Facultad de Ciencias
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- Preparation of multifunctional superhydro- and hydro-oleophobic coatings with self-cleaning capacities for construction materials(2024-10-21) Alvarez-Galindo, J.I. (José Ignacio); Navarro-Blasco, I. (Iñigo); Tena-Santafé, V.M. (Víctor M.); Fernandez-Alvarez, J.M. (José María)Versatile coatings were developed to protect mortar surfaces across a broad range of applications, from preserving architectural heritage to modern civil engineering projects. These coatings utilize super-hydrophobic (SPHB) and hydro-oleophobic (OHB) materials, incorporating a nanostructured photocatalyst (Bi2O3-ZnO 8/92). To prevent the aggregation of the nanophotocatalyst, non-ionic dispersants such as Brij35, TritonX-100, and Tween20 were added. The coatings were applied to lime and limecement mortar substrates, and their properties¿such as hydro- and oleo-repellence, photocatalytic activity (through NOx abatement studies), and self-cleaning performance (dye degradation studies)¿were evaluated. Generally, mortars with SPHB coatings exhibited higher photocatalytic activity compared to those with OHB coatings. To simulate real-world conditions, the samples underwent artificial climate aging to assess their durability. Microstructural examination by SEM was addressed to evaluate the alteration degree of the coatings. Their retained effective hydrophobic properties, photocatalytic activity, and self-cleaning performance even after accelerated weathering tests. Future studies aim to apply these coatings to earthen mortars and earthen building materials, in particular by improving the hydrophobicity of the materials.
- Optimized Phase Change Material-Enhanced Lime Renders for Energy-Efficient Building Envelopes: Thermal and Durability Characterization(2024-10-21) Alvarez-Galindo, J.I. (José Ignacio); Kyriakou; Rubio-Aguinaga, A. (Andrea); Navarro-Blasco, I. (Iñigo); Fernandez-Alvarez, J.M. (José María)The construction sector's substantial contribution to global energy consumption and carbon emissions necessitates the development of innovative, sustainable building materials (PachecoTorgal et al., 2014; UN Environment Programme, 2019; Fei et al., 2021). Lime mortars, traditionally used as renders for building envelopes, are experiencing renewed interest due to their low environmental impact and compatibility with heritage conservation (Campo and Grosso, 2022; Manoharan and Umarani, 2022; Rodriguez-Navarro et al., 2023). This research focuses on the optimization of lime renders through the incorporation of microencapsulated Phase Change Materials (PCMs), specifically PCM24 and PCM18, which exhibit melting temperatures of 24°C and 18°C, respectively. These PCMs are designed to enhance thermal regulation in different climatic zones by storing and releasing heat at temperatures critical to building comfort (Saffari et al., 2017; Li et al., 2021). The optimized lime renders were formulated with the simultaneous addition of a superplasticizer, an adhesion booster, and a pozzolanic agent, ensuring improved workability, adhesion, and durability, key factors for their application in building envelopes. This study emphasizes the need to not only improve the energy efficiency of the material but also ensure its long-term durability, as sustainable construction requires materials that maintain performance over extended periods (Cunha, Aguiar and Ferreira, 2017).
- 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.
- 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.
- 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.
- Obtaining repair lime mortars by mixing aerial lime and nanosilica(University of the West of Scotland, 2013-09-11) 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.
- Effect of a polypropylene fibre on the behaviour of aerial lime-based mortars(Elsevier, 2011-02) Lanas, J. (Javier); Alvarez-Galindo, J.I. (José Ignacio); Izaguirre, A. (Ana)A polypropylene fibre was added to lime-based mortars in order to check whether they were improved by this admixture. Different properties of lime-based mortars were evaluated: fresh state behaviour through water retention, air content and setting time; hardened state properties such as density, shrinkage, water absorption through capillarity, water vapour permeability, long-term flexural and compressive strengths, pore structure through mercury intrusion porosimetry, and durability assessed by means of freezing-thawing cycles. An improvement in some properties of aerial lime-based mortars - such as permeability, mechanical strengths, reduction in macroscopic cracks or durability in the face of freezing-thawing cycles - was achieved when fibre was added at a low dosage. When a larger amount of additive was used, only the reduction in cracks and the durability of the material were improved.
- Effect of water-repellent admixtures on the behaviour of aerial lime-based mortars(Elsevier, 2009-11) Lanas, J. (Javier); Alvarez-Galindo, J.I. (José Ignacio); Izaguirre, A. (Ana)Two different anionic surfactants, sodium oleate and calcium stearate, commercialized as water repellents for cement-based mortars, were added to lime-based mortars in order to check whether they were improved by these admixtures. Different properties of lime-based mortars were evaluated: fresh state behaviour through water retention, air content and setting time, hardened state properties such as density, water absorption through capillarity, water vapour permeability, long-term compressive strengths, pore structure through mercury intrusion porosimetry, and durability assessed by means of freezing-thawing cycles. A clear improvement in lime-based mortars was achieved when sodium oleate was added: strong capillarity reduction and excellent durability in the face of freezing-thawing processes, without any compressive strength drop. The mechanism for this improvement was related to air void formation due to the air entraining ability of these surfactants. Insolubility of calcium stearate turned out to be responsible for fewer air bubbles - as SEM examination revealed – and showed lower effectiveness.
- Study of the mechanical behavior of masonry repair lime-based mortars cured and exposed under different conditions(Elsevier, 2006-05) Lanas, J. (Javier); Sirera-Bejarano, R. (Rafael); Alvarez-Galindo, J.I. (José Ignacio)Specimens of aerial and hydraulic lime-based mortars to be used in restoration works were prepared, hardened and subjected to different environments in order to study their mechanical behavior and durability. Outside exposure, weathering cycles in a climatic chamber, SO2-rich environment, freezing–thawing cycles and indoor exposure were selected to expose (as control group) the mortars. Flexural and compression strength tests were performed at 7, 14, 21 and 28 days. Porosity values and SEM/EDAX analysis were used to evaluate the microstructural changes. Flexural strength has been strongly influenced by the RH of the environments. Outside exposure improves, in general, the compressive strength, whereas SO2 chamber only provides the strength in hydraulic specimens. Porosity reduction has been related with a strength increment. In climatic chamber, the porosity increment matches a gradual higher degree of alteration. A strength reduction has been determined through a fracture mechanism using the cracks of climatic alteration. In SO2 chamber, sulfation appears as a surface phenomenon, giving gypsum in aerial specimens and gypsum and syngenite in hydraulic specimens, as SEM/EDAX confirms. Freezing–thawing cycles showed a high destruction capacity. Hydraulic specimens endured better durability tests than aerial specimens: a discussion on the mortar durability was also introduced.
- Ageing of lime mortars with admixtures: durability and strength assessment(Elsevier, 2010-07) Lanas, J. (Javier); Alvarez-Galindo, J.I. (José Ignacio); Izaguirre, A. (Ana)Lime-based mortars modified with admixtures were prepared and subjected to different environments such as outdoor and indoor exposures, climatic chamber, SO2-chamber, and freezing-thawing cycles. The influence that the different admixtures (water repellents, water retainers, polypropylene fibre and a viscosity modifier) had on the pore size distribution of the hardened specimens was assessed and related to the water absorption capacity, and hence to the durability. Ageing resistance and mechanical strengths improved when additives reduced the water intake and increased the air-content. High dosages of water repellents were necessary to enhance the durability, sodium oleate being the most effective additive to endure freezing processes. Also the low tested dosage of fibre, a water retainer (guar gum derivative), and a starch proved to be useful. SO2 deposition caused the formation of calcium sulphite hemihydrate as the main degradation product. A very small amount of calcium sulphate dihydrate was observed. A crystal habit composed of acicular agglomerates of calcium sulphite hemihydrate was detected in SO2 deposition on calcareous materials.