Sand is widely used in construction, often providing strength, bulk, and stability to materials like concrete, mortar, asphalt, and cement. But not all sand is the same as some have rocks and impurities that make them less resistant and stable for use in construction.
The main types of sand used in construction range from concrete sand to pit sand, natural or river sand, manufactured sand (M-sand), utility sand, and fill sand. These types of sands have unique properties that make them ideal for various types of construction.
Are you interested in learning more about sand types used in construction? Continue reading as we discuss the main features and properties of different sand types and how to use them in construction.
Why Is Sand Important in Construction?
Sand is among the most used materials in construction, with its usage often determining the strength and durability of the resulting structure. When using sand, the rule of thumb is to avoid contaminated products mixed with clay, topsoil, or vegetation.
Using impure sand affects the formation of proper bonds between the cement and the sand. Poor bonds usually translate to structures that aren’t as sturdy and strong as they would be if the right type of sand was used.
Sand is an important ingredient in most construction projects as it can be mixed with lime or cement to create high-quality mortar for plaster and for joining bricks or stone. Sand is also used with coarse aggregate and cement to create concrete. Construction workers also use sand together with lime or cement to make screed for flooring.
1. Utility Sand
Utility sand is usually produced from crushing high-quality industrial quartz, which allows for the formation of uniform grain shapes. This type of sand has a coarse texture and usually contains a mixture of beige, tan, white, gray, and brown particles.
The uniform particles allow the sand to compact well, allowing for widespread usage as a base material for concrete. Utility sand contains natural minerals that provide both stability and durability to the building under construction.
2. Masonry Sand
Masonry sand is a fine-grained, pure type of sand utilized in the creation of concrete or mortar. This type of sand is mostly used in laying bricks, stones, or blocks, thus making it perfect for patio construction.
Masonry sand can also add to the aesthetic appeal of homes as it can create a clean, neat white line between bricks or blocks, thus making the outdoors extra appealing.
3. Concrete Sand
Concrete sand consists of granite rock, gneiss, or limestone. This sand has angular granules and works best when mixed with cement. Besides usage in concrete, concrete sand can also be used in bedding pipes.
This type of sand is usually crushed in a quarry and filtered severally to remove huge fragments and large rocks. As a type of coarse sand, concrete sand can be mixed with water and cement and used in walking paths and patios. Concrete sand can also act as a filling material since it’s larger than white sand.
4. Fill Sand
Fill sand consists of extremely fine rock particles that might have disintegrated into sand over time or may have been subjected to crushing machines severally. This sand type has an impressive compaction rating but is unfortunately susceptible to displacement and shifting.
Many contractors prefer fill sand due to its attractiveness and affordability. Fill sand is also ideal when used in wet areas with drainage problems. On most occasions, fill sand is used as backfill around septic tanks and as a base for the concrete.
5. Industrial Sand
Industrial sand is a name that refers to high purity silica sand with controlled sizing. This sand type is widely used in building and construction projects. Whole grain silica is usually added to specialty cement, roofing shingles, flooring compounds, asphalt mixtures, and skid-resistant surfaces.
The use of industrial sand provides flexural strength and packing density without compromising the binding system’s chemical properties. Industrial sand also works as a functional extender, which adds anti-corrosion and weathering properties to sealants, caulks, and epoxy-based compounds.
6. Crushed Stone Sand
Crushed stone sand is widely tipped as the natural successor of river sand. This type of sand usually contains no impurities, which makes it ideal for use in concrete. Crushed stone sand is a type of M-sand as it undergoes a thorough crushing process and testing before being released for construction work. This sand type is widely used in plastering.
7. Fine Crushed Limestone Gravel
Limestone gravel is a typically coarse material but can be used to make solid compact surfaces when crushed. However, fine crushed limestone gravel is not ideal when it comes to water drainage. As a result, this type of sand is preferred for patios and for supporting indoor flooring.
Sources of Sand Used in Construction
There are three main sources of sand used in construction, river sand, crushed sand, and pit sand. River sand is usually obtained from river banks, while pit sand is obtained by digging deep pits. On the other hand, crushed sand is obtained by the strategic crushing of rocks (to fine particles) in quarries.
While the sea is also a source of sand, sea sand isn’t ideal for construction due to its high salt content, which promotes corrosion and also causes efflorescence.
With various types of sand to choose from, it’s vital to use one that complements the design of a project. Depending on the source, sand tends to have different properties that may either favor or hinder a specific type of construction.
Below are some of the main types of sand by source.
Pit sand is a coarse type of sand and is normally found approximately 2-3 meters underground. This type of sand is obtained naturally when deep-enough pits are dug on the earth’s surface. The resulting grains are usually sharp, angular, rough, and coarse. These features enable the sand to make strong bonds on surfaces.
Unlike sea sand with high salt levels, pit sand is usually free from salt, eliminating the chances of efflorescence and excessive absorption of moisture once used in construction. When using pit sand, it’s crucial to check on the degree of coarseness to ensure it isn’t beyond the acceptable limits.
River sand is highly unsustainable and continues to become rare as construction activities boom. Also called natural sand, river sand is categorized as fine sand and is usually found near streams and river banks. The softness of river sand allows for its usage in concrete and masonry work. River sand is also ideal for plastering, RCC, and several other block works.
The main caveat with river sand is that it tends to have high silica content. Therefore, before using river sand in construction, it is advisable to check on silica content to ensure it’s below 5%. River sands also have high moisture content, which means it won’t require high amounts of water when used in construction.
Manufactured sand is a more sustainable alternative to river sand. This type of sand is usually manufactured in plants or factories by crushing granite. The main aim of manufactured sand is to provide an ecological and economical alternative to natural sand.
Quarry stones and rocks are usually blasted and consequently subjected to several crushing cycles to reduce the particle sizes of the resulting sand. The sand obtained from blasting and crushing quarry stones is then sieved and washed. Washing and sieving the sand is done to remove impurities and fine particles.
The resulting sand is then tested before experts deem it fit for use as a construction aggregate. As revealed by The Screed Scientist, manufactured sand should pass easily through a 3/8 sieve after production. If the sand manages to pass through the sieve, it is ready and ideal for construction projects.
The production of manufactured sand is currently driven by several factors such as environmental sustainability, the need for fine aggregate, and scarcity of natural sand. Below is a brief explanation of the importance of manufactured sand.
World Wide Shortage of Natural Sand
The biggest problem with natural sand is the risk of over mining to satisfy market demands. The wide-spread mining of river and pit sand has led to the gradual depletion of natural sand, which affects the ecological balance.
Sand dredging is banned or heavily taxed in most parts of the world, a testament to worldwide commitment towards limiting the usage of natural sand. Manufactured sand provides construction workers with the opportunity to use fine sand without damaging the environment.
Increased Need for Fine-Aggregate in Construction
Sand is used in almost all construction projects. And since manufactured sand has better properties in terms of purity and overall quality, it has gradually transformed into the go-to sand for large scale construction projects.
M-sand is usually subjected to several crushing cycles to ensure the final product has finer particles and is free of impurities that would weaken concrete or screed.
Need for Cheaper Sand Alternatives
The scarcity of natural sand means merchants prefer selling at the highest bidder. The cost of mining and purifying river sand, coupled with transportation costs, can make the total costs considerably high and consequently unsustainable over a long period.
Manufactured sand is often produced in quarries, meaning the location won’t depend on the presence of water bodies. This can lower the cost of operation considerably, more so since transport costs will be considerably reduced compared to long-distance transportation of natural sand.
Advantages of Using Sand in Construction
Sand is arguably the most used material in construction. Below are some of the main advantages associated with using sand in construction:
- Affordable: Most contractors prefer using sand in a concrete mix or as a construction base due to its cost-efficiency. Sand can be cheaply acquired from the quarry, especially if bought in large quantities. This plays a pivotal role in lowering the overall cost of construction, especially since sand performs well as an adulterant, eliminating the need for more expensive products.
- Durable: Sand isn’t susceptible to deterioration or corrosion by pests, making it durable when used in asphalt and concrete. Moreover, sand usually contains small particles of shells, decomposed rock, corals, and minerals (depending on location), which add to the overall strength. However, it’s advisable to check on the ingredients present in a particular type of sand before using it in construction.
- Multi-functional: Sand is arguably among the most versatile building materials. Contractors can use sand on highways, filters, pavements, playground sandboxes, and golf courses. Sand is also widely used as a soft aggregate in concrete, making it hugely important to construction projects. Another proof of sand’s versatility is its ability to be used for decorative purposes.
Tests That Can Ascertain the Properties of Sand
- To detect organic impurities in the sand: For this test, a solution of caustic soda or sodium hydroxide is added to the sand and stirred. A change from the normal coloration to a brownish color indicates the presence of organic matter in the sand.
- To detect clay: The presence of clay in the sand will affect its binding properties, making it less effective. To test for clay, water is placed in a transparent jar and with a proportional quantity of sand. The water-sand mixture is then shaken vigorously and allowed to settle. A distinct layer will form atop the sand if the clay is present.
- To detect salt: The best way to detect salt in the sand is by actually tasting a sample. The sand should be cleaned well before tasting with the tip of the tongue. A salty taste means the sand has salt content.
Why Is Sand Used in Mortar and Concrete?
- Helps to increase the bulk of mortar: While sand doesn’t directly increase mortar’s overall strength, it does play a huge role as an adulterant. Sand helps to increase the volume of the mortar, thus reducing the need for additional materials.
- Prevents shrinkage of mortar: The presence of sand helps prevent excessive shrinkage of mortar when drying. This helps to reduce the chances of the mortar cracking during settling.
- Increases overall surface area: Sand functions by subdividing the binding material (paste) into a thin manageable film, consequently increasing the surface area for spreading and adhering.
- Helps to increase the overall strength of concrete: Since sand acts as a filler, it helps to ensure that the overall volume of the concrete increases significantly. The more the volume of concrete, the lesser the air present, which translates to a stronger product.
Crushed Sand vs. Natural Sand: The Main Differences
Crushed sand, also called manufactured sand, is the more sustainable alternative to natural sand extracted from river beds or river banks. Below are some of the main differences between the two main types of sand used in construction.
Crushed or manufactured sand is primarily obtained in a quarry. It is carefully manufactured by crushing quarry stones, rocks, and larger aggregate pieces into fine particles either in a factory or quarry. On the other hand, natural sand is naturally available and doesn’t need to be ground or blasted into tiny particles.
Due to repeated blasting and refining, crushed sand is usually angular or cube-shaped. Crushed sand also has a rough texture, which makes it ideal for use in concrete. Contrastingly, natural sand is usually rounded and has a smooth surface. The rough texture of crushed sand makes better bonds in concrete than natural sand`s smooth surface.
Crushed sand usually has no moisture content, which makes it ideal for forming strong mortar and concrete. The reduced moisture content in crushed sand gives construction workers more flexibility when mixing with water and cement, making it possible to achieve the right ratios.Due to its location in river beds and the damp underground, natural sand is usually high in moisture content. Consequently, extra caution must be taken when mixing natural sand with cement and water to ensure the resulting concrete doesn’t have too much water.
Manufactured or crushed sand has high compressive and flexural strengths, making it ideal for heavy construction and foundations. Contrastingly, natural sand has lower flexural and compressive strengths, making it more appropriate for light construction such as plastering and block works.
Crushed or manufactured sand doesn’t contain any marine products or adulterations and is thus safe for use in concrete. Natural sand, depending on where it’s extracted, can contain marine products like grass, clay lumps, shells, mica, algae, and bones, all of which are harmful to concrete.
With so many different types of sand available, it’s important to choose one that best fits the specific construction needs of a project.
Generally, it’s best to go with the various types of manufactured sand as they’re usually produced in controlled environments, leading to fewer impurities that can affect concrete integrity.
Using natural sand obtained from river beds might lead to inconsistent results when preparing concrete, which explains why most civil engineers are leaning towards manufactured concrete in small, medium, and large scale construction projects.
- Dreamlands Design: Importance Of Getting the Right Quality Of Sand
- Cement Concrete: Types Of Sand Grain
- Nearsay: What Is Concrete Sand
- The Constructor: Manufactured Sand
- Civil Today: Properties Of Good Sand
- Civil Read: Types Of Sand Used In Construction
- Builders Sand And Gravel Inc: Understanding Sand
- Science Direct: Crushed Rock Sand
- Almanaratain: Importance Of Sand In Construction
- Hunker: Does Gravel Make The Best Base For A Concrete Slab
- For Construction Pros: The Science Of Soil Compaction
- The Balance: Efflorescence
- For Construction Pros: The Science Of Soil Compaction
- Wikipedia: Flexural Strength