Banca de DEFESA: TIAGO MANOEL DA SILVA AGRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : TIAGO MANOEL DA SILVA AGRA
DATE: 24/02/2022
TIME: 10:00
LOCAL: Auditório Pós-Graduação em Engenharia Civil on line
TITLE:

Evaluation of Pozolanicity of Sludge from the Water Treatment Process

KEY WORDS:

Water treatment sludge ash; High-strength pozzolan; Pozzolanic activity; Metakaolin; Calcium hydroxide

PAGES: 78
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

The cement industry is one of the biggest CO2 generators in the world. With global warming, solutions to replace Portland cement clinker have been studied. One of them is the use of sludge ash from water treatment plants (WTP) as a supplementary cementitious material. This work aims to analyze the pozzolanic properties of calcined WTP sludge and make it viable as a pozzolan for cementitious products. After collection, the sludge was placed for drying in the open air, and then dried in an oven. In addition to dry sludge (LETA), calcined sludge was used at temperatures of 600°C (CLETA600), 700°C (CLETA700) and 800°C (CLETA800). After calcination, milling for one hour was conducted for homogenization and particle sizereduction. The characterization of the sludge was performed using particle size analyzer,Blaine fineness, Le Chatelier flask density, X-ray diffraction, and thermogravimetric tests. Itwas observed that the sum of the oxides Al2O3+SiO2+Fe2O3 above 75% and the high content of kaolinite in the dry sludge were indicative that the sludge could present pozzolanic activity after processing. The standardized tests to quantify pozzolanicity were performedthrough compressive strength in mortars following the Brazilian standards NBR 5751 and NBR 5752. These tests showed that all samples could be characterized as pozzolan. In addition to  these tests on hydrated lime pastes, calcium hydroxide consumption was analyzed using X-ray diffraction, thermogravimetry and infrared spectroscopy. The results showed that the sample CLETA600, which showed the lowest pozzolanic activity in the compressive strength tests, was the one that presented the highest consumption of calcium hydroxide, unlike the compressive strength tests. These results with pastes also corroborated the data obtained in the electrical conductivity test. Finally, it was concluded that the WTP sludge ash can be considered a safe pozzolan to be applied in cementitious products, however, only a case-by- case study with the association of standardized and non-standardized techniques is possible to fully understand the analyzed material.

BANKING MEMBERS:
Presidente - 1670637 - ANTONIO ACACIO DE MELO NETO
Interna - 1128124 - ROMILDE ALMEIDA DE OLIVEIRA
Externo à Instituição - ROMILDO MORANT DE HOLANDA - UFRPE