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Aggregate
Construction aggregate, or simply aggregate, is a broad category of coarse- to medium-grained particulate material used in construction. Traditionally, it includes natural materials such as sand, gravel, crushed stone. As with other types of aggregates, it is a component of composite materials, particularly concrete and asphalt. Aggregates are the most mined materials in the world,[1][2] being a significant part of 6 billion tons of concrete produced per year.[3] Aggregate serves as reinforcement to add strength to the resulting material. Due to the relatively high hydraulic conductivity as compared to most soil types, 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 building foundations, roads, and railroads (aggregate base). It has predictable, uniform properties, preventing differential settling under the road or building. Aggregates are also used 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 require no form of binding agent.[4] More recently, recycled concrete and geosynthetic materials have also been used as aggregates.
East Sussexis aceremonial countyinSouth East England. It is bordered byKentto the north-east,West Sussexto the west,Surreyto the north-west, and theEnglish Channelto the south. The largest settlement is the city ofBrighton and Hove, and the county town isLewes.
The county has an area of 1,792 km2(692 sq mi) and a population of 822,947.[5][6]The latter is largely concentrated along the coast, where the largest settlements are located: Brighton and Hove (277,105),Eastbourne(99,180), andHastings(91,490).[7]The centre and north of the county are largely rural, and the largest settlement isCrowborough(21,990).[7]Forlocal governmentpurposes, East Sussex comprises anon-metropolitan county, with five districts, and theunitary authorityof Brighton and Hove. East Sussex and West Sussexhistoricallyformed a single county,Sussex.
The north-east of East Sussex is part of theWeald, asandstoneanticlinethat was once an extensive woodland. The highest point in this area is Crowborough Hill (242 m (794 ft)), part of the High Weald uplands. The south-west of the county is part of theSouth Downs, a rollingchalkescarpmentthat stretches west into West Sussex and Hampshire.Ditchling Beacon(248 m (814 ft)) is the highest point. Where the downs reach the sea, they form high cliffs such as theSeven Sisters, where erodeddry valleyscreate an undulating skyline.[8]The county does not contain large rivers, but its largest are theRother, which forms part of the boundary with Kent, theCuckmere, and theOuse, which rises in West Sussex and flows throughLewesbefore reaching the English Channel atNewhaven.[9]
