Properties of natural reinforced earth-bases composites: advantages and drawbacks with synthetic reinforcemen

The increase of awareness of the need to improve the sustainability of the construction industry and the concurrent development of "Green Technologies" has led to the raise of bio-composite materials with natural reinforcements for building applications. This process has involved the revival of the interest in the use of natural reinforced earth materials. Of these, the earthy materials with natural or synthetic reinforcements belong to a field that hasn’t been very much developed beyond traditional or emergency applications in architecture. The most determining aspect to develop products and systems based on reinforced earth based composites is the huge diversity on its physical and mechanical properties. Composites properties depend on diverse variables, among which are those concerning the type of soil and ground grain, type of reinforcement fibers (natural or synthetic), natural conditions in which were obtained, processing methods and characteristics of the possible matrices used as stabilizers. This paper aims for a comprehensive review of literature of the available natural or synthetic reinforced earth based composites. General characteristics of the mainly used reinforcement agents depending on its origin, type, composition, structure, chemical composition and mechanical properties of the studied material (animal hair, jute, sisal, coir, flax, hemp, pineapple fiber, bamboo, rice husk, oil palm, etc). Moreover, different processing methods to improve physical and chemical characteristics, together with processing systems and factors affecting the production and characteristics of these composites will be considered (moisture content, type of reinforcement, ratios, distribution, coupling agent, etc.). The present review is intended to update the overview the research of these kind products as well as to outline the main objectives and issues addressed in these current lines of research

New Frontiers in Cementitious and Lime-Based Materials and Composites

Cement and lime currently are the most common binders in building materials. However, alternative materials and methods are needed to overcome the functional limitations and environmental footprint of conventional products. This Special Issue dedicated to “New frontiers in cementitious and lime-based materials and composites” gathers selected reviews and experimental articles that showcase the most recent trends in this multidisciplinary field. Authoritative contributions from all around the world provide important insights into all areas of research related to cementitious and lime-based materials and composites, spanning from structural engineering to geotechnics, including materials science and processing technology. This Topical Collection is intended to foster innovation and help researchers and developers to identify new solutions for a more sustainable and functional built environment

Reuse of Recycled Plastic for Subgrade Treatment

Disposal of solid waste becomes a global issue due to it contains a large amount of non- degradable polymers and may lead to many environmental issues. With the scarcity of space for landfilling and due to ever increasing cost, finding ways to handle these wastes without endangering the environment is crucial. One of these methods is to use plastic wastes as one of the pavement materials. In this study, a new method of subgrade soil stabilization of pavement is proposed where soil will be stabilized by mixing only plastic with soil for the treatment of subgrade. In order to demonstrate and quantify the benefit of plastic in improving subgrade soil, HDPE, PET and PP have been shredded and mixed with soil. Standard laboratory tests were conducted to assess the stabilization\u27s impact. These tests were carried out on four plastic contents of 2%, 3%, 4%, and 5% of the soil weight in natural and stabilized soils. The tests were the standard compaction test, unconfined compressive strength (UCS) test, hydraulic conductivity test and swelling tests. According to laboratory test results, the presence of plastics reduces the stabilized soils\u27 maximum dry density (MDD) and optimal moisture content (OMC), both of which are necessary for the construction of lightweight embankments. Additionally, the UCS of soils significantly improved by up to 88%, 75%, and 57% for HDPE, PET, and PP, respectively. The findings of the laboratory tests also showed that plastic treatment enhanced the soil\u27s hydraulic conductivity, and that the degree of this increase was more significant at larger dosages. PET showed the best result regarding increasing the hydraulic conductivity of plastic treated soil. By mixing plastics with soil, the hydraulic conductivity was increased by 100 times approximately. Similarly, when the soil is mixed with plastic, the swelling behavior of soil is reduced significantly. Soil showed 73%, 71% and 67% improvement regarding swelling when the soil was treated with 5% of HDPE, PET and PP, respectively

Sustainability in Geotechnics: The Use of Environmentally Friendly Materials

Implementing environmentally friendly and cost-effective solutions is a pressing need to fulfill the United Nations Sustainable Development Goals (SDGs) set to be achieved by 2030. Thus, the requirement to execute the design, construction and maintenance of civil engineering structures and infrastructures as sustainably as possible are big challenges currently faced by civil and geotechnical engineers. This book, compiling the papers published during the 2020–2021 biennium in the Topical Collection, “Sustainability in Geotechnics: The Use of Environmentally Friendly Materials”, is intended help tackle those challenges. Several topics are covered by the 23 papers published herein, including: sustainable ground improvement techniques; replacement of raw materials such as soils and aggregates by recycled materials; soil reinforcement with alternative materials; sustainable solutions using geosynthetics; low-carbon solutions for stabilization of contaminated soils; and bioengineering techniques to prevent soil erosion. The Guest Editor expects that this book can be very useful towards the achievement of more environmentally friendly solutions, in particular in the field of geotechnical engineering

Polymer Geogrids: A Review of Material, Design and Structure Relationships

Geogrids are a class of geosynthetic materials made of polymer materials with widespread transportation, infrastructure, and structural applications. Geogrids are now routinely used in soil stabilization applications ranging from reinforcing walls to soil reinforcement below grade or embankments with increased potential for remote-sensing applications. Developments in manufacturing procedures have allowed new geogrid designs to be fabricated in various forms of uniaxial, biaxial, and triaxial configurations. The design flexibility allows deployments based on the load-carrying capacity desired, where biaxial geogrids may be incorporated when loads are applied in both the principal directions. On the other hand, uniaxial geogrids provide higher strength in one direction and are used for mechanically stabilized earth walls. More recently, triaxial geogrids that offer a more quasi-isotropic load capacity in multiple directions have been proposed for base course reinforcement. The variety of structures, polymers, and the geometry of the geogrid materials provide engineers and designers many options for new applications. Still, they also create complexity in terms of selection, characterization, and long-term durability. In this review, advances and current understanding of geogrid materials and their applications to date are presented. A critical analysis of the various geogrid systems, their physical and chemical characteristics are presented with an eye on how these properties impact the short- and long-term properties. The review investigates the approaches to mechanical behavior characterization and how computational methods have been more recently applied to advance our understanding of how these materials perform in the field. Finally, recent applications are presented for remote sensing sub-grade conditions and incorporation of geogrids in composite materials

Possibilities of the Utilization of Plastic Particles from PET Bottles for the Soil Reinforcement

Import 05/08/2014V mé bakalářské práci jsem si dal za úkol zjistit pozitivní vliv náhodně rozptýlených plastových částic z prázdných PET lahví na pevnostní a deformační charakteristiky zeminy. V současnosti je proces stáčených vod do plastových lahví nejrychleji se rozvíjejícím nápojovým průmyslem. Jedna z možných variant způsobu recyklace je využit nastříhané PET lahve ke zvýšení některých parametrů únosnosti zemin, především smykové pevnosti. Vycházel jsem z vědeckých článků zabývajících se tímto tématem, ale rovněž jsem se snažil dospět k vlastním závěrům na základě výsledků vlastních laboratorních zkoušek. Nejprve byly provedeny zkoušky se zeminou neobsahující PET částice. Po jejich vyhodnocení byl stanoven postup pro měření zeminy s rozptýlenými plastovými částicemi. Součástí práce jsou grafické výstupy jednotlivých zkoušek a protokoly.In my work, I have set myselve the task to find a positive effect of randomly dispersed plastic particles from empty PET bottles on the strength and deformation characteristics of the soil. At present, the process of discharged water into plastic bottles is the fastest growing beverage industry. One of the possible options of recycling is to use cutted PET bottles for increasing parameters of soil bearing capacity, especially shear strength. I used scientific articles dealing with this topic, but I wanted to try to come to my own conclusions based on the results of my own laboratory exams. First, I performed examinations with soil containing no PET particles. After its evaluation, I set procedure for measuring soil mixed with plastic particles. The thesis includes graphical outputs of the tests and protocols.Prezenční224 - Katedra geotechniky a podzemního stavitelstvívýborn

Efecto de la adición de polímeros reciclados PET en las propiedades físicas y mecánicas de la subrasante del AA. HH Las Flores (Km 3) - C.P. Tangay, Nuevo Chimbote – 2021

El presente trabajo de investigación tiene como objetivo principal el determinar el efecto de la adición de polímeros reciclados PET en las propiedades físicas y mecánicas de la subrasante del AA. HH Las Flores (Km 3) - C.P. Tangay, Nuevo Chimbote. Se realizó la adición de polímeros reciclados PET, en porcentajes de 7%, 11% y 13 %, a la muestra extraída mediante la elaboración de calicatas a una profundidad de 1.50 m, a lo cual, se realizará ensayos en laboratorio mediante las normas de ASTM y MTC; el material obtenido para los ensayos se realizó del tramo previamente seleccionado, progresiva Km 6+200 – Km 9+200, la cual es de trocha carrozable. Se realizaron los ensayos de compactación al terreno natural, debido a que el suelo es SP (arena mal graduada), se realizó la prueba de densidad máxima para determinar la densidad de máxima compactación. El mismo método se utilizó cuando se adiciono los polímeros reciclados PET en distintas cantidades (7%, 11% y 13 %). Luego de obtener los valores de la máxima densidad de compactación, se realizaron ensayos CBR a las calicatas con la adición de PET ya mencionada. Con todos los resultados obtenidos llegamos a la conclusión, que el mejor índice de CBR, se obtuvo cuando el terreno natural se adiciono el 11% de polímeros reciclados PET obteniendo los valores de 29.51% y 35.10%, logrando así un incremento de 63% y 64% del CBR con respeto al valor obtenido del terreno natura