Microwaves were used to accelerate the curing of alkali activated hwangtoh paste (AAHP); the resulting compressive strength, porosity and composition were then compared against conventional heat-cured specimens. This found that a compressive strength of ∼20 MPa can be developed within 4 h, versus 72 h with conventional heat. While the 29Si NMR analysis showed the similar trends in the chemical shift with the curing time, the MIP results showed that the microwave-cured AAHP contained a greater cumulative pore volume and mean pore size than the conventional thermal-cured AAHP of the equal strength. The compressive strength of microwave-cued AAHP was attributed to the formation of a well-crystallized hydroxysodalite phase and an internal temperature gradient generated during curing.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) ( 2012-0002335 ). In addition, in part, this study was supported by a Korea University grant. It is also noted that this study made use of the KBSI NMR and SEM facility at Seoul, Korea.
© 2015 Elsevier Ltd. All rights reserved.
Copyright 2015 Elsevier B.V., All rights reserved.
- <sup>29</sup>Si solid-state NMR
- Alkali activation
- Microwave curing
- Physical properties
ASJC Scopus subject areas
- Civil and Structural Engineering
- Building and Construction
- General Materials Science