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Standards for coarse aggregate and fine aggregate

Release time:Apr.20.2024 Views:0

Sand and gravel aggregate is one of the main components of concrete.(stone crusher) It is also one of the important raw materials in various infrastructure projects such as bridges, highways, railways, and housing construction. It is divided into coarse aggregate and fine aggregate. The coarse aggregate is mixed The material plays the role of a skeleton and is responsible for building up the large skeleton. The fine aggregate plays the role of filling the mixture and is responsible for filling the gaps in the large skeleton. The cement is then used to fill the small gaps formed by the fine aggregate to form a A dense mass, that is, concrete. However, do you know what specifications of materials fine aggregate and coarse aggregate refer to?

1

Coarse aggregate

Coarse aggregate - gravel

Aggregates with a particle size greater than 4.75 mm are coarse aggregates, also known as stones, and are generally divided into 5-1 stones, 1-2 stones, 1-3 stones, 2-4 stones, and 4-6 stones.

2

Coarse aggregate 1

(1)5-1 stones

Represents gravel with a particle size of 5-10mm, commonly known as guar rice stone.

(2)1-2 stones

Represents gravel with a particle size of 10-20mm, mostly used in surface roads and concrete.

(3)1-3 stones

Represents gravel with a particle size of 16-31.5mm.

(4)2-4 stones

Represents 24 points, the international standard is 1/4-1/2 inch, and the particle size is 10-15mm gravel.

(5)4-6 stones

Represents 46 points, the international standard is 1/2-3/4 inch, and the particle size is 15-20mm gravel.

Excessive needle and flake particles in coarse aggregate will worsen the workability of concrete and affect its strength. Therefore, the content of needle and flake particles in coarse aggregate should be controlled within a certain range.

Fine aggregate - sand

Aggregate with a particle size less than 4.75 mm, fine aggregate, is also called sand. Common fine aggregates are divided into coarse sand, medium sand, fine sand and extra fine sand. Coarse sand and medium sand are used for concrete, fine sand is used for plastering and jointing, and medium sand is suitable for ordinary concrete.

3

Coarse aggregate 2

Particle size and fineness modulus of sand:

(1) Coarse sand: the fineness modulus is 3.7-3.1. The average particle size is more than 0.5mm, also known as large sand, 05 sand.

(2) Medium sand: The fineness modulus is 3.0-2.3. The average particle size is 0.5-0.35mm.

(3) Fine sand: The fineness modulus is 2.2-1.6. The average particle size is 0.35-0.25mm, also called surface sand.

(4) Extra fine sand: the fineness modulus is 1.5-0.7. The average particle size is less than 0.25mm.

The particle shape and surface characteristics of fine aggregate will affect its bonding with cement and the fluidity of the concrete mixture. Nowadays, artificial sand has many advantages such as large production output and controllable quality of finished materials. The current market share is gradually increasing. rising.

In addition, in the concrete mix volume method, the proportion of coarse and fine aggregates is a very important factor. Coarse and fine aggregates account for 65% to 75% of the volume of concrete. There are certain differences in the selection of aggregates for concrete that require different properties for different uses. Specifically, The proportion of coarse and fine aggregate still depends on the use and requirements of the concrete.

However, whether it is coarse aggregate or fine aggregate, it needs to be mined and processed, and the production and processing process requires a complete sand and gravel production line to realize the processing of aggregates. Generally speaking, the composition of a sand and gravel aggregate production line is Feeding system, conveying system, crushing system, and screening system. The crushing system is the heart of the sand making production line. It consists of a crusher and a sand making machine and can crush various sand and gravel raw materials into the required particle size.

Xingao Heavy Industry is a large-scale crushing and sand-making equipment manufacturer. We can provide equipment configuration and installation training for a complete set of sand and gravel production lines. Through feeders, jaw crushers, hammer crushers, cone crushers, and vertical shaft sand making With the cooperation of machines, vibrating screens and other equipment, it can efficiently complete the simultaneous production of materials of different specifications such as coarse aggregate and fine aggregate, with excellent particle shape and continuous gradation.