What is Mortar?
It is a plastic mixture of binding material (like cement, lime, etc), fine aggregates (like sand, surkhi, etc), water and any admixture approved by the engineer in-charge. This is used to bond masonry or structural units. There are different types of mortar used in construction industry. The following are the type of mortar depending upon the material used to prepare the mix.
- Cement mortar
- Lime mortar
- Gauged mortar (or combination mortar)
- Surkhi mortar
What is Cement Mortar?
It is a mixture of cement, sand and water; where cement acts as a binding material. The proportion of cement to sand varies from 1:2 to 1:6 depending upon strength desired for a particular work.
What is Lime Mortar?
It is a mixture of lime (fat lime or hydraulic lime), sand and water. Fat lime, which acts as a binding material, is added for preparing mortar when it is to be used in masonry work and hydraulic lime is added when mortar is to be used in foundation work or in damp conditions. Generally, lime to sand ratio is kept 1:2.
What is Gauged Mortar (or Combination Mortar)?
It is a mixture of cement, lime, sand and water. The process of adding cement to lime mortar to improve its quality is termed as gauging and mortar thus prepared is known as gauged mortar. The preparation of cement to lime mortar by volume is about 1:6 to 1:9. This type of mortar combination (i.e. lime and cement) is strong, dense and economical.
What is Surkhi Mortar?
It is a mixture of lime, surkhi and water. It is lime mortar in which sand is substituted by surkhi for economy and strength.
Surkhi is finely powered burnt clay and generally made from slightly under burnt bricks. Good surkhi should be perfectly clean and free from any admixture of foreign substances.