Let’s explain the definition, meaning and characteristics and also the functions of sand in this comprehensive article:
Sand which is used as fine aggregate in the preparation of cement or lime mortars, consists of small angular rounded grains of silica (Sio2) and is formed by decomposition of sand stone under the effect of weathering agencies.
Sand is of two types i.e Natural and Artificial. Natural sand may be river sand, sea sand, nala sand. River sand should not be used for mortars which are exposed to weather. Sea sand contains salt contents hence it should be washed with fresh water before use . Artificial sand is prepared by crushing stones and gravel to powder.
Characteristics of Sand
Six main characteristic of sand are featured as following:
1. It should be clean and free from coatings of clay and silt.
2. It should be free from hygroscopic salts.
3. It should have coarse, angular, hard and sharp grains.
4. It should not contain organic matter.
5. It should be strong and durable.
6. It should be chemically inert.
Functions of Sand
Functions of sand can be broadly summarized below:-
1. On drying it prevents the cracks in the mortar.
2. It is used for making mortars of desired strength by varying it proportion with the binding material (cement or lime).
3. It increases the density of mortars.
4. It reduces the shrinkage of the binding material.
5. It helps in early setting of mortar.
6. It is added to the binding material to make the mortar economical