For lime concrete, ...............
📜 Understanding Lime Concrete
Lime concrete is a type of concrete where lime is used as the primary binding material instead of cement. It was a common construction material before the widespread use of Portland cement. It consists of lime, aggregate (like sand, gravel, or brickbats), and water. Compared to modern cement concrete, lime concrete is less strong and gains strength much more slowly, but it is more flexible and breathable.
🔬 Detailed Analysis of the Options
This question tests key properties of lime concrete. Let's analyze each statement.
A. Slump is 50 to 75 mm
This is a correct statement. The slump test measures the workability or consistency of fresh concrete. For lime concrete, a slump value in the range of 50 to 75 mm indicates a good, workable mix that is suitable for placing and compacting.
B. Flexural strength at 90 days is 0.2 N/mm²
This is a correct statement. Flexural strength measures a material's ability to resist bending. Lime concrete develops strength slowly. A typical value for its flexural strength after 90 days of curing is around 0.2 N/mm².
C. Compressive strength at 90 days is 1.5 N/mm²
This is a correct statement. Compressive strength is the most common measure of concrete quality. For lime concrete, a typical 90-day compressive strength is about 1.5 N/mm². This is significantly lower than Portland cement concrete but sufficient for many traditional applications like foundations and base courses.
D. All options are correct
This is the correct answer. Since statements A, B, and C are all factually correct descriptions of the typical properties of lime concrete, this option is the most appropriate choice.
📊 Summary: Typical Properties of Lime Concrete
| Property | Typical Value | Description |
|---|---|---|
| Slump | 50 - 75 mm | Measures workability of fresh mix. |
| 90-day Compressive Strength | ~ 1.5 N/mm² | Resistance to crushing loads. |
| 90-day Flexural Strength | ~ 0.2 N/mm² | Resistance to bending loads. |
💡 Study Tips
- Remember the Trio: Memorize these three key values for lime concrete: Slump (50-75 mm), 90-day Compressive Strength (1.5 N/mm²), and 90-day Flexural Strength (0.2 N/mm²).
- Slow Strength Gain: Note the "90 days" timeframe. This is a key characteristic of lime—it hardens and gains strength much more slowly than cement.
- Context is Key: Compare these values to modern cement concrete (which has a 28-day compressive strength of 20-40 N/mm² or more) to understand just how different lime concrete is.