Banca de QUALIFICAÇÃO: RAFAEL COSTA MANTA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : RAFAEL COSTA MANTA
DATE: 24/10/2023
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

Influence of Hydrated Lime on coating mortars: An investigation of microstructural, morphological, chemical and mechanical aspects

KEY WORDS:

mortar; coating; hydrated lime; shrinkage; characterization techniques.

PAGES: 81
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

Mortars are construction materials produced from Portland cement, fine aggregate, and water, and are commonly used for coating surfaces and laying masonry blocks. Hydrated lime Ca(OH)₂ can be added to mortar with the aim of improving certain specific properties. However, the addition of lime can also have adverse effects on the mortar, such as shrinkage. The main goal of this study is to assess the influence of hydrated lime in rendering mortars by varying the dosage and analyzing microstructural, morphological, chemical, and mechanical aspects. To investigate this phenomenon, the precursor materials were characterized, including fine natural aggregate, Portland cement, hydrated lime, and used blocks. Subsequently, masonry work was carried out, including the application of rendering mortar to walls and the production of test specimens, with the determination of consistency indices for different mortar proportions. For the masonry walls, tensile bond strength tests were performed. For the test specimens, mechanical tests for tensile flexural and compressive strength were conducted. Samples of hardened mortar were extracted for analysis using techniques and material characterizations such as TG, FTIR, XRD, and XRF. Partial results showed that an increase in the proportion of hydrated lime in the mixture is directly related to a decrease in mechanical strength. The increase in the proportion of hydrated lime led to more cracks and an apparent decrease in rendering adhesion. An increase in consistency and plasticity was observed in the proportions with more hydrated lime. XRF analysis revealed that the studied mortars are primarily composed of CaO, SiO2, Fe2O3, and Al2O3. The FTIR results were used to investigate the influence of hydrated lime on the vibrational modes of cementitious mortar, and SEM analysis revealed differences in morphological formation. XRD analysis allowed for the identification of phases in the samples. Mortars with and without lime (1:1:6 and 1:0:6) exhibited similar mass loss during temperature application, losing just over 3%. However, the mortar with a proportion of 1:5:6 lost approximately 16.24% of its total mass.

COMMITTEE MEMBERS:
Externo à Instituição - LEONARDO BARBOSA TORRES DOS SANTOS - INPE
Externa à Instituição - LILIAN KÁSSIA CAVALCANTE DA SILVA DE ASSIS - UPE
Externo à Instituição - ÂNGELO JUST DA COSTA E SILVA - UPE