Explanation:

In civil engineering, aggregates are the most important components of concrete. They are the granular materials that are used as filler and binding materials in the construction of concrete structures. Aggregates can be of different shapes, sizes, and textures, which affect the properties of the concrete. The statement that is odd or not correct is option 'D' - single-size aggregate.

What are aggregates?

Aggregates are the granular materials that are used as filler and binding materials in the construction of concrete structures.

Types of aggregates

Aggregates can be of different shapes, sizes, and textures, which affect the properties of the concrete. The common types of aggregates are:

- Rounded aggregate: These are smooth and rounded in shape, such as river gravel and pebbles.
- Irregular or partly rounded aggregate: These are irregular in shape and partly rounded, such as crushed rock and quarry dust.
- Angular flaky aggregate: These are angular and flat in shape, such as crushed stone and sand.
- Single-size aggregate: These are uniform in size and shape, such as sand and gravel of a single size.

Why is single-size aggregate not correct?

The statement that is odd or not correct is option 'D' - single-size aggregate. This is because using single-size aggregates can result in poor compaction, lower strength, and higher cement content. It can also lead to bleeding and segregation, which can affect the overall quality of the concrete. Therefore, it is important to use a combination of different sizes and shapes of aggregates to achieve the desired properties of the concrete.

Conclusion

In conclusion, the choice of aggregates is an important factor in determining the properties and quality of concrete. Single-size aggregates are not recommended, and it is advisable to use a combination of different sizes and shapes of aggregates to achieve the desired properties of the concrete.