TYPES OF MORTAR TYPES OF MORTAR Lime Mortar

TYPES OF MORTAR

TYPES OF MORTAR • • • Lime Mortar Lime – Surkhi Mortar Mud Mortar Cement Mortar Puzzolana mortar

FUNCTION OF SAND SURKHI IN MORTARS Functions of sand: • It reduces shrinkage of the building material. • It prevents development of cracks in the mortar on drying. • It helps in making mortars and concretes of desired strength by varying its proportions with the binding material. • A well graded sand adds to the density of mortars and concretes. Functions of surkhi: • It provides brick color and make the mortar economical

LIME MORTAR: • Lime mortar is a type of mortar composed of lime and an aggregate such as sand, mixed with water. • Lime mortar is primarily used in the conservation of buildings originally built using lime mortar, but may be used as an alternative to ordinary portland cement.

Limemortar • The paste is prepared by mixing lime and sand or surkhi in suitable proportions in addition to water. • If surkhi is to be added in lime mortar the equal proportions of sand surkhi should be mixed with lime. • These mortars are inferior to cement mortars in strength as well as water tightness. • These mortars should not be used for underground works as they set in the presence of carbon dioxide and break up in damp conditions. • This type is used for construction work above ground level i. e. exposed positions.

Mud mortar: • The paste is prepared by mixing suitable clay, soil with water. • The soil which is used for preparing mud mortar should be free from grass, pebbles etc. • These are the cheapest mortars but weakest in strength. • These mortars are used for brickwork of ordinary buildings and for plastering walls in rural areas.

Cement mortar: • The paste is prepared by mixing cement and sand in suitable proportions in addition to water. • The general proportion is 1 part of cement to 2 -8 parts clean sand. • These mortars must be use within half an hour, i. e. ; before initial setting time of the cement. • This type is used for all engineering works where high strength is desired such as load bearing walls, deep foundations, flooring etc.

• When mixing by hand, the sands and cement are heaped up on a mixing board or in a wheel barrow and repeatedly turned over and over until thoroughly mixed. • The color of the dry mix will change as the cement is distributed throughout - there should be no 'streaking' of cement, and no clumps of pure sand or pure cement. • Once the dry ingredients are mixed, the water can be added.

• When using a mechanical mixer, add half a bucket (2 or 3 liters) of clean cold water to the empty drum before adding the dry ingredients in sequence. • Add 4 measures of sand then 1 of cement, followed by 4 sand, then another cement and so on until the required quantity is in the mixer. • This ensures a more thorough mix than adding, say, 20 measures of sand then 5 measures of cement. • Again, the water is added to the revolving drum once the dry ingredients are thoroughly blended, a bit at a time until the required consistency is achieved.

For wide joints in paving or for stonework, either as paving or as walling, a coarser mortar is often preferred - replace half of the building/soft sand with grit/sharp sand. Youwill probably find that a coarse mortar such as this requires less gauging water to achieve a working consistency than does a bricklaying/general purpose mortar. Mortar for Wide Joints 2 x Building Sand plus 2 x Grit Sand plus 1 x cement

SPECIAL MORTARS �Fire – Resistant Mortar �Lightweight Mortar �Packing Mortar �Sound Absorbing Mortar �X-Ray Shielding mortar

Fire resistant mortar: • The paste is prepared by mixing aluminous cement and finely crushed fire bricks (1: 2) in suitable proportions in addition to water. • The usual proportion are 1 part aluminous cement to 2 parts of finely crushed fire bricks. • These are generally used for lining furnaces, ovens and fire places with fire bricks.

Light weight mortar: • The paste is prepared by mixing wood powder, wood sawing or saw dust with cement or lime mortar. • In such mortars fibers of jute coir or asbestos fibers can also be used. • These are generally used as fiber plasters in sound and heat proof construction.