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According to the Equivalent Concrete Performance Concept a concrete composition, deviating from the EN 206-1, can still be accepted, provided that certain conditions are fulfilled.
A concrete composition not composed by the standard EN 206–1, can be acknowledged, only if the new concrete shows a performance equal to the standardized concrete concerning environmental classes. Cement content and water-cement ratio are important elements hereby. The comparison with standardized concrete is tested according to the following properties:
When the new concrete scores equally or better, a certificate of utilization can be obtained from certificating organizations.
The valid standards concerning concrete are:
These national annexes serve to elaborate the functional description of the Equivalent Concrete Performance Concept.
Standardized concrete is a highly durable material, predominantly thanks to the increasing amount of cement at stricter environmental classes. But cement is a costly component and has a relatively powerful impact on the environment.
Partly because of this, alternative binders such as fly ashes and slags are applied in the concrete sector. As a result, the content of Portland cement can be reduced in many cases. Other recycled raw materials can also contribute to a more economic or less environmental polluting concrete composition.
1. Usage of residual products from the concrete industry, for example stone dust (from crushing aggregates), concrete slurry (from washing mixers) or concrete waste
2. Usage of residual products from other industries, for example fly ash from coal plants and slags from the metallurgical industry
3. Usage of new types of cement with reduced environmental impact (mineralized cement, limestone addition, waste-derived fuels)
To respect the Kyoto Protocol, the CO2-emission should be reduced. Green concrete exists out of recycling or is composed is such a manner, that it is as environmental-friendly as possible. A few conditions before the term green concrete may be used:
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminum combined. Globally, the ready-mix concrete industry, the largest segment of the concrete market, is projected to exceed $600 billion in revenue by 2025. This widespread use results in a number of environmental impacts. Most notably, the production process for cement produces large volumes of greenhouse gas emissions, leading to net 8% of global emissions. Other environmental concerns include widespread illegal sand mining, impacts on the surrounding environment such as increased surface runoff or urban heat island effect, and potential public health implications from toxic ingredients. Significant research and development is being done to try to reduce the emissions or make concrete a source of carbon sequestration, and increase recycled and secondary raw materials content into the mix to achieve a circular economy. Concrete is expected to be a key material for structures resilient to climate disasters, as well as a solution to mitigate the pollution of other industries, capturing wastes such as coal fly ash or bauxite tailings and residue.
A cement is a binder, a substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum. Several types of portland cement are available. The most common, called ordinary portland cement (OPC), is grey, but white Portland cement is also available. Its name is derived from its resemblance to Portland stone which was quarried on the Isle of Portland in Dorset, England. It was named by Joseph Aspdin who obtained a patent for it in 1824. However, his son William Aspdin is regarded as the inventor of "modern" portland cement due to his developments in the 1840s.
Slag is a by-product of smelting (pyrometallurgical) ores and used metals. Broadly, it can be classified as ferrous, ferroalloy or non-ferrous/base metals. Within these general categories, slags can be further categorized by their precursor and processing conditions.
Asphalt concrete is a composite material commonly used to surface roads, parking lots, airports, and the core of embankment dams. Asphalt mixtures have been used in pavement construction since the beginning of the twentieth century. It consists of mineral aggregate bound together with asphalt, laid in layers, and compacted. The process was refined and enhanced by Belgian-American inventor Edward De Smedt.
Fly ash, flue ash, coal ash, or pulverised fuel ash – plurale tantum: coal combustion residuals (CCRs) – is a coal combustion product that is composed of the particulates that are driven out of coal-fired boilers together with the flue gases. Ash that falls to the bottom of the boiler's combustion chamber is called bottom ash. In modern coal-fired power plants, fly ash is generally captured by electrostatic precipitators or other particle filtration equipment before the flue gases reach the chimneys. Together with bottom ash removed from the bottom of the boiler, it is known as coal ash.
Green 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. This requires close cooperation of the contractor, the architects, the engineers, and the client at all project stages. The Green Building practice expands and complements the classical building design concerns of economy, utility, durability, and comfort. In doing so, the three dimensions of sustainability, i.e., planet, people and profit across the entire supply chain need to be considered.
Glass recycling is the processing of waste glass into usable products. Glass that is crushed or imploded and ready to be remelted is called cullet. There are two types of cullet: internal and external. Internal cullet is composed of defective products detected and rejected by a quality control process during the industrial process of glass manufacturing, transition phases of product changes and production offcuts. External cullet is waste glass that has been collected or reprocessed with the purpose of recycling. External cullet is classified as waste. The word "cullet", when used in the context of end-of-waste, will always refer to external cullet.
Refuse-derived fuel (RDF) is a fuel produced from various types of waste such as municipal solid waste (MSW), industrial waste or commercial waste.
Construction aggregate, or simply aggregate, is a broad category of coarse- to medium-grained particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Aggregates are the most mined materials in the world. Aggregates are a component of composite materials such as concrete and asphalt; the aggregate serves as reinforcement to add strength to the overall composite material. Due to the relatively high hydraulic conductivity value as compared to most soils, aggregates are widely used in drainage applications such as foundation and French drains, septic drain fields, retaining wall drains, and roadside edge drains. Aggregates are also used as base material under foundations, roads, and railroads. In other words, aggregates are used as a stable foundation or road/rail base with predictable, uniform properties, or as a low-cost extender that binds with more expensive cement or asphalt to form concrete. Although most kinds of aggregate require a form of binding agent, there are types of self-binding aggregate which do not require any form of binding agent.
Fiber-reinforced concrete or fibre-reinforced concrete (FRC) is concrete containing fibrous material which increases its structural integrity. It contains short discrete fibers that are uniformly distributed and randomly oriented. Fibers include steel fibers, glass fibers, synthetic fibers and natural fibers – each of which lend varying properties to the concrete. In addition, the character of fiber-reinforced concrete changes with varying concretes, fiber materials, geometries, distribution, orientation, and densities.
Tire recycling, or rubber recycling, is the process of recycling rubbish tires that are no longer suitable for use on vehicles due to wear or irreparable damage. These tires are a challenging source of waste, due to the large volume produced, the durability of the tires, and the components in the tire that are ecologically problematic.
Coal combustion products (CCPs), also called coal combustion wastes (CCWs) or coal combustion residuals (CCRs), are categorized in four groups, each based on physical and chemical forms derived from coal combustion methods and emission controls:
Eco-Cement is a brand-name for a type of cement which incorporates reactive magnesia, another hydraulic cement such as Portland cement, and optionally pozzolans and industrial by-products, to reduce the environmental impact relative to conventional cement. One problem with the commercialization of this cement, other than the conservatism of the building industry, is that the feedstock magnesite is rarely mined.
Co-processing is the use of waste as raw material, or as a source of energy, or both to replace natural mineral resources and fossil fuels such as coal, petroleum and gas in industrial processes, mainly in energy intensive industries (EII) such as cement, lime, steel, glass, and power generation. Waste materials used for Co-processing are referred to as alternative fuels and raw materials (AFR).
Concrete is produced in a variety of compositions, finishes and performance characteristics to meet a wide range of needs.
Geopolymer cement is a binding system that hardens at room temperature.
Products made from a variety of materials can be recycled using a number of processes.
Green building is a technique that aims to create structures that are environmentally responsible and resource-efficient throughout their lifecycle – from siting to design, construction, operation, maintenance, renovation, and demolition. A 2009 report by the U.S. General Services Administration evaluated 12 sustainably designed GSA buildings, and found they cost less to operate
The environmental impact of concrete, its manufacture and applications, are complex, driven in part by direct impacts of construction and infrastructure, as well as by CO2 emissions; between 4-8% of total global CO2 emissions come from concrete. Many depend on circumstances. A major component is cement, which has its own environmental and social impacts and contributes largely to those of concrete.
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