Aggregate construction , or simply " aggregate ", is a broad category of rough-to-medium grain materials used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Aggregates are the most mined material in the world. Aggregates are components of composite materials such as concrete and asphalt concrete; aggregate serves as an amplifier to add strength to the overall composite material. Due to relatively high hydraulic conductivity values ​​compared to most soils, aggregates are widely used in drainage applications such as French foundations and drains, septic drains, retaining wall drains, and side-use side canals. Aggregates are also used as a base material under foundations, roads, and railroads. In other words, the aggregate is used as a stable or rigid foundation with predictable and uniform properties (eg to help prevent differential settling under a road or building), or as a low-cost loading that binds with more expensive cement or asphalt to form concrete.
The preferred bitumenous aggregate size for road construction is given in EN 13043 as d/D (where the range represents the smallest and largest particle boundary mesh lattice). The same classification size is used for larger protective rock sizes in EN 13383, EN 12620 for concrete aggregates, EN 13242 for the base layer of road construction and EN 13450 for train weights.
The American Society for Testing and Materials (ASTM) publishes a full list of specifications including ASTM D 692 and ASTM D 1073 for a variety of construction aggregate products, which, with their individual designs, are suitable for specific construction purposes. These products include certain types of coarse and fine aggregates designed for uses such as additives for asphalt and concrete mixtures, as well as other construction uses. The state transportation department further refines aggregate material specifications to adjust aggregate use to the needs and availability of supply at their particular location.
Sources for these basic materials can be grouped into three main areas: Mining of mineral deposits, including sand, gravel, and stone; use of slag waste from iron and steel manufacture; and recycling of concrete, which itself is primarily made of mineral aggregates. In addition, there are several (minor) materials used as special mild aggregates: clay, pumice, pearlite, and vermiculite.
Video Construction aggregate
History
People have used sand and rock for the foundations for thousands of years. Significant improvements of aggregate production and use occurred during the Roman Empire, which used aggregate to build its extensive road and waterway networks. The discovery of concrete, which is important for architecture utilizing the arch, creates a permanent, direct demand for construction aggregates.
M. menulis gods architecture :
Economics shows the right materials and site management, as well as the balance of costs and common sense in construction work. It will be observed if, in the first place, the architects do not demand things that can not be found or made ready without a huge cost. For example: there is not everywhere that there are many sand holes, debris, firs, clear firs, and marble... Where there are no sand holes, we must use the types swept by rivers or seas. and other problems that we must solve in the same way.
Maps Construction aggregate
Modern production
The advent of modern blasting methods enables the development of mines, which are now used worldwide, wherever the existing aggregate quality sedimentary rocks are present. In many places, good limestone, granite, marble or rocks of other quality rock-deposition rocks do not exist. In these areas, natural sand and gravel are mined for use as aggregates. Where rock, sand and gravel are not available, construction demand is usually filled with aggregate shipments by rail, barge or truck. In addition, aggregate demand can be partially met through the use of slag and recycled concrete. However, the available tonnage and lower quality of these materials prevent them from becoming a viable replacement for aggregates that are mined on a large scale.
The mining of large rocks and sand and gravel is near almost all population centers due to the high cost of transportation relative to the low value of the product. Aggregate trucks over 40 kilometers are usually not economical. It is a capital-intensive operation, utilizing large earth moving equipment, belt conveyors, and machines designed specifically to destroy and separate aggregate sizes, to create different product stocks.
According to the USGS, 2006 US crushed stone production was 1.72 billion tonnes worth $ 13.8 billion (compared to 1.69 billion tonnes valued at $ 12.1 billion in 2005), where limestone is 1.080 million tonnes worth $ 8 , 19 billion out of 1,896 quarts, granite is 268 million tons valued at $ 2.59 billion from 378 quarries, traprock is 148 million tons worth $ 1.04 billion from 355 quarries, and the remaining other types of stones of 729 quarries. Limestone and granite are also produced in large quantities as dimensional stones. Most of the destroyed rocks are driven by heavy trucks from mine/factory to the point of sale or first use. According to the USGS, US sand and gravel production in 2006 was 1.32 billion tons worth $ 8.54 billion (compared to 1.27 billion tons valued at $ 7.46 billion in 2005), where 264 million tons were valued at $ 1, 92 billion is used as a concrete aggregate. The majority is again driven by trucks, not by electric trains.
At present, the total aggregate demand of the US by the final market is 30% -35% for non-residential buildings (offices, hotels, shops, factories, government buildings and institutions, etc.), 25% for roads, and 25% for housing.
Recycled materials for aggregates
The largest volume of recyclable materials used as construction aggregates are blast furnaces and furnace steel furnaces. The slag is either air-cooled blowing kilns (slow cooling in the open) or granulated (formed by quenching slag liquid in water to form particles like glass of sand). If slag granule kilns access lime free during hydration, it develops strong hydraulic cement properties and can partially replace portland cement in the concrete. Slag stoves are also air-cooled. In 2006, according to USGS, air-cooled kiln slag furnaces sold or used in the US were 7.3 million tonnes valued at $ 49 million, blasted sea cucumber stoves sold or used in the US were 4.2 million tonnes valued at $ 318 million, and steel slag furnaces sold or used in the US is 8.7 million tonnes worth $ 40 million. Sales of air-cooled kiln blast furnaces in 2006 were used for bases and road surfaces (41%), asphalt concrete (13%), ready-mix concrete (16%), and the rest for other uses. Sales of sea cucumber blast furnaces in 2006 were used for cement material (94%), and the rest for other uses. Sales of furnace steel slags in 2006 were used for bases and road surfaces (51%), asphalt concrete (12%), for filling (18%), and the rest for other uses.
Aggregate cups, mixed colors that are broken into small sizes, are replaced for many construction and utility projects where the gravel is crushed or crushed, often saving municipalities such as Tumwater City, Washington Public Works, thousands of dollars (depending on the size of the project). Glass aggregates are not sharp to handle. In many cases, the state Department of Transportation has specifications for use, size and percentage of quantity to use. A common application is like a bed pipe - placed around a ditch, rainwater or drinking water pipe to transfer the weight from the surface and protect the pipe. Another common use is as a filler to bring the level of concrete floor even with the foundation. The use of glass aggregates helps close loops in glass recycling in many places where glass can not be melted into new glass.
Aggregates themselves can be recycled as aggregates. Unlike sand and gravel deposits or rocks suitable for crushing into aggregates, which can be anywhere and may require overburden removal and/or blasting, recyclable aggregate "deposits" tend to be concentrated near urban areas, and production from they can not be raised or lowered to meet aggregate demand. The supply of recycled aggregates depends on the physical damage of the structure and its destruction. Recycling plants can be repaired or moved; Mobile factories with smaller capacities work best for asphalt-aggregate recycling. Recycled materials usually vary greatly in quality and properties.
Many aggregate products of various types are recycled for other industrial uses with economic and environmental benefits to the local and surrounding areas. Contractors save on disposal costs and aggregate less buried or stacked and abandoned. In Bay City, Michigan, for example, there are recycling programs for unused products such as mixed concrete, blocks, bricks, pebbles, rocks, and other materials used. Materials are destroyed to provide a subbase for roads and driveways, among other destinations.
According to the USGS in 2006, 2.9 million tons of Portland (including aggregate) concrete cement worth $ 21.9 million was recycled, and 1.6 million tons of concrete (including aggregate) asphalt $ 11.8 million was recycled, either by crushed stone operations. More than both materials are recycled by construction and dismantling companies not in USGS surveys. For sand and gravel, the USGS survey for 2006 showed that 4.7 million tonnes of concrete cement worth $ 32.0 million was recycled, and 6.17 million tons of concrete asphalt worth $ 45.1 million was recycled. Again, more than both materials are recycled by construction and demolition companies not in this USGS survey. The Construction Materials Recycling Association shows that there are 325 million tons of recoverable construction and crushing materials produced each year.
Many geosynthetic aggregates are also made from recycled materials. Being a polymer based, recyclable plastic can be reused in aggregate new age production. For example, the EZflow Ring Industrial Group product line is manufactured with geosynthetic aggregate pieces of more than 99.9% recycled polystyrene. This polystyrene, which should have been destined for landfill, was collected, melted, mixed, reformulated and expanded to create low-density aggregates that retain high strength properties while under press load. Such geosynthetic aggregates replace conventional pebbles while simultaneously increasing porosity, increasing hydraulic conductivity and eliminating fine dust "fine" attached to gravel aggregates that otherwise clog and interfere with the operation of many drainage applications.
Production of recycled aggregates in the UK
Recycled aggregates in the UK are defined as aggregates resulting from the processing of inorganic materials previously used in construction. To ensure the inert aggregate, it is made from materials that are tested and marked under the European Waste Codes.
In 2008, 210 million tons of aggregates were produced in the UK, of which 67 million tons were recycled products, according to the Quarry Products Association (QPA). The Waste and Resource Action Program (WRAP) has produced the Quality Protocol for regulated aggregate production. Recycled aggregates are delivered with documentation stating it has been manufactured using a quality assurance system for the manufacturing process to ensure that aggregate complies with relevant European standards.
See also
- Aggregate (composite), Aggregate base
- Aggflow: Aggregate Crop Analysis Software
- Aggregate alkaline reaction
- Alkali-silica reactions
- Pozzolanic reaction
- Concrete
- Stone destroyed
- Stone dimensions: Recycle and reuse of stones
- Marble
- The metal road
- Light-surface-dry
- Hoggin
References
Quote
Source
- UEPG - European Aggregate Association
- Samscreen International
- National Stone, Sand & amp; Gravel Association
- The American Society for Testing Materials
- Gravel Watch Ontario
- Concrete & amp; Oregon Combined Aggregate Producer
- Portland Cement Association
- Interactive Maturity Articles on Aggregates
- The 2006 USGS Mineral Yearbook: Stone, Crushed
- 2005 USGS Mineral Yearbook: Stone, Crushed
- The USGS Mineral Manual 2006: Sand and Gravel Construction
- 2005 USGS Mineral Yearbook: Sand and Pebble Construction
- Aggregate Construction, in June 2007 Mining Engineering (personal membership)
- The USGS Mineral Manual 2006: Iron & amp; Steel Slag
- Aggregates from Natural Resources and Recycling-Economic Assessment
- Construction Material Recycling Association
- MN DNR Agribusiness Resources Excavation Program - Land and Mineral Division
- Excavation in Recycled Depth
- Recycled bone and Primary aggregate production figures
Source of the article : Wikipedia
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