Browsing by Keyword "Characterization"
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Item Chemical and Mechanical Characterization of a Novel CSA Blended Cement Based on CDW Inorganic Fractions(Springer Science and Business Media B.V., 2023) Frías, Moisés; Martínez-Ramírez, Sagrario; Fernández-Carrasco, Lucía; Giménez, Rosario García; de la Villa, Raquel Vigil; Monasterio, Manuel; Moreno-Juez, Jaime; Vegas-Ramiro, Iñigo J.; TRAZABILIDAD CIRCULARCement is a construction material widely used to improve the socio-economic development of a society. However, for its production path, it needs significant amounts of raw materials (limestone, clay, bauxite, etc.), which is currently outside the Environmental Policies. For this reason, any alternative to manufacture sustainable eco-cement based on the circularity of industrial waste is a priority line for the cement sector. This work presents the characterisation results of a calcium sulfoaluminate cement clinkerized (CSA-L), in a laboratory muffle at 1250ºC for 60 min, by partial replacement of raw materials by different construction and demolitions wastes (CDW) from the fine fraction of concrete (<5 mm), deconstruction building laminated glass and recycled gypsum. Subsequently, its physical-mechanical behaviour (water demand, setting times, soundness, mechanical properties and microporosity) was analysed in an eco-blended cement made by combining 90% OPC and 10% CSA (commercial and clinkerized ones), as preliminary studies for the manufacture of eco-cement materials for 3D printing. The results obtained demonstrate the feasibility of using CDW as secondary raw materials for the formation of a CSA eco-cement, with a mineralogical composition consisting of 24% Ye’elimite (C4A3$), 6% Larnite (α-C2S) and 31% Brediggite (Ca7Mg(SiO4)4. This eco-CSA-L cement shows an enriched nature in Brediggite with respect to commercial CSA-C cement. The binary mixture of cements (OPC + 10% CSA-L) shows a rheological and mechanical behaviour close to the reference OPC.Item Development of ultra-high performance concretes with self-healing micro/nano-additions(2017-05-01) García Calvo, J. L.; Pérez, G.; Carballosa, P.; Erkizia, E.; Gaitero, J. J.; Guerrero, A.; Gerrero, A.; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓN; Tecnalia Research & InnovationUHPC are developed in present paper incorporating an innovative self-healing system based on two micro/nano-additions: silica microcapsules containing epoxy sealing compound (CAP) and amine functionalised silica nanoparticles. Although CAP are well integrated within the cementitious matrix, their inclusion promotes a reduction in the mechanical performance so CAP could act as weak points. However, the inclusion of these additions refines pore distribution thus increasing the expected durability in aggressive media. An effective autonomous self-healing capacity is assessed/confirmed which is unexpectedly higher in the concretes with the lower healing additions content studied. This capacity depends on the crack width and the healing period considered.Item Reduction of the calcium leaching rate of cement paste by addition of silica nanoparticles(2008-08) Gaitero, J. J.; Campillo, I.; Guerrero, A.; Tecnalia Research & InnovationCalcium leaching is a degradation process that consists in the progressive dissolution of the cement paste as a consequence of the migration of the calcium ions to the aggressive solution. Although it is a well known phenomenon, a way of reducing it has not been found yet. The aim of this work is to prove how the addition of small amounts of silica nanoparticles to the cement paste can induce such reduction. The experimental results obtained have shown that nanosilica increases the strength of the cement paste about a 30% in cured samples and more than a 100% in the asymptotically leached ones. At the level of the structure of the C-S-H gel, silica nanoparticles increase the average length of the silicate chains and reduce their polymerization as calcium dissolves. An important decrease of the degradation in terms of porosity and amount of calcium lost has also been observed.