Sand is nothing but quartz whereas clay is composed of many other chemically active minerals like illite, kiolinite, etc. If the size of sand is in between 4.75 mm (about 5 mm) and 0.150 mm, then it is known as a fine aggregate.
Sand is used for making concrete, mortars, and plasters and also for filling under floor, basem*nts.
To avoid transport expenses as it plays a major part of the cost of sand, as far as possible local sand is preferred to maintain the economy in construction.
Sand is used for the different items of the construction depending on its fineness. Due to an increase in construction projects, natural sand which is usually available from local river beds or pits is becoming more difficult to get and in cost also.
According to recent research, the crushed rock and fly ash have taken the place of sand in constructions.
Sources of Sand
Sand is classified into various types according to the source of supply such as:
River sand
This sand is obtained from large rivers. It is usually fine in size. Proper care should be taken while taking the sand from rivers so that there is no clay mixed with the sand.
Pit sand
This is obtained from old stream beds, where it is sharp and generally coarse.
Stream sand
This type of sand is obtained from small streams near hills which have drained out in summer. It is usually coarse in size.
Crushed stone sand
This is obtained from the screenings left from crushed stone, which generally contains a high percentage of dust and clay. Special crushers are used for making fine aggregate from rocks because of the difficulty in getting natural sand.
Sea sand
This sand is obtained from beaches. It is usually good for most of the works if they are free from detrimental salts except reinforced concrete works. These types of sands are avoided to use in many constructions, if necessary, washed in fresh water and used.
Impurities in sand
The main impurities present in the sand are clay, silt, salts, mica and organic matter. Sand is sometimes specified that the sum of all impurities should not exceed 5 per cent and should be free from shells, wood particles, etc.
Usually, 8 per cent silt and 2 to 3 per cent of mica are allowed in the sand for mortar and concrete, exceed in percentage can reduce the strength of mortar and concrete.
Sand for concrete work
Depending on the percentage of the various sizes of sand present in a sample, sand for making concrete is grouped into five zones - Very coarse, Coarse, Fine, Very fine and Very very fine.
Most of the particles present in the sand may be of 4.75 mm or 5 mm. The main criterion for division into coarse and fine can be 0.6 mm in size. It becomes coarse sand if the major part is above 0.6 mm in size and fine sand if the major part is below 0.6 mm. Particles that cannot be seen by a naked eye is silt.
In soil mechanicals by examining the particle sizes, sand is further classified into:
Coarse sand: 4.5 mm to 2.0 mm
Medium sand: 2.0 mm to 0.425 mm
Fine sand: 0.425 mm to 0.075 mm
Very fine and Very very fine sands are not recommended in structural concrete even though they provide good strength but shows difficulties in surface finishing of concrete.
Fine sand provides more cohesion than coarse sand as it requires less quantity compared to other sands in concrete.
While making concrete, coarse aggregates from rocks will need more sand than fine aggregates, based on that the concrete mix can be designed to fit the available sand and coarse aggregates.
Check Out: Coarse Aggregates in Construction - Characteristics and Uses
FAQs
Sand is commonly used in construction, often providing bulk, strength, and stability to other materials such as asphalt, concrete, mortar, render, cement, and screed.
Why is sand used in building? ›
Builder's sand has a range of applications but is primarily used to provide bulk and strength to other construction materials due to its flexibility and smooth application. Builder's sand can be mixed with water and cement to make concrete or a mortar that is perfect for bricklaying, as well as pointing applications.
Why is sand important? ›
Sand is the foundation of human construction and a fundamental ingredient in concrete, asphalt, glass and other building materials. But sand, like other natural resources, is limited and its ungoverned extraction is driving erosion, flooding, the salination of aquifers and the collapse of coastal defences.
What are the advantages of sand in construction? ›
Advantages: Easy to work with: Sand is an abundant and relatively inexpensive material that is easy to work with and can be used in a variety of applications. Durable: It is also a durable material that can withstand harsh weather conditions and has excellent drainage properties.
What are the benefits of sand in concrete? ›
Well-graded sand allows for better packing, reducing voids, and increasing concrete strength. Optimal particle size distribution enhances the mixture's performance. Workability and Consistency: Sand lubricates particles, improving the mix's workability and consistency.
What would happen if we had no sand? ›
Sand is the key ingredient in cement and asphalt. Roads and buildings, bridges and foundations – none would exist without it. Sand is also an essential element in windows – in homes and buildings, car windscreens, smartphone screens, laptop screens.
Is there a construction sand shortage? ›
The ongoing surge in demand for sand has made it a scarce commodity. This natural resource is commonly used in computer microchips, construction, and is an active ingredient in cosmetics. But the current supply of this material has not been able to keep up with the speed of global urbanization.
Is sand suitable for construction? ›
While river sand and concrete sand are suitable for most construction applications, for specialized purposes, such as levelling or filling, pit sand, utility sand, or fill sand may be more appropriate. M-sand can be considered as an environmentally friendly alternative to river sand.
Which source of sand is not useful for construction purposes? ›
Desert sand, on the other hand, is plentiful. This sand is not used in construction, as its grains are too smooth and fine to bind together for building materials.
What is the difference between construction sand and regular sand? ›
Play Sand contains much finer, smaller particles that feel softer to the touch and stick together better for building sandcastles and best for playing with toy trucks. Construction Sand typically contains larger particles that are better for improving drainage and adding strength to concrete.
Conversely increasing the proportion of damp sand to 2 1/2 parts means that there will actually be 2 parts of sand to 4 parts of coarse aggregate, which gives the desired 50 percent figure and a denser, and consequently stronger, concrete.
What is the purpose of sand under a concrete slab? ›
The simple answer is to prevent the concrete from cracking and breaking. If you provide a good foundation for your concrete, it will last longer, and you won't have to repour it in a few years.
Does sand make concrete stronger? ›
Concrete is rated on a system that indicates the strength of the mix after it's cured for approximately a month. To make the concrete stronger, add more cement or less sand. The closer you bring the ratio to an even one-to-one of sand to cement, the stronger the rating becomes.
What purposes can sand be used for? ›
Sand containing silica is used for making glass in the automobile and food industry- even household products for the kitchen. Sand is a strong strand which is used for plaster, mortar, concrete, and asphalt.
What is the difference between building sand and normal sand? ›
The difference between the two is that Builders Sand is seen as a slightly less coarse and can be free of unwanted additives. On the other hand, Sharp Sand has had other materials, most likely in the form of clay and iron, added to the mixture therefore it can contain larger pieces.
Is sand good to build a house on? ›
The key lies in choosing the right sand. The wrong kind of sand, like rounded desert sand or alluvial sand that becomes unstable during the rainy season, is not suitable for building. Nowadays, with the proper foundation or technology, it is possible to build stable structures on sand.
