Capítulos de libro (Fac. de de Ciencias)
Permanent URI for this collectionhttps://hdl.handle.net/10171/70278
See
42 results
Results
- Green way of improving the thermal efficiency of mortars by the addition of biobased phase change materials(MATEC Web of Conferences, 2024-09-16) Alvarez-Galindo, J.I. (José Ignacio); Rubio-Aguinaga, A. (Andrea); Navarro-Blasco, I. (Iñigo); Fernandez-Alvarez, J.M. (José María)The thermal efficiency of air lime-based mortars was improved by directly integrating varying amounts (5 wt. %, 10 wt. %, and 20 wt. %) of a biobased Phase Change Material (PCM) into the fresh mortars. The composition of this PCM is vegetable oils and other organic wastes from the agri-food sector. To optimise the mortar formulation, different chemical additives and mineral admixtures were added. The mortar formulation was meticulously designed to produce rendering mortars that are easily workable, crack-free, and fully adherent for use in building envelopes. Positive outcomes in thermal efficiency tests have demonstrated the ability of these materials to store thermal latent energy, offering an environmentally friendly alternative to enhance the thermal comfort of building inhabitants.
- Estudio Voltamétrico de la complejación del cobre(II) en las Rías Gallegas(Universidade de Aveiro, 2000) Cobelo-García, A. (Antonio); Prego, R. (Ricardo); Fernandez-Alvarez, J.M. (José María)En el presente trabajo se propone una metodología que permite la cuantificación de la fracción lábil y la concentración total de Cu en las Rías Bajas Gallegas.
- Obtaining of repair lime renders with microencapsulated phase change materials: optimization of the composition, application, mechanical and microstructural studies(University of Ljubljana, Slovenia, 2022-09-21) Alvarez-Galindo, J.I. (José Ignacio); Rubio-Aguinaga, A. (Andrea); Navarro-Blasco, I. (Iñigo); Fernandez-Alvarez, J.M. (José María)Different batches of repair lime rendering mortars were designed by mixing microencapsulated Phase Change Materials (PCMs) and other additives. The final aim of these renders is to improve the thermal efficiency of the envelope of the Built Heritage, while allowing the practitioners to apply a render with positive final performance. The combinations of the PCMs in different weight percentages, a superplasticiser (to increase the fluidity of the render keeping constant the mixing water), an adhesion improver and a pozzolanic additive were studied. The adhesion of these renders onto bricks and limestone specimens and the shrinkage and cracking of the mortars were studied in detail. X-ray diffraction technique was used to study the composition and evolution of the carbonation process. Compressive strength measurements were studied in hardened specimens. In addition, the porous structure of the rendering mortars was studied by mercury intrusion porosimetry to assess the effect of the PCMs' addition. Samples underwent accelerated climatic ageing to study their durability and the preservation of the thermal efficiency. Results have shown that these thermally enhanced mortars are feasible materia Is for real-life application in the context of architectural heritage restoration and conservation.
- Enhancement of latent heat storage capacity of lime rendering mortars(University of Ljubljana, Slovenia, 2022-09-21) Alvarez-Galindo, J.I. (José Ignacio); Rubio-Aguinaga, A. (Andrea); Navarro-Blasco, I. (Iñigo); Fernandez-Alvarez, J.M. (José María)Microencapsulated Phase Change Materials (PCMs) were included in air lime rendering mortars in order to improve the thermal comfort of the inhabitants and the energy efficiency of buildings of the Architectural Heritage under the premises of mínimum intervention and maximum compatibility. Three different PCMs were tested and directly added during the mixing process to fresh air lime mortars in three different percentages: 5, 10 and 20 wt. %. Some chemical additives were also incorporated to improve the final performance of the renders: a starch derivative as an adhesion booster; metakaolin as pozzolanic addition to shorten the setting time and to increase the final strength; anda polycarboxylated ether as a superplasticizer to adjust the fluidity of the fresh renders avoiding an excess of mixing water. The specific heat Cp, the enthalpy ti.H ascribed to the phase change and the melting temperature of the PCMs were determined by Differential Scanning Calorimetry (DSC). The capacity of the renders to store/release heat was demonstrated at a laboratory scale. The favourable results proved the effect of these PCMs w ith respect to the thermal performance of these rendering mortars, offering a promising way of enhancement of the thermal efficiency of building materiaIs of the Cultural Heritage.
- Lipid and polymeric nanocapsules(IntechOpen, 2022) Vélaz-Rivas, I. (Icíar); Rochin-Wong, S. (Sarai)In recent years, innovative drug nanocarriers have been developed to enhance stability, bioavailability, and provide sustained release. In this chapter, systems based on natural macromolecules, lipids, or polymeric/polyelectrolyte nanocapsules and their principal chemical and functional characteristics are described. Nano-vesicular systems are especially relevant in different fields. Particularly, a promising potential is offered by systems based on colloidal nanocapsules, that exhibit a typical core-shell structure in which the drug can be confined into the cavity or in the polymeric coating that surrounds it. Both the cavity and the active substance can be lipophilic or hydrophilic and in solid or liquid form depending on the materials and methods used, making these nanocapsules attractive carriers for drug delivery. In addition, a compilation of different methods and materials employed in the preparation of these nanosystems and a recent review of applications of lipid and polymeric nanocapsules have been made, focussing on the encapsulation of drugs.
- Obtaining of repair lime mortars by mixing aerial lime and nanosilica(University of the West of Scotland, 2013-12-31) Lanas, J. (Javier); Sirera-Bejarano, R. (Rafael); Alvarez-Galindo, J.I. (José Ignacio); Duran-Benito, A. (Adrian); Navarro-Blasco, I. (Iñigo); Fernandez-Alvarez, J.M. (José María)This work deals with the effect of the nanosilica addition on the performance of aerial lime mortars. Several lime mortars were prepared and modified upon the addition of 3, 6, 10 and 20 wt.% of nanosilica. The presence of nanosilica increased the water demand of the fresh mixtures and reduced the appearance of superficial cracks after the spreading of the mortars onto a porous stone. Setting time underwent a delay when the amount of nanosilica ranged from 3 to 10 wt.%. However, samples with 20 wt.% of nanosilica showed a shortened setting time compared to plain lime mortars. Nanosilica reacted with Ca(OH)2 particles, yielding C-S-H compounds and, acting as a nanofiller, nanosilica also caused a pore blockage in the mesoporous range. These facts resulted in an increase in both compressive strength and durability after undergoing freezing-thawing processes. Overall, the addition of nanosilica clearly improves several characteristics of the aerial lime mortars in order to prepare enhanced mixtures to be used for restoration works.
- Lime-based rendering mortars with photocatalytic and hydrophobic agents: assessment of the water repellency and biocide effect(RILEM Publications S.a.r.l., 2019-07-16) Alvarez-Galindo, J.I. (José Ignacio); Navarro-Blasco, I. (Iñigo); Martinez-de-Tejada, G. (Guillermo); Tasci, B. (Burcu); Gonzalez-Sanchez, J.F. (Jesús Fidel); Fernandez-Alvarez, J.M. (José María)Different rendering mortars were prepared by mixing air lime and air lime-pozzolanic nanosilica with TiO2 and sodium oleate as, respectively, photocatalytic and water repellent agents, added in bulk. The aim of the work was to design and obtain new rendering mortars with improved durability focusing in the reduction of the water absorption of these materials and in their self-cleaning and biocide effect. To achieve a better distribution of the TiO2 particles, which was expected to enhance their efficiency, different dispersing agents were also incorporated to the fresh mixtures. Four diverse polycarboxylate ethers superplasticizers and a poly-naphthalene-sulfonate were tested. Workability and fluidity of the fresh rendering mortars were determined to guarantee the applicability of the final products. Water contact angle was monitored with the aim of assessing the hydrophobicity of the mortars lent by the water repeller. The biocide effect was studied by means of the culture of a strain of Pseudomonas fluorescens. The colonization of the mortars’ surface was analyzed by determining the number of colonies forming units (CFU) after several days subjecting the samples to suitable T and RH conditions. At the same time, the surface of the mortars was irradiated with solar light to activate the photocatalyst. Results showed the efficiency of the sodium oleate in reducing the water uptake of the rendering mortars. Good compatibility between the water repellent agent, the pozzolanic additive and some of the polycarboxylate superplasticizers was observed. The presence of the photocatalyst was found to be very effective in preventing microbiological colonization.
- Hydrophobized lime grouts prepared with microsilica and superplasticizers(RILEM Publications S.a.r.l., 2019-07-16) Sirera-Bejarano, R. (Rafael); Alvarez-Galindo, J.I. (José Ignacio); Duran-Benito, A. (Adrian); Navarro-Blasco, I. (Iñigo); Gonzalez-Sanchez, J.F. (Jesús Fidel); Fernandez-Alvarez, J.M. (José María)This work reports the obtaining of lime-based grouts as repairing materials. Microsilica was added as pozzolanic additive to enhance the compressive strength of the hardened grouts. Sodium oleate, as water repellent admixture, and different superplasticizers (SPs) were also incorporated to reduce the water absorption and to enhance the injectability of the grouts. Polycarboxylate ether (PCE), polynaphthalene sulfonate (PNS), melamine sulfonate (MMS) and polyacrylic acid (PA) were tested as SPs. Regarding the fluidity of the grouts, PCE was seen to improve the injectability, followed by PNS, MMS and PA. However, PCE addition was also accompanied by a severe delay in the setting time. The other three superplasticizers did not provoke significant delays in the hardening of the samples. The water contact angle underwent an increase pointing to an effective hydrophobization of the surface as a consequence of the water repellent admixture. The combination with PCE was the most effective in keeping the water repellency in comparison with the control sample (lime grout + oleate). MMS yielded high compressive strengths and durability of the mortars, in the face of freezing-thawing cycles, was enhanced.
- Active photocatalytic-superhydrophobic coating with TiO2-ZnO nano-heterostructures for lime mortars(RILEM Publications S.a.r.l., 2019-07-16) Alvarez-Galindo, J.I. (José Ignacio); Navarro-Blasco, I. (Iñigo); Speziale, A. (Alessandro); Gonzalez-Sanchez, J.F. (Jesús Fidel); Fernandez-Alvarez, J.M. (José María)Active coatings to be applied onto hardened surfaces of lime rendering and masonry mortars and stones of the Built Heritage were developed. Nano-heterostructures of TiO2/ZnO (50:50 and 10:90) were obtained by Flame Spray Pyrolysis as photocatalytic agents with expanded sensitivity towards solar light, instead of the restricted UV dependence of the pure TiO2 or ZnO. A superhydrophobic medium was simultaneously prepared and photocatalytic nanoparticles were added to obtain the coatings. The active products were expected to prevent the water absorption of the substrates and the subsequent degradation effects as well as to allow the stones and mortars to act as self-cleaning materials, reducing the dirt deposition and the biological colonization. Dispersions were applied onto the surface of lime mortars and siliceous stone. Measurements of the photocatalytic oxidation activity of the coatings were carried out by means of the NO degradation, showing a very good efficiency of the nanoparticles even at long term tests (values of NO oxidation of ca. 35%). Water contact angle assessment evidenced a strong hydrophobization of the treated surfaces, with WCA values higher than 140⁰. The results proved the synergistic effect of these coatings with respect to the durability of the treated substrates, giving rise to a promising way of preventive conservation for building materials of the Cultural Heritage.
- Morteros de relleno con base cal con adición puzolánica y diversos aditivos(Servicio de Publicaciones de la Universidad de Navarra, 2018-05-15) Sirera-Bejarano, R. (Rafael); Alvarez-Galindo, J.I. (José Ignacio); Duran-Benito, A. (Adrian); Navarro-Blasco, I. (Iñigo); Gonzalez-Sanchez, J.F. (Jesús Fidel); Fernandez-Alvarez, J.M. (José María)Los morteros de relleno o inyección, especialmente destinados a reparación de cavidades y defectos de albañilería, deben fluir adecuadamente en estado fresco y combinar resistencia y durabilidad. Para conseguir algunas de estas características pueden utilizarse aditivos químicos: superplastificantes, para mejorar la fluidez; adiciones puzolánicas, para conseguir resistencias adecuadas en ambientes con limitado acceso de CO2 y una mejora de la durabilidad; e hidrofugantes, de manera que, sin perjudicar la permeabilidad de estos materiales al vapor de agua, se evite la penetración de agua por capilaridad mejorando la durabilidad. Sin embargo, en la mayor parte de los casos, toda la información disponible se circunscribe al efecto de un único aditivo, sin contemplar el posible efecto conjunto o incluso sinérgico de las combinaciones más interesantes de dos o más aditivos y/o adiciones puzolánicas. El estudio de las sinergias entre estos componentes ofrece posibilidades muy interesantes de avance científico-técnico. Precisamente este es el objetivo del trabajo: diseño de nuevos morteros de inyección de cal que puedan ser utilizados para la restauración del Patrimonio Edificado mediante combinación adecuada de aditivos superplastificantes (éteres de policarboxilato, condensados de naftaleno-formaldehído, sulfonato de melamina y ácido poliacrílico), hidrofugante (oleato sódico) y adiciones minerales puzolánicas (microsílice y metacaolín).