Using Sewage-Sludge Ash as Filler in Bituminous Mixes

In this study, the behavior of bituminous mixes made with sewage sludge ash (SSA) as mineral filler was investigated. The behavior of these mixes was evaluated with the Cantabro, indirect tensile strength, water sensitivity, permanent deformation, and resilient modulus tests. The results show that SSA waste may be used in bituminous mixes at approximately 2–3% weight percent, maintaining adequate levels of cohesion and adhesion in the mixtures, which is comparable to mixtures made with active fillers such as hydrated lime and cement. Moreover, its use does not increase permanent deformations. However, the resilient modulus test gave slightly lower results for mixes made with SSA than for mixtures made with other fillers. It may be concluded that SSA waste may be used as a filler for bituminous mixes with better results than for mixes made with limestone fillers and with similar results for mixes made with other fillers such as hydrated lime and cement.This work has been financed by the University of Alicante through projects VIGROB-256 and GRE10-28 and by the Valencian Provincial government through Project GV/2012/113

Determination of the Most Influential Factors in the Concentration of Bacteria in Coastal Waters

Control of water quality of coastal waters is essential to ensure the safety of bathers. Therefore, the current legislation establishes maximum concentration levels of faecal bacteria, in particular Escherichia coli and intestinal Enterococci. After several studies, it is known that there are environmental and physical factors such as the level of urbanization of the beach, sediment type, rainfall, salinity and water temperature, which influence the concentration of these bacteria. However, there are many other factors, such as the morphology of the beach, its orientation relative to waves and the proximity of spills, that can affect the survival of these bacteria and therefore directly influence the water quality in the coastal zone. In this article, 270 beaches between the provinces of Valencia and Granada (Spain) were analysed. It was observed that the local factors that further affect the concentration of faecal bacteria in coastal water are the presence of meadows of Posidonia oceanica, the orientation of the beach with respect to the direction of the most common incident waves and the agricultural discharges in the sea.This research has been partially funded by Universidad de Alicante through the project ‘Estudio sobre el perfil de equilibrio y la profundidad de cierre en playas de arena’ (YGRE15-02)

60 Years of Urban Development in Denia and its Influence on the Marineta Cassiana Beach

Everyone is aware of the special relationship that man has with the coast; from the beginning of man- kind, humans have been attracted to the littoral zone for the construction of settlements and the use of its resources. Subsequently, humans have evolved, leaving an increasingly large footprint on this medium. Hence, there is a need to deepen our knowledge to protect against the threat that we ourselves pose. Coastal regression mainly due to the lack of sediment is a global problem. The environmental, economic and social interest makes the study of coastal regression a major problem in the institutions. This article places the study area in Denia (Alicante, Spain). In this population, for some time, there has been concern about the effect on the beaches of the sharp erosion of the coastline. The Marineta Cassiana beach has been chosen for this study because of its special location and the set of elements of the environment. Thus, with respect to the beach study, it is observed that the land beside it is a fully urbanized area, which has suffered due to the pressure of development in this area since 1956, limited as it is by background mountains. Therefore, this study encompasses different aspects of the regression of the coast. To this end, a study of the historical evolution of the beach since 1956 has been carried out. The hydrological modelling of river basins discharging to the beach and their changes due to the alteration of the landscape has been carried out, using dynamics and morphological characterization of the area and an analysis of the erosion of these basins. Also, the historical evolution of the surf on the beach, as well as changes in the morphology of the coast, which have influenced the marine climate, have been taken into account

Internal Sulphate Attack in Masonry Mortars with Thaumasite Formation

The present paper focuses on the study of mortar samples where expansions with thaumasite formation occur as a consequence of sulphate attack. The samples correspond to a masonry mortar used in a rural construction located in the Spanish province of Toledo made of cement with limestone filler addition CEM II/AL. Composition and microstructure of the mortars have been analysed by means of scanning electron microscopy (SEM) using secondary and backscattered electrons (BSE) and X-ray diffraction (XRD). The results show that aggregates are contaminated with gypsum, which is the source of the sulphates for the internal attack. It seems that thaumasite is formed through an ettringite transformation where aluminium atoms are replaced with silicon atoms by means of a solid solution. The study highlights that thaumasite can be formed in warm weather through an internal sulphate attack due to gypsum contamination of aggregates.This research was funded by Ministerio de Economía y Competitividad (Spain) through the Research Project BIA2010-20913-C02-02 (PREDICEX) and BIA2011-28798-C02-02 “La reacción sulfática interna entre áridos con distintos compuestos de azufre y cementos de diferente contenido de aluminatos”

Mechanical properties of boards made in biocomposites reinforced with wood and Posidonia oceanica fibers

The development of biocomposites has valorized some natural products related to natural processes or crop industries. In this regard, Posidonia oceanica is a marine phanerogam typical of Mediterranean coasts, in which due to tourism industry a lot of resources are destined to remove and treat Posidonia residues left on beaches. In this work an alternative to recycle this natural waste has been studied. Biocomposites with Posidonia and pine-wood particles were tested as an alternative to structural wood particle boards used in construction. Different substitution ratios (pine by Posidonia) were prepared in two different polymeric matrices and their mechanical properties were tested. Particles boards made in 75% Posidonia oceanica and 25% wood particles and a MDI matrix (20–30% by fibers mass) showed the best strength and stiffness to density ratios. This stiffness was even similar to a panel made totally in wood and MDI in the same dosage, i.e. 75% of pine fibers could be replaced by Posidonia with low stiffness loss.The authors would like to thank the University of Alicante for its financial support, VIBGROB-212-(GRESMES)

Exposing Sustainable Mortars with Nanosilica, Zinc Stearate, and Ethyl Silicate Coating to Sulfuric Acid Attack

Obtaining durable materials that lengthen the service life of constructions and thereby contribute to sustainability requires research into products that improve the durability of cementitious materials under aggressive conditions. This paper studies the effects of sulfuric acid exposure on four mortar types (control mortar, mortar with nanosilica, mortar with zinc stearate, and mortar with an ethyl silicate coating), and evaluates which of them have better performance against the acid attack. After 28 days of curing, the samples were exposed to a sulfuric acid attack by immersing them in a 3% w/w of H2SO4 solution. Physical changes (mass loss, ultrasonic pulse velocity, open porosity, and water absorption), and mechanical changes (compressive strength) were determined after the sulfuric acid exposure. A scanning electron microscope (SEM) was used to characterize the morphology of the surface mortars after the exposure. The control mortar had the highest compressive strength after the acid attack, although of the four types, the zinc stearate mortar showed the lowest percentage of strength loss. The zinc stearate mortar had the lowest mass loss after the acid exposure; moreover, it had the lowest capillary water absorption coefficient (demonstrating its hydrophobic effect) both in a non-aggressive environment and acid attack.This research was funded by the University of Alicante (GRE13-03) and (VIGROB-256)

Effects of Multiple Supplementary Cementitious Materials on Workability and Segregation Resistance of Lightweight Aggregate Concrete

In view of the global sustainable development, it is imperative that supplementary cementing materials (SCM) be used for replacing cement in the concrete industry and several researchers have shown that mineral admixtures can enhance the workability of lightweight aggregate concrete (LWAC) mixture and its strength. In view of the beneficial effects of using SCM in LWAC, this article aims to verify the possible influence of the use of different types of SCM in the segregation phenomenon of LWAC. Three different SCM were studied: Silica Fume (SF), Fly Ash (FA) and Posidonia oceanica Ash (PA). For each SCM, three mixtures were prepared, considering three different percentage substitutions of cement. An image analysis technique was applied to estimate the segregation in each sample. The results show that a substitution of cement by other materials with different grain size, considering a constant water binder ratio, may also result in a variation of the consistency of concrete and the viscosity of the mortar matrix, which may contribute to increase or reduce segregation.This research was supported by the University of Alicante (GRE13-03) and (VIGROB-256)

A multidisciplinary approach for the investigation of a rock spreading on an urban slope

Landslides are very complex processes controlled by multiple factors. The knowledge and characterization of these factors is essential for a comprehensive understanding of the mechanisms and kinematics of the instabilities and for an efficient design of corrective measures. The aim of this work is to combine traditional geological and geotechnical techniques with geophysical, remote sensing and forensic techniques for obtaining a whole picture of an active lateral spreading affecting the Finestrat municipality in Alicante, SE Spain. Geomorphological, geotechnical and geophysical techniques (i.e. ground penetrating radar and refraction seismic) have provided essential information about the geometry, structure and petro-physical properties of the slope. A Terrestrial Laser Scanner was used for recognizing the most important sets of discontinuities affecting the rock mass and to evaluate the activity of the landslide slope. Complementarily, a forensic analysis of the building damage completed the available datasets, yielding very useful kinematic information of the landslide. Finally, a sensitivity analysis of the stability of the rock slope has been performed considering both block toppling and block sliding models. Therefore, the multisource analysis performed in this work has allowed the identification and characterization of a complex lateral spreading, highlighting its effectiveness for a comprehensive understanding of this type of landslide.This work has been supported by the University of Alicante under the project GRE14-04, Generalitat Valenciana under the project GV/2011/044, by the Ministry of Education, Culture and Sport trough the project PRX14/00100, by the Spanish Ministry of Economy and Competitiveness and EU FEDER funds under project TIN2014-55413-C2-2-P, by Swiss National Science Foundation (project numbers 138015 and 144040) and by the European Commission project MOMIT (Ref. no 777630). The second author would like to acknowledge the support received from the H2020 Program of the European Commission under the Marie Skłodowska-Curie Individual Fellowships (MSCA-IF-2015-705215)

Effects of Using Mine Tailings from La Unión (Spain) in Hot Bituminous Mixes Design

Currently, political policies aimed at curbing the abuse of natural resources have given rise to a conscientiousness leading to the reevaluation of wastes. Wastes generated from previous mining operations greatly impact the environment, often leaving a legacy of elevated concentrations of heavy metals in the surrounding soil and water. In this study, two types of waste from the mining district of La Union (Spain) were used to study their use as a component of road wearing courses. The physical and mechanical characteristics were determined to identify the optimal content of bitumen, as well as the fatigue resistance using the four-point beam fatigue test, in all the mixtures manufactured. The mine tailings exhibited adequate physical and mechanical properties to be utilized as a coarse aggregate for a wearing course. The results indicate that one of the studied mine tailing forms could be used as a wearing course component, since it has properties similar to a control mix that is typically used in wearing course construction.This work was financed by the University of Alicante through Projects VIGROB-256 and GRE10-28 and by the Valencian Community through project GV/2012/113

Dedicación a la asignatura de Trabajo Final de Grado (TFG) en el Grado de Ingeniería Civil

El Trabajo final de Grado se concibe, desde el punto de vista académico, como una asignatura obligatoria de 12 créditos ECTS. Se imparte en el segundo semestre de cuarto curso. La elaboración de este trabajo requiere un seguimiento y tutela continuada de docentes, con experiencia en la elaboración de proyectos de este tipo, y finaliza con la exposición y defensa frente a un tribunal. Tal y como indica la Guía Docente de la asignatura, el TFG consiste en la realización de un proyecto de natura profesional dentro del ámbito de la Ingeniería Civil. Este proyecto de debe sintetizar e integrar las diferentes competencias que han sido adquiridas durante los estudios del Grado en Ingeniería Civil. Resumen entre 150 y 200 palabras sobre el contenido del trabajo. En esta titulación se forman grupos de 10-15 estudiantes a cargo de un profesor que realiza el seguimiento y tiene una docencia reglada de 30 horas para el seguimiento de los trabajos. No obstante, el tutor suele invertir del orden de 7 horas en la tutorización personalizada del alumno