Sand is a commonly used ingredient of mortar. Quality of sand is important to produce good mortar. Followings are the functions of sand as one of the ingredients of mortar.  

 Function of Sand in Mortar

  • Generally, sand is not used in mortar to increase its strength. Rather it is mainly used as an inert material to increase the volume of mortar for the economy. 
  • Using sand in the right amount can produce cheap mortar without hampering mortar strength.
  • Sand subdivides the paste of cementing materials into a thin film which is the basic principle involved in using all cementing materials.
  • Sand offers the requisite surface area for the film of cementing materials to adhere and to spread.
  • Sand helps to prevent mortar shrinkage. It also prevents cracking of mortar during setting.
  • Well-graded sand increases the density of mortar.
  • Sand allows Carbon-Di-oxide from the atmosphere to reach to some depth in case of ft lime mortars and thereby improves their setting capability. 
  • It is also claimed that some chemical reaction takes place between silica (SiO2) of sand grains and the constituents of the cementing materials to form a hardened mass. 

References:

  • A text Book of Engineering Materials by Dr. M.A. Aziz