Microstructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures

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 (calc...

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Autores principales:	Jan Pizoń, Beata Łaźniewska-Piekarczyk
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	cement accelerating admixtures concrete microstructure SEM Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85
Acceso en línea:	https://doaj.org/article/1aa3f45de1bf4814b20d16ab0b5cc34c
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spelling	oai:doaj.org-article:1aa3f45de1bf4814b20d16ab0b5cc34c2021-11-11T17:52:19ZMicrostructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures10.3390/ma142163001996-1944https://doaj.org/article/1aa3f45de1bf4814b20d16ab0b5cc34c2021-10-01T00:00:00Zhttps://www.mdpi.com/1996-1944/14/21/6300https://doaj.org/toc/1996-1944The 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.Jan PizońBeata Łaźniewska-PiekarczykMDPI AGarticlecementaccelerating admixturesconcretemicrostructureSEMTechnologyTElectrical engineering. Electronics. Nuclear engineeringTK1-9971Engineering (General). Civil engineering (General)TA1-2040MicroscopyQH201-278.5Descriptive and experimental mechanicsQC120-168.85ENMaterials, Vol 14, Iss 6300, p 6300 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	cement accelerating admixtures concrete microstructure SEM Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85
spellingShingle	cement accelerating admixtures concrete microstructure SEM Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85 Jan Pizoń Beata Łaźniewska-Piekarczyk Microstructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures
description	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.
format	article
author	Jan Pizoń Beata Łaźniewska-Piekarczyk
author_facet	Jan Pizoń Beata Łaźniewska-Piekarczyk
author_sort	Jan Pizoń
title	Microstructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures
title_short	Microstructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures
title_full	Microstructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures
title_fullStr	Microstructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures
title_full_unstemmed	Microstructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures
title_sort	microstructure of cem ii/b-s pastes modified with set accelerating admixtures
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/1aa3f45de1bf4814b20d16ab0b5cc34c
work_keys_str_mv	AT janpizon microstructureofcemiibspastesmodifiedwithsetacceleratingadmixtures AT beatałazniewskapiekarczyk microstructureofcemiibspastesmodifiedwithsetacceleratingadmixtures
_version_	1718431988373782528

Microstructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures

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