Banca de DEFESA: MARIA LUIZA RAMALHO DE ARAÚJO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIA LUIZA RAMALHO DE ARAÚJO
DATE: 13/12/2022
TIME: 14:00
LOCAL: Pós-Graduação em Engenharia Civil
TITLE:

Ternary Mixtures Based On Hydrated Lime, Metakaolin And Sugarcane Bagasse Ash

KEY WORDS:

Sugarcane bagasse ash; metakaolin; supplementary cementitious materials; pozzolan

PAGES: 75
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

The use of supplementary cementitious materials (SCM), known in the Brazilian literature as mineral additions, to replace Portland cement was a very important advance for the development of cementitious materials. The present work aims to characterize the ternary mixtures of sugarcane bagasse ash (SCBA) in natura, metakaolin (MK) and hydrated lime, as well as the possible pozzolanicity among the compositions of SCBA and metakaolin, so that they can be used as addition to Portland cement. For this, 21 compositions were prepared in different combinations of materials of 100% content of SCBA and Metakaolin, with variations of 5 in 5% between the materials, ranging from 100% SCBA to 100% Metakaolin, to identify as materials that have pozzolanic potentials in relation to XRD tests and NBR 5751:2015 standard. However, in the assays to determine the pozzolanic activity index by NBR 5752:2015, were only studied of the 10, 20, 30, 50, 60, 75 and 100% of SCBA in natura compositions with MK, to observe the strength of Portland materials, analyzing the percentages of SCBA in natura with the highest concentration among them. The stages were constituted firstly by the characterization of the materials, then by the microstructural analysis of the mixtures with the identification of the main phases and the indicative of the levels of consumption of calcium hydroxide from the variations of substitution of each material, and finally, by the indirect evaluation of pozzolanic activity with lime (ABNT NBR 5751, 2015) and with cement (ABNT NBR 5752, 2014). The microstructural results obtained by the diffractograms showed a greater consumption of calcium hydroxide as the percentage of metakaolin increased and the ash content of sugarcane bagasse decreased. This trend was repeated for the results of the compressive strength tests with lime, verifying that a substitution of up to 55% SCBA in natura in ternary mixtures with metakaolin and hydrated lime can be indirectly considered a pozzolanic material. Above that, the mixtures are not considered pozzolanic according to the limit of 6MPa determined by the standard. As for the compressive strength test with cement at 28 days, standardized by NBR 5752 (ABNT, 2014), it was found that the compositions containing ash with up to 60% of SCBA in natura in mixtures with metakaolin can be considered pozzolanic. In this way, it is possible to produce a pozzolanic material from a ternary composition by mixing a low potential material such as SCBA in natura, a high reactivity material (metakaolin) and hydrated lime for use as pozzolanic materials. Therefore, it is possible to solve the problem of SCBA that generates waste without destination throughout Brazil and in the State of Pernambuco.

COMMITTEE MEMBERS:
Externo à Instituição - JOÃO PAULO CASTRO GOMES
Externo à Instituição - MARCELO HENRIQUE FARIAS DE MEDEIROS - UFPR
Externo à Instituição - ALEX NEVES JUNIOR - UFMT
Presidente - 1670637 - ANTONIO ACACIO DE MELO NETO