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Enhanced Metakaolin Reactivity in Blended Cement with Additional Calcium Hydroxide
- Source :
- Materials, Materials; Volume 15; Issue 1; Pages: 367, Materials, Vol 15, Iss 367, p 367 (2022)
- Publication Year :
- 2022
- Publisher :
- MDPI, 2022.
-
Abstract
- This study aims to increase the pozzolanic reactivity of metakaolin (MK) in Portland cement (PC) blends by adding additional calcium hydroxide (CH_add) to the initial mixture. Cement paste samples were prepared with PC, MK and water with a water-to-binder ratio of 0.6. Cement replacement ratios were chosen from 5 to 40 wt.% MK. For higher replacement ratios, i.e., 20, 30 and 40 wt.% MK, CH_add was included in the mixture. CH_add-to-MK ratios of 0.1, 0.25 and 0.5 were investigated. Thermogravimetric analysis (TGA) was carried out to study the pozzolanic reactivity after 1, 7, 28 and 56 days of hydration. A modified mass balance approach was used to normalize thermogravimetric data and to calculate the calcium hydroxide (CH) consumption of samples with CH_add. Results showed that, without CH_add, a replacement ratio of 30 wt.% or higher results in the complete consumption of CH after 28 days at the latest. In these samples, the pozzolanic reaction of MK turned out to be restricted by the amount of CH available from the cement hydration. The increased amount of CH in the samples with CH_add resulted in an enhanced pozzolanic reaction of MK as confirmed by CH consumption measurements from TGA.
- Subjects :
- metakaolin
Technology
Microscopy
QC120-168.85
pozzolanic reaction
calcined clay
QH201-278.5
Engineering (General). Civil engineering (General)
thermogravimetric analysis (TGA)
supplementary cementitious materials (SCMs)
calcium hydroxide
Article
TK1-9971
Descriptive and experimental mechanics
General Materials Science
Electrical engineering. Electronics. Nuclear engineering
TA1-2040
Subjects
Details
- Language :
- English
- ISSN :
- 19961944
- Volume :
- 15
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Materials
- Accession number :
- edsair.doi.dedup.....8a5517bc3d785fbf04eeac8f2f61e46d