Banca de DEFESA: EVILANE CASSIA DE FARIAS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : EVILANE CASSIA DE FARIAS
DATA : 28/03/2019
HORA: 14:00
LOCAL: Auditório do CTEC
TÍTULO:

Evaluation of durability against the combined attack of CO2 and
Cl ̄ in self-compacting concretes with high levels of sugar cane biomass
waste and metakaolin


PALAVRAS-CHAVES:

Self-compacting concrete, sugarcane biomass waste,
metakaolin, chloride ions, carbonation, durability.


PÁGINAS: 173
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Civil
SUBÁREA: Construção Civil
RESUMO:

The self-compacting concrete (SCC) with low comsumption of cement is an
alternative to produce concretes that less attack the environment. The
comercial pozzolans, such as metakaolin (MK), and the agroindustrial residues,
for example the sugarcane biomass waste (RBC), can be used for the benefit of
the sustainability, associated woth the possibility of maintaining, or improving,

the rheological, mechanical and durability properties of the SCC. Among the
mechanisms of concrete degradation, the main causers of corrosion are the
attack by carbonation and the attack by chloride ions. Thus, the present work
aims to analyze the performance of self-compacting concretes with high levels
of MK and RBC submitted to the independent and combined action of
carbonation (CO2) and chloride ions (Cl ̄). The CO2 attack occurred in an
accelerated way through a carbonation chamber and the exposition to the
chloride ions was done through cycles of wetting and drying. For this, SCCs
with partial cement substitution in percentages up to 50% were analyzed, with
five traces being performed: one with cement only, one with 30% RBC, the third
with 20% RBC and 20% metakaolin, the fourth with 30% RBC and 10%
metakaolin, and the latter with 30% RBC and 20% metakaolin. Subsequently,

the SCCs properties were evaluated in the fresh state to attest the self-
adherence criteria recommended by NBR 15823 (ABNT, 2017). In the

hardened state, were made the tests of compressive strength, depth of
penetration of CO2 and Cl ̄, diffusion of chloride ions by the non-stationary
method, ultrasonic pulse velocity, electrical resistivity, corrosion potential, water
absorption by capillarity and physicial indexes. The results showed being
possible to produce self-compacting concretes with low comsumption of cement
using RBC and MK and with resistances above 40MPa. The poor performance
against carbonation of SCCs with mineral additions can be mitigated by
increasing the coating thickness. On the other hand, when exposed to chloride,
the concretes with additional cimentitious show better performance. The
presence of free chloride in the samples of the SCCs causes a lower
carbonation front. The Cl ̄ attack occurs much more severely than the
carbonation. Finally, among the aggressive environments analyzed, the
combined carbonation and chloride situation was the one that caused the
greatest damage in relation to the corrosion of the reinforcement.


MEMBROS DA BANCA:
Externa à Instituição - ANA CECILIA VIEIRA DA NOBREGA - UFPE
Externo à Instituição - GIVANILDO ALVES DE AZEREDO - UFPB
Interna - 1717461 - LUCIANA DE FIGUEIREDO LOPES LUCENA
Presidente - 022.621.844-96 - MARCOS ALYSSANDRO SOARES DOS ANJOS - IFRN
Externa ao Programa - 1507841 - MARIA DAS VITORIAS VIEIRA ALMEIDA DE SA
Notícia cadastrada em: 28/03/2019 13:32
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