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  • Construction aggregate

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    Limestone quarry. 10 mm graded crushed basalt rock or aggregate, for use in concrete, called "blue metal" in Australia. 20 mm graded aggregate. A gravel and sand extraction facility in Međimurje County, Croatia. 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 concrete; 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 road side 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 (e.g. to help prevent differential settling under the road or building), or as a low-cost extender that binds with more expensive cement or asphalt to form concrete. Preferred bituminous aggregate sizes for road construction are given in EN 13043 as d/D (where the range shows the smallest and largest square mesh grating that the particles can pass). The same classification sizing is used for larger armour stone sizes in EN 13383, EN 12620 for concrete aggregate, EN 13242 for base layers of road construction and EN 13450 for railway ballast. The American Society for Testing and Materials publishes an exhaustive listing of specifications including ASTM D 692 and ASTM D 1073 for various construction aggregate products, which, by their individual design, are suitable for specific construction purposes. These products include specific types of coarse and fine aggregate designed for such uses as additives to asphalt and concrete mixes, as well as other construction uses. State transportation departments further refine aggregate material specifications in order to tailor aggregate use to the needs and available supply in their particular locations. Sources for these basic materials can be grouped into three main areas: Mining of mineral aggregate deposits, including sand, gravel, and stone; use of waste slag from the manufacture of iron and steel; and recycling of concrete, which is itself chiefly manufactured from mineral aggregates. In addition, there are some (minor) materials that are used as specialty lightweight aggregates: clay, pumice, perlite, and vermiculite.

  • Mike Gravel

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    Maurice Robert "Mike" Gravel (; born May 13, 1930) is an American politician who was a Democratic United States Senator from Alaska from 1969 to 1981 and a candidate in the 2008 U.S. presidential election. Born and raised in Springfield, Massachusetts, by French-Canadian immigrant parents, Gravel served in the U.S. Army in West Germany, and he later graduated from the Columbia University School of General Studies. He moved to Alaska in the late 1950s, becoming a real estate developer and entering politics. He served in the Alaska House of Representatives from 1963 to 1966 and also became Speaker of the Alaska House. Gravel was elected to the U.S. Senate in 1968. As a Senator, Gravel became nationally known for his forceful but unsuccessful attempts to end the draft during the War in Vietnam and for putting the Pentagon Papers into the public record in 1971 at some risk to himself. He conducted an unusual campaign for the Democratic nomination in 1972 for Vice President of the United States, and then played a crucial role in getting Congressional approval for the Trans-Alaska pipeline in 1973. He was re-elected to the Senate in 1974, but gradually alienated most of his Alaskan constituencies and his bid for a third term was defeated in a primary election in 1980. Gravel returned to business ventures and went through difficult times, suffering corporate and personal bankruptcies amid poor health. He has been a quixotic advocate of direct democracy and the National Initiative. In 2006, Gravel began a run for the Democratic nomination for President of the United States to promote those ideas. His campaign gained an Internet following and national attention due to forceful, humorous, and politically unorthodox debate appearances during 2007, but he found very little support in national polls or in 2008 caucuses and primaries. In March 2008, he announced that he was switching to the Libertarian Party to compete for its presidential nomination and the inclusion of the National Initiative into the Libertarian Platform. At the Libertarian National Convention of 2008 he failed on both counts, and he announced that his political electoral career had ended. He subsequently became an executive for a marijuana products company and continued to speak out on various political issues including Democratic Party politics.

  • Oldcastle Materials

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    Oldcastle Materials Inc. is a leading supplier of asphalt, concrete, and other building materials, and also offers construction and paving services. The Atlanta-based company is a subsidiary of CRH plc, a publicly traded international group of diversified building materials businesses, and has approximately 18,000 employees at 1,200 locations, as of March 2018.

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