Aggregates are an essential component of construction, used to mix with cement, bitumen, lime, gypsum or other adhesive to form concrete or mortar. They provide bulk, stability, wear or erosion resistance, and other desired physical properties to the finished product. Aggregates are used in construction to provide drainage, fill voids, protect pipes, and provide hard surfaces. They are also used in water filtration and wastewater treatment processes.
Water will seep through a ditch filled with aggregates more quickly than through the surrounding soil, allowing surface water to drain from an area. This technique is often used along roads to disperse water collected from the asphalt surface. Aggregate materials help make concrete mixes more compact and reduce the consumption of cement and water. They also contribute to the mechanical strength of concrete, making them an indispensable ingredient in the construction and maintenance of rigid structures. Large, solid and coarse-grated particles of aggregate form the basic structural elements of concrete.
The gaps between the larger coarse-aggregate particles are filled with smaller particles. The gaps between the smaller particles are filled with even smaller particles. Finally, the voids between the smaller coarse-grained aggregate particles are filled with the larger fine aggregate particles. In turn, the voids between the larger fine aggregate particles are filled with smaller fine aggregate particles, the voids between the smaller fine aggregate particles are filled with even smaller particles, and soon. Finally, the gaps between the finer grains are filled with cement.
You can see from this that the better the aggregate is classified (that is, the better the particle size distribution), the more solidly all the voids will be filled, and the denser and stronger the concrete will be. The biggest cost ratio for using aggregates as filler is that it helps concrete producers save big money. Cement usually costs seven or eight times more than stone and sand. Cement is necessary, but strength can still be preserved when using well-graded aggregates that cost significantly less. Aggregates represent 60-80% of the concrete volume and 70-85% of its mass. It is unlikely that you will find any building that will be built without them.
One of their most important uses is in concrete production, where they provide strength and consistency. As a result, they are heavily relied upon in construction for office blocks, houses and many other commercial and residential properties. Polystyrene can also be recycled into low-density aggregates that maintain high strength properties under compressive loads. The American Society for Testing and Materials publishes an exhaustive list of specifications including ASTM D 692 and ASTM D 1073 for various construction aggregate products. Aggregates can also be used to make other products such as blocks, tiles, pipes, bridge beams, flooring systems or premixed ready-to-pour liquid paste. They are key ingredients in mortar manufacturing, glass production and agriculture. Finally, they are essential for keeping railway tracks safe by providing a rigid skeletal structure and reducing space occupied by cement paste.
The gravel that can be seen between tracks is essential for keeping wooden sleepers in place.