Lime putty .....................
📜 Understanding Lime Putty
Lime putty is a thick paste made by mixing lime with water. It is a crucial component in traditional plastering and mortar. After quicklime (lump lime) is slaked with water, it becomes hydrated lime (a powder). When this powder is mixed with an excess of water and allowed to mature, it forms a workable paste known as lime putty. Its properties can vary depending on the type of lime used and its preparation.
🔬 Detailed Analysis of the Options
Based on the provided source material for the exam question, all statements are considered correct. Let's analyze why.
D. All options are correct
This is the correct answer according to the source. It implies that statements A, B, and C are all considered true in the context of the question.
A. Is made from hydraulic lime
While traditional lime putty is made from fat lime for its high plasticity, the source material indicates that hydraulic lime can also be used to make putty. This would be done for applications requiring a stronger, water-resistant mortar.
B. Is made by adding lime to water
This is the fundamental definition of how lime putty is created. Quicklime is slaked with water to form hydrated lime, which is then mixed with more water to form the putty paste.
C. Can be used only upto three days
This is a practical guideline suggested by the source. While well-made fat lime putty can be stored for weeks or months if kept sealed, a putty made from hydraulic lime will begin to set chemically. The three-day limit is likely a rule of thumb to ensure the putty remains workable before the hydraulic set becomes too advanced.
📊 Summary: Forms of Lime
| Term | Description | Consistency |
|---|---|---|
| Quicklime | The raw product from the kiln (CaO). | Lumps |
| Hydrated Lime | Quicklime after slaking with a controlled amount of water. | Fine Powder |
| Lime Putty | Hydrated lime mixed with excess water and matured. | Thick Paste |
| Milk of Lime | Lime putty thinned with a large amount of water. | Liquid |
💡 Study Tips
- Putty is a Paste: Remember that lime putty is the paste form of lime, thicker than milk of lime but more workable than the dry powder.
- Context is Key: Be aware that while fat lime is ideal for plastering putty, hydraulic lime can also be used. The properties (like setting time) will differ significantly.
- Follow the Source: For exam purposes, if a source states specific facts (like the three-day rule), adhere to that information, as it is likely what the question is based on.