SILVA, J. C.; CARDOSO.J.S.; http://lattes.cnpq.br/0710458134295111; SILVA, Jucimara Cardoso da.
Abstract:
Sugarcane bagasse ash (CBCA) is an industrial residue from sugarcane processing
plants, whose improper disposal is harmful to the environment. In this research, CBCA
was studied as a sustainable application in the stabilization of expansive soils, to
investigate the advantages of this residue in the control of high rates of soil expansion.
Expansive soils present volumetric instability when suffering humidity variation and
their behavior is characterized by the volume increase (expansion) when there is an
increase in humidity and volume reduction (contraction) when they lose moisture,
therefore, when used as support capacity in constructions, without being treated and
stabilized properly, cause several problems in road works, canals and buildings. The
physical, chemical and mineralogical characteristics of the expansive soil (activated
calcium bentonite + sand misture), the SCBA and the SCBA/soil mixtures of this
research were investigated through the tests of specific gravity of the grains,
granulometric analysis, compaction, Atteberg limits, pH, adsorption of methylene blue,
X-ray diffraction (XRD), X-ray fluorescence (XRF), single compressive strength and
unidirectional expansion. The results revealed that the soil is highly expansive, with
expansion potential of up to 20%, plasticity index of 37,80%, presence of the clay
mineral montmorillonite, high cation exchange capacity (CEC) and a colloidal activity
indicating the presence of a clay active to very active. The CBCA presented a
percentage of approximately 23% of magnesium and calcium oxides in its composition.
Both materials studied here present alkaline pH and the addition of BCCA contents to
the soil caused a 4% increase in soil pH. The addition of contents from 12,50% of
SCBA reduced the expansion potential by 99% and the CEC value of the studied soil by
approximately 67%. The results of the simple compressive strength tests did not present
consistent and satisfactory data for additions below 25%, however, for additions above
25%, the samples tested indicated the possibility of potentially cementing characteristics
of CBCA. Finally, it can be seen that CBCA is an industrial waste with great potential
for new applications in the stabilization of expansive soils.