Abstract:
In older buildings, clay bricks have been widely used as a primary construction material
due to their excellent heat retention, erosion resistance, and fire-resistant properties.
Biochar, produced by heating biomass without oxygen, has numerous benefits:
insulation, air quality, emission reduction, humidity control, radiation shielding, water
management, and environmental well-being. Clay, a versatile mineral substance, shapes
effortlessly for art, pottery, construction, ceramics, agriculture, science, and industry.
Clay bricks offer limited thermal insulation and hence the incorporation of biochar
enhanced thermal insulation properties due to its porosity. The main objective of this
research was therefore to evaluate the physical and mechanical properties of porous
bricks made from biochar and clay soil. The Specific objectives included characterizing
the properties of the materials, fabricating clay-biochar-bricks, evaluating the properties
of the fabricated bricks and relating the properties of the clay-biochar bricks with pure
clay bricks. This study utilized clay and maize biochar to create porous bricks for
building. The methodology involved material collection, characterization, experimental
design and brick fabrication through hydroplastic forming. The clay and biochar were
blended by varying the biochar from 5% to 15%, firing temperature from 700 o C to
1000 o C and compacting pressure from 0.1 to 1.5N/m 2 . The clay used in the study had a
plasticity of liquid of 49, plastic limit of 24.95, plastic index of 24.05, particle size of
2mm, main chemical composition of 69.45% (SiO 2 ), 21.29%, (Al 2 O 3 ),2.25% (K 2 O),
2.07% (TiO) and3.40% Fe 2 O 3 The biochar used had an average particle size of 2mm,
moisture content of 0.0933% and 30% carbon. The fabricated porous clay brick was
characterized by the bulk density value of 1.418g/cm2, water absorption of 24.009%,
thermal conductivity of 0.688W/mK and compressive strength of 8.408N/mm 2
respectively. From the results of this study it was concluded that clay and biochar can be
used as an alternative raw material for porous brick production. Further work should
study on the effects of temperature, pressure and biochar on other bricks properties not
studied and do the cost analysis involved in production of bricks.
