract [en]

Mechanochemical activation can be defined as a process able to induce structural disorder through intensive grinding. In certain conditions, it may increase the chemical reactivity of the processed material. The process is extensively utilized in extractive metallurgy, synthesis of nanocomposites or pharmacology. It is also considered an environmentally friendly alternative to activate kaolinitic clay avoiding high calcination temperature. This paper aims to give a comprehensive overview of the process, its evolution, process parameters and applications. The paper focuses on the mechanochemical treatment of natural clay minerals, aiming at their transformation into cementitious or pozzolanic materials. It provides a summarized review of the theories related to the mechanochemistry and discusses commonly used models. The paper also analyzes various key factors and parameters controlling the mechanochemical activation process. The optimization and control of the several factors, as the filling ratio, the grinding media, the velocity, the time of grinding, etc., can promote developments and new research opportunities on different fields of application. Examples of applications, with a special focus on mechanochemically activated clay minerals and their use as cementitious binders, are listed as well.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Mechanochemistry, Grinding, Mechanochemical activation, Clay minerals, Kaolin
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-73879 (URN)10.1007/s00710-019-00666-y (DOI)000475666800002 ()2-s2.0-85065650673 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-07-12 (johcin)

Available from: 2019-05-08 Created: 2019-05-08 Last updated: 2019-08-16Bibliographically approved
Tole, I., Habermehl-Cwirzen, K. & Cwirzen, A. (2019). Mechanochemically activated clay as asustainable cementitious binder. In: : . Paper presented at 2nd International Conference on Sustainable Building Materials PROCEEDINGS ICSBM 2019 (pp. 73-79). , 3
Open this publication in new window or tab >>Mechanochemically activated clay as asustainable cementitious binder
2019 (English)Conference paper, Published paper (Refereed)
Abstract [en]

High-temperature requirements, emission of hazardous substances from cement kilns and the significantCO2 footprint in the calcination step are factors requiring special attention in the cement industry. Local andcommonly occurring clays can be a sustainable alternative for producing cementitious binders. Structuraldisorder in natural clay minerals can be induced through mechanochemical activation (MCA), by whichthe material develops an enhanced reactivity. The treatment of a Swedish natural clay through intensivegrinding is carried out in order to assess its potential as a sustainable cementitious binder. Several grindingparameters influence a MCA product. The filling ratio of the jar, the rotation speed, the time of grinding,as well as wet and dry environment, are variated to optimize the MCA process. The MCA process doesnot require high temperatures or added chemicals and shorter processing times can avoid high-energyrequirements during fine grinding. The structural changes of the clay were analysed by X-Ray Diffraction(XRD). Analysis of the particle size distribution of the raw and processed clay suggested a correlation withthe grinding duration. An increased ratio of grinding media versus the amount of ground material, whilelonger grinding duration increased the overall efficiency of the MCA process. The strength activity index(SAI) indicated an enhanced pozzolanic activity for the mechanochemically processed clay. Compressivestrength tests have shown a strong correlation between an enhanced amorphization rate and increasedcompressive strength values.

Keywords
alternative cementitious binders, mechanochemical activation, sustainable building materials, mechanochemistry, clay.
National Category
Engineering and Technology
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-76601 (URN)
Conference
2nd International Conference on Sustainable Building Materials PROCEEDINGS ICSBM 2019
Available from: 2019-11-04 Created: 2019-11-04 Last updated: 2019-11-04
Tole, I., Habermehl-Cwirzen, K. & Cwirzen, A. (2019). Optimization of the Process Parameters Controlling the Degree of Amorphization during Mechanical Activation of Clay Using the Taguchi Method. In: 1st International Conference on  Smart Materials for Sustainable Construction—SMASCO 2019, Luleå, Sweden, 10–12 December 2019: . Paper presented at Smart Materials for Sustainable Construction—SMASCO 2019. Proceedings, 34
Open this publication in new window or tab >>Optimization of the Process Parameters Controlling the Degree of Amorphization during Mechanical Activation of Clay Using the Taguchi Method
2019 (English)In: 1st International Conference on  Smart Materials for Sustainable Construction—SMASCO 2019, Luleå, Sweden, 10–12 December 2019, Proceedings, 2019, Vol. 34Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Mechanical activation in a planetary ball mill (BM) is an environmentally friendly process able to enhance the chemical and pozzolanic activity of natural clays. Those materials can be used as supplementary cementitious materials (SCMs) to partially replace Portland cement in concrete. The process parameters of the BM are directly related to the degree of amorphization and thus to the enhancement of the chemical activity. Design of experiments (DOE) is a well-known statistical tool, which can assist in selecting optimized conditions and in obtaining systematic data. However, full factorial design requires a large number of experiment. Taguchi method is based on the use of an Orthogonal Array (OA) to evaluate optimization of the selected factors but with less required experiments. In this study, three factors, each on 2 levels, were selected: ball to powder ratio (B/P) with level 3 and 25, time of grinding with level 5 and 20, and water to powder ratio (W/P) with level 0 and 1. The degree of amorphization (DOA) was selected as the main response for the Taguchi method. DOA was calculated as the ratio between the integral intensities of the main peak of the kaolinite [001] before and after grinding. For dry grinding, the predicted optimized value of DOA complied with the experimental results. Maximized DOA value was achieved for B/P equal to 25 and the grinding duration of 20. This method can be a valuable tool to predict the amorphization degree of minerals present in the natural clay, leading to the optimization of the mechanical activation process.

Place, publisher, year, edition, pages
Proceedings: , 2019
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ltu:diva-76737 (URN)
Conference
Smart Materials for Sustainable Construction—SMASCO 2019
Available from: 2019-11-18 Created: 2019-11-18 Last updated: 2019-11-27
Buasiri, T., Habermehl-Cwirzen, K., Krzeminski, L. & Cwirzen, A. (2019). Piezoresistive Load Sensing and Percolation Phenomena in Portland Cement Composite Modified with In-Situ Synthesized Carbon Nanofibers. Nanomaterials, 9(4), Article ID 594.
Open this publication in new window or tab >>Piezoresistive Load Sensing and Percolation Phenomena in Portland Cement Composite Modified with In-Situ Synthesized Carbon Nanofibers
2019 (English)In: Nanomaterials, ISSN 2079-4991, Vol. 9, no 4, article id 594Article in journal (Refereed) Published
Abstract [en]

Carbon nanofibers (CNFs) were directly synthesized on Portland cement particles by chemical vapor deposition. The so-produced cements contained between 2.51–2.71 wt% of CNFs; depending on the production batch. Several mortar mixes containing between 0 and 10 wt% of the modified cement were produced and the electrical properties at various ages and the load sensing capabilities determined. The percolation threshold related to the electrical conductivity was detected and corresponded to the amount of the present CNFs, 0.271, 0.189, 0.135 and 0.108 wt%. The observed threshold depended on the degree of hydration of the Portland cement. The studied mortars showed a strong piezoresistive response to the applied compressive load reaching a 17% change of the electrical resistivity at an applied load of 3.5 MPa and 90% at 26 MPa. This initial study showed that the studied material is potentially suitable for future development of novel fully integrated monitoring systems for concrete structures.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
Carbon nanofibers, CVD, percolation, piezoresistive response, compressive load
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-73574 (URN)10.3390/nano9040594 (DOI)000467768800110 ()30974888 (PubMedID)2-s2.0-85065309577 (Scopus ID)
Funder
Vinnova, 2016-03285Swedish Transport Administration, TRV2017/57560
Note

Validerad;2019;Nivå 2;2019-04-15 (oliekm)

Available from: 2019-04-11 Created: 2019-04-11 Last updated: 2019-08-23Bibliographically approved
Buasiri, T., Habermehl-Cwirzen, K. & Cwirzen, A. (2019). State of the Art on Sensing Capability of Poorly or Nonconductive Matrixes with a Special Focus on Portland Cement–Based Materials. Journal of materials in civil engineering, 31(11)
Open this publication in new window or tab >>State of the Art on Sensing Capability of Poorly or Nonconductive Matrixes with a Special Focus on Portland Cement–Based Materials
2019 (English)In: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 31, no 11Article in journal (Refereed) Published
Abstract [en]

Concrete is a well-established and the most used but also well-characterized building material in the world. However, many old and new-build structures suffer from premature failures due to extensive deterioration and decreased load-bearing capacity. Consequently, structural monitoring systems are essential to ensure safe usage of concrete structures within and beyond the designed life. Traditional monitoring systems are based on metallic sensors installed in crucial locations throughout the structure. Unfortunately, most of them have a relatively low reliability and very short life span when exposed to often very harsh environments. The ideal solution is therefore to develop a smart concrete having itself self-sensing capability. A number of studies show that conductive cementitious matrixes will undergo changes in their electrical resistivity with variations of stresses, strains or, developing microcracking. This can be used as a reliable tool to measure changes. This review provides a comprehensive overview of several non-conductive matrixes, with special focus on Portland cement based materials showing self-sensing capabilities by description of detection mechanisms, sensing capabilities, limitations and potential applications.  

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2019
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-75725 (URN)10.1061/(ASCE)MT.1943-5533.0002901 (DOI)000486184800009 ()
Note

Validerad;2019;Nivå 2;2019-08-28 (johcin)

Available from: 2019-08-28 Created: 2019-08-28 Last updated: 2019-10-04Bibliographically approved
Rajczakowska, M., Habermehl-Cwirzen, K., Hedlund, H. & Cwirzen, A. (2019). The effect of exposure on the autogenous self-healing of Ordinary Portland cement mortars. Materials, 12(23), Article ID 3926.
Open this publication in new window or tab >>The effect of exposure on the autogenous self-healing of Ordinary Portland cement mortars
2019 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 23, article id 3926Article in journal (Refereed) Published
Abstract [en]

Exposure conditions are critical for the autogenous self-healing process of Portland cement based binder matrixes. However, there is still a significant lack of fundamental knowledge related to this factor. The aim of this paper was to investigate and understand the effects of various potentially applicable curing solutions on the efficiency of the crack closure occurring both superficially and internally. Four groups of exposures were tested, including exposure with different water immersion regimes, variable temperatures, application of chemical admixtures, and use of solutions containing micro particles. The self-healing process was evaluated externally, at the surface of the crack, and internally, at different crack depths with the use of optical and scanning electron microscopes (SEM). The phase identification was done with an energy dispersive spectrometer combined with the SEM. The results showed very limited self-healing in all pure water-based exposures, despite the application of different cycles, temperatures, and water volumes. The addition of a phosphate-based retarding admixture demonstrated the highest crack closure, both internally and externally. The highest strength recovery and a very good crack closure ratio was achieved in water exposure containing micro silica particles. The main phase observed on the surface was calcium carbonate, and internally, calcium silicate hydrate, calcium carbonate, and calcium phosphate compounds. Phosphate ions were found to contribute to the filling of the crack, most likely by preventing the formation of a dense shell composed of hydration phases on the exposed areas by crack unhydrated cement grains as well as by the additional precipitation of calcium and phosphate-based compounds. The micro sized silica particles presumably served as nucleation sites for the self-healing products growth. Changes in the chemical composition of the self-healing material were observed with a distance from the surface of the specimen.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
autogenous self-healing, cementitious materials, cracking, exposure, microstructure, calcium phosphate
National Category
Infrastructure Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-76526 (URN)10.3390/ma12233926 (DOI)31783574 (PubMedID)
Note

Validerad;2019;Nivå 2;2019-12-09 (johcin)

Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2019-12-09Bibliographically approved
Tole, I., Habermehl-Cwirzen, K., Rajczakowska, M. & Cwirzen, A. (2018). Activation of a Raw Clay by Mechanochemical Process: Effects of Various Parameters on the Process Efficiency and Cementitious Properties. Materials, 11(10), Article ID 1860.
Open this publication in new window or tab >>Activation of a Raw Clay by Mechanochemical Process: Effects of Various Parameters on the Process Efficiency and Cementitious Properties
2018 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 11, no 10, article id 1860Article in journal (Refereed) Published
Abstract [en]

The efficiency of the mechanochemical activation (MCA) is influenced by various process parameters as well as by the properties of the treated material. The main objective of this research was to optimize the MCA process, gaining enhancement of the chemical reactivity of a Swedish raw clay, which is going to be used as an alkali-activated cementitious binder. The effects of the amount of water, the filling ratio, the rotation speed, and the grinding duration on the amorphization degree were evaluated by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Generally, wet and dry processes showed an extensive amorphization of both kaolinite and muscovite minerals present in the studied clay. On the contrary, quartz was amorphized mainly by the wet grinding process. The efficiency of both dry and wet grinding processes was enhanced by the increased number of grinding media versus the amount of the activated material. However, longer processing times caused significant agglomeration while a higher rotational speed enhanced the amorphization. Preliminary tests have shown that alkali activation of the processed clays produced hardened samples. Furthermore, the increased amorphization corresponded to the increased compressive strength values.

Place, publisher, year, edition, pages
MDPI, 2018
Keywords
clay minerals, dry grinding, fine grinding, mechanochemical activation, mechanochemistry, wet grinding
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-71035 (URN)10.3390/ma11101860 (DOI)30274273 (PubMedID)2-s2.0-85054276282 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-10-03 (marisr)

Available from: 2018-09-30 Created: 2018-09-30 Last updated: 2019-04-02Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7279-6528

Search in DiVA

Show all publications