What Aggregates are available and where do they come from?

What Aggregates are available and where do they come from?

Aggregates are derived from two basic sources – Hard rock quarries, and Sand quarries.

Hard rock quarries employ explosives and mechanical crushing plant to produce aggregate for use in concrete. The physical nature of these aggregates is that they have sharp edges as a result of the crushing process. They provide better strength properties for concrete because their angular nature provides additional mechanical interlock within the concrete – enhancing its strength.

Sand quarries employ dry and wet methods of sand extraction from ancient sand deposits. These deposits were once rivers or streams. The movement of water over millions of years produces rounded (approximately spherical) aggregate particles. Mechanical methods are used to separate the aggregates (often called pebbles) from the sand.

The nature of natural quarried materials is that variation is inevitable over the life of the quarry and some materials may contain traces of naturally occurring iron which can lead to stains developing on the surface of the finished concrete some time after construction is complete.

There are seven basic aggregate types on offer through Vic Mix in various sizes: 7mm, 14mm and 20mm. However, other specialist aggregates can be sourced for the right project.