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Advances in Materials Science and Engineering
Volume 2014 (2014), Article ID 326458, 11 pages
http://dx.doi.org/10.1155/2014/326458
Research Article

Carbonation Characteristics of Alkali-Activated Blast-Furnace Slag Mortar

1School of Architecture, Chonnam National University, Gwangju 500-757, Republic of Korea
2Department of Plant Architectural Engineering, Kyonggi University, Suwon-si, Gyeonggi-do 443-760, Republic of Korea

Received 13 May 2014; Accepted 14 July 2014; Published 7 August 2014

Academic Editor: Bin Li

Copyright © 2014 Keum-Il Song et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Alkali-activated ground granulated blast-slag (AAS) is the most obvious alternative material for ordinary Portland cement (OPC). However, to use it as a structural material requires the assessment and verification of its durability. The most important factor for a durability evaluation is the degree of carbonation resistance, and AAS is known to show lower performance than OPC. A series of experiments was conducted with a view to investigate the carbonation characteristics of AAS binder. As a consequence, it was found that the major hydration product of AAS was calcium silicate hydrate (CSH), with almost no portlandite, unlike the products of OPC. After carbonation, the CSH of AAS turned into amorphous silica gel which was most likely why the compressive strength of AAS became weaker after carbonation. An increase of the activator dosage leads AAS to react more quickly and produce more CSH, increasing the compaction, compressive strength, and carbonation resistance of the microstructure.