Estudo de matrizes cimentícias ternárias contendo sílica ativa e nanossílica

• Autor(a) principal: Pereira, Ana Paula de Oliveira
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10917
• topic: Concreto; Microestrutura; Durabilidade; Sílica ativa; Nanossílica; Concrete; Microstructure; Durability; Silica fume; Nanosilica; ENGENHARIAS::ENGENHARIA CIVIL::CONSTRUCAO CIVIL

The reinforcement corrosion, which significantly affects the country's coastal regions, is a serious and costly pathological manifestation for civil construction. Within this scenario, the literature shows that silica fume and nanosilica are highly effective pozzolans for increasing the strength and durability of structures in general. Even so, there are few studies that analyze in depth the microstructural changes that occur in this material through the combined use of these two additions. Therefore, it was sought with this work to explain the microstructural mechanisms, responsible for the increase of durability in cementitious matrices, produced with additions of active silica fume and nanosilica in a fixed optimum content in partial replacement to the Portland cement mass and in two water/bind (w/b) (0.4 and 0.6). For this, several techniques were used, including analytical and imaging techniques: pore solution analysis, Scanning Electron Microscopy (SEM), X-ray microtomography, thermal analysis and calorimetry, in addition to mechanical characterization. The results showed that the combination of the additions promoted the reduction of pore solution's conductivity and ionic strength, changes in the evolution of hydration and hydrated products and greater compacting, densification and transformation of the porous structure of the concrete with up to 50% compressive strength increments. Keywords: Concrete, microstructure, durability, silica fume, nanosilica.