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Master's Dissertation
DOI
https://doi.org/10.11606/D.3.2020.tde-01042021-155040
Document
Author
Full name
Paulo Henrique Ferreira Loz
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2020
Supervisor
Committee
Angulo, Sérgio Cirelli (President)
Rebmann, Markus Samuel
Torres, Sandro Marden
Title in Portuguese
Avaliação multiescala da rugosidade de agregados graúdos naturais.
Keywords in Portuguese
Agregados
Concreto
Interferômetros
Microestrutura
Rugosidade
Scanner 3D
Abstract in Portuguese
A rugosidade dos agregados influencia o desempenho do concreto no estado fresco e no endurecido. Agregados com elevadas rugosidades melhoram as propriedades na interface pasta-agregado, mas aumentam a viscosidade do concreto, devido ao aumento do atrito entre as partículas. Apesar da importância da rugosidade, não há estudos que realizem uma análise multiescala (macro e micro), impedindo uma melhor compreensão dos seus efeitos no concreto. Diante disto, esse trabalho propõe um estudo multiescala da rugosidade de diferentes agregados. Para tanto, a rugosidade dos agregados foi medida através da interferometria óptica, que fornece dados quantitativos em 3D. Seistipos de agregados foram analisados e apresentaram rugosidades distintas entre si, em ambas escalas (macro e micro). As análises petrográficas mostraram que a rugosidade pode estar relacionada com o tamanho e quantidade dos grãos da microestrutura da rocha. O escaneamento 3D foi utilizado para caracterizar o formato das partículas e complementar os dados de rugosidade considerando o volume, permitindo a determinação da área superficial volumétrica (ASV) dos agregados, na microescala de observação. A medida física da área superficial (AS) obtida pela técnica de adsorção de azul de metileno obteve indícios de boa correlação com a AS obtida pelo interferômetro.
Title in English
Multiscale analysis of roughness of coarse natural aggregates.
Keywords in English
3D scanner
Coarse aggregates
Interferometer
Microstructure
Roughness
Abstract in English
The roughness of aggregates influences the performance of the concrete in the fresh and hardened state. Aggregates with high roughness improve the properties at the pasteaggregate interface but increase the viscosity of the concrete due to the increased friction between the particles. Despite the importance of roughness there are no studies that perform a multiscale analysis (macro and micro), preventing a better understanding of its effects on concrete. Therefore, this work proposes a multiscale study of the roughness of different aggregates. For this purpose, the roughness of the aggregates was measured through optical interferometry, which provides quantitative data in 3D. Six types of aggregates were analyzed and presented different roughness in both scales (macro and micro). Petrographic analyses showed that the roughness may be related to the size and quantity of the grains in the microstructure of the rock. The 3D scanning was used to characterize the particle shape and complement the roughness data with the volume, allowing the determination of the volumetric surface area (VSA) of the aggregates at the microscale of observation. The physical measurement of the specific surface area (SSA) obtained by the methylene blue adsorption technique obtained evidence of good correlation with the interferometer SSA.
 
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Publishing Date
2021-04-05
 
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