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K.O. Kjellsen

Bio: K.O. Kjellsen is an academic researcher from Norwegian University of Science and Technology. The author has contributed to research in topics: Fly ash & Ettringite. The author has an hindex of 4, co-authored 4 publications receiving 936 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the effect of minor additions of limestone powder on the properties of fly ash blended cements was investigated using isothermal calorimetry, thermogravimetry (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) techniques, and pore solution analysis.

849 citations

Journal ArticleDOI
TL;DR: In this article, the interaction between limestone powder and fly ash in ternary composite cement is investigated, and the synergistic effect of fly ash and limestone powder is confirmed and it translates to improved mechanical properties that persist over time.
Abstract: The interaction between limestone powder and fly ash in ternary composite cement is investigated. Limestone powder interacts with the AFm and AFt hydration phases, leading to the formation of carboaluminates at the expense of monosulphate and thereby stabilizing the ettringite. The effect of limestone powder on OPC may be restricted due to the limited amount of aluminate hydrates formed by the hydration of OPC. The additional aluminates brought into the system by fly ash during its pozzolanic reaction amplify the mentioned effect of limestone powder. This synergistic effect between limestone powder and fly ash in ternary cements is confirmed in this study and it translates to improved mechanical properties that persist over time.

345 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of the curing temperature (5, 20 and 40°C) on the degree of hydration, amount of bound water and calcium hydroxide, porosity and the development of mechanical properties was investigated on pastes and mortars prepared with fly ash (FA) and limestone (L) Portland composite cements.
Abstract: The effect of the curing temperature (5, 20 and 40°C) on the degree of hydration, amount of bound water and calcium hydroxide, porosity and the development of mechanical properties was investigated on pastes and mortars prepared with fly ash (FA)–limestone (L) Portland composite cements. Increasing the curing temperature for ordinary Portland cement (OPC) leads to a more inhomogeneous distribution of hydration products, resulting in an increased coarse porosity and therefore a lower compressive strength after 7 days and longer. In contrast, the FA containing mortars showed higher compressive strength with increasing curing temperature up to 90 days. The reaction of the FA is increased at 40°C and strongly retarded at 5°C. At 20 and 40°C, FA reduces the porosity at later ages. The replacement of 5% of the OPC or FA by L powder did not impair the strength at 5 and 20°C, but lowered strength slightly at 40°C for the FA blended cements. The porosity appears to be the dominating factor regarding the compressive strength, independent of whether part of the OPC is replaced by FA and L powder or not.

68 citations

Journal ArticleDOI
TL;DR: SEM examinations of freshly-mixed and early-age mortars reveal complex features that appear to influence subsequent development of the hardened state microstructure as discussed by the authors, such as layers of entirely water-filled space a few micrometers thick adjacent to many of the sand grain surfaces.

10 citations


Cited by
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Journal ArticleDOI
TL;DR: The use of silica-rich SCMs influences the amount and kind of hydrates formed and thus the volume, the porosity and finally the durability of these materials.

1,920 citations

Journal ArticleDOI
TL;DR: In this article, the effect of minor additions of limestone powder on the properties of fly ash blended cements was investigated using isothermal calorimetry, thermogravimetry (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) techniques, and pore solution analysis.

849 citations

Journal ArticleDOI
TL;DR: In this paper, the coupled substitution of metakaolin and limestone in Portland cement (PC) was investigated and the mechanical properties were studied in mortars and the microstructural development in pastes by X-ray diffraction, thermogravimetry analysis, mercury intrusion porosimetry and isothermal calorimetry.

763 citations

Journal ArticleDOI
TL;DR: A review of the advances in knowledge provided by research in these areas can be found in this paper, emphasizing the impact of the research on the field and emphasizing the benefits of these advances.

614 citations

Journal ArticleDOI
TL;DR: The Cemdata18 database as mentioned in this paper contains thermodynamic data for common cement hydrates such as C-S-H, AFm and AFt phases, hydrogarnet, hydrotalcite, zeolites, and M-S -H that are valid over temperatures ranging from 0 to at least 100°C.

526 citations