This investigation centers on early concrete technology used in Seguin, Texas, during the mid-19th century. Over the course of fifty years, more than ninety concrete structures were built in Seguin. Over the last century, these have dwindled to twenty extant structures. Much of the previous Seguin concrete era research has focused on the historical narrative and architectural description. This study aims to answer questions that previous research has not — it investigated the raw materials used in making Seguin’s concrete. The results provide new information about the Seguin concrete structures, providing guidance for their long-term maintenance. The materials analysis uses instrumental techniques such as scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray diffraction to determine the chemical composition and crystalline structure of the cement binder from several extant structures in Seguin. Gathering both qualitative and quantitative data for the binder allowed us to identify the raw materials used in the concrete and better understand the construction methods. Studying the materials and methods increased our understanding of these historic structures and will inform future preservation efforts. / text

Este trabalho pretende contribuir para o avanço nos estudos de parâmetros e procedimentos objetivos para avaliação estética de superfícies de concreto aparente e de materiais para preenchimento de lacunas neste material, de forma a atender requisitos especificados em projetos de conservação de edifícios modernos. Como objeto de estudo foi escolhido o Edifício Vilanova Artigas, sede da Faculdade de Arquitetura e Urbanismo da Universidade de São Paulo, obra arquitetônica que apresenta as características que motivaram o assunto abordado. Pautada pelas diretrizes de conservação do patrimônio construído defendidas por entidades como o Conselho Internacional de Monumentos e Sítios, a reparação dos danos dessas superfícies deve manter a unidade estética da obra, reconhecida por sua cor, textura e forma. O trabalho experimental possibilitou a comparação entre as superfícies do concreto original e de amostras de argamassas cimentícias, elaboradas com diferentes traços, pigmentos, aditivos e proteção superficial. As avaliações de aparência se basearam em métodos comparativos de dados colorimétricos no sistema CIE L*a*b* e por método perceptual com base em escala tonal. As investigações de textura foram feitas com materiais aplicados sobre as superfícies das argamassas frescas e as de geometria por estudo analítico para reparos nas empenas do edifício estudado. / This work intends to contribute to the advancement in the study of objective parameters and procedures for aesthetic evaluation of apparent concrete surfaces and materials to fill gaps in this material, in order to meet the requirements specified in conservation projects of modern buildings. The object of study was the Vilanova Artigas Building, headquarters of the Faculty of Architecture and Urbanism of the University of São Paulo, an architectural work that presents the characteristics that motivated the subject. Guided by the guidelines of conservation of the built heritage defended by entities like International Council of Monuments and Sites, the repair of the damages of these surfaces must maintain the aesthetic unity of the work, recognized by its color, texture and shape. The surfaces of the original concrete and samples of cement mortars, elaborated with different mix design, pigments, additives and surface protection were evaluated. The appearance evaluations were based on comparative methods of colorimetric data in the CIE system L * a * b * and by perceptual method based on tonal scale. The texture investigations were made with materials applied on the surfaces of the fresh mortars and those of geometry by analytical study for the conservation of the studied building.