Concrete is a composite material made up of a combination of natural materials such as gravel, sand, and crushed rock. The size of the particles determines whether it is a coarse-grained aggregate (e.g., gravel) or a fine aggregate (e.g., sand). The resulting concrete can be used in its natural state or crushed, depending on its intended use and application. Aggregate is a term used to describe a collection of granular building materials.
It is used to create concrete slabs and form surfaces and substrates, making it an essential material for residential and commercial projects. But how does the size, weight, moisture content, and gradation of each aggregate affect the characteristics of concrete? It can be a single size material, typically 20 mm, 14 mm, 10 mm, or 7 mm, or a graded aggregate consisting of a single size aggregate mixture. Once processed, aggregates must be handled and stored properly to minimize segregation and degradation and prevent contamination. Recycled concrete is also a viable source of aggregate and has been successfully used in granular subbases, soil cement, and new concrete.
Concrete aggregates are produced to Australian standards (AS 275) or to more specific customer requirements. The term concrete aggregates encompasses a variety of products, but they are generally summarized as stone and sand in coarse-grained and fine grades. If you are considering exposed aggregate for your garden, you will need to pay more attention to the materials used to create the aggregate mix. The aggregate is a collection of inert granular material comprising up to 60% to 80% of a typical concrete mix.
The more packed the particles of the aggregate are, the greater their strength and therefore the greater the strength of the concrete. A variety of materials are used as aggregates in concrete, each affecting the quality of the concrete in different ways. Leveling limits and maximum aggregate size are specified because these properties affect the amount of aggregate used as well as cement and water requirements, workability, pumpability, and concrete durability. The aggregate is also very important for the strength, thermal and elastic properties of concrete, dimensional stability and volume stability. Aggregates play an important role in freshly mixed and hardened concrete properties, mix ratios and economy.