TY - JOUR

T1 - Role of ɣ-Al2O3 on the mechanical and microstructural properties of metakaolin-based geopolymer cements

AU - Tchakouté, Hervé K.

AU - Kamseu, Elie

AU - Banenzoué, Charles

AU - Rüscher, Claus H.

AU - Andreola, Fernanda

AU - Tchamo, Claudia C.L.

AU - Leonelli, Cristina

N1 - Funding information: Hervé Tchakouté Kouamo gratefully acknowledges the Alexander von Humboldt Foundation for financial support the purchase of equipment under the grant N° KAM/1155741 STP.

PY - 2018/3/14

Y1 - 2018/3/14

N2 - The main target of this work is to investigate the influence of ɣ-Al2O3 on the properties of metakaolin-based geopolymer cements. The kaolin used as starting material for producing geopolymer cements contains approximately 28 and 64% of gibbsite and kaolinite, respectively. This kaolin was transformed to metakaolins by calcination at 500, 550, 600, 650, and 700 °C for 1 h. Gibbsite contained in kaolin was transformed to γ-Al2O3 during the calcination process. The hardener was obtained by mixing commercial sodium silicate and sodium hydroxide solution (10 M) with a mass ratio sodium silicate/sodium hydroxide equal to 1.6:1. Geopolymer cements, GMK-500, GMK-550, GMK-600, GMK-650, and GMK-700, were obtained using the prepared hardener with a mass ratio hardener/metakaolin equal to 0.87:1. It could be seen that the specific surface area of metakaolins decreases with increasing the calcination temperature of kaolin owing to the formation of the particles of γ-Al2O3. The compressive strengths 18.21/29.14/36.61/36.51 increase in the course GMK-550/GMK-600/GMK-650/GMK-700. The X-ray patterns and micrograph images of geopolymer cements, GMK-600, GMK-650, and GMK-700, indicate the presence of γ-Al2O3 in their structure. It was typically found that γ-Al2O3 remains largely unaffected during the geopolymerisation, and therefore could act as an inert filler and reinforce the structure of geopolymer cements. [Figure not available: see fulltext.].

AB - The main target of this work is to investigate the influence of ɣ-Al2O3 on the properties of metakaolin-based geopolymer cements. The kaolin used as starting material for producing geopolymer cements contains approximately 28 and 64% of gibbsite and kaolinite, respectively. This kaolin was transformed to metakaolins by calcination at 500, 550, 600, 650, and 700 °C for 1 h. Gibbsite contained in kaolin was transformed to γ-Al2O3 during the calcination process. The hardener was obtained by mixing commercial sodium silicate and sodium hydroxide solution (10 M) with a mass ratio sodium silicate/sodium hydroxide equal to 1.6:1. Geopolymer cements, GMK-500, GMK-550, GMK-600, GMK-650, and GMK-700, were obtained using the prepared hardener with a mass ratio hardener/metakaolin equal to 0.87:1. It could be seen that the specific surface area of metakaolins decreases with increasing the calcination temperature of kaolin owing to the formation of the particles of γ-Al2O3. The compressive strengths 18.21/29.14/36.61/36.51 increase in the course GMK-550/GMK-600/GMK-650/GMK-700. The X-ray patterns and micrograph images of geopolymer cements, GMK-600, GMK-650, and GMK-700, indicate the presence of γ-Al2O3 in their structure. It was typically found that γ-Al2O3 remains largely unaffected during the geopolymerisation, and therefore could act as an inert filler and reinforce the structure of geopolymer cements. [Figure not available: see fulltext.].

KW - Geopolymer cements

KW - Gibbsite

KW - Hardener

KW - Kaolin

KW - Metakaolins

KW - γ-AlO

UR - http://www.scopus.com/inward/record.url?scp=85043683631&partnerID=8YFLogxK

U2 - 10.1007/s10971-018-4616-z

DO - 10.1007/s10971-018-4616-z

M3 - Article

AN - SCOPUS:85043683631

VL - 86

SP - 305

EP - 315

JO - Journal of Sol-Gel Science and Technology

JF - Journal of Sol-Gel Science and Technology

SN - 0928-0707

IS - 2

ER -