TITLE:
An Experimental Study on the Use of Fonio Straw and Shea Butter Residue for Improving the Thermophysical and Mechanical Properties of Compressed Earth Blocks
AUTHORS:
Etienne Malbila, Simon Delvoie, David Toguyeni, Shady Attia, Luc Courard
KEYWORDS:
Fonio Straw, Shea Butter Residue, Stabilization, Compressed Stabilized Earth Blocks, Thermophysical and Mechanical Properties
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.8 No.3,
May
15,
2020
ABSTRACT: The efficient use of building materials is one of the responses to
increasing urbanization and building energy consumption. Soil as a building
material has been used for several thousand years due to its availability and
its usual properties improving and stabilization techniques used. Thus, fonio
straws and shea butter residues are incorporated into tow soil matrix. The
objective of this study is to develop a construction eco-material by recycling
agricultural and biopolymer by-products in compressed earth blocks (CEB)
stabilization and analyze these by-products’ influence on CEB usual properties. To do this, compressed stabilized earth
blocks (CSEB) composed of clay and varying proportion (3% to 10%) of fonio
straw and shea butter residue incorporated were subjected to thermophysical,
flexural, compressive, and durability tests. The results obtained show that the
addition of fonio straw and shea butter residues as stabilizers improves
compressed stabilized earth blocks thermophysical and mechanical performance
and durability. Two different clay materials were studied. Indeed, for these
CEB incorporating 3% fonio straw and 3% - 10% shea butter residue, the average compressive strength and three-point bending strength values after 28 days old are
respectively 3.478 MPa and 1.062 MPa. In terms of CSEB thermal properties, the average
thermal conductivity is 0.549 W/m·K with 3% fonio straw and from 0.667 to 0.798
W/m. K is with 3% - 10% shea butter residue and the average thermal diffusivity is 1.665.10-7 m2/s
with 3% FF and 2.24.10-7 m2/s
with 3.055.10-7 m2/s with 3% - 10%
shea butter residue, while the average specific heat mass is between 1.508 and
1.584 kJ/kg·K. In addition, the shea butter residue incorporated at 3% - 10%
improves CSEB water repellency, with capillary coefficient values between 31
and 68 [g/m2·s]1/2 and a
contact angle between 43.63°C and 86.4°C. Analysis of the results shows that,
it is possible to use these CSEB for single-storey housing construction.