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The preparation of new monodisperse polycrystalline palladium nanoparticles uniformly distributed on the surface of polymers, by simply adding a palladium(II) solution in water to the polymers, is described. The polymer supported palladium nanoparticles material was used as an efficient portable and reusable catalyst for the stereoselective semihydrogenation reaction of internal alkynes to (Z)-alkenes in green solvents., We gratefully acknowledge financial support from the Ministerio de Economía y Competitividad, Spain, and Fondo Europeo de Desarrollo Regional (FEDER) (Projects CTQ2015-71353-R and MAT2017-84501-R) and Junta de Castilla y León, Consejería de Educación y Cultura y Fondo Social Europeo (Projects BU051U16 and BU061U16). This research has made use of the high performance computing resources of the Castilla y León Supercomputing Center (SCAYLE, https://www.scayle.es), financed by the European Regional Development Fund (ERDF). J. G.-C. thanks Ministerio de Economía y Competitividad for his predoctoral FPU fellowship. This paper is dedicated to the memory of the late Dr Stefano Marcaccini.

In this study, different lightweight expanded glass aggregates (LEGAs) were produced from glass cullet and various carbonated wastes, through a thermal impact process. The effects of LEGA microstructure and morphology on both the adherence to the cement paste and the mechanical properties of mortars after 28 days of curing were studied. The properties of lightweight mortars made of either LEGAs or expanded clay aggregates were compared. The results demonstrated the feasibility of using LEGAs to produce glass lightweight aggregate mortar, with flexural and compressive strength values ranging from 5.5 to 8.2 MPa and from 28.1 to 47.6 MPa, respectively. The differences in mechanical properties were explained according to the microstructures of the fracture surfaces. Thus, arlite-type ceramic aggregates presented surface porosities that allowed mortar intrusion and the formation of an interconnected interface; although the surfaces of the vitreous aggregates were free from porosity due to their vitreous nature, the mortars obtained from different wastes presented compressive and flexural strengths in the range of lightweight mortars

We study the application of fatigue loads as an activation agent of the self-healing mechanism of concrete. This can lead to improvements in the strength of the material, contrary to the idea that cyclic loads can only generate damage. A fiber-reinforced concrete was produced and characterized under compressive fatigue. The strength of runout specimens, which resisted from a minimum of 165000 cycles until more than a million, showed a mean increase of 23%. Microstructure analyses were performed to confirm this increment as the result of a self-healing process, including X-ray Diffraction, Thermogravimetric and Differential Thermal Analyses, Back Scattering Electron Microscopy, and Mercury Intrusion Porosimetry. Results show the presence of new hydration products and a reduction of porosity, which explain the improvement of the concrete capacity. As a mechanical result, the relationship between strain rate and fatigue life is found to be unique for every fatigue stress level.

The use of fly ash from coal-fired power plants as SCMs is widely known. The fight against climate change requires the closure of many coal-fired power plants, which may mean that this material may become scarce in the near future. However, ash landfills may be an important source of SCMs in the future. This work analyzes the use of landfill ash treated mechanically and chemically to increase its reactivity (AVR) in the production of blended cements (70% cement/30% AVR) and hybrid alkaline cements (30% cement + 70% AVR). The mortar mechanical strength and hydration kinetics were determined by isothermal conduction calorimetry. The hydration products were characterized by XRD.

Certain concrete codes include, among other actions to ensure the durability of concrete structures, the measurement of different properties that can be an indirect index to evaluate the durability of concrete subjected to certain types of environments. This work aims to analyze the influence of several factors (nature of the aggregate, water/cement ratio, prior treatment), in the results obtained on concretes manufactured with aggregates of different nature commonly found in large areas of the Iberian Peninsula, when measuring two possible durability indicators: the depth of water penetration under pressure, used in Spanish legislation, and resistivity

El empleo de hormigones fabricados con cementos tipo Portland (OPC) en la construcción acarrea un problema medioambiental derivado del alto consumo energético y de las elevadas emisiones de gases de efecto invernadero que conlleva la producción del clínker del OPC. Por ello, desde el sector de la construcción, se lleva trabajando intensivamente para disminuir la huella de carbono asociada. Las principales vías de reducción de estas emisiones son: 1) el uso de combustibles alternativos con alto poder calorífico en los procesos de fabricación del cemento (por ejemplo, aceites usados); 2) la optimización de la transferencia de calor en la etapa de precalcinación de producción del clínker; 3) la sustitución del clínker por adiciones minerales naturales o residuos de distinta naturaleza y tipología (escorias y cenizas procedentes de procesos térmicos, lodos de papelera, arenas de fundición, espumas de azucarera, residuos vegetales, etc). El beneficio medioambiental que supone esta última práctica es doble puesto que a la reducción del consumo de combustibles fósiles (al disminuir el contenido en clínker para una misma cantidad de material) se añade el hecho de que muchas de las adiciones empleadas son residuos de otras industrias, por lo que se consigue una reutilización/valorización que evita su almacenamiento en vertedero. En algunos casos, la sustitución del clínker puede ser total, como en los cementos obtenidos por activación de geopolímeros y los cementos belíticos; en otros casos, la sustitución es parcial, dando lugar a las denominadas mezclas binarias, ternarias o cuaternarias (multiadiciones), en función del número de adiciones empleadas en la mezcla. En los últimos años, con estas alternativas se están logrando mezclas base cemento con comportamiento mecánico y durable similar e incluso mejorado al obtenido con cementos convencionales. A parte de estos cementos multiadiciones, existen ocasiones en las que el empleo de elevados contenidos de adiciones minerales

Shrinkage is an intrinsic phenomenon of concretes that implies a decrease in volume. In concrete elements exposed to the environment, shrinkage can promote cracking that compromises its durability. One of the main purpose of developing expansive concretes is the mitigation of this shrinkage and the resulting cracking, although they may also be used for self-stressing reinforcement. Expansive concretes are usually fabricated by using expansive agent type K that is a powdered material with hydraulic properties. Expansive agent type K forms ettringite during its hydration process, but several aspects related to the microstructural mechanisms involved in the expansion performance of cement pastes with this type of expansive agent are not well known. In the present work, different microstructural techniques were considered to evaluate two issues related with this special type of material. The first one focuses on evaluating the possible microstructural mechanisms associated to the shrinkage observed in these expansive cementitious materials, even in isolated conditions or with outer water supply. The second one aims to appraise the influence of the pore microstructure content in the expansion obtained, to define the main microstructural mechanism involved in the generation of the expansion. The results obtained indicate that the transformation of low crystalline ettringite to low crystalline monosulfate could be responsible for the shrinkage detected after the maximum expansion is reached, being this phenomenon related to the surrounding environmental/curing conditions. Regarding the second issue, it seems that the main mechanism responsible for the expansion obtained is the in-situ precipitation of the constituent components from the expansive agent anhydrous grains components with the subsequent ettringite formation, but not the diffusion of these components and further ettringite precipitation as some authors have previously mentioned.

Water-soluble coronenes, that form nanoparticles by self-association, work as new fluorescent materials by complexation with cucurbit[7]uril, as well as selective turn-on fluorogenic sensors for nitroaromatic explosives with remarkable selectivity, by using only water as solvent., NATO Science for Peace and Security Programme (SPS G5536), Ministerio de Ciencia, Innovación y Universidades-FEDER (PID2019-111215RB-100 and RTI2018-102040-B-100), Junta de Castilla y León, Consejería de Educación y Cultura y Fondo Social Europeo (BU263P18) and “la Caixa” Foundation (LCF/PR/PR12/11070003) for financial support. A.R.C. thanks Secretaría General de Universidades (FPU18/03225).

This article describes four fluorescent membrane tension probes that have been designed, synthesized, evaluated, commercialized and applied to current biology challenges in the context of the NCCR Chemical Biology. Their names are Flipper-TR®, ER Flipper-TR®, Lyso Flipper-TR®, and Mito Flipper-TR®. They are available from Spirochrome.

A structure–activity relationship (SAR) study in terms of G-quadruplex binding ability and antiproliferative activity of six fluorescent perylenemonoimide (PMIs) derivatives is reported. A positive charge seems to be the key to target G4. This study also reveals the importance of the element substitution in the potential biological activity of PMIs, being the polyethylene glycol (PEG) chains in the peri position responsible for their antiproliferative activity. Among them, the cationic PMI6 with two PEG chains is the most promising compound since its fluorescence is enhanced in the presence of G-quadruplex structures. Moreover, PMI6 binds to the human telomeric G-quadruplex hTelo with high affinity and displays a high antiproliferative potential towards HeLa (cervical adenocarcinoma), A549 (lung adenocarcinoma) and A2780 (ovarian adenocarcinoma) cells. Its fate can be followed inside cells thanks to its fluorescent properties: the compound is found to accumulate in the mitochondria.

La tesis trata sobre la síntesis y utilización de materiales modificados, para el reconocimiento de distintas sustancias por fluorescencia o para el desarrollo de catalizadores de reacciones orgánicas de interés. En la primera parte de la tesis se desarrollaron sensores de sustancias tóxicas como mercurio (II) y plomo (II), midiendo en muestras de pescado y disolución respectivamente. Por otro lado, se perfeccionó un sensor para la detección de TATP en fase gas, explosivo sin uso militar utilizado en ataques terroristas. Además, y en complemento a lo anterior, se trabajó con sensores para detectar toxinas alimentarias como la cereulida, o moléculas de interés biológico/toxicológico como el monóxido de carbono. En una segunda parte, se modificaron una serie de materiales con partículas metálicas de oro o paladio para la catálisis de reacciones orgánicas de importancia en la industria; presentando ventajas como ser reciclables, alto rendimiento de reacción y gran selectividad en los productos., The topic of the thesis was the synthesis and modification of materials, for the detection of different substances by fluorescence or to the development of new catalysts for organic reactions. Several probes were developed for the detection of toxic substances such as mercury (II) or lead (II), measuring their presence in fish samples or in solution, respectively. In addition, Silica-Based materials were modified in order to the detect TATP in vapour phase, an explosive with no military use and employed in terrorist attacks. Furthermore, other probes were synthesized and tested for other analytes, such as food toxins (cereulide) or molecules with biological/toxicological interest, such as carbon monoxide. In the second part of the thesis, polymeric materials were modified with gold or palladium metallic particles and employed for the catalysis of organic reactions with industrial importance, presenting several advantages over traditional catalyst.

Fiber reinforcement of concrete is an effective technique of providing ductility to concrete, increasing its flexural residual strength while reducing its potential for cracking due to drying shrinkage. There are currently a wide variety of industrial fibers on the market. Recycled steel fibers (RSF) from tires could offer a viable substitute of industrialized fibers in a more sustainable and ecofriendly way. However, mistrust exists among users, based on fear that the recycling process will reduce the performance, coupled with the difficulty of characterization of the geometry of the RSF, as a consequence of the size variability introduced by the recycling process. This work compares the behavior of RSF from tires compared with industrialized steel or polypropylene fibers, evaluating the fresh state, compressive strength, flexural residual strength, and drying behavior. The concept of Equivalent Fiber Length (EFL) is also defined to help the statistical geometrical characterization of the RSF. A microstructural analysis was carried out to evaluate the integration of the fiber in the matrix, as well as the possible presence of contaminants. The conclusion is reached that the addition of RSF has a similar effect to that of industrialized fibers on concrete¿s properties when added at the same percentage.

The determination of thermal conductivity of cement-based materials is relevant from the perspective of buildings¿ energy efficiency. The absence of unified tests for its measurement in mortars and concrete results in a heterogeneity of the data available in the literature. This work¿s purpose is to determine the relevant influence from a a statistical viewpoint that three factors; degree of saturation, measuring time and use of a conductive paste, have in the measurement of the conductivity using the hot-wire needle probe method in two concretes with different thermal behavior: standard-weight concrete and lightweight concrete. The results obtained allow for the establishment of recommendations for future researchers on the minimum information to be included in their reports of thermal conductivity of cement-based materials by the needle probe method, the need to treat outliers, the most favorable saturation conditions and measuring times, as well as the possible benefits of using conductive pastes., La determinación de la conductividad térmica en materiales cementicios es relevante desde el punto de vista de la eficiencia energética de edificios. La ausencia de ensayos unificados en morteros y hormigones da como resultado una heterogeneidad de los datos disponibles en la literatura. El objetivo del trabajo es determinar la influencia estadísticamente relevante que tres factores, grado de saturación, tiempo de medición y uso de una pasta conductora, tienen en la medición de la conductividad con aguja de hilo caliente en dos hormigones con diferente comportamiento térmico: hormigón de peso convencional y hormigón ligero. Los resultados permiten establecer recomendaciones para futuros investigadores sobre la información mínima a incluir en sus informes de conductividad térmica de materiales cementicios por el método de aguja de hilo caliente, la necesidad de tratar valores atípicos, las condiciones de saturación y tiempos de medición más favorables, así como posibles beneficios de utilizar una pasta conductora.

Self‐healing concrete has the potential to optimise traditional design approaches; however, commercial uptake requires the ability to harmonize against standardized frameworks. Within EU SARCOS COST Action, different interlaboratory tests were executed on different selfhealing techniques. This paper reports on the evaluation of the effectiveness of proposed experimental methodologies suited for self‐healing concrete with expansive mineral additions. Concrete prisms and discs with MgO‐based healing agents were produced and precracked. Water absorption and water flow tests were executed over a healing period spanning 6 months to assess the sealing efficiency, and the crack width reduction with time was monitored. High variability was reported for both reference (REF) and healing‐addition (ADD) series affecting the reproducibility of cracking. However, within each lab, the crack width creation was repeatable. ADD reported larger crack widths. The latter influenced the observed healing making direct comparisons across labs prone to errors. Water absorption tests highlighted were susceptible to application errors. Concurrently, the potential of water flow tests as a facile method for assessment of healing performance was shown across all labs. Overall, the importance of repeatability and reproducibility of testing methods is highlighted in providing a sound basis for incorporation of self‐healing concepts in practical applications.

The present paper deals with one of the main problems related to concrete structural elements, the tendency to crack as a consequence of its low tensile strength. This cracking limits the performance and durability of the concrete. Previous works by the authors showed the feasibility of using innovative expansive grouts in order to avoid or limit this cracking. These expansive grouts are based on the use of inorganic expansive agents promoting the increase of certain hydrates content. Two different agents were considered: type K (based on calcium sulfoaluminate) and type G (based on calcium oxide). The developed expansive grouts presented high penetration ability in the crack in order to prevent the ingress of aggressive agents and regain (totally or partially) the initial uncracked concrete mechanical properties. One of the difficulties encountered has been finding an adequate test method to evaluate the effecitiveness of the repairing. The influence of including expansive agents on the mechanical properties of the grouts was evaluated, as well as their expansive performance under uniaxial restraining conditions. The influence in the compressive strength depends on the used expansive agent type as well as the expansion performance, this last behavior strongly dependent on the expansive agent dosage considered. According to the obtained results, expansive grouts with 5% in weight cement content of expansive agent were used to evaluate their crack sealing efficacy. In order to overcome the difficulties encountered in previous works, the sealing efficacy of the grouts was evaluated by ad-hoc methods developed by the authors, in special cylindrical specimens of 150x300 mm where simulated cracks were made at the cross section center of the samples during the casting process. These cracks were sealed with the expansive grouts at 28 days of curing and, after that, the sealed samples were subjected to drying conditions during six months. After this exposure period, the eff

The main objective of the work presented in this paper is to evaluate the effectiveness of using three inorganic expansive agents in developing expansive cementitious grouts for sealing concrete cracks. Two of the agents were ettringite-based (K and NK) and one was CaO-based (G). Nine expansive cement grouts and one non-expansive cement grout were developed, and their expansive and mechanical performance were characterized. Additionally, an original method based on the water penetration test is proposed to evaluate the sealing capability of the produced grouts which has demonstrated high feasibility in determining the sealing effectiveness of the cement grouts designed. After sealing the simulated cracks, a strong decrease (≈80%) of the water penetration was detected when using 5% in weight cements of G or NK agents. An important but lower decrease (≈50%) was detected by using 5% of K agent. Moreover, the results obtained in the Brazilian test indicated that sealing with expansive cement grouts allows a high integration of the sealing material within the surrounding concrete element, achieving good mechanical bonding, so the sealing material and concrete act as a compact sole material. BSEM-EDAX analyses also showed slight evidence of chemical interaction between the sealing expansive grout and the surrounding concrete when using NK agent, but strong evidence of physical interaction since the penetration of some kind of amorphous hydrates from the grout side to the concrete side was detected.

Expansive concretes based on the formation of ettringite from calcium sulfoaluminate agents are presented as an effective alternative to minimize the problems derived from shrinkage and low tensile strength at the early ages of the concrete. However, determining the mechanism responsible for the expansion is still a controversial issue today. In this study, the influence of three doses of expansive agent on fresh state and on compressive strength and magnitude of free expansion under two curing environments was evaluated on a reference mixture of self-compacting concrete (SCC). The microstructural evolution of the hydrates and anhydrous related with the expansive phenomena was also studied. From our observations it seems that an eminently amorphous ettringite is formed and that this ettringite would be strongly related to expansion. As a result, the influence of the ratio w/cementitious material and curing environment on the magnitude of the expansion as well as the influence of this on the mechanical properties of the SCCs was identified.