LIME

SAYAN MUNSHI

B.ARCH SEM 5

SCHOOL OF PLANNING AND ARCHITECTURE

POORNIMA UNIVERSITY, JAIPUR

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INTRODUCTION1

Lime is derived from limestone which is a rocks which contains 80% or more of calcium or

magnesium carbonates, including marble, chalk, oolite, and marl. Lime is a natural mineral

(native lime) CaO which occurs as a product of coal seam fires and in altered limestone

xenoliths in volcanic eject. It is used in large quantities as building and engineering

materials (including limestone products, concrete, and mortar).

Lime used in building materials is broadly classified as "pure", "hydraulic", and "poor" lime

which can be natural or artificial.

USE AS A BUILDING MATERIAL1

The Romans used two types of lime mortar to make Roman concrete, which allowed them

to revolutionize architecture, sometimes called the Concrete Revolution.

Uses include:

o lime mortar

o lime plaster

Figure 1: lime cycle

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o lime render

o lime-ash floors

o tabby concrete

o whitewash

o mineral paint,

PROPERTIES OF LIME1

Lime has many qualities as a building material which including workability as:

cohesion

adhesion

air content

water content

crystal shape

board-life

spread ability

flow ability

bond strength

comprehensive strength

setting time

sand-carrying capacity

hydrolocity

free lime content

vapor permeability

flexibility

resistance to sulfates.

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LIME AS A VERNACULAR MATERIAL2

Lime has been used as a building material

in most part of the Indian sub-continent.

Lime is a widely available material found

almost in every state of India thus being a

locally available material for construction

it has been used for wide purpose from

construction to plastering and even white

washing.

Lime was used by people due to the

significant property of lime which has

made it capable to be used widely as a

construction material.

One of the most important early

references to lime mortar comes from

‘Vitruvius De Architectura’ written c.25

BC. Lime plaster was found to be in wide

use since 6th century in India.

3Building found to be using lime as a primary building material are:

Decorative lime plasters of Ellora caves (6th century)

Houses of the site of Kali-bangan, Rajasthan

Structures at the Buddhist settlement of Nagarjuna-Konda

The city of Kausambi (350AD) in Uttar Pradesh

The mosques within the region of Bengal

Charminar (themosque of the four minarets), Hyderabad

The tomb of Muhammad Qutb Shah in Hyderabad, India

The Krishan Mandir temple(built in 1830)in the village of Krishankot in Punjab

Figure 2: lime plaster in Hydrabad

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CHARACTERISTICS OF LIME

1. Lime allows buildings to breathe

Lime was found to be one of the most

important. One of the reasons lime binders

are promoted by the Society for the

Protection of Ancient Buildings for repairs

is because they are vapor permeable and

allow buildings to breathe. This reduces

the risk of trapped moisture and

consequent damage to the building fabric.

2. Lime provides a comfortable

environment

Porous and open textured materials such as

lime plasters, help to stabilize the internal

humidity of a building by absorbing and releasing moisture. This makes for a more

comfortable environment and reduces surface condensation and mould growth.

3. The use of lime has ecological benefits

Lime has less embodied energy than cement.

Free lime absorbs carbon dioxide in the setting process of carbonation.

It is possible to produce lime on a small scale.

The gentle binding properties of lime enable full re-use of other materials.

A very low proportion of quicklime will stabilize clay soils.

Small quantities of lime can protect otherwise vulnerable, very low energy materials

such as earth construction and straw bales.

4. Lime binds gently with early adhesion

The fine particle size of lime, far smaller than cement, is linked to the root meaning of

the word lime, which is ‘sticky material’. Due to the fine particle size, lime mixes

Figure 3: Illustration of a breathing wall

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penetrate minute voids in the background more deeply than other materials. They

bind gently and the stickiness gives good adhesion to other surfaces.

5. Lime mortar can protect adjacent materials

Lime mortars with a high free lime content are porous and permeable. These

characteristics allow lime mortars to protect adjacent materials by handling moisture

movements through the building fabric and protecting them from harmful salts.

6. Lime renders can assist drying out by evaporation

Dense and impermeable renders can

trap moisture within the building fabric.

Trapped moisture is often the agent for

various decay mechanisms. Dense

renders used in conjunction with softer

materials or on weaker backgrounds can

cause serious problems by creating local

stresses. High calcium lime renders

allow evaporation and reduce the risk of

trapped moisture and decay. In simple

terms, the greater the extent of pure

lime and permeability the better this is

for the building. This needs to be

balanced with durability, however, and

some reduction in permeability may be

necessary to obtain adequate weathering

qualities, hence the advantage of feebly

hydraulic limes for external use.

7. Lime mixes have good workability

The ability of a mortar or plaster to remain smooth and moldable, even against the

suction it may experience from porous building materials, is termed workability. Good

workability greatly assists good workmanship, helping to achieve full joints with good

bonding to the other materials. This is what makes lime based mixes such a pleasure

to use. The workability provided by the lime allows the inclusion of widely graded and

sharp aggregates in the mix. These enhance both the performance and the aesthetic of

the finished work.

Figure 4: Section through soft mortar joints

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8. Lime binders can be durable and have stood the test of time

When used carefully, lime is exceptionally durable. Caesar’s Tower at Warwick Castle

has stood the test of time for over 600 years, and many cathedrals have stood longer.

An outstanding example is the Pantheon Temple in Rome which has a lime concrete

dome spanning over 43 meters (142 feet). This has survived for nearly 2000 years.

9. Lime finishes are beautiful

The double refraction of light through calcite crystals give a unique aesthetic

combining a soft texture with a luster that has a liveliness and delight of its own. The

graceful softness apparent in lime based materials is a visual indication of their

intrinsic permeability, workability and soft binding properties. They can rapidly

develop a rich patina which has a glowing translucent quality.

10. Lime contributes to a healthy environment

Lime is caustic and has been extensively used, often in the form of lime wash, for its

disinfectant qualities. Lime is also used for water purification. Lime mortars, plasters,

renders and lime wash have been used to create hygienic surfaces and improve

comfort conditions within buildings for thousands of years.

11. Self-Healing

The nature of ground conditions and the elements are such that all buildings are

subject to varying degrees of movement over time. When buildings made with lime

are subject to small movements they are more likely to develop many fine cracks than

the individual large cracks which occur in stiffer cement-bound buildings. Water

penetration can dissolve the ‘free’ lime and transport it. As the water evaporates this

lime is deposited and begins to heal the cracks. This process is called autogenous, or

self- healing.

12. Free lime encourages the growth of calcite crystals

Calcite crystals are a different shape to those formed by the more complex compounds

in hydraulic lime and cements. The crystals form in voids in lime rich environments.

The growth of calcite crystals adds strength over time and generally provides a more

open and permeable material than the denser eminently hydraulic and OPC mixes

with little or no free lime.

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13. Local limes enhance regional identity and diversity

The diversity of limestone types provides variety and local distinctiveness. Different

limes will vary in color, texture and setting properties. Local limes have a regional

identity, they give a sense of place and provide a continuous link with the local

aesthetic. Local color is the obvious example in respect of lime washes.

14. Disfiguring by cement can be avoided by the use of lime

On site the temptation to use quick and easy solutions for short term gain can lead to

long term problems. The attraction of using excess cement to be ‘safe’ is

understandable if not desirable. The fact that it is plentiful, inexpensive and readily

available adds to the problem. There is a high probability that over-strong and dense

mixes that are not fit for purpose will be used in excess. The physical damage and

unsightly aesthetic that results from this can be avoided by the use of lime.

15. Indefinite shelf life

Non-hydraulic limes have an indefinite shelf life when stored without access to air,

usually as a putty under water or in sealed containers. In fact the quality of the putty

improves the longer it is stored.

REFFERENCES:

1. WIKIPEDIA.ORG

2. https://www.researchgate.net/publication/259513991_Characterization_of_lime_

plasters_used_in_16th_century_Mughal_monument

3. http://authors.elsevier.com/a/1Rb6A3O1E110bg

4. https://www.academia.edu/415892/A_Short_History_of_the_Use_of_Lime_as_a_B

uilding_Material_Beyond_Europe_and_North_America

5. https://www.buildinglimesforum.org.uk/why-use-lime