Microstructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures
| Autor: | Jan Pizoń, Beata Łaźniewska-Piekarczyk |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
cement
Technology Materials science Aluminate microstructure Clinker (cement) Article chemistry.chemical_compound Hydration reaction General Materials Science accelerating admixtures Cement Microscopy QC120-168.85 QH201-278.5 Slag Engineering (General). Civil engineering (General) Cement kiln TK1-9971 Compressive strength chemistry Chemical engineering Descriptive and experimental mechanics visual_art Calcium silicate SEM visual_art.visual_art_medium concrete Electrical engineering. Electronics. Nuclear engineering TA1-2040 |
| Zdroj: | Materials, Vol 14, Iss 6300, p 6300 (2021) Materials Volume 14 Issue 21 |
| ISSN: | 1996-1944 |
| Popis: | The presented paper aims to describe the influence of accelerating admixtures on the properties and microstructure of cement pastes and mortars. Blended slag cement CEM II/B-S containing two different clinkers (differing amounts of siliceous and aluminous phases) and four types of accelerators (calcium nitrate, sodium hydroxide, cement kiln dust, and crystal seeds) were used in research. Compressive strength tests (after 12, 24, 48 h of curing), Scanning Electron Microscope (SEM) observations together with an Energy Dispersive Spectroscopy (EDS) analysis, Mercury Intrusion Porosimetry (MIP) tests, and X-ray diffraction (XRD) analysis were conducted. Results have shown that SEM and EDS examination of the microstructure of cement pastes modified with accelerating admixtures at the observed points did not reveal differences that would be sufficient to explain the changes in compressive strength. Still, the increase in amorphous phase content indicates a faster hydration reaction rate for all pastes modified with accelerating admixture. It is backed up also by lower non-hydrated compounds content. All admixtures accelerate the hydration reaction of calcium silicate phases of cement, but only NaOH and cement kiln dust (CKD) influence the aluminate phase reaction rate. The pore volume is independent of the clinker type, while the pore size distribution is not. |
| Databáze: | OpenAIRE |
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