Efecto de los elementos lineales del paisaje sobre la generación y conectividad de la escorrentía: evaluación de dos escenarios en un agro-ecosistema del Prepirineo oscense

Los principales agentes de la erosión del suelo son el impacto de las gotas de lluvia y la escorrentía, siendo la acumulación de las partículas desagregadas en lagos y embalses una de sus consecuencias negativas. Sin embargo, el papel que juegan los elementos lineales del paisaje (ELP: caminos asfaltados y de tierra, terrazas de cultivo, muros elevados, franjas de vegetación densa, acequias de riego y colectores, pequeños asentamientos) sobre la redistribución espacial de la escorrentía es un aspecto no resuelto en su totalidad y cuyo estudio resulta de interés, especialmente en la aplicación de modelos de predicción. En este trabajo, aplicamos el modelo hidrológico DR2 en un agro-ecosistema de secano de tamaño medio (246 ha) del Prepirineo oscense, bajo dos escenarios de ELP: el actual y otro con nuevos ELP acorde a la nueva PAC para proteger los cultivos y los lagos del área de estudio. Los resultados muestran que a escala anual, la escorrentía que llega a los cultivos y lagos se reduce en un 46% de la superficie que se pretende proteger y con una efectividad promedio del 80 y del 48% para los cultivos y vegetación de ribera, respectivamente, allí donde se ha observado esta reducción. Por lo tanto, los nuevos ELP ejercen un papel efectivo de protección del suelo frente a los procesos de desagregación y transporte por escorrentía que actualmente se observan en el área de estudio y su creación resulta de interés para la protección de otras áreas afectadas por procesos de intensa erosión.Este trabajo ha contado con la financiación del proyecto “Mitigación de la colmatación del espacio natural de las Lagunas de Estaña (Huesca) bajo difer entes escenarios de cambio climático: eficiencia de las “áreas verdes” de la nueva PAC sobre la retención del suelo y agua” (Número de Expediente 2012 GA LC 034) del Gobierno de Aragón y de la Obra Social “la Caixa”.Peer Reviewe

Efecto del envejecimiento y de la acción del agua en la fisuración de las mezclas asfálticas

Asphalt mixtures cracking is one of the most common deterioration mechanisms in flexible pavements. This phenomenon is due to both the application of loads and the degradation of the material as a result of its exposure to environmental conditions. The main factors affecting the mixtures durability are ageing and the action of water. This is the reason why analyzing the cracking resistance of mixtures subjected to moisture damage, aged and subjected to moisture damage after ageing becomes a key factor in the prevention of pavement damage and failure. The objective of this thesis was precisely to study the effect of ageing, the action of water and temperature in the mixtures cracking. To this end, two different tests were used: a direct tensile test (Fénix) and a strain sweep cyclic test (EBADE). Both were applied on unconditioned mixtures, aged mixtures, mixtures subjected to moisture damage and aged mixtures subjected to moisture damage. Results show the great influence of ageing and test temperature on the cracking behavior of mixtures, especially when they combine with one another, while the effect of the action of water has less influence for the studied conditions. Thus, the applicability of Fénix and EBADE tests in the study and design of asphalt pavement materials is highlighted. A new methodology was proposed to estimate the fatigue laws of mixtures based on the EBADE test results. This allows the effect of different variables (ageing, test temperature or binder type and content) to be studied on the asphalt mixtures fatigue life. Otherwise (from the classic time sweep tests), it would require too much time. Finally, the introduction of rest periods in cyclic tests for the study of fatigue cracking of mixtures shows the importance of the sequence of applied loads in mixtures fatigue life, as well as the different behavior of mixtures depending on their stiffness.La fisuración de las mezclas bituminosas es uno de los mecanismos de deterioro más frecuentes en los pavimentos flexibles. Este fenómeno se produce tanto por la aplicación de cargas, como por la degradación del material consecuencia de su exposición a las condiciones ambientales. Los principales factores que afectan a la durabilidad de las mezclas son el envejecimiento y la acción del agua. Es por este motivo que analizar la resistencia a la fisuración de mezclas envejecidas y/o sometidas a daño por humedad se convierte en un factor clave en la prevención contra el deterioro y el fallo de los pavimentos. El objetivo de esta tesis es precisamente estudiar el efecto del envejecimiento, de la acción del agua y de la temperatura en la fisuración de las mezclas. Para ello, se han utilizado dos tipos de ensayo: un ensayo de tracción directa (Fénix) y un ensayo cíclico de barrido de deformaciones (EBADE), aplicados sobre mezclas no acondicionadas, envejecidas, sometidas a daño por humedad y envejecidas y sometidas a la acción del agua. Los resultados obtenidos han mostrado la gran influencia del envejecimiento y de la temperatura de ensayo en el comportamiento a fisuración de las mezclas, especialmente cuando se combinan entre ellos, mientras que, para las condiciones estudiadas, el efecto de la acción del agua ha tenido menos influencia. Esto pone de manifiesto la aplicabilidad de los ensayos Fénix y EBADE en el estudio y diseño de los materiales que forman los pavimentos asfálticos. A partir de los resultados del ensayo EBADE, se ha propuesto una nueva metodología para estimar las leyes de fatiga de las mezclas, lo cual permite estudiar el efecto de diferentes variables (envejecimiento, temperatura de ensayo o tipo y dotación de ligante) sobre la vida a fatiga de las mezclas asfálticas, que de otra forma (a partir de los ensayos clásicos de barrido de tiempo) requeriría demasiado tiempo. Por último, la introducción de periodos de reposo en los ensayos cíclicos para el estudio de la fisuración por fatiga de las mezclas ha mostrado la importancia que tiene la secuencia de la aplicación de solicitaciones en su vida a fatiga, así como el comportamiento diferenciado de la mezcla en función de su rigidez

Efecto del envejecimiento y de la acción del agua en la fisuración de las mezclas asfálticas

Asphalt mixtures cracking is one of the most common deterioration mechanisms in flexible pavements. This phenomenon is due to both the application of loads and the degradation of the material as a result of its exposure to environmental conditions. The main factors affecting the mixtures durability are ageing and the action of water. This is the reason why analyzing the cracking resistance of mixtures subjected to moisture damage, aged and subjected to moisture damage after ageing becomes a key factor in the prevention of pavement damage and failure. The objective of this thesis was precisely to study the effect of ageing, the action of water and temperature in the mixtures cracking. To this end, two different tests were used: a direct tensile test (Fénix) and a strain sweep cyclic test (EBADE). Both were applied on unconditioned mixtures, aged mixtures, mixtures subjected to moisture damage and aged mixtures subjected to moisture damage. Results show the great influence of ageing and test temperature on the cracking behavior of mixtures, especially when they combine with one another, while the effect of the action of water has less influence for the studied conditions. Thus, the applicability of Fénix and EBADE tests in the study and design of asphalt pavement materials is highlighted. A new methodology was proposed to estimate the fatigue laws of mixtures based on the EBADE test results. This allows the effect of different variables (ageing, test temperature or binder type and content) to be studied on the asphalt mixtures fatigue life. Otherwise (from the classic time sweep tests), it would require too much time. Finally, the introduction of rest periods in cyclic tests for the study of fatigue cracking of mixtures shows the importance of the sequence of applied loads in mixtures fatigue life, as well as the different behavior of mixtures depending on their stiffness.La fisuración de las mezclas bituminosas es uno de los mecanismos de deterioro más frecuentes en los pavimentos flexibles. Este fenómeno se produce tanto por la aplicación de cargas, como por la degradación del material consecuencia de su exposición a las condiciones ambientales. Los principales factores que afectan a la durabilidad de las mezclas son el envejecimiento y la acción del agua. Es por este motivo que analizar la resistencia a la fisuración de mezclas envejecidas y/o sometidas a daño por humedad se convierte en un factor clave en la prevención contra el deterioro y el fallo de los pavimentos. El objetivo de esta tesis es precisamente estudiar el efecto del envejecimiento, de la acción del agua y de la temperatura en la fisuración de las mezclas. Para ello, se han utilizado dos tipos de ensayo: un ensayo de tracción directa (Fénix) y un ensayo cíclico de barrido de deformaciones (EBADE), aplicados sobre mezclas no acondicionadas, envejecidas, sometidas a daño por humedad y envejecidas y sometidas a la acción del agua. Los resultados obtenidos han mostrado la gran influencia del envejecimiento y de la temperatura de ensayo en el comportamiento a fisuración de las mezclas, especialmente cuando se combinan entre ellos, mientras que, para las condiciones estudiadas, el efecto de la acción del agua ha tenido menos influencia. Esto pone de manifiesto la aplicabilidad de los ensayos Fénix y EBADE en el estudio y diseño de los materiales que forman los pavimentos asfálticos. A partir de los resultados del ensayo EBADE, se ha propuesto una nueva metodología para estimar las leyes de fatiga de las mezclas, lo cual permite estudiar el efecto de diferentes variables (envejecimiento, temperatura de ensayo o tipo y dotación de ligante) sobre la vida a fatiga de las mezclas asfálticas, que de otra forma (a partir de los ensayos clásicos de barrido de tiempo) requeriría demasiado tiempo. Por último, la introducción de periodos de reposo en los ensayos cíclicos para el estudio de la fisuración por fatiga de las mezclas ha mostrado la importancia que tiene la secuencia de la aplicación de solicitaciones en su vida a fatiga, así como el comportamiento diferenciado de la mezcla en función de su rigidez.Postprint (published version

Ageing and temperature effect on the fatigue performance of bituminous mixtures

The ageing of asphalt mixes, together with their exposure to low temperatures, causes a progressive increase of cracking. In this paper, the effect of ageing and temperature on the fatigue of asphalt concretes made with two types of binders, conventional (50/70) and polymer modified bitumen (PMB), is studied. For this purpose, specimens previously subjected to an accelerated laboratory ageing process were tested by a strain sweep test at different temperatures (-5°C, 5°C and 20°C). Results were compared with the obtained from the unaged specimens showing the relative importance of ageing, temperature and type of bitumen on the parameters that determine the fatigue life of the mixture. The mixtures behaviour becomes more brittle with ageing and the decrease of temperature. However, ageing hardly has an effect on fatigue at lower temperatures. In general, mixtures made with polymer modified bitumen have a better fatigue performance to ageing and temperature.Peer ReviewedPostprint (published version

Obtaining the fatigue laws of bituminous mixtures from a strain sweep test: effect of temperature and aging

Fatigue is associated with the deterioration caused by applying repeated loads, and is affected by temperature or aging. Generally, time sweep tests are used to simulate fatigue, in order to obtain the fatigue laws. However, this requires too much time, often preventing its use. A method to estimate the fatigue laws from a strain sweep test is presented. The test was performed on a semi-dense mixture with different types of binder (unconditioned or aged) tested at different temperatures. This test is able to estimate fatigue laws more quickly, allowing the effect of different factors on the mixtures' fatigue life to be studied.Peer ReviewedPostprint (author's final draft

Photosensitizer-Mesoporous Silica Nanoparticles Combination for Enhanced Photodynamic Therapy

Mesoporous silica nanoparticles (MSNs) are widely known for their versatile applications. One of the most extended is as drug delivery systems for the treatment of cancer and other diseases. This review compiles the most representative examples in the last years of functionalized MSNs as photosensitizer carriers for photodynamic therapy (PDT) against cancer. Several commercially available photosensitizers (PSs) demonstrated poor solubility in an aqueous medium and insufficient selectivity for cancer tissues. The tumor specificity of PSs is a key factor for enhancing the PDT effect and at the same time reducing side effects. The use of nanoparticles and particularly MSNs, in which PS is covalently anchored or physically embedded, can overcome these limitations. For that, PS-MSNs can be externally decorated with compounds of interest in order to act as an active target for certain cancer cells, demonstrating enhanced phototoxicity in vitro and in vivo. The objective of this review is to collect and compare different nanosystems based on PS-MSNs pointing out their advantages in PDT against diverse types of cancers.We gratefully acknowledge financial support from MCIN/AEI/10.13039/501100011033 (project PID2020-114347RB-C32), and Gobierno Vasco-Eusko Jaurlaritza (project IT1639-22). R.P.-M. thanks UPV/EHU, MIU and NGEU for their postdoctoral contract (MARSA21/71)

Complexity of the behaviour of asphalt materials in cyclic testing

This paper compares the results obtained in two types of cyclic tension-compression tests, a time sweep test, constant strain amplitude, and a strain sweep test, increasing strain amplitude every 5000 cycles, called EBADE (standing for the Spanish words for strain sweep test). This comparison has shown that the rapid loss of stiffness during the initial part of cyclic testing is recoverable in bituminous materials. It has been found that reversible phenomena dominate in asphalt binders, while in mixtures are as important as damage. A damage equation has been proposed to describe the evolution of the material distress during the phase II in time sweep tests. In addition, a new methodology to estimate the fatigue law of bituminous mixtures is proposed.Peer ReviewedPostprint (author's final draft

Effect of the use of Marpol waste as a partial replacement of the binder for the manufacture of more sustainable bituminous mixtures

This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of Pavement Engineering on 2022, available online at: http://www.tandfonline.com/10.1080/10298436.2022.2046275Society must move towards an economy in which sustainability is its main driving force. A sustainable solution to avoid sending waste to landfill, the consumption of raw materials and, therefore, the depletion of natural resources, is the reuse or recycling of waste. Here, pavement engineering has great potential, as waste can be used for the manufacture of bituminous mixes. In particular, one of these residues is Marpol, which is generated during shipping, maintenance and cleaning operations, including wastewater and waste other than cargo waste. There are few studies on the analysis of its use in mixtures. Thus, in this work, the effect of partially replacing the binder of bituminous mixtures for another obtained from the treatment of Marpol oily waste was studied in order to contribute to environmental sustainability and circular economy. For this, water sensitivity, deformation and cracking resistance were analysed of two asphalt mixtures whose binder was partially replaced by Marpol binder. Furthermore, the binder ageing resistance was studied. The results obtained from the laboratory, plant and test section mixture were very close to those obtained for the reference. These results have demonstrated the feasibility of partially replacing the conventional binder by one obtained from Marpol waste.This research was funded by the Centre for Industrial Technological Development (CDTI) of the Spanish Ministry of Economy and Competitiveness within the framework of the project “Nuevo ligante bituminoso para firmes de carreteras a partir de técnicas de recuperación de residuos oleosos derivados del Marpol” (IDI-20180889).Peer ReviewedPostprint (author's final draft

Effect of nanomaterials on ageing and moisture damage using the indirect tensile strength test

Environmental conditions as well as traffic loads lead to the deterioration of asphalt pavements during their service life. For this reason, the use of nanomaterials that improve the mixtures behaviour could be interesting. The behaviour of two mixtures made with binder modified with nanoclay and nanoiron, and their strength against ageing and moisture damage is studied. Mixtures have been subjected to ageing by two procedures: extended heating, Long-Term Oven Ageing (LTOA), and ultraviolet (UV) plus rainfall simulation, Tecnico Accelerated Ageing (TEAGE). The results show that nanoclay improves the mixture behaviour against ageing, while nanoiron does against moisture damage.Peer ReviewedPostprint (author's final draft

Sustainable asphalt mixtures by partial replacement of fine aggregates with low-grade magnesium carbonate by-product

The utilisation of large quantities of raw materials for asphalt mixtures manufacturing, such as aggregates, is an environmental issue that must be addressed. This concern has led to valorising waste and by-products as more sustainable alternative raw materials. This research is aimed at evaluating the use of a low-grade magnesium carbonate (LG-MC) by-product as a partial replacement of fine aggregates and as a filler of asphalt mixtures. A mechanical analysis has been performed studying the effect of this by-product on the moisture sensitivity, cracking resistance and cohesion loss resistance of asphalt mixtures. Cracking resistance was assessed under different temperatures (20, 5 and -5 ºC) and conditions (unconditioned and aged). Results indicated that moisture sensitivity and cohesion loss resistance of asphalt mixtures with LG-MC by-product were not affected, obtaining similar results to those of the reference mixture. A protective effect in the mixture cracking resistance was observed using LG-MC. At low temperatures or after ageing, this by-product tends to maintain ductility to a greater extent. The study indicates that LG-MC is suitable as a partial substitute for the fine fraction of aggregates, as well as for the total amount of filler in asphalt mixtures manufacturing for road pavements