We’re all used to seeing sand at the beach, however, did you know that the buildings you live and work in and the pavements that you walk on are all made up of sand? When we talk about sand in construction, we’re generally talking about material that is much coarser than the grains of sand that you would find on the beach. Sand is a primary component for making concrete, mortar and plaster, so you shouldn’t be surprised to find they make up the buildings around you.
Sand in construction should generally be clean and free of stones and other impurities. To ensure there is no excess clay, silt and dust, you can use washed sand if this is a requirement in your construction. Although it is important to remember that washed sand this will have a different grittiness to that of unwashed sand.
There are many different types of sand that can be used in construction with each of them being used for different purposes.
1) River Sand
As the name suggests, this is taken from rivers and tends to be fine in size. There should be specific care taken when obtaining river sand in order to ensure that no clay is mixed into the sand. Using this sand in construction will result in a smoother finish.
2) Pit Sand
Pit sand is typically used within mortar, thanks to its hard and coarse texture obtained from old stream beds. The importance of using pit sand in construction is that the cement produced has strength but is not smooth.
3) Crushed Stone Sand
The screenings left from the process of crushing stones, makes up crushed stone sand, which is typically used for the drainage properties it possesses. This is a popular option, with many uses from ready-mix concrete to filter stones.
4) Sea Sand
As you’d probably guess, sea sand is retrieved from beaches and has wide range of potential uses as long as it is free from detrimental salts. However, one use of this sand in construction shouldn’t be used for is reinforced concrete works.
5) Fine crushed limestone gravel
Typically a very coarse material, fine crushed limestone gravel can be used to create solid compact surfaces, meaning that this does not provide the best drainage options. This type of sand tends to be used to support indoor flooring as well as patios.
6) Coarse crushed limestone gravel
Alternatively to the fine crushed limestone gravel, coarse crushed limestone gravel provides a better drainage option thanks to the larger particle sizes. This sand tends to be one of the most popular options for use in construction gravel, thanks to the excellent drainage properties and the ability to support heavy loads.
Materials in Sand
The main materials that sand is made up of are; clay, silt, salts, mica and organic matter and should be free from all types of wood and shell particles. Sand in construction is generally made up of 8% silt and 2-3% of mica for use in mortar and concrete. If the measurements are exceeded this can cause a significant difference to the strength of the mortar and concrete.
Using Sand In Concrete Work
When using sand in concrete, there are 5 different zones to consider; very coarse, coarse, fine, very fine, and very very fine. Particles in sand range from 4.75mm to 5mm, with the difference between coarse and fine being as small as 0.6mm.
With its many types and uses it’s clear to see that there is a significant importance of using sand in construction, with many of the buildings around us having been constructed with sand in some way or another. However, it is crucial to consider the different purposes of each sand when choosing the sand to use in each of your construction works.