Deterioration of stones- Various factors responsible
The principal agencies responsible for causing deterioration of stone are given below:
1) Alternate wetness and drying
4) Living organisms
5) Impurities in the atmosphere
6) Nature of mortar
7) Temperature variation
9) Vegetable growth
10) Mutual decay
1) Alternate wetness and drying:
The stones are made wet by various agencies such as rain frost, dew, etc. The wet surface is dried by sunshine. It is found that stones subjected to wetness and drying wear out quickly.
In very cold places the moisture present in the atmosphere is deposited in pores of stones. At freezing point, the moisture freezes and in doing so, Expands in volume and causes the splitting of stone.
3) Wind: Also help in the deterioration of the stone. Strong wind can cause fine particles to strike against the stone and cause its decay.
4) Living organisms: Some living organisms like worms and bacteria act upon stones and decorate them.
5) Impurities in the atmosphere: The impurities in atmosphere adverse effects on the stone the acids and fumes are predominant in an industrial town.
6) Nature of mortar:
The nature of mortar used has a binding material in stone may be such that it may chemically react with any one of the constituents of stone.
7) Temperature variation:
The rise of temperature results in the expansion of stones. The Fall of temperature causes the contraction of stones. If the rise and fall of temperature are frequent, the stones are easily deteriorated.
Pure rainwater has no effect on stone. Rainwater its passage downward dissolves oxygen, carbon dioxide, and other gases and does not remain pure. These gases act adversely on stone and cause decay of stones.
9) Vegetable growth: The Creepers and certain trees develop on the stone surface with their roots in joints and keep stone surface damp. At the same time they try to expand and deteriorating the stone.
10) Mutual decay:
If different stones are used together there may be physical and chemical reactions leading to mutual decay. It is found that when limestone and sandstone are used together there is a tendency for sandstone to decay.
Preservation of stones:
The preservation of stones becomes necessary to guard against its disintegration by the atmosphere. For the preservation of stone preservatives applied on the surface of stone.
- Oil Paints
- A solution of alum and soap
- Solution of baryta
- Linseed oil
- Coal tar
- Silicate coating
- Pointing and plastering