agregatlar

Agregatlar are granular materials composed of rock fragments of varying sizes that are used as fillers and structural components in construction and engineering. They are largely inert, not participating in chemical reactions with binders, and they contribute to the volume, strength, and durability of concrete, asphalt, and other composites.

They are typically divided into natural aggregates and manufactured aggregates. Natural aggregates include sands, gravels, and crushed stones mined from quarries, riverbeds, or sea beds. Manufactured aggregates are produced by processing industrial by-products or waste materials, such as blast-furnace slag, expanded clays or shales, and recycled concrete aggregate (RCA). By size, aggregates are categorized as fine (usually passing the 4.75 mm sieve) and coarse (retained on that sieve).

Applications include concrete, road bases, asphalt pavements, drainage layers, and rail-ballast. Important properties are grading (particle size distribution), shape, hardness and abrasion resistance, density, porosity and moisture absorption, and resistance to freeze–thaw and chemical attack. Quality is checked for deleterious substances (clay, silt, organics) and conformity to regional standards.

Standards and testing vary by region; examples include ASTM C33 for concrete aggregates and EN 12620 for aggregates used in concrete in Europe. Environmental considerations focus on quarry impact, carbon footprint, and the recycling of demolished concrete into RCA or other recycled aggregates to reduce waste and resource use.