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European Journal of Applied Sciences – Vol. 12, No. 5
Publication Date: October 25, 2024
DOI:10.14738/aivp.125.17552.
Balde, M. Y., Kepdieu, J. M., Tchanang, G., Baldé, S., & Djangang, C. N. (2024). Doping Portland Cement with Natural Clay and
Bauxite Mineral Additives from Débélé: Effects on the Mechanical Strength of Mortars. European Journal of Applied Sciences,
Vol - 12(5). 43-56.
Services for Science and Education – United Kingdom
Doping Portland Cement with Natural Clay and Bauxite Mineral
Additives from Débélé: Effects on the Mechanical Strength of
Mortars
Mamadou Yaya Balde
Department of Inorganic Chemistry, University of Yaoundé I, BP 812 Yaoundé,
Cameroon, Department of Chemistry, Université Gamal Abdel Nasser de Conakry,
BP 1147 Conakry, Guinea and Guinean Environmental Research Institute (IREG),
BP ;1615, Conakry, Guiné
Jean Marie Kepdieu
Department of Inorganic Chemistry,
University of Yaoundé I, BP 812 Yaoundé, Cameroon
Gustave Tchanang
Department of Inorganic Chemistry,
University of Yaoundé I, BP 812 Yaoundé, Cameroon
Souleymane Balde
Department of Chemistry,
Université Gamal Abdel Nasser de Conakry, BP 1147 Conakry, Guinea
ChantaleNjiomou Djangang
Department of Inorganic Chemistry,
University of Yaoundé I, BP 812 Yaoundé, Cameroon
ABSTRACT
In the course of this experimental work, which led to the substitution of Portland
cement by 20% by mass of mineral additives, the mechanical compressive
strength of hybrid cements was evaluated at different ages: 7, 28, 42 and 90 days.
The effect of bauxite on the development of mechanical strength was also
assessed. The study showed that the hybrid cements obtained had appreciable
mechanical strengths, with values ranging from 14 to 34.6 MPa for the series of
mortars containing a single additive, compared with 15 to 36.4 MPa for hybrids
containing two mineral additives. This study demonstrated the positive effect of
adding raw bauxite powder to the cementitious medium, resulting in an increase
in mechanical strength from 6.59% to 42.31% when the quantity of B varied from
5 to 15% for the B-Ab hybrids. In the B-Ar series, this increase ranged from 6 to
29.83%. The mechanical performance of the composite cements obtained means
that they can be used in a variety of masonry applications, in compliance with
technical construction standards in a difficult economic context.
Keywords: Hybrid cement, mineral additives, strength, bauxite, Clay, Guinea.
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European Journal of Applied Sciences (EJAS) Vol. 12, Issue 5, October-2024
INTRODUCTION
Clays and bauxites are among Guinea's potential industrial minerals [1, 2, 3, 4, 5]. These
minerals have been used by mankind since antiquity to manufacture a variety of utilitarian
products that are present everywhere in our daily lives. These include building and domestic
materials, medical and cosmetic materials, electronic and transport materials (including
aeronautics), materials for renewable energy, paper and so on. These natural resources,
which are very abundant in Guinea, can be used either as raw materials to manufacture
various products or as additives to a raw material to create or improve the functional
properties of new products in response to changing uses [6, 7, 8, 9].
However, despite the ever-accelerating consumption of manufactured products based on
these industrial minerals, their production is underdeveloped in Guinea, despite their
abundance. Indeed, clays, the classic raw materials for cement and ceramics matrices, have so
far only been exploited for artisanal pottery, while bauxite, whose reserves are ranked first in
the world, is only used for aluminum extraction [2, 3, 10, 11, 12, 13,14]. Yet these resources
could, for example, be transformed into basic building materials for walls, roofs and floors,
providing a solution to the precarious housing situation that is still a concern in Guinea and
most other Sub-Saharan African countries.
At the same time, companies and public authorities are becoming increasingly intransigent
with regard to the pollution problems caused by the carbon dioxide released and the high
consumption of raw materials and energy during the manufacture of Portland cement. In the
case of the cement industry, carbon dioxide (CO2) results from the combustion of
hydrocarbons (natural gas or fuel oil) and from the decarbonation of calcium carbonate,
contained in the raw material, during the clinker manufacturing process. To this end, one of
the challenges facing the cement industry is to produce a high-performance cement at a
competitive cost, with a less degrading environmental impact [15, 16, 17]. The use of mineral
additives, which are abundant and less costly, could be a solution to this major challenge,
making it possible to improve certain properties or impart special properties to building
materials [18, 19].
It is well known that the mineral substances used as additives in cement works or as additives
in the manufacture of mortar or concrete are those which contribute, through their physical,
hydraulic and pozzolanic activity, to improving the behaviour of cements in the fresh state as
well as in the hardened state. These include natural pozzolans, fly ash, blast furnace slag, clays
and silica fume. These products become more active in alkaline cement solutions, giving rise
to new hydrates that provide concretes and mortars with greater mechanical strength and
durability [20, 21].
Previous studies have shown that Débélé clays and bauxites have pozzolanic properties [2, 4,
5]. This is because these resources, in finely divided form and in the presence of moisture,
react chemically with calcium hydroxide at ordinary temperature to form compounds with
binding properties [3, 4, 22, 23]. This favours their use in the formulation of mortars,
construction materials used to bind elements together, ensure the stability of the structure
and fill the gaps between building blocks. According to NBN EN 998-2, a mortar is a mixture
composed of one or more inorganic binders, aggregates, water and, in some cases, additions