Banca de DEFESA: LUIS FERNANDO TONHOLO DOMINGOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUIS FERNANDO TONHOLO DOMINGOS
DATE: 09/12/2022
TIME: 14:00
LOCAL: online
TITLE:

Physical-mechanical behavior of geopolymer matrices produced by the “one-part” method  based on fly ash and rice husk ash

KEY WORDS:

Geopolymer matrices. “One-part” method. Fly ash. Rice husk ash

PAGES: 88
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

The production of Portland cement (CP) has become, over the decades, one of the main
responsible for harmful environmental impacts caused by the emission of high amounts of
carbon dioxide, arising from its production and application in the construction industry.
Currently, as a way to minimize this environmental degradation, there is great interest in the
use of industrial and agro-industrial waste as a raw material for obtaining and developing new
binders, in order to meet market demand and provide technological options that are mainly,
environmentally sustainable. Among these residues are source materials of aluminosilicates
(Al2O3.SiO2), such as fly ash, and species rich in silica (SiO2), such as rice husk ash (CCA),
which when reacting with an alkaline medium are capable of forming rigid and highly
cementitious structures. These structures are popularly known as geopolymer matrices,
geopolymers or inorganic polymers; where they have been studied by researchers around the
world as a way to replace with Portland cement in some applications. The pioneering
methodology in the production of geopolymers is known as “two-parts geopolymers” and,
currently, represents a dangerous and difficult application on a large scale, as it requires the
preparation of highly alkaline and viscous solutions. Adversely and innovatively, the “one-part
geopolymers” method is based on the production of dry mixtures with precursor and activator
materials, analogous to the production of Portland cement, representing a greater acceptance in
the market. Thus, this research project aims to produce geopolymer matrices via a "one-part"
method based on fly ash and CCA, in addition to investigating the feasibility of using
agroindustrial waste (CCA) to obtain alternative and sustainable materials for future
applications in engineering. The research development is divided into three distinct stages. The
first stage consists of an extensive bibliographical review that helped in the realization of this
work, in addition to the general and specific objectives. The second stage involves the
preparation and explores, through characterization techniques, the efficiency of precursor
materials (flying ash and CCA) in the production of goepolymer matrices. Finally, the third
stage covers the production of dry mixes for subsequent manufacture of geopolymers. At this
stage, the proportion by weight of calcined material (HCCA and H) that was able to generate
matrices with more satisfactory mechanical, physical and morphological properties is also
investigated. In general, those manufactured from the partial replacement of fly ash by 30% by
weight of calcined material involving CCA (HCCA30CV), showed the best properties. Finally,
the results obtained reveal that the capture of agro-industrial residues for applications in
cementing structures, in addition to generating an important benefit to the environment, is, in
fact, a potential for the future of engineering.

BANKING MEMBERS:
Presidente - 1507262 - KURT STRECKER
Externa ao Programa - 1348442 - PATRICIA BENEDINI MARTELLI
Externo ao Programa - 2695307 - LEANDRO JOSE DA SILVA
Externa à Instituição - SIMONE PEREIRA TAGUCHI BORGES - UFRRJ
Externo à Instituição - ALFEU SARAIVA RAMOS - UNIFAL-MG