http://lattes.cnpq.br/2842006503104872; QUEIROZ, Abílio José Procópio.
Abstract:
This study aimed to develop ecological bricks consisting of soil and cassava wastewater -
effluent from the production of cassava flour - with viability of use, without the use of water
and burning and giving adequate disposal to this liquid residue of high potential of negative
environmental impact, in the perspective of development and materialization of social
technology. The technology developed was based on ABNT's NBR 10833/12 which deals with
the production of soil-cement bricks. The soils worked were extracted from sedimentary
deposits in the Paraíba river basin in Barra de São Miguel, Juazeirinho and Santa Cecília, and
the manipueira in the Jenipapo District, Puxinanã, PB. Priviously to the composition of the
masses and preparation of the test bodies, the raw materials were prepared and characterized
using XRD, EDX, Casagrande, granulometry, TG and DTA techniques for soils and, for
cassava wastewater, readings from pH, conductivity and specific gravity, and tests to determine
the contents of VSS, FSS, TSS, COD, N, P, K and other chemical elements. Soils are similar
in physicochemical characteristics and have all the conditions required for use in reference
technology (soil-cement brick) in terms of plasticity and granulometry, and the cassava
wastewater, with its composition based on water (90.9% , according to the TG curve) and with
high concentration of organic solids, when compared to other effluents, allowed a good alloy
in the mass. The compositions of the masses were defined based on preliminary tests with small
specimens that showed resistance of 3.41 ± 0.73 MPa, indicating the feasibility of
manufacturing with soil and cassava wastewater. The bodies produced in mechanical and
hydraulic presses were tested for variations in size, mass, water absorption and compressive
strength, and some results were not satisfactory, as there was no resistance to water absorption
and resistance ranged from 0.795 ± 0.419 MPa, that is, the maximum was 1.215 MPa, for
composition with 90% of soil, 10% of sand and 12% of cassava wastewater. The bricks did not
meet the technical requirements for use in civil construction under these conditions, however,
this is not able to support condemnation of the developed parts, considering: the application of
coatings or waterproofing, for protection against humidity, the use of additives to the mass and
the use for purposes that require less resistance. From a social and environmental point of view,
the viability of the use of the manipueira in substitution of water in the production of ceramic
pieces without burning was proved, offering adequate destination for this effluent and pointing
out a new technology to benefit semi-arid communities.
