Banca de DEFESA: VICTOR MARCELO ESTOLANO DE LIMA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : VICTOR MARCELO ESTOLANO DE LIMA
DATE: 15/12/2022
TIME: 08:30
LOCAL: Programa de Pós-Graduação em Engenharia Civil
TITLE:

Binary Mixtures of Sugarcane Bagasse Ash And Alkali-Activated Slag

KEY WORDS:

Blast furnace slag; Alkaline activation; Sugarcane bagasse ash

PAGES: 187
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

Sugarcane bagasse ash (SBA) has little potential to be used as fertilizer, and for this reason its end is usually accumulated in piles within the sugarcane plantation land or illegal dumping in another land. This waste has significant pozzolanic potential provided it is treated with controlled grinding and calcination. These processes, however, increase the final cost of the product and can make it unfeasible. In this context, this thesis proposes to use SBA without processing (in natura) and benefited only by calcination for safe encapsulation in structural mixtures based on alkali-activated blast furnace slag. To achieve the main objective, the influence of ash on the physical, mechanical and microstructural properties of mixtures with activated slag will be analyzed. Two variations in the type of ash were used: raw and calcined (both without grinding); two types of alkaline activator: sodium silicate and metasilicate; three variations in the water/binder ratio: 0.45, 0.55 and 0.65; and four variations in the alkaline activator content: 3.0, 4.5, 6.0 and 7.5%. The tests used to evaluate the physical properties were: flow table (consistency table), water absorption, compressive strength, flexural strength and ultrasound pulse velocity to evaluate the physical and mechanical properties of mortars; in addition to X-ray diffraction, scanning electron microscope, thermogravimetry and infrared spectrometry tests to evaluate the microstructure in the pastes. The results showed that the optimal dosages of 4.5 and 6.0 of Na₂O (%) provided the best balance between mechanical performance, costs and CO₂ emissions, therefore, these dosages were chosen in mixtures with ash. In general, the results of mixtures with slag and SBA showed a decrease in compressive strength proportional to the replacement content at 28 days. Scanning electron microscopy analysis revealed the way in which the organic particles from SBA formed in the alkali-activated matrix. Even so, it was concluded that in addition to the economic and environmental benefits, the use of raw or only calcined SBA in alkali-activated matrices has potential for practical application for specific purposes, such as repair mortars, but new targeted studies need to be developed.

COMMITTEE MEMBERS:
Externo à Instituição - FLÁVIO DE ANDRADE SILVA - PUC - RJ
Externo à Instituição - ROMILDO MORANT DE HOLANDA - UFRPE
Externo à Instituição - SANDRO MARDEN TORRES - UFPB
Presidente - 2994651 - TIAGO ANCELMO DE CARVALHO PIRES DE OLIVEIRA
Externa à Instituição - YÊDA VIEIRA PÓVOAS - UPE