Banca de DEFESA: THAÍS PINTO LOBO SIQUEIRA
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.DISCENTE : THAÍS PINTO LOBO SIQUEIRA
DATA : 19/03/2020
HORA: 14:00
LOCAL: PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA CIVIL
TÍTULO:
USE OF GRANITIC ROCK FINES (FRG) AND MANUFACTURED SAND FOR SELF-COMPACTING CONCRETE PRODUCTION
PALAVRAS-CHAVES:
Self-compacting concrete. Self-compacting mortar. Fine granitic rock. Manufactured sand
PÁGINAS: 244
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Civil
RESUMO:
The durability and safety of concrete structures are directly related to the efficiency of their execution. In densely reinforced structures or with complex geometries, filling the molds is difficult, which may result in concrete failures that compromise the performance and durability of the structure. Thus, self-compacting concrete (SCC) appears as a possible solution to this problem, as it has the ability to flow only by the action of its own weight. In this way, the use of SCC in buildings has numerous advantages, such as: better surface finish, speed in execution and greater architectural freedom. For this, SCC typically has a high dosage of superplasticizer additives and/or viscosity modifiers and a high content of fines to guarantee the necessary rheological characteristics, which ends up making the product more expensive. With this, the use of granite rock fines (FRG) appears as a possible solution, since its incorporation helps to obtain the necessary properties, reducing the consumption of additives and, consequently, the cost of concrete. In addition to FRG, manufactured sand can be used to partially replace natural sand, in order to reduce the environmental and social impacts related to its excessive extraction. Therefore, the present work aims to study the dosage of SCCs, with addition of FRG and partial replacement of natural sand by manufactured sand, in order to obtain mixtures with adequate rheological parameters and performance in the hardened state, using for this lower content of additive superplasticizer and aiming to eliminate the need to incorporate the viscosity modifying additive. First, the physical, chemical and mineralogical characterization of the FRG was carried out, followed by paste analysis to determine the levels of fines to be used. Subsequently, analyzes in the fresh state were carried out on self-compacting mortars (mortars that make up self-compacting concrete) to determine the volume of fine aggregate by mini-V funnel and mini slump test tests. In SCCs, the fresh state analyzes aimed to determine the performance of the different formulations through the slump test, T500, visual stability index, V-funnel, L-box, J-ring and segregation column. Finally, the properties of concretes and mortars in the hardened state were evaluated by checking its compression and bending traction strength, water absorption by apparent capillarity, apparent porosity and density. For the SCCs, the drying shrinkage of the specimens was also analyzed. The results show that mortars and concretes dosed with simultaneous incorporation of FRG and manufactured sand showed mechanical performance equivalent to the reference dosages. In addition, it was found that the incorporation of FRG is the factor with the greatest influence on the increase in viscosity and reduction of apparent porosity and water absorption by capillarity of the analyzed matrices while the manufactured sand has no significant influence. It is also noticed that all the studied dosages, with isolated and simultaneous incorporation of FRG and manufactured sand, presented less drying shrinkage when compared to the reference dosage.
MEMBROS DA BANCA:
Interno - 2137887 - CLEBER MARCOS RIBEIRO DIAS
Presidente - 1779028 - DANIEL VERAS RIBEIRO
Externo à Instituição - JOAO LUIZ CALMON NOGUEIRA DA GAMA - UFES
Externo à Instituição - RAFAEL GIULIANO PILEGGI
Externo ao Programa - 1475073 - VANESSA SILVEIRA SILVA