TITLE:
Adding Hydrated Lime in a Material Made of Clayey Soil and Fibres: Formulation and Effects on Thermo-Mechanical Properties
AUTHORS:
Fati Zoma, Fabien H. Yonli, Etienne Malbila, David Y. K. Toguyeni, Ivon B. Hassel
KEYWORDS:
Local Material, Hydrated Lime, Hibiscus sabdariffa Fibre, Thermo-Mechanical Properties, Porosity
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.8 No.3,
May
28,
2020
ABSTRACT: In this
study, we have focused our investigations on effect of adding hydrated lime on
a locally made composite material, based on clayey earth (soil) and Hibiscus sabdariffa fibres, for envelope
(walls) in the building. Prior to sample’s formulation, we selected an
appropriate mineral (soil) material based on criteria as: plasticizer power for
good workability, dense coarse particles to withstand loads and finally porous
structure to take advantage of air insulating character. We then formulated,
following a mixing process by shearing and compaction by vibration that we
recommend, two composite materials (A), (B) which contain respectively 1%
Fibres plus 1% lime, 1% Fibres plus 3% lime. We determined thermal properties
by the mean of KD2 Pro thermal analyzer, compression strength accordingly to
the standard NF P 18-406, porosity following volumetric and gravimetric methods and pH of
soil-hydrated lime solution. As
results, up to 5% of hydrated lime, the measured pH is inferior to 12:
mineralization of vegetal fibres is highly unlikely. Moreover, we observe that
the addition of hydrated lime resulted in a reduction in the number of cracks
and their depths; Samples (A) and (B) have a rather compact appearance than the
case 1% Fibres without lime (material (C)). Furthermore, with lime
stabilization, the insulating potential is improved while the thermal inertia
has been deteriorated compared to material (C). However,
compressive strength decreases with lime, which could be due to the presence of
fibres that would inhibit the hardening of the lime. At last, with 3.39% ±
3.07% MPa, 2.27% ± 11.30% MPa for samples (A), (B) respectively, the minimum required by
CRATerre-EAG (guide of CDI, 1996) for construction of envelope (walls) of
single storey (ground floor) buildings is met.