Browsing by Author "Santamaría, A."
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Item Early concrete structures: Patented systems and construction features(CRC Press/Balkema, 2016) Marcos, I.; San-José, J. T.; Cuadrado, J.; Santamaría, A.; Garmendia, L.; Díez, J.; Van Balen, Koen; Verstrynge, Els; Van Balen, Koen; Tecnalia Research & Innovation; E&I SEGURAS Y RESILIENTESReinforced concrete structures came to Spain in the late-nineteenth century, somewhat after the development of this new construction material elsewhere in Europe. Their introduction was pioneered in industrialized areas, especially Northern Spain, under systems first patented in other European countries. Local constructors built structures under patents with little or no explanation for calculation, design and construction technique. Some of these buildings from the recent past are now listed buildings. This study centres on three construction projects under patented systems: Our Lady of "La Antigua", Orduña (Monier system), "La Ceres" flour mill, Bilbao, (Hennebique system) and Alhóndiga, Bilbao (Blanc system). Preliminary structural studies analyzed morphology, reinforcements, concrete strength and pathological processes in each structure. Results are compared with information taken from the patent systems in use at the time. This useful information on the structures, which may be expanded in future research, clearly describes the relationship between their theoretical specifications and the built reality.Item Erratum: The role of a dechlorinated PVC as compatibiliser for PVC/polyethylene blends (Polymer Bulletin (2002) 48:3 (283-290))(2002) Zarraga, A.; Muñoz, M. E.; Peña, J. J.; Santamaría, A.; SGItem Estudio reológico de mezclas de porcelana reciclada para el moldeo por inyección(2001) Agote, I.; Odriozola, A.; Gutiérrez, M.; Santamaría, A.; Quintanilla, J.; Coupelle, P.; Soares, J.; EXTREMAT; Centros PRE-FUSION TECNALIA - (FORMER); SGThe aim of this work is to investigate the possibility of using waste porcelain for injection moulding. Five formulations of porcelain containing different amounts of recycled porcelain have been studied. Flow properties of these formulations have been analysed and related to injection behaviour.Item Fracture toughness evaluation of fiber-reinforced concrete manufactured with siderurgic aggregates.(2019) Ortega-López, V.; Revilla-Cuesta, V.; Skaf, M.; Fiol, F.; Santamaría, A.; García-Llona, A.; Piñero, I.; Tecnalia Research & Innovation; E&I SEGURAS Y RESILIENTESSteel production in electric arc furnaces generates a principal waste stream in the form of Electric Arc Furnace Slag (EAFS), also known as “black slag”. The well-researched and advantageous properties of EAFS guarantee its successful use as aggregate in the manufacture of concrete (CEAFS). In contrast, fiber-reinforced concrete is widely employed, especially in concrete pavements and slabs, for improved cracking resistance and “ductile” post-cracking behavior. In this research, the toughness and ductile behavior of these fiber-reinforced CEAFS is tested with various methods, using different types of (metallic and synthetic) fibers in EAFS mixes. The metallic fiber concretes showed better results than the fiber concretes in terms of toughness, first-crack strength, limit of proportionality, and post-cracking behavior. The recycling process of EAFS makes a relevant contribution to the circular economy and therefore to global sustainability.Item A Rheological Study of Porcelain Feedstock for Injection Moulding(2000-11) Agote, I.; Odriozola, A.; Gutierrez, M.; Santamaría, A.; Quintanilla, J.; Coupelle, P.; Soares, J.; EXTREMAT; Centros PRE-FUSION TECNALIA - (FORMER); SGThe aim of this work is to re-use porcelain rejects in the injection-moulding process. Five types of hard porcelain powders for injection moulding were studied. These powders contained different amounts of recycled porcelain. The same commercial binder was used in all cases. In order to confirm the possibility of using this powder, the evaluation of the flowability of different feedstocks using rheological parameters (e.g. effect of powder characteristics, melt viscosity, activation energy, yield stress, power law index and rheological index), and the correlation of these parameters with injection behaviour was done.Item Rheological study of waste porcelain feedstocks for injection moulding(2001-12) Agote, I.; Odriozola, A.; Gutierrez, M.; Santamaría, A.; Quintanilla, J.; Coupelle, P.; Soares, J.; EXTREMAT; Centros PRE-FUSION TECNALIA - (FORMER); SGFive types of hard porcelain powders for injection moulding have been studied, using the same commercial binder in all cases. These powders contained different amounts of recycled porcelain, since one of the principal aims of this work is to reuse waste porcelain in the injection moulding process. The evaluation of the flowability of different feedstocks was carried out using rheological parameters, like critical powder volume concentration (CPVC), melt viscosity, activation energy, yield stress, powder law index and rheological index. The correlation of these parameters with injection behaviour was established, in order to confirm the possibility of using this moulding process with recycled porcelain powders.Item Specific rheological and electrical features of carbon nanotube dispersions in an epoxy matrix(2010-05) Chapartegui, M.; Markaide, N.; Florez, S.; Elizetxea, C.; Fernandez, M.; Santamaría, A.; POLIMEROSThe rheological analysis of epoxy pre-polymer/MWCNT dispersions indicates that a physical network is formed. This is destroyed with an imposed shear, giving a viscoplastic and shear thinning behavior. Such destruction is not reflected in dynamic viscoelastic experiments, due to the very rapid recovery of the MWCNT network in the pre-polymer matrix. This responds to the observed lower electrical than rheological percolation threshold. Electrical conductivity results fulfill electron hopping/tunnelling mechanism, which implies a tube-tube distance close to 5. nm. However, rheological percolation requires nanotubes should touch each other, since no polymer chains are implied in the network.