Aggregates of Yuleba Minerals

1. Aggregates of Yuleba Minerals

2. “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.

3. Aggregate SourcesIgneous rockThese rocks are primarily crystalline and are formed by the cooling of molten rock material beneath the earth’s crust.Sedimentary rocks

5. 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.).

6. 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). 

8. Mineral Properties An aggregate’s mineral composition largely determines its physical characteristics and how it behaves as a material. Therefore, when selecting an aggregate source, knowledge of the quarry rock’s mineral properties can provide an excellent clue as to the suitability of the resulting aggregate. 

9. 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.

11. 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.

12. 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.

14. 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.

15. 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

16. 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.

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

18. For more information , please visit http://www.yulebaminerals.com.au/