masterThesis
Propriedades de concretos leves autoadensáveis com agregados leves artificiais produzidos a partir da calcinação de resíduos agroindustrial e de mineração
Fecha
2020-10-29Registro en:
SOUSA, Jemima Tabita Ferreira de. Propriedades de concretos leves autoadensáveis com agregados leves artificiais produzidos a partir da calcinação de resíduos agroindustrial e de mineração. 2020. 85f. Dissertação (Mestrado em Engenharia Civil) - Centro de Tecnologia, Universidade Federal do Rio Grande do Norte, Natal, 2020.
Autor
Sousa, Jemima Tabita Ferreira de
Resumen
Self-compacting concrete (SCC) is an important example of new technology and alternative
to the use of conventional concrete. The rheological parameters demonstrated by this type of
concrete, provide high fluidity and cohesion that results in the ability to fill and resistance to
segregation, as well as optimize concrete processes and reducing labor costs. Currently, due to
the lack of resistant soil to support loads of buildings in urban agglomerations, studies have
been carried out in search of possibilities that result in a lower weight for the structure, as well
as ease of transportation, execution and thermoacoustic properties. The self-compacting
lightweight concrete (SCLC) then emerges as a possible alternative for grouping the benefits
of SCC and structural lightweight concrete (SLC). In the production of these concretes, the
lightweight aggregate most used in the world and in Brazil is still an expanded clay, with its
national production concentrated in the Southeast Region. In this context, studies carried out
by Leal de Souza (2019) and Souza (2019), verified the viability of producing lightweight
aggregates from the sintering of industrial residues and regional raw materials (Rio Grande do
Norte/Brazil), as waste from sugar cane biomass ash (SCBA), scheelite residue (RPS) and
local clays. In view of the above, the present study listed some of the lightweight aggregates
that were developed by Leal de Souza (2019) and Souza (2019), and analyzed their influence
on the composition of self-compacting lightweight concretes, investigating their efficiency
and behavior in comparison with SCLC produced with commercial lightweight aggregate.
The concretes were subjected to characterization tests in the fresh state, where the properties
of fluidity, apparent viscosity, visual stability and passing ability were evaluated, through
slump flow tests, flow time (t500), visual stability index and J-ring, respectively, and
measurement of fresh density. In the hardened state, tests were performed to determine the
mechanical properties, with the compressive strength test at 7 and 28 days, with the
measurement of the dry density for each age, and the durability parameters through the
diffusion of chloride ions. The results obtained showed the viability of producing selfcompacting lightweight concrete with unconventional lightweight aggregates. Both in the
fresh and in the hardened state, all mixtures met the requirements established in the standard,
with final density ranging between 1.94 to 2.03 g/cm³ and compressive strength at 28 days
between 36.72 to 26.11 MPa. The mixtures with lightweight aggregates of SCBA showed a
constant performance and similar to the performance of concrete with commercial lightweight
aggregate, demonstrating to be a promising material for use in self-compacting lightweight
concretes. Still, it was found that the physical properties of the lightweight aggregates influenced the results obtained in the fresh and hardened state, making the lightweight
aggregate the main responsible for limiting and influencing the properties of the concretes.