Banca de QUALIFICAÇÃO: Mariana Rezende Schuab

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : Mariana Rezende Schuab
DATA : 04/07/2017
HORA: 09:00
LOCAL: Centro Federal de Educação Tecnológica de Minas GeraisAvaliação
TÍTULO:

Evaluation of the retraction in alkali-activated mortars for structural repair with Portland cement concrete substrate.

 

PALAVRAS-CHAVES:

Alkali-activated mortar; Geopolymer mortar; Structural repair mortar; Retraction.

 

PÁGINAS: 59
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Civil
SUBÁREA: Construção Civil
RESUMO:

The occurrence of structural repairs of reinforced concrete is subject to increasead growth, since there is  many buildings, in old age, exposed to weather and other conditions adverse to durability and, consequently, deteriorated. Repair mortars must meet the requirements for workability, durability and compatibility with the substrate. In this work, different mixtures, based on various combinations between alkaline activated precursors (metacaulim and blast furnace slag) with different combinations between the activating solutions (sodium silicate and sodium hydroxide) were evaluated in relation to their suitability for the repair in concrete structures. Initially, 20 preliminary formulations were tested, which were submitted to the flow table test, to ensure adequate workability. Preliminary formulations enabled the definition of the most adequate results of modulus of elasticity and compressive strength of the mortars, in comparison to the results presented by the concrete used in the substrate. After the respective tests, at 28 days, 5 formulations were adopted, among the initially proposed, and an intermediate formulation, totaling 6 formulations of mortar. Then, selected mortars - molded with two percentages (0% and 0,25%) of polypropylene (PP) fibers, of length 6mm, to mitigate the effects of retraction - were applied with a layer of 2 cm in a 30 MPa Portland cement concrete CPV-ARI (40 x 40 cm and 8 cm high) concrete substrate whose surface was prepared to maintain uniform roughness. Then, retraction and pullout evaluation tests were performed. After evaluating the results, the formulations with the best performance were selected to perform new moldings with different percentages of fiber, since the evaluated ones were not satisfactory. In addition, free retraction tests, indicative of durability, flexural tensile and scanning electron microscopy, should be performed at the interface between the mortar and the substrate.

MEMBROS DA BANCA:
Externo ao Programa - AUGUSTO CESAR DA SILVA BEZERRA
Interno - CONRADO DE SOUZA RODRIGUES
Presidente - PAULO HENRIQUE RIBEIRO BORGES
Externo à Instituição - WHITE JOSE DOS SANTOS - UFMG