Top 10 Different Types of Aggregates | Classification & Uses

What are Aggregates?

Aggregates are the main ingredient in making materials of Concrete and Mortar which occupies 70-80% of Concrete Volume. Aggregate as a filler with binding material is the derived product of Sedimentary, Igneous and Metamorphic rocks and thus it is hard, strong, and durable. It can also be made from blast furnace slag. As aggregates are used in large quantities in the manufacturing of concrete, they have a significant effect on the properties of the Concrete. Therefore, it is vitally important to choose the right variety and quality before constructing. Unlike other making materials like cement and water, this does not require any special storage place and has negligible effects when exposed to various climatic conditions.

Types of Aggregates & Classifications:

1. Based on Geological Origin: There are different types of Aggregates

Natural Aggregates: These are one of the types of aggregates and are obtained from naturally obtained rocks like Sedimentary, Igneous and Metamorphic rocks. Sand and gravel are also fallen into this type of aggregates. As these Aggregates are naturally obtained which may have a lot of impurities, so it should be sieved and washed before used in Concrete.

2. Based on Size: They can be classified as following types of aggregates

Coarse Aggregate: Aggregate retained on 4.75 mm sieve are known as Coarse Aggregates. They are obtained by natural fragmentation or by artificially crushing the rocks. The maximum size of coarse aggregate can be 80 mm.

Fine Aggregate: Aggregates that are passed through a 4.75 mm sieve are classified as Fine Aggregates. They are natural sand, crushed stone, and crushed gravel stone. The minimum size of fine aggregates can be 0.06 mm.

Graded Aggregate: Aggregate which passes through a particular size of the sieve is

known as graded aggregate. For example, a 12mm aggregate passes through the 12 mm size of the sieve.

All-in-Aggregate: These aggregates are naturally available which consist of various fractions of coarse and fine sizes of aggregates are known as All-in- Aggregates.

3. Based on Shape: They can be classified as

Rounded Aggregates: These aggregates are round due to the friction of water. So, they are obtained from river, seashore. These have minimum voids of about 32% in the concrete. These aggregates have a poor interlocking bond and require minimum cement paste.

Irregular Aggregates: As these aggregates are irregular in shape and thus have a strong locking bond. So, these are used for making ordinary concrete. These aggregates have 36% voids and require more cement paste than rounded aggregates.

Angular Aggregates: These aggregates are rough, sharp, and angular which provides a solid bond. So, these can be recommended to use in the construction of pavements. These aggregates have about 40% voids and require comparatively more cement paste.

Flaky Aggregates: These aggregates are generally rough and very sharp. It can be better explained using an example. The mean sieve size for an aggregate passing through 30mm and retained on 40 mm sieve is (30+40)/2=35 mm. The minimal lateral dimension is less than 0.6 x 35 mm=21 mm, the aggregate is known as Flaky Aggregate. Generally, If the thickness of aggregate should be less than the width and length of the aggregate, it can be identified as Flaky Aggregates.

Take a look at the top 10 different types of Aggregates and their classifications. Check the best-crushed stone type for concrete used in construction.

Read More: https://constructionkart.in/types-of-aggregates-and-classification/

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