• search hit 29 of 105
Back to Result List

Metakaolin as an Additive in Composite Cement

  • Metakaolin made from kaolin is used around the world but rarely in Vietnam where abundant deposits of kaolin is found. The first studies of producing metakaolin were conducted with high quality Vietnamese kaolins. The results showed the potential to produce metakaolin, and its effect has on strength development of mortars and concretes. However, utilisation of a low quality kaolin for producingMetakaolin made from kaolin is used around the world but rarely in Vietnam where abundant deposits of kaolin is found. The first studies of producing metakaolin were conducted with high quality Vietnamese kaolins. The results showed the potential to produce metakaolin, and its effect has on strength development of mortars and concretes. However, utilisation of a low quality kaolin for producing Vietnamese metakaolin has not been studied so far. The objectives of this study were to produce a good quality metakaolin made from low quality Vietnamese kaolin and to facilitate the utilisation of Vietnamese metakaolin in composite cements. In order to reach such goals, the optimal thermal conversion of Vietnamese kaolin into metakaolin was carried out by many investigations, and as such the optimal conversion is found using the analysis results of DSC/TGA, XRD and CSI. During the calcination in a range of 500 – 800 oC lasting for 1 – 5 hours, the characterisation of calcinated kaolin was also monitored for mass loss, BET surface, PSD, density as well as the presence of the residual water. It is found to have a well correlation between residual water and BET surface. The pozzolanic activity of metakaolin was tested by various methods regarding to the saturated lime method, mCh and TGA-CaO method. The results of the study showed which method is the most suitable one to characterise the real activity of metakaolin and can reach the greatest agreement with concrete performance. Furthermore, the pozzolanic activity results tested using methods were also analysed and compared to each other with respect to the BET surface. The properties of Vietnam metakaolin was established using investigations on water demand, setting time, spread-flowability, and strength. It is concluded that depending on the intended use of composite cement and weather conditions of cure, each Vietnamese metakaolin can be used appropriately to produce (1) a composite cement with a low water demand (2) a high strength of composite cement (3) a composite cement that aims to reduce CO2 emissions and to improve economics of cement products (4) a high performance mortar. The durability of metakaolin mortar was tested to find the needed metakaolin content against ASR, sulfat and sulfuric acid attacks successfully.show moreshow less

Download full text files

Export metadata

Metadaten
Document Type:Doctoral Thesis
Author:Dr.-Ing. Thu Ha Phung Thi
DOI (Cite-Link):https://doi.org/10.25643/bauhaus-universitaet.1976Cite-Link
URN (Cite-Link):https://nbn-resolving.org/urn:nbn:de:gbv:wim2-20130705-19764Cite-Link
ISBN:978-3-00-042655-1
Publisher:F. A. Finger-Institut für Baustoffkunde
Place of publication:Weimar
Referee:Prof. Dr.-Ing. habil. Jochen StarkGND, Prof. Dr.-Ing. Wolfgang Breit
Advisor:Prof. Dr.-Ing. Horst-Michael LudwigORCiDGND
Language:English
Date of Publication (online):2013/04/07
Date of first Publication:2012/11/30
Date of final exam:2013/08/05
Release Date:2013/07/05
Publishing Institution:Bauhaus-Universität Weimar
Granting Institution:Bauhaus-Universität Weimar, Fakultät Bauingenieurwesen
Institutes:Fakultät Bauingenieurwesen / F. A. Finger-Institut für Baustoffkunde
Pagenumber:119
Tag:cement
GND Keyword:metakaolin; composite cement; durability
Dewey Decimal Classification:600 Technik, Medizin, angewandte Wissenschaften
BKL-Classification:51 Werkstoffkunde
56 Bauwesen
Licence (German):License Logo Creative Commons 4.0 - Namensnennung-Nicht kommerziell-Keine Bearbeitung (CC BY-NC-ND 4.0)