Banca de DEFESA: LISIEUX FEITOSA GONDIM PIPOLO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LISIEUX FEITOSA GONDIM PIPOLO
DATE: 28/07/2021
TIME: 09:00
LOCAL: https://meet.google.com/biw-dvqh-ksk
TITLE:

Study of cement paste with partial and total replacement of manipueira by mixing water.

KEY WORDS:

Cement paste. Biopolymer. Manipueira. Cement hydration. By-product

PAGES: 92
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Construção Civil
SPECIALTY: Materiais e Componentes de Construção
SUMMARY:

Cement paste is the union of two basic inputs in the civil construction sector, water, and cement. From it, mortar and concrete, the most consumed elements in the construction industry, are prepared. Given the great demand for these inputs, some questions arise about the environmental impact, regarding the high consumption of natural resources and the social impact of the use of treated water for less noble activities than human supply. In this way, researches have been developed to replace the traditional materials of cement paste with by-products that provide similar or better properties in cementitious materials and minimize the consumption of natural goods by replacing them with by-products from other productive activities. The cassava processing process (Manihot esculenta Crantz) for the production of starch and flour generates cassava, a milky liquid by-product that flows from the roots during the pressing process with a high content of hydrocyanic acid and high biochemical oxygen demand (BDO). In 2020, Brazil was responsible for the production of 18.96 million tons of cassava root, which is equivalent to 14.95 ton/ha. It is estimated that the production of manipueira reaches a ratio of 3:1, for each 3kg of pressed roots, 1 of cassava leaves is generated. Accumulation in small surrounding areas or its disposal in water bodies (alteration of self-purification and eutrophication capacity). Considering this context, the objective of this research is to analyze the behavior of the cement paste in the fresh and hardened state, in addition to its microstructure when replacing totally and partially the hydration water by liquid cassava. In this way, seven proportions of replacement of liquid cassava by the hydration water of the cement paste in 10%, 15%, 20%, 25%, 50%, 75%, and 100% were studied. The characterization of cement and manipueira (by-product) was carried out. Next, the pastes were analyzed for their properties in the fresh state (normal consistency, mini-slump, and setting time) and hardened (compressive strength, flexural tensile strength, capillary absorption, immersion absorption, bulk density). They were carried out in the samples of compositions of l counted with Scanning Electron Microscopy (SEM), X-Ray Diffraction (DRX), X-Ray Fluorescence (FRX), and Thermogravimetry (TG/DTG). In the fresh state, the presence of manipueira caused a delay in setting time and promoted a plasticizer behavior to the cement pastes in all the proposed formulations. In the hardened state, it promoted an increase in compressive strength in formulations with up to 20% replacement and a sharp drop in other proportions. It was also verified a decrease in specific mass, an increase in the void index, and absorption by capillarity in all variations of replacing the cassava tree with water. The results indicated that the formulation of the cement paste with replacement of the hydration water by cassava plant with the best performance in the evaluated items was 20%, making the by-product, cassava mill viable, as a viable material for application in cement-based products.

BANKING MEMBERS:
Presidente - 1149564 - WILSON ACCHAR
Interna - 1717461 - LUCIANA DE FIGUEIREDO LOPES LUCENA
Externa à Instituição - JAQUELIGIA BRITO DA SILVA
Externa à Instituição - SHEYLA KAROLINA JUSTINO MARQUES - IFAl
Externo à Instituição - VAMBERTO MONTEIRO DA SILVA - IFPB