Classification, Types & Uses of Sand in Construction
Sand is one of the prior materials for Making Concrete. If the modular size of Fine Aggregate is less than 0.07 mm, then it is called Sand. So, it is used as a fine aggregate in mortar and concrete.
Sand is nothing but a granular form of Silica. The Sand used in Construction should be quartz (silicon dioxide), light grey or whitish variety and should be free from silt. The Fineness or Particle size of the sand should be in such a way that when the sand passed through 2-mm IS sieve, it should be retained fully on 90-micron IS sieve.
Classification of Sand:
Sand can be classified on various basis. They are as follows:
On the Basis of Mineral Composition: Depending upon the mineral composition, Sand can be classified into quartz, felspar and carbonaceous types
On the Basis of Particle Size: Depending upon the Particle Size of Sand, it can be divided into three.
If the Fineness Modulus (F.M) lies between 2.90 to 3.20, it is named as Coarse Sand
If the Fineness Modulus (F.M) lies between 2.60 to 2.90, it is called as Medium Sand
If the Fineness Modulus (F.M) lies between 2.20 to 2.60, it is defined as Fine Sand
On the Basis of Source: Depending upon the Source of Sand, it can be classified into three
Due to the natural disintegration of rocks or stream depositions, Natural Sand is formed.
By crushing the hard stones, Crushed Sand is Obtained.
By crushing the natural gravel, Crushed Gravel Sand is Produced.
On the Basis of Particle Size Distribution: Particle Size Distribution is nothing but the percentage of fine sand obtained when 100% sand passed through the various micron sieves. On the basis of the particle size distribution, they are divided into four, they are Grading Zone I, II, III and IV.
Sand types cannot be Categorised into a specific number as it is available in a number of forms in the Earth. A few types can be listed based upon the market availability as below:
River Sand: It is clearly known from its name that it is the sand obtained from the banks of the river and river beds. This sand is found in the purest form as it is obtained from the running water and is round, fine, polished due to water friction. This Sand is used for all types of Construction works but especially recommended for Plastering works due to its naturally profound properties.
Sea Sand: It is obtained from Seashores. This sand is also fine, polished and round. It cannot be used directly in Construction as it contains salt which the weakens the strength of the mortar and delays setting time of cement. If this sand is free from salts, it can be used for all civil engineering works.
Pit Sand: This type of sand is extracted by digging up the earth soils. Granular size is bigger than the river sand, so it can be used for mortars
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