Aggregates of Yuleba Minerals

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Aggregates of Yuleba Minerals
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• Aggregate is a collective term for the mineral
  materials such as sand, gravel and crushed.
  Aggregates can either be natural or manufactured.
  Natural aggregates are generally extracted from
  larger rock formations through an open excavation
  (quarry). Extracted rock is typically reduced to
  usable sizes by mechanical crushing. Manufactured
  aggregate is often the by product of other
  manufacturing industries.

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• Aggregate SourcesIgneous rockThese rocks are
  primarily crystalline and are formed by the
  cooling of molten rock material beneath the
  earths crust.Sedimentary rocks

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• These rocks are formed from deposited insoluble
  material. This material is transformed to rock by
  heat and pressure. Sedimentary rocks are layered
  in appearance and are further classified based on
  their predominant mineral as calcareous
  (limestone, chalk, etc.), siliceous (chert,
  sandstone, etc.) or argillaceous (shale, etc.).

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Metamorphic rock

• These are igneous or sedimentary rocks that have
  been subjected to heat and/or pressure great
  enough to change their mineral structure so as to
  be different from the original rock.Manufactured
  rock typically consists of industrial by products
  such as slag or specialty rock that is produced
  to have a particular physical characteristic not
  found in natural rock (such as the low density of
  lightweight aggregate). 

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Mineral Properties

• An aggregates mineral composition largely
  determines its physical characteristics and how
  it behaves as a material. Therefore, when
  selecting an aggregate source, knowledge of the
  quarry rocks mineral properties can provide an
  excellent clue as to the suitability of the
  resulting aggregate. 

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• Relationships between mineral and physical
  properties are quite complex, making it difficult
  to accurately predict how a particular aggregate
  source will behave based on mineral properties
  alone.

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Chemical Properties

• While relatively unimportant for loose aggregate,
  aggregate chemical properties are importantb in a
  construction material. Aggregate surface
  chemistry can determine how well a binder will
  adhere to an aggregate surface. Poor adherence,
  commonly referred to as stripping, can cause
  premature structural failure. In PCC, aggregates
  containing reactive forms can react expansively
  with the alkalis contained in the cement paste.

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• This expansion can cause cracking, surface
  popouts and spalling. Note that some aggregate
  chemical properties can change over time,
  especially after the aggregate is crushed. A
  newly crushed aggregate may display a different
  affinity for water than the same aggregate that
  has been crushed and left in a stockpile for a
  year.

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Physical Properties

• Aggregate physical properties are the most
  readily apparent aggregate properties and they
  also have the most direct effect on how an
  aggregate performs as either a pavement material
  constituent or by itself as a base or sub base
  material.

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• Commonly measured physical aggregate properties
  are (Roberts et al., 1996) Gradation and
  size Toughness and Abrasion Resistance
  Durability and soundness Particle shape and
  surface texture Specific gravity Cleanliness
  and deleterious materials Moisture Content

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• These are not the only physical properties of
  aggregates but rather the most commonly measured.
  Tests used to quantify these properties are
  largely empirical. The physical properties of an
  aggregate can change over time. For instance, a
  newly crushed aggregate may contain more dust and
  thus be less receptive to binding with an asphalt
  binder.

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• Yuleba Minerals (www.yulebaminerals.com.au )
  produces a range of natural aggregates that are
  used widely throughout Roma, Chinchilla, Miles,
  Surat and Southern Queensland.

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• For more information , please visit

http//www.yulebaminerals.com.au/