Details
| Original language | English |
|---|---|
| Pages (from-to) | 188-194 |
| Number of pages | 7 |
| Journal | Applied clay science |
| Volume | 107 |
| Early online date | 12 Feb 2015 |
| Publication status | Published - 1 Apr 2015 |
Abstract
Three different kaolins (K1, K2, K3) from sources in Cameroon were applied for producing geopolymer cements. The kaolins differ significantly in their gibbsite and quartz contents. Thermal transformation (700°C, 4h) into their metakaolins MK1, MK2, MK3 shows the total loss of crystalline kaolinite and reveal the typically rather broad bump in the X-ray pattern. Gibbsite becomes dehydrated into γ and χ-Al2O3. Geopolymer cements (GP1, GP2, GP3) were obtained using freshly prepared sodium silicate solutions (NWG) with a ratio NWG/MK=0.87. It could be observed that the initial (60/80/90min) and final (90/140/160min) setting time increases and their 28day compressive strength (49/39/30MPa) decreases in the course GP1/GP2/GP3. It is discussed that the higher content of quartz in K1 (up to 22wt.%), compared to K2 (10wt.%) and K3 (8wt.%) promotes higher strength values and decreased setting times. Gibbsite was not present in K1, but up to 11wt.% in K2 and 28 wt.% in K3, transformed in its dehydrated forms remains unreacted during geopolymerization. Therefore, the higher content of gibbsite in the kaolinite could be related to a lower strength. The reacted volumes and compositions of the geopolymer become almost the same in all three cases. A content of 30-50% of unreacted metakaolin was proved in all cases.
Keywords
- Compressive strength, Geopolymer, Gibbsite, Kaolin, Metakaolin, γ- and χ-AlO
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geology
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: Applied clay science, Vol. 107, 01.04.2015, p. 188-194.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Influence of gibbsite and quartz in kaolin on the properties of metakaolin-based geopolymer cements
AU - Tchakoute, H. K.
AU - Rüscher, C. H.
AU - Djobo, J. N.Y.
AU - Kenne, B. B.D.
AU - Njopwouo, D.
N1 - Publisher Copyright: © 2015 Elsevier B.V.
PY - 2015/4/1
Y1 - 2015/4/1
N2 - Three different kaolins (K1, K2, K3) from sources in Cameroon were applied for producing geopolymer cements. The kaolins differ significantly in their gibbsite and quartz contents. Thermal transformation (700°C, 4h) into their metakaolins MK1, MK2, MK3 shows the total loss of crystalline kaolinite and reveal the typically rather broad bump in the X-ray pattern. Gibbsite becomes dehydrated into γ and χ-Al2O3. Geopolymer cements (GP1, GP2, GP3) were obtained using freshly prepared sodium silicate solutions (NWG) with a ratio NWG/MK=0.87. It could be observed that the initial (60/80/90min) and final (90/140/160min) setting time increases and their 28day compressive strength (49/39/30MPa) decreases in the course GP1/GP2/GP3. It is discussed that the higher content of quartz in K1 (up to 22wt.%), compared to K2 (10wt.%) and K3 (8wt.%) promotes higher strength values and decreased setting times. Gibbsite was not present in K1, but up to 11wt.% in K2 and 28 wt.% in K3, transformed in its dehydrated forms remains unreacted during geopolymerization. Therefore, the higher content of gibbsite in the kaolinite could be related to a lower strength. The reacted volumes and compositions of the geopolymer become almost the same in all three cases. A content of 30-50% of unreacted metakaolin was proved in all cases.
AB - Three different kaolins (K1, K2, K3) from sources in Cameroon were applied for producing geopolymer cements. The kaolins differ significantly in their gibbsite and quartz contents. Thermal transformation (700°C, 4h) into their metakaolins MK1, MK2, MK3 shows the total loss of crystalline kaolinite and reveal the typically rather broad bump in the X-ray pattern. Gibbsite becomes dehydrated into γ and χ-Al2O3. Geopolymer cements (GP1, GP2, GP3) were obtained using freshly prepared sodium silicate solutions (NWG) with a ratio NWG/MK=0.87. It could be observed that the initial (60/80/90min) and final (90/140/160min) setting time increases and their 28day compressive strength (49/39/30MPa) decreases in the course GP1/GP2/GP3. It is discussed that the higher content of quartz in K1 (up to 22wt.%), compared to K2 (10wt.%) and K3 (8wt.%) promotes higher strength values and decreased setting times. Gibbsite was not present in K1, but up to 11wt.% in K2 and 28 wt.% in K3, transformed in its dehydrated forms remains unreacted during geopolymerization. Therefore, the higher content of gibbsite in the kaolinite could be related to a lower strength. The reacted volumes and compositions of the geopolymer become almost the same in all three cases. A content of 30-50% of unreacted metakaolin was proved in all cases.
KW - Compressive strength
KW - Geopolymer
KW - Gibbsite
KW - Kaolin
KW - Metakaolin
KW - γ- and χ-AlO
UR - http://www.scopus.com/inward/record.url?scp=85027951735&partnerID=8YFLogxK
U2 - 10.1016/j.clay.2015.01.023
DO - 10.1016/j.clay.2015.01.023
M3 - Article
AN - SCOPUS:85027951735
VL - 107
SP - 188
EP - 194
JO - Applied clay science
JF - Applied clay science
SN - 0169-1317
ER -