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The difference between graded sand and gravel and graded gravel

Release time:Apr.17.2024 Views:0

Grading refers to the distribution of particles of various sizes of aggregates, (stone crusher)which can be determined through sieve analysis tests. For example: 2-gradation means mixing stones of two different particle sizes together, and 3-gradation means mixing three different particle sizes. The stones are mixed together, the grade is required for structural strength, and the grading is required for construction technology, economy and temperature control.


Graded sand and graded gravel of various specifications are often seen in sand and gravel production lines. They are widely used in the base and sub-base of green pavement and cement concrete pavement. The main difference between the two lies in the aggregates.

1

750 thick medium fine


Different aggregates


Graded sand and gravel: divided into natural grading and artificial grading. Fine sand is mixed with a small amount of gravel, which includes sand and gravel (gravel), which is often referred to as fine aggregate and coarse aggregate in concrete. According to experiments A mixture of integrated coarse and fine aggregates with different particle sizes determined through chamber proportioning tests. The proportioning varies according to the specific engineering design.


Graded gravel: Artificial grading, using machines to manually break stones into stones with different particle sizes. It only refers to gravel, which is the coarse aggregate in concrete. It does not include sand (fine aggregate) and is of different specifications. The aggregates are mixed in a certain proportion to form a mixture of coarse, medium and fine gravel aggregates and stone chips. When its particle composition meets the specified dense gradation requirements, it is called graded gravel.


Different ratios


Graded gravel: Its mix ratio refers to the proportion of cement, sand and gravel in the masonry materials. Depending on the materials used, it can change the slurry, strength and other properties of the mortar. Therefore, it is important for the user to adjust the mixing gradation ratio according to the required performance. Generally speaking, the commonly used grading ratio is 1:1.5:3 or 1:2:4. That is, cement:sand:gravel=1:1.5:3 or 1:2:4. This grading ratio usually acts on Large to medium-sized gravel (fine sand or small gravel is also acceptable) to maintain the flowability and strength of the mortar; when processing large to medium-sized gravel, an increase in the amount is needed to improve their bonding force, so it will Choose a mix ratio of 1:1.5:3; for finer gravel, such as dust, sand or fine gravel, you can use less cement, that is, a mix ratio of 1:2:4, because it is better Mixing and "gluing" the gravel together increases the strength of the mortar and reduces construction costs. There are also some other grading ratios, such as 1:2:5, 1:2.5:5, etc., which can be fine-tuned according to the characteristics of the masonry materials and construction needs to make the mixing value reach the specified range, or according to actual needs. Rigorous testing to find the best grading ratio for different construction applications.


In addition, it stipulates that the diameter of all particles cannot be greater than 50mm. In order to better meet the compaction degree, and in order to prevent frost heaving and softness, attention should be paid to controlling the content and plasticity index of fine materials less than 0.5mm.


Graded sand and gravel: The mix ratio is generally 75% stone and 25% sand. Because of the graded sand and gravel, it is required to achieve a certain density. Stone accounts for 75%, which can provide a certain strength, because the strength of stone is relatively high, and the gaps between the stones are filled with sand to achieve a relatively dense whole, so the sand material accounts for the total weight Around 25%.


Graded sand and gravel are sometimes used as cushions, called graded gravel cushions. The graded gravel requires particle sizes between 5 and 40 mm, of which the content of 25 to 40 mm is not less than 50%.


Different uses


Graded gravel: The gravel needs to be screened into different sizes first, and then the gravel of different particle sizes is configured together according to the requirements. According to the configuration method, it can be divided into two types: continuous grading and discontinuous grading. Different grading The combination of gravel can increase the compactness of the mixture and better fill the pores. It has good water permeability and diffuse stress, and assumes a transitional function. It is mainly used to enhance the strength of the pavement structure and is mostly used to build highways. The base layer and gravel cushion can be used for individual foundation pits and trenches, or for whole-house replacement.


Graded sand and gravel: The gravel plays the role of a skeleton, and the sand serves as a fine aggregate to fill the skeleton. It is generally used for ground cushion, etc. When used as a cushion for asphalt pavement in medium-humid and humid road sections, it should be When adding lime to the gradation, the fine materials can be appropriately increased. The amount of lime added accounts for 8% to 12% of the fine material content. The purpose is to increase the strength and stability of the cushion.


With the rapid development of the economy, the demand for graded gravel and gravel is increasing day by day. Xingao Heavy Duty Work is a professional sand and gravel aggregate production line designer and equipment manufacturer, focusing on the field of sand and gravel aggregate crushing. It can not only provide infrastructure industries, mining crushing, industrial sand making, green building materials and other fields with an hourly output of 100-6000 tons of sand and gravel aggregate production line equipment required, and at the same time can provide them with a full range of sand and gravel aggregate production line design and construction plans.