TY - JOUR

T1 - Influence of alumina on the compressive strengths and microstructural properties of the acid-based geopolymers from calcined indurated laterite and metakaolin

AU - Tchakouté, Hervé K.

AU - Bewa, Christelle N.

AU - Fotio, Daniel

AU - Dieuhou, Cedric M.

AU - Kamseu, Elie

AU - Rüscher, Claus H.

N1 - Funding Information: Dr. Tchakouté Kouamo Hervé gratefully acknowledges the Alexander von Humboldt-Stiftung for its financial support this work under grant N° KAM/1155741 GFHERMES-P .

PY - 2021/8

Y1 - 2021/8

N2 - The main objective of this work is to investigate the influence of alumina on the compressive strengths and microstructural properties of the acid-based geopolymers using calcined indurated laterite and metakaolin. These raw materials have been replaced by 0, 5, 10, 15 and 20 mass% of calcined bauxite. Phosphoric acid with molarity 10 M was used as a chemical reagent. The compressive strengths of the acid-based geopolymers increase with increasing the calcined bauxite content. Those from the substitution of calcined laterite by calcined bauxite are ranging from 21.45 to 47.95 MPa and higher compared to those from metakaolin (12.55 and 21.97 MPa). TG and DSC curves of all acid-based geopolymers indicate the decomposition of AlPO4.H2O at between 230 and 248 °C to an amorphous phase. In addition to this mineral, those from calcined laterite show the transformation of amorphous FePO4·2H2O at in the range 451–788 °C to the crystalline FePO4. The micrography images of the acid-based geopolymers indicate the formation of dense amorphous geopolymer matrices. It was found that the alumina incorporated in the acid-based geopolymers increases the compressive strengths. The presence of hematite in the calcined laterite leads to the formation of amorphous FePO4·2H2O which could contribute to enhancing exponentially the compressive strengths of the acid-based geopolymers.

AB - The main objective of this work is to investigate the influence of alumina on the compressive strengths and microstructural properties of the acid-based geopolymers using calcined indurated laterite and metakaolin. These raw materials have been replaced by 0, 5, 10, 15 and 20 mass% of calcined bauxite. Phosphoric acid with molarity 10 M was used as a chemical reagent. The compressive strengths of the acid-based geopolymers increase with increasing the calcined bauxite content. Those from the substitution of calcined laterite by calcined bauxite are ranging from 21.45 to 47.95 MPa and higher compared to those from metakaolin (12.55 and 21.97 MPa). TG and DSC curves of all acid-based geopolymers indicate the decomposition of AlPO4.H2O at between 230 and 248 °C to an amorphous phase. In addition to this mineral, those from calcined laterite show the transformation of amorphous FePO4·2H2O at in the range 451–788 °C to the crystalline FePO4. The micrography images of the acid-based geopolymers indicate the formation of dense amorphous geopolymer matrices. It was found that the alumina incorporated in the acid-based geopolymers increases the compressive strengths. The presence of hematite in the calcined laterite leads to the formation of amorphous FePO4·2H2O which could contribute to enhancing exponentially the compressive strengths of the acid-based geopolymers.

KW - Acid-based geopolymers

KW - AlPO·HO

KW - Amorphous FePO·2HO

KW - Bauxite

KW - Laterite

KW - Metakaolin

UR - http://www.scopus.com/inward/record.url?scp=85106378553&partnerID=8YFLogxK

U2 - 10.1016/j.clay.2021.106148

DO - 10.1016/j.clay.2021.106148

M3 - Article

AN - SCOPUS:85106378553

VL - 209

JO - Applied clay science

JF - Applied clay science

SN - 0169-1317

M1 - 106148

ER -