Study of porous concrete multifunctional urban surfaces

RESUMEN: Los pavimentos de hormigón poroso son un tipo de firmes permeables, considerados uno de los Sistemas Urbanos de Drenaje Sostenible (SUDS) más completos. Su estructura porosa es adecuada para que el tráfico rodado y los peatones puedan transitar sobre ellos, mientras permiten que el agua proveniente de la lluvia se infiltre a las capas inferiores hasta llegar al subsuelo, o se almacene para un uso posterior, controlando la escorrentía superficial, y disminuyendo la contaminación del agua. En la presente tesis doctoral se ha trabajado en el desarrollo de una nueva metodología de diseño que permita el incremento de la resistencia mecánica, manteniendo una infiltración del agua adecuada. Se han empleado diversos agregados, granulometrías, aditivos y fibras, métodos de compactación, así como materiales alternativos al cemento (geopolímeros), evaluados mediante diversos ensayos mecánicos, hidráulicos y superficiales. Discutiendo y comparando los resultados con herramientas estadísticas y de análisis multi-criterio para obtener las dosificaciones óptimas.ABSTRACT: Porous concrete pavements are considere done of the most complete Sustainable Urban Drainage Systems (SUDS). Its porous structure is suitable for road traffic and pedestrians, while allowing rainwater to infiltrate into the inner layers reaching the subsoil, or to be stored for later use, controlling surface runoff, decreasing water pollution. The present doctoral thesis has worked on the development of a new methodology of design that allows the increase of mechanical resistance while maintaining an adequate water infiltration. Different aggregates, gradations, additives and fibers, and compaction methods have been used, as well as alternative materials to cement (geopolymers), evaluated through various mechanical, hydraulic and superficial tests. Results have been discussed and compared through statistical and multi-criteria analysis tools to obtain the optimal dosages

Evaluation of the Effect of Different Compaction Methods on Porous Concrete Pavements: Correlation with Strength and Permeability

ABSTRACT: The main purpose of this article is to evaluate the correlation between the indirect tensile strength and the permeability capacity of porous concrete (PC) pavements. The compaction method employed plays a critical role in this correlation. However, even though PC pavements have been studied in many places around the world, using different compaction methods, a profound analysis of these methods has not been carried out yet. This research introduces a study of five different compaction methods: axial compression, gyratory, impact, multilayer impact, and tamping rod, with diverse treatments in each one to obtain the best correlation between the indirect tensile strength and permeability capacity. Results demonstrated that the impact compaction method at 50 blows on only one side of the sample gives the best strength-permeability correlation, with an indirect tensile (IT) strength value of 2.75 MPa and a permeability (k) capacity of 0.56 cm/s

Physical and Mechanical Characterization of Sustainable and Innovative Porous Concrete for Urban Pavements Containing Metakaolin

ABSTRACT: Alternative materials to replace cement in pavements have recently been widely studied with the purpose of decreasing the environmental impacts that the construction industry generates. In this context, the implementation of sustainable urban drainage systems has grown, especially with porous pavements, with the intention to reduce water and environmental impacts. In the present investigation, the addition of alternative materials to minimize the use of cement in porous concrete pavements is evaluated. Starting from a partial substitution of Portland cement with metakaolin, experimental geopolymer concretes were produced with metakaolin and waste basalt powder according to several dosages. Two sets of mixtures were analyzed to evaluate the Porous Concrete Design (PCD) methodology for porous concrete mixtures with alternative materials. A deep analysis was proposed for the evaluation of the mechanical and volumetric properties of the mixtures. Results demonstrated that replacing 5% of cement with metakaolin can increase both permeability and indirect tensile strength. Geopolymer mixtures can achieve permeability significantly higher than the traditional porous concrete, but this decreases their indirect tensile strength. However, considering the promising results, an adjustment in the mix design of the geopolymer mixtures could increase their mechanical properties without negatively affecting the porosity, making these materials a suitable alternative to traditional porous cement concrete, and a solution to be used in urban pavements

Selection of Additives and Fibers for Improving the Mechanical and Safety Properties of Porous Concrete Pavements through Multi-Criteria Decision-Making Analysis

Despite the number of environmental advantages that porous concrete (PC) pavements can provide, they are mainly used in light-traffic roads, parking lots and sidewalks due to their low mechanical strength. This research focuses on the common additives employed in PC pavements, according to a literature review, with the aim of increasing their mechanical strength while maintaining an acceptable infiltration capacity. The results demonstrated that the combination of superplasticizers and air-entraining additives can provide indirect tensile strength values over 2.50 MPa, with an infiltration capacity over 0.40 cm/s. In addition, polypropylene fibers were seen to provide very good safety properties, preserving some structural integrity in the case of failure. All mixtures studied obtained outstanding skid resistance results under both dry and wet condition

Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

Evaluación del diseño y ordenamiento de fraccionamientos de vivienda en serie con respecto a la eficiencia de los servicios públicos municipales

Tesis de Licenciatur

Multifunctional Porous Concrete Urban Pavements for a More Sustainable and Resilient Future

Many cities around the world are handling many problems derived from urbanization, resulting in an uncontrolled growth of cities. Moreover, Climate Change effects are affecting all countries and specially cities. In this context, urban drainage and paving strategies demand a bigger economical investment to avoid a great impact in citizens quality of life, and in the environment. The main objective of this research is to contribute, in an innovative way, with the construction of concrete urban pavements by studying, quantifying and trying to join together a series of characteristics and benefits that are analyzed nowadays, but in a separately way. Trying to achieve an integrated pavement, with resilient properties (adapted to Climate Change) and more sustainable (economically, socially and environmentally)

Multi-criteria optimum mixture design of porous concrete pavement surface layers

ABSTRACT: Research has been done to obtain a Porous Concrete (PC) mixture capable of bearing heavy traffic loads while maintaining sufficient air voids (AV) to percolate water into the ground. This research aims to establish several design parameters in PC mixture dosage in order to generate a multi-criteria methodology that helps to obtain a final product, which is beneficial for both citizens and environment. Compression strength, indirect tensile strength, permeability, skid resistance, and stiffness modulus were evaluated, employing different aggregate gradations (AG), water to cement (w/c) and sand to cement (s/c) ratios, designing with the Porous Concrete that the right addition of sand and AG can improve mechanical capacity Design (PCD) methodology. Results demonstrated by around 10% and permeability rates by around 25%. This investigation provides a starting point for the use of additives in PC mixtures that helps to bring multifunctional properties such as heat island mitigation, air purification (photo-catalysis) and noise reduction, among others.This study was funded by the Spanish Ministry of Economy and Competitiveness and the European Union (ERDF) through the project SUPRIS-SUReS (Ref. BIA2015-65240-C2-1-R)

Informática para las Matemáticas, Matemáticas para la Informática, Informática Aplicada

In this paper, we describe the research lines of the Computer Science team at the Universidad de La Rioja. It is a more than 10 years old project, grouping 16 researchers and with an important interdisciplinary orientation, covering several Computer Science areasEn este artículo presentamos un recorrido a grandes rasgos por las líneas de investigación del grupo de Informática de la Universidad de La Rioja. Se trata de un proyecto que se prolonga desde hace más de 10 años, que actualmente engloba a 16 personas, y que con la incorporación de investigadores con distintos intereses ha conseguido coordinar un grupo interdisciplinar, que cubre áreas diversas de la Informática