Conservation methods 13 2-2013

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VARIOUS METHODS OF CONSERVATION APPLIED AT

MOHENJO-DARO

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•Pushtas:

•Aims “Pushta” is our regional term for Mudbrick and of mud embankment provide to amud or mud brick wall base, installed as aprotection or as reinforcement for the existingfoundation. In general, as they are presentlyused at Mohenjo-Daro, pushtas are only appliedto fired or mud brick walls, Pushtas are built outfrom the surface plane of the wall Typically theyare constructed in a stepped pattern and thencovered with mud mortar to smooth the sides.

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Location: B No.7 H No , III E/W R, 46

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• Buttress:As more of less temporary emergencymeasures, buttress have prevented collapse ofman walls throughout the site, withoutdamaging the material of the wall. Thistreatment is still in use throughout the site.

Underpinning:

• Reinforcement of walls by rebuilding collapsed ordeteriorated sections of the wall base with burnt brick,maintaining the surface plane , setting or thereplacement of bricks in mud mortar.

• Formulation : Mud mortar formula is 60% clay, 35%salt, 5% sand. The standard for lime-based mortars forspecial applications is 1 part lime putty/6 parts riversand (n.b: lime-based mortars should only be used atthe prescribed locations, such as the Stupa platform,non-original areas of the Great bath or highly visitedreconstructed areas where additional durability isessential).

Repair of brick course:

• The aim of brick course repairs is to sensitively repaircourses that have collapsed from failed mortar joints, butare still in place, returning them to a generally regularcourse pattern, well-bonded to the adjacent brick units.Ambient conditions for application like all mortar work, it isbest done out of direct strong sun.

• Wall capping with mud bricks:

• A practice since at least 1956, renewed in 1993, with the aim of preventing excessive penetration into the wall cavity by rain water, used in 1993 on practically every wall

• Mud Slurry:

• Sprayed or splashed on wall as sacrificial coating (Scope of the application unknown, but used widely all over site.

• Pointing:

• Pointing aims to return joints between bricks to a state ofsound bonding, in which the matrix of the wall is restoredand the wall is protected from excessive moisturepenetration through mortar joints. It is best to do pointingwork out of direct, strong sun whenever possible.

• Mud Plaster:

• To provide a thick sacrificial surface where the mechanisms of salt decay and rain erosion will take place instead of in the ancient material.

• Mud Brick Flooring:

• Used to replace salt-laden earth, repair washouts and to even room levels for drainage purposes.

• Removal of salt-laden earth and replacement with sweet earth:

• Including the removal of waste from sacrificial coatings.

• Wall capping:

• The aim of wall capping is to provide a protective covering over the wall prevent entry of rain water into the wall top.

• Barriers:

• The construction of low-rise barriers to divert the flow of run-off from a large area to another less-sensitive location or drainage area ,other most effective site works.

• Wall base protection:

• Wall base protection is widely used at site to prevent the erosionof earth supporting wall foundations, and to prevent water fromstanding at wall base where it could soften foundations andincrease rising damp. The treatment involves the addition ofcompacted sweet earth at wall bases to form a positive slopekeeping rain water away from the wall.

Reinforcement:• The reinforcement of gullies utilizes existing drainage

paths by reinforcing them so that they can effectivelycontain quantities of run-off and transport the waterto safe discharge areas. Gullies are reinforced byreshaping them into “V” shaped channels and liningthem with compacted sweet earth.

Sloping:• Adding or removing earth in order to direct run-off in a

particular direction. The treatment is very effective atreducing erosion and preventing the softening orundercutting of foundations at sensitive structures.

•Leveling:• Leveling involves the addition and /or removing of earth

to spread run-off over an even surface.it is generally usedto allow more efficient evaporation of rain water, but mayalso be effective at slowing the velocity of run-off.

• Ponding:• In some cases, when relatively small amounts

of run-off cannot be drained from an enclosed area such as a low lying room) the use of filling and sloping away from the walls to create a pond in the center of the room may be the most effective drainage measure.

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The end