Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/192343

Title

Kinetics of geopolymerization: role of Al2O3 and SiO2

Author(s)

Silva, P. D.;  Sagoe-Crentsil, K.;  Sirivivatnanon, V.

Abstract

The early-stage reaction kinetics of metakaolin/sodium silicate/sodium hydroxide geopolymer system have been investigated. The setting and early strength development characteristics, and associated mineral and microstructural phase development of mixtures containing varying SiO2/Al2O3 ratios, cured at 40 °C for up to 72 h, were carefully studied. It was observed that setting time of the geopolymer systems was mainly controlled by the alumina content. Essentially, the setting time increased with increasing SiO2/Al2O3 ratio of the initial mixture. Up to a certain limit, the SiO2/Al2O3 ratio was also found to be responsible for observed high-strength gains at later stages. An increase in the Al2O3 content, i.e. for low SiO2/Al2O3 ratio, led to products of low strength, accompanied by microstructures with increased amounts of Na–Al–Si-containing “massive” phases (grains). EDAX analyses showed that the SiO2/Al2O3 ratios of geopolymer gel phases were quite similar to those of the starting mixtures, but with an overall lower Na content. Most importantly, this study clearly demonstrates that the properties of resulting geopolymer systems can be drastically affected by minor changes in the available Si and Al concentrations during synthesis.

Publication type

Journal article

Source

Cement and Concrete Research, Vol. 37, no. 4 (Apr 2007), pp. 512-518

Publication year

2007

FOR Code(s)

0905 Civil Engineering;  1202 Building

Keyword(s)

Alumina;  Geopolymers;  Inorganic polymers;  Kinetics;  Mechanical properties;  Microstructure;  Phase development;  Polymerization;  Reaction kinetics;  Setting time;  Silica;  Sodium hydroxide;  Strength of materials

Publisher

Pergamon

ISSN

0008-8846

Publisher URL

http://dx.doi.org/10.1016/j.cemconres.2007.01.003

Copyright

Copyright © 2007.

Additional information

K. Sagoe-Crentsil is incorrectly named on the paper as 'K. Sagoe-Crenstil'. This error has been corrected in this record to facilitate ease of its discovery.

Peer reviewed