What is Lime Mortar???

Introduction (What is Lime Mortar):

Lime mortar is ancient Indians first used mortar for temples, forts and historic structures.

Lime mortar is typically used as plastering, masonary (either stone or bricks) and as a binding material.

There are two types of lime is there,

• Hydraulic lime Mortar
• Fat lime Mortar

Hydraulic Lime Mortar:

• In this mortar hydraulic lime and sand in 1:2 ratio is used in very damp conditions
• Mostly it is suitable for waterlogged areas.

Fat Lime Mortar:

• In this mortar, fat lime is used and the quantity of fat is lime is almost 2 to 3 times greater than sand requirements.
• Mainly this type of mortar is used in dry work, where the high plasticity is required.

Definition (Lime Mortar):

• Lime mortar is mortar in which lime (hydraulic lime or fat lime) is used as binding material in combination with sand and water.
• Basically, fat lime and hydraulic lime is used in lime mortars.
• Fat lime mortar is used commonly and for damp situations hydraulic lime mortar is used
• Lime mortar is ancient type of mortar and widely used in historic structures along with stones.

Properties of Lime Mortar:

• It is more plastic and workable when it is wet in condition.
• It has good workability and working properties when it made from excessive calcium lime.
• It also develops slow lateral strength for very long time.
• It does not set by action of water loss due to absorption and evaporation.
• Provides strength and strong surface if used in plastering.
• It provides strong bond between the joints when used in masonary joints.

ADVANTAGES OF LIME MORTAR:

• Lime mortar can be re worked for up to 24 hours as it has great setting time.
• It reduces the wastage when used in silos structures.
• It also reduces the movement in joints.
• It possesses the constant prime quality and colour of mortar.
• As it possesses constant colour, it enhances the masonary joints in various masonary.
• It also acts as water shedding barrier when used in masonary.
• This provides the breathable types of construction.
• By the end of the finish of life, this mortar also permits masonary to be recycled.
• It absorbs the CO₂ while curing processes.
• Makes use of much less energy to produce than cement.

DISADVANTAGES OF LIME MORTAR:

• Quick setting time of lime mortar has limitations on casting.
• Lime mortar can not be repaired with cement mortar as it does not form bond between lime and cement mortar when it gets harden.
• An excessive amount of initial chemical set ignores the importance of extended carbonation of the non-hydraulic component.
• The danger that segregation occurs, whereby the cement separates from the lime as the mortar dries and hardens.
• The use of cement leads the consumer to deal with gold lime mortars as it has been purely hydraulic lime or cement.
• Ph of mortar drops about 8.6 when lime mortar get dried and harden.

Uses Of Lime Mortars:

The Lime mortar can be used as plastering, joinery and in masonary.

• For Foundation Works: fat lime mortar can be used in all types of foundation work in dry sub grade – water table is 2.4 m below the foundations level.
• For All Masonry Works: loading – 20 to 60 tonnes/m² (light and medium loading)
  • Fat lime and hydraulic lime, both are suitable.
  • Lime mortar can be replaced by cement mortar.
  • To bind stones, bricks or concrete blocks together

Lime mortar cannot be applied when:

• Sub grade soil is moist water table is within 2.4 m.
• Heavy loading is expected.
• Construction is massive and very thick.

Precautions:

• Mortars with hydraulic lime should be used within 4 hours after mixing.
• Lime mortars with surkhi should be used within 24 hours after mixing.
• Composite (lime and cement) mortars should be used within 2 hours after mixing.
• All lime mortar shall be kept wet after grinding. The workers who are to handle lime mortar should protect their skin by using oil, rubber gloves etc

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