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Aggregates

What Are Aggregates and What Are They Used For?

“Aggregates” may be a foreign term to the uninitiated, but its comprehensive use in the construction industry makes it a very familiar sight to most people, especially in urban areas. Every building site, whether residential or commercial, as well as highway and road construction, need this essential building material in some form or another, as it includes sand, gravel, crushed stone, and recycled concrete.

As a raw mined product, aggregates can be put to many uses or serve as components in the production of concrete and asphalt. The proportionate use of primary aggregate is as follows:


•    36% for the manufacture of concrete;
•    10% for the manufacture of cement, which is also used in concrete;
•    26% for road construction;
•    20% for other construction uses and fills
•    2% for railway ballast; and
•    6% for industrial and other uses, such as the manufacture of mortar (4%), manufacture of glass (1%) and use in agriculture (1%).

Constructional in General

In construction, aggregates are used to provide drainage, fill voids, protect pipes, and to provide hard surfaces. They are also used in water filtration and sewage treatment processes. Water will percolate through a trench filled with aggregate more quickly, than it will through the surrounding soil, thus enabling an area to be drained of surface water.

Concrete

Concrete is a mixture of aggregates, cement and water. The purpose of the aggregates within this mixture is to provide a rigid skeletal structure and to reduce the space occupied by the cement paste. It is either supplied precast (blocks, tiles, pipes, bridge beams, flooring systems, etc.) or ready-mixed (as a liquid paste ready for pouring). It is used for the foundations, walls, floors and roofs of buildings, as well as bridges, dams and other structures.

Asphalt and Roadstone

This category includes not just roads, but also pavements, airport runways, playgrounds, car parks and pathways. Road layers consist of differently sized aggregates for specific reasons; the roadstone sub-base layer’s role is to give strength and act as a solid platform for the layers above. The binder course, commonly called “asphalt”, is the main load-bearing layer and provides an even plane for the surface course. The surface course provides the road with protection from the weather, but also provides the final running surface that must be resistant to abrasion and skidding.

Mortar

Mortar consists of sand, cement and water. In some circumstances, lime may also be added, together with admixtures (chemicals to control setting and workability) and/or pigments, if required. They are used to bond bricks or concrete blocks together in walls and to provide weather protection.

Railway ballast

A very tough aggregate is needed to support the considerable weight of a train and of the track itself. It is used to distribute the load of a passing train, in order to avoid serious damage to the ground, or other structures, underneath. Similarly the railway track and sleepers must be held in place firmly and not move as a train passes along them.

Quicksand is the preferred supplier of sand, bricks, aggregates and cement in the greater Pretoria-Midrand area. Our vast experience and close ties with manufacturers, quarrying operations and suppliers, allows us to identify and source “fit for purpose” products at the best prices.

The aggregates that we supply are sourced from more than 20 different quarries in our area of operations, with the most popular categories being Graded Filling, Concrete Mix 19 and 13mm, Crusher Stone, Slag Products, Drain Stone and Dump Rock/Gabion Stone. Please contact us for great service and great products.