Shotcrete or sprayed concrete (Gunite®) is concrete or mortar conveyed through a hose and pneumatically projected at high velocity onto a surface, as a construction technique. It is typically reinforced by conventional steel rods, steel mesh, or fibers.
Shotcrete is usually an all-inclusive term for both the wet-mix and dry-mix versions. In pool construction, however, shotcrete refers to wet mix and gunite to dry mix. In this context, these terms are not interchangeable.
Shotcrete is placed and compacted at the same time, due to the force with the nozzle. It can be sprayed onto any type or shape of surface, including vertical or overhead areas.
Shortcreting has proved to be the best method for construction of curved surfaces. Domes are now much easier to construct with the advent of shotcrete technology. Tunnel linings are also becoming easy with this technology. Not only are these but there a wide range of applications where this technology has been a leading one. This technical paper includes the concept of shotcrete and how it differs from conventional concrete. It also enumerates the different types of process involved in shotcreting i.e. dry mix process and wet mix process. Advantages of shotcrete and its applications in various fields like tunneling, canals, buildings etc. are specified in detail. This paper presents an overview of shotcreting technology along with its applications.
DEFINITION OF SHOTCRETE:-
Shotcrete is a mortar or high performance concrete conveyed through a hose and pneumatically projected at high velocity onto a backing surface. It is the force of this spraying action that leads to compaction of the concrete or mortar which then forms layers of concrete to the required thickness. Shotcreting has been an acceptable way of placing cementitious material in a variety of applications.
Usually patented polypropylene fibers are included in the shotcrete which increases the cohesive nature of the shotcrete through mechanically binding the cementitious materials together. This mechanism reduces the rebound waste that occurs through the shotcreting process and these fibers also resist plastic shrinkage and cracking through their ability to enhance the early stage tensile strength of concrete.
Shotcrete also gives better surface finishes and reduces surface tearing on non- linear sections. Cementitious material containing the poly propylene fibers resist cycles of freezing and thawing and also reduces the chances of water and chemical penetrations.
A presentation on High Performance Concrete - High performance concrete is a concrete mixture, which possess high durability and high strength when compared to conventional concrete.
Shotcrete normally has a greater compressive strength then cast in place concrete due to lower water to cement ratio.
The guniting is the most effective process of repairing concrete work which has been damaged due to inferior work or other reasons. It is also used for providing an impervious layer.
Vacuum concrete is the type of concrete in which the excess water is removed for improving concrete strength.
The water is removed by use of vacuum mats connected to a vacuum pump.
The main aim of this technique is to extract extra water from concrete surface using vacuum dewatering.
what is polymer concrete, types, properties, material used in manufacturing process , manufacturing process, applications and their advantages. case study on polymer composite concrete.
Micro-piling is one of the efficient and cost effective ground improvement technique which can be use various condition. It can use to support foundation as well as soil retention.
Workability of concrete is defined as the ease and homogeneity with which a freshly mixed concrete or mortar can be mixed, placed, compacted and finished. Strictly, it is the amount of useful internal work necessary to produce 100% compaction.
Shortcreting has proved to be the best method for construction of curved surfaces. Domes are now much easier to construct with the advent of shotcrete technology. Tunnel linings are also becoming easy with this technology. Not only are these but there a wide range of applications where this technology has been a leading one. This technical paper includes the concept of shotcrete and how it differs from conventional concrete. It also enumerates the different types of process involved in shotcreting i.e. dry mix process and wet mix process. Advantages of shotcrete and its applications in various fields like tunneling, canals, buildings etc. are specified in detail. This paper presents an overview of shotcreting technology along with its applications.
DEFINITION OF SHOTCRETE:-
Shotcrete is a mortar or high performance concrete conveyed through a hose and pneumatically projected at high velocity onto a backing surface. It is the force of this spraying action that leads to compaction of the concrete or mortar which then forms layers of concrete to the required thickness. Shotcreting has been an acceptable way of placing cementitious material in a variety of applications.
Usually patented polypropylene fibers are included in the shotcrete which increases the cohesive nature of the shotcrete through mechanically binding the cementitious materials together. This mechanism reduces the rebound waste that occurs through the shotcreting process and these fibers also resist plastic shrinkage and cracking through their ability to enhance the early stage tensile strength of concrete.
Shotcrete also gives better surface finishes and reduces surface tearing on non- linear sections. Cementitious material containing the poly propylene fibers resist cycles of freezing and thawing and also reduces the chances of water and chemical penetrations.
A presentation on High Performance Concrete - High performance concrete is a concrete mixture, which possess high durability and high strength when compared to conventional concrete.
Shotcrete normally has a greater compressive strength then cast in place concrete due to lower water to cement ratio.
The guniting is the most effective process of repairing concrete work which has been damaged due to inferior work or other reasons. It is also used for providing an impervious layer.
Vacuum concrete is the type of concrete in which the excess water is removed for improving concrete strength.
The water is removed by use of vacuum mats connected to a vacuum pump.
The main aim of this technique is to extract extra water from concrete surface using vacuum dewatering.
what is polymer concrete, types, properties, material used in manufacturing process , manufacturing process, applications and their advantages. case study on polymer composite concrete.
Micro-piling is one of the efficient and cost effective ground improvement technique which can be use various condition. It can use to support foundation as well as soil retention.
Workability of concrete is defined as the ease and homogeneity with which a freshly mixed concrete or mortar can be mixed, placed, compacted and finished. Strictly, it is the amount of useful internal work necessary to produce 100% compaction.
Disaster Management refers to manage disaster response in the country. India has been traditionally vulnerable to the natural disasters on the account of its unique geo-climatic conditions. Floods, droughts, cyclones, earthquakes and landslides would have been a recurrent phenomena. About 60% of the landmass is prone to earthquakes of various intensities; over 40 million hectares is prone to floods; about 8% of the total area is prone to cyclones and 68% of the area is susceptible to drought. In the decade 1990-2000, an average of about 4344 people lost their lives and about 30 million people were affected by disasters every year.
The loss in terms of private, community and public assets has been astronomical.At the global level, there has been considerable concern over natural disasters. Even as substantial scientific and material progress is made, the loss of lives and property due to disasters has not decreased. In fact, the human toll and economic losses have mounted up. It was in this background that the United Nations General Assembly, in 1989, declared the decade 1990-2000 as the International Decade for Natural Disaster Reduction with the objective to reduce loss of lives and property and restrict socio-economic damage through concerted international action, was specially certified in developing countries.
The super cyclone in Orissa in October, 1999 and the Bhuj earthquake in Gujarat in January, 2001 underscored the need to adopt a multi dimensional endeavour involving diverse scientific, engineering, financial and social processes; the need to adopt multi disciplinary and multi sectoral approach and incorporation of risk reduction in the developmental plans and strategies.
Fibers are usually used in concrete to control cracking due to plastic shrinkage and to drying shrinkage. They also reduce the permeability of concrete and thus reduce bleeding of water. Some types of fibers produce greater impact–, abrasion–, and shatter–resistance in concrete. Generally fibers do not increase the flexural strength of concrete, and so cannot replace moment–resisting or structural steel reinforcement. Indeed, some fibers actually reduce the strength of concrete.
The amount of fibers added to a concrete mix is expressed as a percentage of the total volume of the composite (concrete and fibers), termed "volume fraction" (Vf). Vf typically ranges from 0.1 to 3%. The aspect ratio (l/d) is calculated by dividing fiber length (l) by its diameter (d). Fibers with a non-circular cross section use an equivalent diameter for the calculation of aspect ratio. If the fiber's modulus of elasticity is higher than the matrix (concrete or mortar binder), they help to carry the load by increasing the tensile strength of the material. Increasing the aspect ratio of the fiber usually segments the flexural strength and toughness of the matrix. However, fibers that are too long tend to "ball" in the mix and create workability problems.
Some recent research[where?] indicated that using fibers in concrete has limited effect on the impact resistance of the materials.[1][2] This finding is very important since traditionally, people think that ductility increases when concrete is reinforced with fibers. The results also indicated that the use of micro fibers offers better impact resistance to that of longer fibers.[1]
The High Speed 1 tunnel linings incorporated concrete containing 1 kg/m³ of polypropylene fibers, of diameter 18 & 32 μm, giving the benefits noted below.
In the controlled demolition industry, building implosion is the strategic placing of explosive material and timing of its detonation so that a structure collapses on itself in a matter of seconds, minimizing the physical damage to its immediate surroundings. Despite its terminology, building implosion also includes the controlled demolition of other structures, such as bridges, smokestacks, towers, and tunnels.
Building implosion (which reduces to seconds a process which could take months or years to achieve by other methods) typically occurs in urban areas and often involves large landmark structures.
The actual use of the term "implosion" to refer to the destruction of a building is a misnomer. This had been stated of the destruction of 1515 Tower in West Palm Beach, Florida. "What happens is, you use explosive materials in critical structural connections to allow gravity to bring it down
Nanotechnology ("nanotech") is manipulation of matter on an atomic, molecular, and supramolecular scale. The earliest, widespread description of nanotechnology[1][2] referred to the particular technological goal of precisely manipulating atoms and molecules for fabrication of macroscale products, also now referred to as molecular nanotechnology. A more generalized description of nanotechnology was subsequently established by the National Nanotechnology Initiative, which defines nanotechnology as the manipulation of matter with at least one dimension sized from 1 to 100 nanometers. This definition reflects the fact that quantum mechanical effects are important at this quantum-realm scale, and so the definition shifted from a particular technological goal to a research category inclusive of all types of research and technologies that deal with the special properties of matter which occur below the given size threshold. It is therefore common to see the plural form "nanotechnologies" as well as "nanoscale technologies" to refer to the broad range of research and applications whose common trait is size. Because of the variety of potential applications (including industrial and military), governments have invested billions of dollars in nanotechnology research. Through 2012, the USA has invested $3.7 billion using its National Nanotechnology Initiative, the European Union has invested $1.2 billion, and Japan has invested $750 million.[3]
Nanotechnology as defined by size is naturally very broad, including fields of science as diverse as surface science, organic chemistry, molecular biology, semiconductor physics, energy storage,[4][5] microfabrication,[6] molecular engineering, etc.[7] The associated research and applications are equally diverse, ranging from extensions of conventional device physics to completely new approaches based upon molecular self-assembly,[8] from developing new materials with dimensions on the nanoscale to direct control of matter on the atomic scale.
Scientists currently debate the future implications of nanotechnology. Nanotechnology may be able to create many new materials and devices with a vast range of applications, such as in nanomedicine, nanoelectronics, biomaterials energy production, and consumer products. On the other hand, nanotechnology raises many of the same issues as any new technology, including concerns about the toxicity and environmental impact of nanomaterials,[9] and their potential effects on global economics, as well as speculation about various doomsday scenarios. These concerns have led to a debate among advocacy groups and governments on whether special regulation of nanotechnology is warranted.
Suspension bridges are suspended from cables. The earliest suspension bridges were made of ropes or vines covered with pieces of bamboo. In modern bridges, the cables hang from towers that are attached to caissons or cofferdams. The caissons or cofferdams are implanted deep into the bed of the lake, river or sea. Sub-types include the simple suspension bridge, the stressed ribbon bridge, the underspanned suspension bridge, the suspended-deck suspension bridge, and the self-anchored suspension bridge. There is also what is sometimes called a "semi-suspension" bridge, of which the Ferry Bridge in Burton-upon-Trent is the only one of its kind in Europe.[19]
The longest suspension bridge in the world is the 3,909 m (12,825 ft) Akashi Kaikyō Bridge in Japan.
In its natural form, bamboo as a construction material is traditionally associated with the cultures of South Asia, East Asia and the South Pacific, to some extent in Central and South America, and by extension in the aesthetic of Tiki culture. In China and India, bamboo was used to hold up simple suspension bridges, either by making cables of split bamboo or twisting whole culms of sufficiently pliable bamboo together. One such bridge in the area of Qian-Xian is referenced in writings dating back to 960 AD and may have stood since as far back as the third century BC, due largely to continuous maintenance.
Bamboo has also long been used as scaffolding; the practice has been banned in China for buildings over six stories, but is still in continuous use for skyscrapers in Hong Kong.[6] In the Philippines, the nipa hut is a fairly typical example of the most basic sort of housing where bamboo is used; the walls are split and woven bamboo, and bamboo slats and poles may be used as its support. In Japanese architecture, bamboo is used primarily as a supplemental and/or decorative element in buildings such as fencing, fountains, grates and gutters, largely due to the ready abundance of quality timber.
Green building (also known as green construction or sustainable building) refers to both a structure and the application of processes that are environmentally responsible and resource-efficient throughout a building's life-cycle: from planning to design, construction, operation, maintenance, renovation, and demolition.[1] This requires close cooperation of the contractor, the architects, the engineers, and the client at all project stages.[2] The Green Building practice expands and complements the classical building design concerns of economy, utility, durability, and comfort.[3]
Leadership in Energy and Environmental Design (LEED) is a set of rating systems for the design, construction, operation, and maintenance of green buildings which was Developed by the U.S. Green Building Council. Other certificates system that confirms the sustainability of buildings is the British BREEAM (Building Research Establishment Environmental Assessment Method) for buildings and large-scale developments. Currently, World Green Building Council is conducting research on the effects of green buildings on the health and productivity of their users and is working with World Bank to promote Green Buildings in Emerging Markets through EDGE (Excellence in Design for Greater Efficiencies) Market Transformation Program and certification.[4] There are also other tools such as Green Star in Australia and the Green Building Index (GBI) predominantly used in Malaysia.
Although new technologies are constantly being developed to complement current practices in creating greener structures, the common objective of green buildings is to reduce the overall impact of the built environment on human health and the natural environment by:
Efficiently using energy, water, and other resources
Protecting occupant health and improving employee productivity
Reducing waste, pollution and environmental degradation
The concept of submerged floating tunnels is based on well-known technology applied to floating bridges and offshore structures, but the construction is mostly similar to that of immersed tunnels: One way is to build the tube in sections in a dry dock; then float these to the construction site and sink them into place, while sealed; and, when the sections are fixed to each other, the seals are broken. Another possibility is to build the sections unsealed, and after welding them together, pump the water out.
The ballast used is calculated so that the structure has approximate hydrostatic equilibrium (that is, the tunnel is roughly the same overall density as water), whereas immersed tube tunnels are ballasted more to weight them down to the sea bed. This, of course, means that a submerged floating tunnel must be anchored to the ground or to the water surface to keep it in place (which of these depends on which side of the equilibrium point the tunnel is)
Sanitation refers to public health conditions related to clean drinking water and adequate treatment and disposal of human excreta and sewage.[1] Preventing human contact with feces is part of sanitation, as is hand washing with soap. Sanitation system aim to protect human health by providing a clean environment that will stop the transmission of disease, especially through the fecal-oral route.[2] For example, diarrhea, a main cause of malnutrition and stunted growth in children, can be reduced through sanitation.[3] There are many other diseases which are easily transmitted in communities that have low levels of sanitation, such as ascariasis (a type of intestinal worm infection or helminthiasis), cholera, hepatitis, polio, schistosomiasis, trachoma, to name just a few.
A range of sanitation technologies and approaches exists. Some examples are community-led total sanitation, container-based sanitation, ecological sanitation, emergency sanitation, environmental sanitation, onsite sanitation and sustainable sanitation. A sanitation system includes the capture, storage, transport, treatment and disposal or reuse of human excreta and wastewater.[4] Reuse activities within the sanitation system may focus on the nutrients, water, energy or organic matter contained in excreta and wastewater. This is referred to as the "sanitation value chain" or "sanitation economy
For dam construction, two cofferdams are usually built, one upstream and one downstream of the proposed dam, after an alternative diversion tunnel or channel has been provided for the river flow to bypass the dam foundation area. These cofferdams are typically a conventional embankment dam of both earth- and rock-fill, but concrete or some sheet piling also may be used. Typically, upon completion of the dam and associated structures, the downstream coffer is removed and the upstream coffer is flooded as the diversion is closed and the reservoir begins to fill. Dependent upon the geography of a dam site, in some applications, a "U"-shaped cofferdam is used in the construction of one half of a dam. When complete, the cofferdam is removed and a similar one is created on the opposite side of the river for the construction of the dam's other half.
The cofferdam is also used on occasion in the shipbuilding and ship repair industry, when it is not practical to put a ship in drydock for repair or alteration. An example of such an application is certain ship lengthening operations. In some cases a ship is actually cut in two while still in the water, and a new section of ship is floated in to lengthen the ship. Torch cutting of the hull is done inside a cofferdam attached directly to the hull of the ship; the cofferdam is then detached before the hull sections are floated apart. The cofferdam is later replaced while the hull sections are welded together again. As expensive as this may be to accomplish, use of a drydock may be even more expensive. See also caisson.
A 100-ton open caisson that was lowered more than a mile to the sea floor in attempts to stop the flow of oil in the Deepwater Horizon oil spill has been called a cofferdam.[4] It did not work, as methane hydrates froze in the upper levels preventing the containment.
Waste management or waste disposal are all the activities and actions required to manage waste from its inception to its final disposal.[1] This includes amongst other things collection, transport, treatment and disposal of waste together with monitoring and regulation. It also encompasses the legal and regulatory framework that relates to waste management encompassing guidance on recycling.
Waste can take any form that is solid, liquid, or gas and each have different methods of disposal and management. Waste management normally deals with all types of waste whether it was created in forms that are industrial, biological, household, and special cases where it may pose a threat to human health.[2] It is produced due to human activity such as when factories extract and process raw materials.[3] Waste management is intended to reduce adverse effects of waste on health, the environment or aesthetics.
Waste management practices are not uniform among countries (developed and developing nations); regions (urban and rural areas), and sectors (residential and industrial).[4]
A large portion of waste management practices deal with municipal solid waste (MSW) which is waste that is created by household, industrial, and commercial activity.[5]
A concrete slab is a common structural element of modern buildings. Horizontal slabs of steel reinforced concrete, typically between 4 and 20 inches (100 and 500 millimeters) thick, are most often used to construct floors and ceilings, while thinner slabs are also used for exterior paving. Sometimes these thinner slabs, ranging from 2 inches (51 mm) to 6 inches (150 mm) thick, are called mud slabs, particularly when used under the main floor slabs[1] or in crawl spaces.[2]
In many domestic and industrial buildings a thick concrete slab, supported on foundations or directly on the subsoil, is used to construct the ground floor of a building. These can either be "ground-bearing" or "suspended" slabs. The slab is "ground-bearing" if it rests directly on the foundation, otherwise the slab is "suspended".[3] For double-storey or multi-storey buildings, the use of a few common types of concrete suspended slabs are used (for more types refer to the Concrete Slab#Design section below):
Beam and block also referred to as Rib and Block, are mostly used in residential and industrial applications. This slab type is made up of pre-stressed beams and hollow blocks and are temporarily propped until set, typically after 21 days.
A Hollow core slab which are precast and installed on site with a crane.
In high rise buildings and skyscrapers, thinner, pre-cast concrete slabs are slung between the steel frames to form the floors and ceilings on each level. Cast in-situ slabs are used in high rise buildings and huge shopping complexes as well as houses. These in-situ slabs are cast on site using shutters and reinforced steel.
The largest-volume of recycled material used as construction aggregate is blast furnace and steel furnace slag. Blast furnace slag is either air-cooled (slow cooling in the open) or granulated (formed by quenching molten slag in water to form sand-sized glass-like particles). If the granulated blast furnace slag accesses free lime during hydration, it develops strong hydraulic cementitious properties and can partly substitute for portland cement in concrete. Steel furnace slag is also air-cooled. In 2006, according to the USGS, air-cooled blast furnace slag sold or used in the U.S. was 7.3 million tonnes valued at $49 million, granulated blast furnace slag sold or used in the U.S. was 4.2 million tonnes valued at $318 million, and steel furnace slag sold or used in the U.S. was 8.7 million tonnes valued at $40 million. Air-cooled blast furnace slag sales in 2006 were for use in road bases and surfaces (41%), asphaltic concrete (13%), ready-mixed concrete (16%), and the balance for other uses. Granulated blast furnace slag sales in 2006 were for use in cementitious materials (94%), and the balance for other uses. Steel furnace slag sales in 2006 were for use in road bases and surfaces (51%), asphaltic concrete (12%), for fill (18%), and the balance for other uses
A ceramic is an inorganic compound, non-metallic, solid material comprising metal, non-metal or metalloid atoms primarily held in ionic and covalent bonds. This article gives an overview of ceramic materials from the point of view of materials science.
The crystallinity of ceramic materials ranges from highly oriented to semi-crystalline, vitrified, and often completely amorphous (e.g., glasses). Most often, fired ceramics are either vitrified or semi-vitrified as is the case with earthenware, stoneware, and porcelain. Varying crystallinity and electron consumption in the ionic and covalent bonds cause most ceramic materials to be good thermal and electrical insulators (extensively researched in ceramic engineering). With such a large range of possible options for the composition/structure of a ceramic (e.g. nearly all of the elements, nearly all types of bonding, and all levels of crystallinity), the breadth of the subject is vast, and identifiable attributes (e.g. hardness, toughness, electrical conductivity, etc.) are hard to specify for the group as a whole. General properties such as high melting temperature, high hardness, poor conductivity, high moduli of elasticity, chemical resistance and low ductility are the norm,[1] with known exceptions to each of these rules (e.g. piezoelectric ceramics, glass transition temperature, superconductive ceramics, etc.). Many composites, such as fiberglass and carbon fiber, while containing ceramic materials, are not considered to be part of the ceramic family.[2]
A highway is any public or private road or other public way on land. It is used for major roads, but also includes other public roads and public tracks: It is not an equivalent term to controlled-access highway, or a translation for autobahn, autoroute, etc.
In North American and Australian English, major roads such as controlled-access highways or arterial roads are often state highways (Canada: provincial highways). Other roads may be designated "county highways" in the US and Ontario. These classifications refer to the level of government (state, provincial, county) that maintains the roadway.
In British English, "highway" is primarily a legal term. Everyday use normally implies roads, while the legal use covers any route or path with a public right of access, including footpaths etc.
The term has led to several related derived terms, including highway system, highway code, highway patrol and highwayman.
The term highway exists in distinction to "waterway".
High-performance fiber-reinforced cementitious composites (HPFRCCs) are a group of fiber-reinforced cement-based composites which possess the unique ability to flex and self-strengthen before fracturing. This particular class of concrete was developed with the goal of solving the structural problems inherent with today’s typical concrete, such as its tendency to fail in a brittle manner under excessive loading and its lack of long-term durability. Because of their design and composition, HPFRCCs possess the remarkable ability to strain harden under excessive loading. In layman’s terms, this means they have the ability to flex or deform before fracturing, a behavior similar to that exhibited by most metals under tensile or bending stresses. Because of this capability, HPFRCCs are more resistant to cracking and last considerably longer than normal concrete. Another extremely desirable property of HPFRCCs is their low density. A less dense, and hence lighter material means that HPFRCCs could eventually require much less energy to produce and handle, deeming them a more economic building material. Because of HPFRCCs’ lightweight composition and ability to strain harden, it has been proposed that they could eventually become a more durable and efficient alternative to typical concrete.
HPFRCCs are simply a subcategory of ductile fiber-reinforced cementititous composites (DFRCCs) that possess the ability to strain harden under both bending and tensile loads, not to be confused with other DFRCCs that only strain harden under bending loads.
The water cycle, also known as the hydrological cycle or the hydrologic cycle, describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water, saline water and atmospheric water is variable depending on a wide range of climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, condensation, precipitation, infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different forms: liquid, solid (ice) and vapor.
The water cycle involves the exchange of energy, which leads to temperature changes. When water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence climate.
The evaporative phase of the cycle purifies water which then replenishes the land with freshwater. The flow of liquid water and ice transports minerals across the globe. It is also involved in reshaping the geological features of the Earth, through processes including erosion and sedimentation. The water cycle is also essential for the maintenance of most life and ecosystems on the planet.
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to toss people around and destroy whole cities. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. The word tremor is also used for non-earthquake seismic rumbling.
At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally volcanic activity.
In its most general sense, the word earthquake is used to describe any seismic event — whether natural or caused by humans — that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests. An earthquake's point of initial rupture is called its focus or hypocenter. The epicenter is the point at ground level directly above the hypocenter.
A paving stone or brick made in any desired shape that can be used for pavements, building bricks or other purposes. these 'eco-friendly' paving bricks are cheaper than the classic model.
Paving stones can be manufactured from waste plastics without requiring significant capital investment. The main component of the mixture can be made from plastic packaging (like bags and transparent films) and it is possible to mix other types of plastic waste in. The process is simple, melting the plastics down and mixing with sand. This mixture can then be moulded into any desired shape to produce paving tiles (such as for pavements)
There are several steps to production. The plastic serves to bind the materials together. The plastic is then melted in a vat over a wood fire. You then add sand and mix it. Then, you pour the mix into a mould and let it dry for 15 minutes.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
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Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
2. CONTENTS
INTRODUCTION
History
DEFINITION OF SHOTCRETE
SHOTCRETE MATERIALS
EQUIPMENTS USED IN SHOTCRETE
SHOTCRETE VERSUS CONVENTIONAL CONCRETE
DRY PROCESSES
WET PROCESS
APPLICATIONS OF SHOTCRETE
ADVANTAGES
DISADVANTAGES
CONCLUSION
REFRENCES
3. INTRODUCTION
•Shortcreting has proved to be the best method for construction
of curved surfaces.
•Domes are now much easier to construct with the advent of
with this shotcrete technology.
•Tunnel linings are also becoming easy technology.
•It also enumerates the different types of process involved in
shotcreting.
4. HISTORY
Shotcrete was invented in the early 1900s by American
taxidermist Carl Akeley.
used to fill plaster models of animals.
In 1911, he was granted a patent.
Until the 1950’s, the wet-mix process was devised, only
the dry-mix process was used.
5. DEFINITION OF SHOTCRETE
•Shotcrete is a mortar or high performance concrete conveyed
through a hose and pneumatically projected at high velocity onto a
receiving surface.
• The applied mixture of cement, aggregate, and water conveyed
through a hose and projected at high velocity onto the application
surface.
7. EQUIPMENTS USED IN SHOTCRETE
Batching and mixing equipment
Admixture dispensers
Air compressor
Nozzles
Shotcrete accelerator
8. SHOTCRETE VS CONVENTIONAL CONCRRETE
conventional concrete is first placed and then compacted in the
second operation.
shotcrete undergoes placement and compaction at the same time.
Shotcrete is more dense, homogeneous, strong, and waterproof.
It can be impacted onto any type or shape of surface, including
vertical or overhead areas.
9. Dry process
Step1: Pre blended, dry or semi-dampened materials are placed
into shotcrete equipment and metered into a hose.
Step2: Compressed air conveys materials at high velocity to the
nozzle where the water is added.
Step3: Then the material is consolidated on receiving surface by
high impact velocity.
10. Advantages of Dry process:
•Easy start up, shutdown and clean up.
•Control of materials is on site.
•Nozzle man can be up to 1000ft horizontally or 500ft
vertically from the gun.
11. Wet process
Step1: All ingredients, including water, are thoroughly mixed and
introduced into the shotcrete equipment.
Step 2: Wet material is pumped to the nozzle where compressed air
is introduced.
Step 3: Mostly wet-process shotcreting is done with premixed
mortar or small aggregate concrete.
12. Advantages of Wet process:
•Little or no formwork is required.
•Cost effective method for placing concrete.
•Ideal for irregular surface applications.
•Allows for easier material handling in areas with
•difficult access.
13. APPLICATION OF SHOTCRETE
Support of underground openings in tunnel, mines, drainages
and bridges.
•Piers / Docks
•Ditches
•Retaining Walls
14. Rehabilitation of subway tunnels construction of domed roofs.
Highway culvert repair
and arch culvert
15. ADVANTAGES:
• Little or no framework is required.
• Cost effective method for placing concrete.
• Ideal for irregular surfaces application.
• Allows for easier material handling in areas with difficult access.
• Easy start up, shutdown and clean up.
• Increase in load bearing capacity due to redistribution of stresses.
• Excellent corrosion resistance.
16. DISADVANTAGES
•Rain may wash out the cement leaving a sandy surface, or it may
saturate the shotcrete and cause sloughing or sagging.
• Strong wind will separate the material between the nozzle and the
point of deposit, reducing the strength.
• It requires skilled and experienced labours.
• A greater degree of geotechnical knowledge is required.
•Improperly applied shotcrete may create conditions much worse
than the untreated condition.
17. CONCLUSION
•The use of Shotcrete to build new concrete structures as well as
to restore and repair existing structures is well known and
documented and it is perhaps the most diverse method available
for concrete construction.
•The use of this innovative technology is increasing day by day
and procedures for its proper performance are well developed
and high quality work is regularly obtained.
•Shotcrete is a viable option for doing superstructure
repair(unformed) and substructure repair (unformed) if done
strictly according to specifications and best practices.
•It is a good substitute for the manual lay-up method for vertical
and overhead applications using rapid set mortar.