Antoine Elimbi
University of Yaoundé I
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Featured researches published by Antoine Elimbi.
RSC Advances | 2016
Jean Noël Yankwa Djobo; Antoine Elimbi; Hervé K. Tchakouté; Sanjay Kumar
This paper looks at the possibility of using low reactive volcanic ash for making geopolymer cement. The research is directed towards (a) alteration of the reactivity of volcanic ash by mechanical activation, and (b) use of mechanically activated volcanic ash for the synthesis of a geopolymer. The effect of mechanical activation was quite visible on particle size distribution and the degree of crystallinity. The disappearance of some anorthite peaks and appearance of quartz peaks in volcanic ashes milled for 120 min demonstrate the change in mineralogy. The appearance of an intense carbonate band with milling time could be related to sorption of atmospheric CO2 on the grains surface during mechanical activation. The manifestation of mechanical activation of volcanic ash was prominent on (a) the reaction kinetics, (b) microstructural development, and (c) physico-mechanical properties of the geopolymer product. The rate constant and extent of geopolymerization increased with milling time but decreased with curing temperature. This decrease is in non-conformity with other alumina-silicate materials used for geopolymerization such as metakaolin and fly ash. FEG-SEM and EDAX results revealed that the geopolymer gel obtained is mixture of poly(ferro-sialate-siloxo) and poly(ferro-sialate-disiloxo) binder type with a formula close to [Ca,Na,K,Mg]–[–Fe–O–]x–[Si–O–Al–O–]1−x–[–Si–O–]y. The physico-mechanical properties changed significantly. Setting time reduced by >95% in samples milled for 60 min or more. The compressive strength which was negligible for 0–30 min milled volcanic ash reached 29–54 MPa after 60–120 min of milling time. Heat curing influenced the early age (7 and 28 days) compressive strength but the 90 day compressive strength of both ambient and heat cured samples were comparable.
Journal of Asian Ceramic Societies | 2014
Jean Noël Yankwa Djobo; Leonel Noumbissié Tchadjié; Hervé K. Tchakouté; B.B.D. Kenne; Antoine Elimbi; Daniel Njopwouo
Abstract The aim of this work is to valorize volcanic scoria by using them as starting material for geopolymers production. Nevertheless, volcanic scoria possesses low reactivity. Various amounts of metakaolin (5%, 10%, 15%, 20% and 25%) were added into two volcanic scoria (ZD and ZG) in order to improve their reactivity. Two alkaline solutions were used to activate the aluminosilicate materials. The starting materials were characterized by particle size distribution, specific surface area, chemical and mineralogical composition. The geopolymers were characterized by the setting time, XRD, FTIR, SEM and compressive strength. The results indicated that volcanic scoria have low specific surface area (2.3 m2/g for ZD, 15.7 m2/g for ZG), high average particle size (d50 = 13.08 μm and 10.68 μm for ZD and for ZG respectively) and low glass phase contents. Metakaolin have a smaller average particle size (d50 = 9.95 μm) and high specific surface (20.5 m2/g). The compressive strength of geopolymers increased in the ranges of 23–68 MPa and 39–64 MPa for geopolymers from ZD–MK and ZG–MK respectively. This study shows that despite the low reactivity of volcanic scoria it can still be used to synthesize geopolymers with good physical and mechanical properties.
Environmental Science and Pollution Research | 2017
Jean Noël Yankwa Djobo; Antoine Elimbi; Hervé K. Tchakouté; Sanjay Kumar
The progress achieved with the use of volcanic ash for geopolymer synthesis has been critically reviewed in this paper. This consists of an overview of mineralogy and chemistry of volcanic ash. The role of chemical composition and mineral contents of volcanic ash on their reactivity during geopolymerization reaction and, consequently, mechanical properties have been accessed. An attempt has been made to establish a relationship between synthesis factors and final properties. A critical assessment of some synthesis conditions has been addressed and some practical recommendations given along with suggestions of future works that have to be done. All this has shown that there are still many works such as durability tests (carbonation, freeze-thaw, resistance, etc.), life cycle analysis, etc. that need to be done in order to satisfy both suitability and sustainability criteria for a large-scale or industrial application.
Construction and Building Materials | 2011
Antoine Elimbi; Hervé K. Tchakouté; Daniel Njopwouo
Construction and Building Materials | 2012
H. Tchakoute Kouamo; Antoine Elimbi; J.A. Mbey; C.J. Ngally Sabouang; Daniel Njopwouo
Ceramics International | 2016
Leonel Noumbissié Tchadjié; Jean Noël Yankwa Djobo; Navid Ranjbar; Hervé K. Tchakouté; B.B.D. Kenne; Antoine Elimbi; Daniel Njopwouo
Ceramics International | 2013
H. Tchakoute Kouamo; J.A. Mbey; Antoine Elimbi; B.B. Kenne Diffo; Daniel Njopwouo
Ceramics International | 2013
H. Kouamo Tchakoute; Antoine Elimbi; B.B. Diffo Kenne; J.A. Mbey; Daniel Njopwouo
Ceramics International | 2008
Chantale Njiomou Djangang; Antoine Elimbi; U.C. Melo; G.L. Lecomte; C. Nkoumbou; J. Soro; J.P. Bonnet; Philippe Blanchart; Daniel Njopwouo
Applied Clay Science | 2008
Chantale Njiomou Djangang; Antoine Elimbi; U.C. Melo; G.L. Lecomte; C. Nkoumbou; Julien Soro; Jacques Yvon; Philippe Blanchart; Daniel Njopwouo