Change search
Link to record
Permanent link

Direct link
Habermehl-Cwirzen, KarinORCID iD iconorcid.org/0000-0001-7279-6528
Alternative names
Publications (10 of 53) Show all publications
Buasiri, T., Kothari, A., Habermehl-Cwirzen, K., Krzeminski, L. & Cwirzen, A. (2024). Monitoring temperature and hydration by mortar sensors made of nanomodified Portland cement. Materials and Structures, 57, Article ID 1.
Open this publication in new window or tab >>Monitoring temperature and hydration by mortar sensors made of nanomodified Portland cement
Show others...
2024 (English)In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 57, article id 1Article in journal (Refereed) Published
Abstract [en]

Mortar beams incorporating carbon nanofibers (CNFs), which were synthesized in situ on Portland cement particles, were used to produce nanomodified Portland cement sensors (SmartCem sensors). SmartCem sensors exhibited an electrical response comparable to a thermistor with a temperature coefficient of resistivity of − 0.0152/ °C. The highest temperature sensing was obtained for the SmartCem sensor, which contained ~ 0.271 wt.% of CNFs. The calculated temperature sensitivity was approximately 11.76% higher in comparison with the mortar beam containing only unmodified Portland cement. SmartCem sensors were used to monitor the cement hydration in large-scale self-compacting concrete beams. The measurements were conducted after casting for 7 days. Additionally, commercially available thermocouple and humidity sensors were used as references. The results showed that changes in electrical resistivity measured by the SmartCem sensor were well aligned with the ongoing hydration processes.

Place, publisher, year, edition, pages
Springer Nature, 2024
Keywords
Nanomodified Portland cement, Carbon nanofibers, CNFs, Temperature sensing, Temperature sensitivity, Temperature sensor, Hydration temperature, Hydration monitoring, Cement-based sensor
National Category
Building Technologies Composite Science and Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-97278 (URN)10.1617/s11527-023-02275-w (DOI)
Funder
VinnovaSwedish Transport AdministrationSvenska Byggbranschens Utvecklingsfond (SBUF)
Note

Validerad;2023;Nivå 2;2023-12-04 (joosat);

Full text license: CC BY

This article has previously appeared as a manuscript in a thesis.

Available from: 2023-05-23 Created: 2023-05-23 Last updated: 2023-12-04Bibliographically approved
Rajczakowska, M., Tole, I., Hedlund, H., Habermehl-Cwirzen, K. & Cwirzen, A. (2023). Autogenous self-healing of low embodied energy cementitious materials: Effect of multi-component binder and crack geometry. Construction and Building Materials, 376, Article ID 130994.
Open this publication in new window or tab >>Autogenous self-healing of low embodied energy cementitious materials: Effect of multi-component binder and crack geometry
Show others...
2023 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 376, article id 130994Article in journal (Refereed) Published
Abstract [en]

Concrete's ability to auto-repair the cracks reduces the need for maintenance and repair. Autogenous self-healing is an intrinsic property of concrete highly dependent on the binder composition. The urgent necessity to decrease CO2 emissions of concrete by replacing cement with “greener” materials provides challenges and opportunities for self-healing cementitious materials. This research aims to verify the self-healing behavior of environmentally friendly multi-component binders. An experimental study is conducted to test the effect of binder composition-related parameters (e.g., phase composition, porosity) and crack geometry on the self-healing efficiency of the “green” mortars. Cementitious materials with 50 wt.%cement replacement with limestone powder blended with fly ash, blast furnace slag, and silica fume are investigated. Sorptivity change, compressive strength regains, and crack closure after self-healing are used to quantify the self-healing efficiency. Quantitative analysis and correlations between chemical composition/microstructural features, geometrical crack characteristics, and self-healing measures are investigated. The results indicate that “green” binder composition affects the self-healing mechanism leading to different levels of performance recovery. Some SCMs-limestone binder formulations enable a better self-healing efficiency than pure OPC or OPC/limestone cementitious materials, presumably due to a synergistic effect between the limestone and the mineral additions. Correlation analysis indicated that geometrical complexity characterized by fractal dimension and tortuosity of the crack does not affect the external crack closure, whereas the fractal dimension and maximum crack width are correlated with the internal crack healing.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Cracking, Microstructure, Mortar, Autogenous self-healing, Low embodied energy, Fractal dimension
National Category
Other Civil Engineering Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-94753 (URN)10.1016/j.conbuildmat.2023.130994 (DOI)2-s2.0-85150247385 (Scopus ID)
Funder
Swedish Transport AdministrationSvenska Byggbranschens Utvecklingsfond (SBUF)
Note

Validerad;2023;Nivå 2;2023-04-12 (hanlid);

Funder: Skanska AB, Sweden;

This article has previously appeared as a manuscript in a thesis

Available from: 2022-12-06 Created: 2022-12-06 Last updated: 2023-05-08Bibliographically approved
Rajczakowska, M., Szeląg, M., Habermehl-Cwirzen, K., Hedlund, H. & Cwirzen, A. (2023). Autogenous self-healing of thermally damaged cement paste with carbon nanomaterials subjected to different environmental stimulators. Journal of Building Engineering, 72, Article ID 106619.
Open this publication in new window or tab >>Autogenous self-healing of thermally damaged cement paste with carbon nanomaterials subjected to different environmental stimulators
Show others...
2023 (English)In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 72, article id 106619Article in journal (Refereed) Published
Abstract [en]

Autogenous self-healing of post-fire damaged concrete enables structure performance auto-recovery leading to reduced repair costs, less generated waste, and lower CO2 emissions. In this paper, to improve the efficiency of this process and understand the underlying mechanism, the self-healing of 0.1 wt% MWCNT-modified and pure cement paste subjected to novel environmental stimulators was tested. High-temperature damage was induced at 200 °C and 400 °C, followed by a self-healing cyclic treatment with water, a mixture of water with phosphate-based retarding admixture, and limewater. The self-healing efficiency of the proposed solutions were compared based on crack closure, strength regains, porosity, and chemical composition changes. The surface crack closure after 200 °C varied between 33% and 60%, whereas for 400 °C, only retarding admixture exposure obtained over 50% crack closure and the most considerable decrease in average crack width of 33% for MWCNT-modified paste. The highest values of compressive strength recovery, equal to 18% and 14%, exceeding the intact specimen's compressive strength, were observed for the MWCNT-modified paste healed in water and limewater. Water exposure with an extended wetting phase enhanced the compressive strength recovery of the MWCNT-modified materials. Strong (r = 0.87) and moderate (r = 0.52) positive correlations were observed between temperature loading and compressive and flexural strength recovery parameters, respectively. Higher porosity and interconnected crack network, caused by high temperature, facilitated the self-healing process. Porosity changes before and after healing were pronounced in contrast to the amount of unhydrated cement, which did not exhibit noticeable changes. The healing mechanism included three processes: calcite formation, further hydration inside the cracks, and rehydration of the bulk cement paste.Previous article in issue

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Compressive strength, Concrete repair, Multi-wall carbon nanotubes (MWCNT), Post-fire recovery, Re-curing, Sustainable structures
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-97064 (URN)10.1016/j.jobe.2023.106619 (DOI)2-s2.0-85154535482 (Scopus ID)
Funder
Swedish Transport AdministrationSvenska Byggbranschens Utvecklingsfond (SBUF)
Note

Validerad;2023;Nivå 2;2023-05-10 (joosat);

Licens fulltext: CC BY License

Available from: 2023-05-10 Created: 2023-05-10 Last updated: 2023-05-10Bibliographically approved
Rajczakowska, M., Szeląg, M., Habermehl-Cwirzen, K., Hedlund, H. & Cwirzen, A. (2023). Interpretable Machine Learning for Prediction of Post-Fire Self-Healing of Concrete. Materials, 16(3), Article ID 1273.
Open this publication in new window or tab >>Interpretable Machine Learning for Prediction of Post-Fire Self-Healing of Concrete
Show others...
2023 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 16, no 3, article id 1273Article in journal (Refereed) Published
Abstract [en]

Developing accurate and interpretable models to forecast concrete’s self-healing behavior is of interest to material engineers, scientists, and civil engineering contractors. Machine learning (ML) and artificial intelligence are powerful tools that allow constructing high-precision predictions, yet often considered “black box” methods due to their complexity. Those approaches are commonly used for the modeling of mechanical properties of concrete with exceptional accuracy; however, there are few studies dealing with the application of ML for the self-healing of cementitious materials. This paper proposes a pioneering study on the utilization of ML for predicting post-fire self-healing of concrete. A large database is constructed based on the literature studies. Twelve input variables are analyzed: w/c, age of concrete, amount of cement, fine aggregate, coarse aggregate, peak loading temperature, duration of peak loading temperature, cooling regime, duration of cooling, curing regime, duration of curing, and specimen volume. The output of the model is the compressive strength recovery, being one of the self-healing efficiency indicators. Four ML methods are optimized and compared based on their performance error: Support Vector Machines (SVM), Regression Trees (RT), Artificial Neural Networks (ANN), and Ensemble of Regression Trees (ET). Monte Carlo analysis is conducted to verify the stability of the selected model. All ML approaches demonstrate satisfying precision, twice as good as linear regression. The ET model is found to be the most optimal with the highest prediction accuracy and sufficient robustness. Model interpretation is performed using Partial Dependence Plots and Individual Conditional Expectation Plots. Temperature, curing regime, and amounts of aggregates are identified as the most significant predictors.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
autogenous self-healing, cementitious materials, high temperature, artificial neural network, ensemble methods, mechanical properties, artificial intelligence
National Category
Other Civil Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-94752 (URN)10.3390/ma16031273 (DOI)2-s2.0-85147941374 (Scopus ID)
Funder
Swedish Transport AdministrationSvenska Byggbranschens Utvecklingsfond (SBUF)
Note

Validerad;2023;Nivå 2;2023-03-01 (joosat);

Funder: Skanska AB

Licens fulltext: CC BY License

This article has previously appeared as a manuscript in a thesis.

Available from: 2022-12-06 Created: 2022-12-06 Last updated: 2023-05-08Bibliographically approved
Teker Ercan, E. E., Cwirzen, A. & Habermehl-Cwirzen, K. (2023). The Effects of Partial Replacement of Ground Granulated Blast Furnace Slag by Ground Wood Ash on Alkali-Activated Binder Systems. Materials, 16(15), Article ID 5347.
Open this publication in new window or tab >>The Effects of Partial Replacement of Ground Granulated Blast Furnace Slag by Ground Wood Ash on Alkali-Activated Binder Systems
2023 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 16, no 15, article id 5347Article in journal (Refereed) Published
Abstract [en]

Cement production contributes significantly to carbon dioxide emissions. Alkali-activated materials offer an environmentally friendly alternative due to their comparable strength, durability and low-carbon emissions while utilizing wastes and industrial by-products. Wood ash is a waste material that shows promising results as a partial replacement for Portland cement and precursors in alkali-activated systems. The aim of this study was to examine the effect of ground wood ash on the mechanical properties of alkali-activated mortars. Wood ash was incorporated as a 0 wt%, 10 wt% and 20 wt% partial replacement for ground granulated blast furnace slag (GGBFS). The wood ashes were ground in a planetary ball mill for 10 and 20 min. Sodium silicate (Na2SiO3), sodium carbonate (Na2CO3), and sodium hydroxide (NaOH) were used as alkali activators. The results demonstrated that ground wood ash improved the mechanical properties of alkali-activated systems compared to untreated wood ash. However, the incorporation of wood ash increased the porosity of the binder matrix.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
wood ash, wood fly ash, ground granulated blast furnace slag, alkali-activated, mortar, ball mill, grinding, isothermal calorimetry
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-100666 (URN)10.3390/ma16155347 (DOI)2-s2.0-85167820806 (Scopus ID)
Funder
Svenska Byggbranschens Utvecklingsfond (SBUF)Luleå University of Technology
Note

Validerad;2023;Nivå 2;2023-08-21 (hanlid);

Funder: Skanska

Available from: 2023-08-21 Created: 2023-08-21 Last updated: 2023-10-11Bibliographically approved
Teker Ercan, E. E., Andreas, L., Cwirzen, A. & Habermehl-Cwirzen, K. (2023). Wood Ash as Sustainable Alternative Raw Material for the Production of Concrete—A Review. Materials, 16(7), Article ID 2557.
Open this publication in new window or tab >>Wood Ash as Sustainable Alternative Raw Material for the Production of Concrete—A Review
2023 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 16, no 7, article id 2557Article in journal (Refereed) Published
Abstract [en]

Different ecological binders have been used to minimize the negative effects of cement production and use on the environment. Wood ash is one of these alternative binders, and there has been increasing research related to this topic recently. The wood ash utilized in the literature primarily originates from power plants and local bakeries, and predominantly wood fly ash is used. This review paper examines the use of wood ash as an ecological binder in two different applications: as a cement replacement and as an alkali-activated material. Studies have shown that while increased wood ash content in concrete and mortars can have negative effects on strength and durability, it is still a promising and developable material. Depending on the chemical composition of the wood ash, the strength and durability properties of concrete might be slightly improved by utilizing wood ash as a replacement for cement, with an optimal replacement level of 10–20%. However, there is a need for more research regarding the effects of wood ash on the durability of cement-based materials and its use in alkali-activated materials. Overall, this review provides a comprehensive overview of the properties of wood ash and its potential applications in conventional concrete and mortars, as well as in alkali-activated materials.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
wood ash, wood fly ash, forest waste, cement replacement, geopolymer, alkali-activated, concrete, mortar, supplementary cementitious materials (SCMs), ecological
National Category
Other Materials Engineering
Research subject
Building Materials; Waste Science and Technology
Identifiers
urn:nbn:se:ltu:diva-96266 (URN)10.3390/ma16072557 (DOI)
Funder
Svenska Byggbranschens Utvecklingsfond (SBUF)
Note

Validerad;2023;Nivå 2;2023-03-30 (johcin);

Funding: Skanska; LTU Creaternity

Available from: 2023-03-30 Created: 2023-03-30 Last updated: 2023-03-30Bibliographically approved
Tole, I., Delogu, F., Qoku, E., Habermehl-Cwirzen, K. & Cwirzen, A. (2022). Enhancement of the pozzolanic activity of natural clays by mechanochemical activation. Construction and Building Materials, 352, Article ID 128739.
Open this publication in new window or tab >>Enhancement of the pozzolanic activity of natural clays by mechanochemical activation
Show others...
2022 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 352, article id 128739Article in journal (Refereed) Published
Abstract [en]

Replacement of cement with supplementary cementitious materials (SCMs) is a proven method to reduce clinker in cement and contribute to decreased CO2 emissions. Natural clays are commonly occurring materials that do not possess pozzolanic activity in their original state. Mechanochemical activation (MCA) can be an alternative and sustainable method to enhance their reactivity. In this study, the pozzolanic reactivity of three natural clays, originating from Sweden, was analyzed after the application of MCA in a planetary ball mill. Strength activity index (SAI), Frattini test, and conductivity test were used to evaluate the pozzolanic reactivity. All processed clays by MCA have achieved a SAI greater than 100%, while the Frattini test indicated an improved pozzolanic activity of samples containing a higher amount of clay minerals. The obtained results show that MCA could improve the pozzolanic reactivity, but the effect depends on the mineralogical composition and particle size of the clays.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Grinding, Blended Cement, Pozzolan, SCMs, Clays
National Category
Other Civil Engineering Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-90356 (URN)10.1016/j.conbuildmat.2022.128739 (DOI)2-s2.0-85137668310 (Scopus ID)
Funder
Swedish Research Council Formas
Note

Validerad;2022;Nivå 2;2022-09-28 (hanlid)

Available from: 2022-04-21 Created: 2022-04-21 Last updated: 2022-09-28Bibliographically approved
Rajczakowska, M., Szelag, M., Habermehl-Cwirzen, K., Hedlund, H. & Cwirzen, A. (2022). Is Cement Paste Modified with Carbon Nanomaterials Capable of Self-Repair after a Fire?. Nordic Concrete Research, 67(2), 79-97
Open this publication in new window or tab >>Is Cement Paste Modified with Carbon Nanomaterials Capable of Self-Repair after a Fire?
Show others...
2022 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 67, no 2, p. 79-97Article in journal (Refereed) Published
Abstract [en]

This manuscript presents preliminary results on the cement paste potential, with and without carbon nanomaterials, to heal high-temperature cracks. Cement paste beams were subjected to thermal loading of 200 & DEG;C and 400 & DEG;C after 28 days of water curing. High temperature caused the formation of microcrack networks on the specimen's surface. Self-healing was achieved by exposing the cracked samples to cyclic water immersion. The efficiency of the process was evaluated based on the crack closure and mechanical properties recovery after 24 days. The results indicated a distinct dependence of the healing on the loading temperature. Carbon nanotubes had a positive effect on self-repair efficiency.

Place, publisher, year, edition, pages
Walter de Gruyter, 2022
Keywords
self-healing, cement paste, nanomaterials, Multi-Wall Carbon Nanotubes, high temperature, microcracking, image analysis
National Category
Infrastructure Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-95679 (URN)10.2478/ncr-2022-0017 (DOI)000915577200006 ()
Funder
Swedish Transport AdministrationSvenska Byggbranschens Utvecklingsfond (SBUF)
Note

Validerad;2023;Nivå 2;2023-02-22 (hanlid);

Funder: Skanska AB

Available from: 2023-02-22 Created: 2023-02-22 Last updated: 2023-02-22Bibliographically approved
Humad, A. M., Provis, J. L., Habermehl-Cwirzen, K., Rajczakowska, M. & Cwirzen, A. (2021). Creep and Long-Term Properties of Alkali-Activated Swedish-Slag Concrete. Journal of materials in civil engineering, 33(2), Article ID 04020475.
Open this publication in new window or tab >>Creep and Long-Term Properties of Alkali-Activated Swedish-Slag Concrete
Show others...
2021 (English)In: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 33, no 2, article id 04020475Article in journal (Refereed) Published
Abstract [en]

The construction of the future is moving in the direction of environmentally friendly materials and the use of various types of industrial byproducts and wastes. The use of blast furnace slag (BFS) for the production of concrete is one of those alternatives. In this study, pastes and concretes based on high-MgO BFS were alkali activated with 10% by weight sodium carbonate, sodium silicate, and a combination of both. Heat treatment and laboratory curing were applied. The results showed that heat treatment was effective at reducing the drying shrinkage of alkali-activated slag concretes and promoting high early strength. However, the sodium carbonate–activated slag concrete specimens showed a reduction in compressive strength at later ages. All concrete specimens tested exhibited high drying shrinkage; the highest values were for sodium silicate–activated concretes and the lowest were for sodium carbonate–activated concretes. All concretes tested showed very large creep, which was partly related to the small maximum aggregate size (8 mm) and the effects of carbonation. The carbonation depth after 12–24 months was significantly smaller for the heat-treated specimens and for concrete activated with sodium silicate. The carbonation process resulted in a more porous binder matrix, leading to long-term strength loss and increased creep, especially for sodium silicate–activated mixes.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2021
Keywords
Alkali-activated slag (AAS) concrete, Shrinkage, Creep of AAS, High-MgO slag, Carbonation
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-81879 (URN)10.1061/(ASCE)MT.1943-5533.0003381 (DOI)000634783300039 ()2-s2.0-85097339464 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-12-07 (alebob)

Available from: 2020-12-07 Created: 2020-12-07 Last updated: 2021-04-19Bibliographically approved
Buasiri, T., Habermehl-Cwirzen, K., Krzeminski, L. & Cwirzen, A. (2021). Novel humidity sensors based on nanomodified Portland cement. Scientific Reports, 11, Article ID 8189.
Open this publication in new window or tab >>Novel humidity sensors based on nanomodified Portland cement
2021 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, article id 8189Article in journal (Refereed) Published
Abstract [en]

Commonly used humidity sensors are based on metal oxides, polymers or carbon. Their sensing accuracy often deteriorates with time, especially when exposed to higher temperatures or very high humidity. An alternative solution based on the utilization of Portland cement-based mortars containing in-situ grown carbon nanofibers (CNFs) was evaluated in this study. The relationship between the electrical resistivity, CNF content and humidity were determined. The highest sensitivity was observed for samples containing 10 wt.% of the nanomodified cement which corresponded to 0.27 wt.% of CNFs. The highest calculated sensitivity was approximately 0.01024 per 1% change in relative humidity (RH). The measured electrical resistivity is a linear function of the RH in the humidity range between 11% and 97%. The percolation threshold value was estimated to be at around 7 wt.% of the nanomodified cement, corresponding to ~0.19 wt.% of CNFs.

Place, publisher, year, edition, pages
Springer Nature, 2021
Keywords
Nanomodified cement, Carbon nanofibers, CNFs, Humidity curing, Humidity sensing, Humidity sensitivity
National Category
Infrastructure Engineering Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-83648 (URN)10.1038/s41598-021-87563-7 (DOI)000640601800023 ()33854122 (PubMedID)2-s2.0-85104479999 (Scopus ID)
Funder
VinnovaSwedish Transport Administration
Note

Validerad;2021;Nivå 2;2021-04-19 (alebob)

Available from: 2021-04-14 Created: 2021-04-14 Last updated: 2023-05-23Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7279-6528

Search in DiVA

Show all publications