Aggregate

The definition of aggregate in commercial construction in Australia 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 raw materials that are produced from natural sources and extracted from pits and quarries . In construction, an aggregate is a material used for mixing with cement, bitumen, lime, gypsum, or other adhesives to form concrete or mortar, providing volume, stability, resistance to wear or erosion, and other desired physical properties to the finished product .

Types of Aggregates Used in Commercial Construction in Australia

Some common types of aggregates used in commercial construction in Australia include:

• Gravel: Composed of rounded stones, gravel is often used in concrete for its smooth texture and rounded shape, which improve the workability of concrete .
• Sand: A fine aggregate, sand significantly influences the strength and workability of concrete .
• Crushed Stone: A versatile aggregate, crushed stone is used in various construction applications, including concrete production, road construction, and landscaping .
• Recycled Concrete Aggregate (RCA): RCA is a sustainable option made from recycled concrete waste, often used in non-structural applications and concrete production .
• Crushed basalt rock or aggregate (also known as "blue metal"): A popular choice for concrete and road construction .
• Recycled aggregates such as Manufactured Sand, Reclaimed Aggregate (RA), Air-cooled Blast Furnace Slag (BFS), Electric Arc Furnace Slag (EAF), Steel Furnace Slag (BOS), Reclaimed Asphalt Pavement (RAP), Used Foundry Sand or Spent Foundry Sand, Glass Cullet, and Scrap Tyres are also available and used in various construction applications .
• Crushed limestone: A popular choice for construction projects in Australia, particularly in the eastern states where limestone is abundant .

Applications of Aggregates in Commercial Construction in Australia

Aggregates are used in various commercial construction applications in Australia, including:

1. Concrete production: Aggregates such as recycled concrete aggregate (RCA), manufactured sand, and air-cooled blast furnace slag (BFS) are used as coarse and fine aggregates in concrete production for building structures, sidewalks, kerbs, and gutters .
2. Road construction: Aggregates like reclaimed asphalt pavement (RAP), reclaimed aggregate (RA), and crushed brick are used in road base courses, subbase materials, and new asphaltic concrete pavements .
3. Asphalt production: Aggregates such as manufactured sand, BFS, and steel furnace slag are used in asphalt production for road construction and maintenance .
4. Structural fill: Aggregates like electric arc furnace slag (EAF) and steel furnace slag are used as controlled low-strength fill materials in commercial construction projects .
5. Pavement stabilization: Aggregates like EAF and BFS are used for pavement stabilization and road maintenance .
6. Drainage and filtration: Aggregates are used in drainage and filtration applications, such as retaining walls, underslab filter blankets, and in any application where free-flowing water with hard, durable rock is required .
7. Landscaping and decorative features: River gravels, in particular, are used in landscape decorative markets, with larger graded products (40-80mm) being used for landscape features .
8. Backfill and site preparation: Aggregates are used as backfill materials in commercial construction sites to provide a stable base for buildings and other structures .
9. Building foundations: Aggregate is used as a base material under building foundations, providing a stable and level surface for construction .
10. Rail construction: Aggregate is used as a base material under rail tracks, providing a stable and level surface for train movement .

Australian Standards for Aggregates in Commercial Construction

The Australian standards for aggregates in commercial construction are outlined in the AS 2758 series, which includes several parts such as AS 2758.1: Concrete aggregates , AS 2758.2: Aggregate for sprayed bituminous surfacing , AS 2758.5: Asphalt aggregates, and AS 2758.7: Railway ballast . These standards provide guidelines for the selection, testing, and use of aggregates in various construction applications, including commercial construction .