| Influence of Calcium Bentonite Addition on the Compressive
Strength, Efflorescence Extent and Drying Shrinkage of
Fly-Ash Based Geopolymer Mortar |
Yi Huang*
Pages : 77-82
DOI : 10.1080/0371750X.2020.1719206 |
| Abstract |
| The influence of calcium bentonite addition on the compressive strength, efflorescence
extent and drying shrinkage of fly-ash based geopolymer mortar was investigated. The
results showed that appropriate amount (e.g. 15 wt%) of calcium bentonite addition
favoured the enhancement of compressive strength mainly because its addition allowed
the geopolymer to tolerate more water glass addition and therefore increased the Si/Al
ratio of geopolymer. The maximum 28 d compressive strength of the geopolymer mortar
with calcium bentonite addition reached 47.8 MPa, which was evidently larger than the
maximum value of the specimen without calcium bentonite addition. Calcium bentonite
addition was also beneficial for the reduction of drying shrinkage percentage of
geopolymer mortar due to water adsorption and volume expansion properties of calcium
bentonite. Moreover, calcium bentonite addition could reduce, even eliminate the
efflorescence mainly due to Na+ adsorption by calcium bentonite through ion exchange.
[Keywords: Geopolymer, Calcium bentonite, Compressive strength, Efflorescence,
Drying shrinkage] |
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