Synthetic sand is currently the main construction material in the construction industry. Compared with traditional natural sand, synthetic sand has more reserves and is cheaper. This article mainly introduces what is synthetic sand, the main characteristics of synthetic sand, and some differences between synthetic sand and natural sand.
What is synthetic sand?
According to international regulations, all machine-made sand and mixed sand that have undergone soil removal treatment are collectively referred to as synthetic sand. Machine-made sand is a rock particle with a particle size of less than 4.75 mm after mechanical crushing and screening, but does not include soft rock and weathered rock particles. Mixed sand is sand made by mixing machine-made sand and natural sand.
It should be noted that there is no prescribed mixing ratio for mixed sand, but it is only required to meet various performance requirements of concrete. However, once mixed sand is used, no matter how large the proportion of natural sand is, it must follow the technical requirements and inspection methods of synthetic sand. At the same time, all sand and gravel are called synthetic sand.
The main characteristics of synthetic sand?
The main characteristics of synthetic sand are generally medium-coarse sand, the fineness modulus is between 2.6 and 3.6, the particle gradation is stable and adjustable, and it contains a certain amount of stone powder, which is mostly triangular. Or cuboid, with rough surface and sharp edges and corners. However, due to the difference in the production source of synthetic sand in various places, and the different production and processing equipment and processes, the grain shape and gradation of the produced sand may be very different.
For example, some synthetic sands have more flake-like particles, and some sands have a particle gradation that is large at both ends and small in the middle, but as long as it can meet all the technical indicators for sand, it can be used in concrete and mortar. Those that do not meet the requirements cannot be used, because the particle shape and gradation of synthetic sand can be adjusted and improved, which is the essential difference between synthetic sand and natural sand.
What is the difference between natural sand and synthetic sand?
First of all, you need to know how to distinguish between the two kinds of sand:
Natural sand: Natural sand is formed by natural conditions, and rock particles with a particle size of less than 5 mm are called natural sand.
Synthetic sand: All machine-made sand and mixed sand that have been treated with soil removal are collectively referred to as synthetic sand. sand is mechanically crushed and screened, and the particle size is less than 4.75 mm, but it does not include soft rock and weathered rock particles. Mixed sand refers to the sand and gravel that is mixed with machine-made sand and natural sand.
The main difference between the two:
Exterior:
Synthetic sand is produced by professional sand-making equipment such as suitable crushers. The sand and gravel materials obtained after crushing are higher in cleanliness. Compared with natural river sand, it has the characteristics of sharp edges and corners and many needles.
Natural sand is formed by natural action, the edges and corners are not obvious, it is relatively round, and the hand feels fine, but it contains a lot of impurities.
Firmness:
The firmness of sand is slightly worse than that of natural sand, but it can still meet the excellent standard in normal use, and there is no problem in ordinary concrete.
Compression resistance:
Synthetic sand has an irregular particle size and often has better adhesion, is more compressive, and lasts longer when bonded to structures such as cement.
Supply side:
Due to years of mining, natural sand resources are becoming less and less, supply is in short supply, and natural sand mining is limited in many places. The sand is different. The raw materials of synthetic sand are sufficient, such as urban construction waste, gravel tailings, leftover scraps, stone chips, gravel, and mine tailings, which can be used as synthetic sand raw materials.
In terms of price:
Under normal circumstances, the price of synthetic sand is much cheaper than that of natural sand.
Processing cycle:
Synthetic sand is processed by sand and gravel equipment. High efficiency, short processing time period and stable output.
Natural sand can only be formed after years of natural action, with a long cycle and a long time.
Prospects:
Due to factors such as environmental protection, restrictions on mining and sustainable development, the mining of natural sand has many restrictions and is in a state of short supply in the market. Therefore, the demand for these sand and gravel can be replaced by sand, so the development prospect is broad.
What are the advantages of synthetic sand compared to natural sand?
Price:
The price of synthetic sand varies from place to place, but it is basically much cheaper than natural sand. Compared with natural sand, synthetic sand is about $3 cheaper per ton. At the same time, due to the shortage of natural sand in the market, synthetic sand has a lot of demand, so there is a huge demand.
Stable Supply:
Due to years of mining, the reserves of natural sand are getting smaller and smaller. But with the rising price, there is no way to guarantee the supply and quality of natural sand. However, there are many resources of sand. As long as there are stones, synthetic sand can be produced. Urban construction waste, stone chips and mine tailings can be used as raw materials for synthetic sand.
Strong and sturdy:
The solid properties of sand are slightly worse than that of natural sand, but they can still reach the standard use level. However, for construction units that are often subject to friction and impact, the sand-lime ratio, crushing index and stone powder content should be controlled.
Environmental protection:
Traditional sand will bring environmental problems such as dust pollution. However, with the continuous improvement of sand production technology, a fully enclosed structure is generally adopted, and each machine is equipped with a water spray device to prevent dust from overflowing.
Any exploitation of natural river sand will change the shape of the bottom of the river bed, thereby changing the direction of water flow, creating complex flow patterns of eddies and backflows. These phenomena will further affect the wider riverbeds, dams and sandbanks by affecting sediment accumulation or sediment erosion, thereby affecting the safety of river banks, bridges and navigation.
Adhesion:
The particle size of sand is more irregular, and when it is bonded with building materials such as cement, it tends to have better adhesion, stronger compression resistance and longer service life.
After natural weathering, river impact and scouring, the surface of natural sand has a certain smoothness, but the bonding effect with other materials in the later stage is poor.
Stone powder content:
Stone refers to materials with a particle size of less than 75um mixed in artificial sand. Common concrete requires no more than 10% of stone powder, and high-strength concrete requires no more than 5%.
Through the tests of cement, mortar and concrete, there is no difference between synthetic sand and natural sand. But generally speaking, artificial sand consumes more water, but the strength of concrete remains basically the same.
Application of natural sand and synthetic sand?
Natural sand is rock particles formed by weathering of rocks. Natural sand is formed by natural conditions. Rock particles with a particle size below 5mm are called natural sand. The natural sand is washed by the river water, so it feels more delicate. Synthetic sand is formed by crushing stones.
Compared with natural sand, synthetic sand has the following differences and advantages:
The material of sand is excellent and stable. Synthetic sand is an artificially selected raw material. The material is uniform and stable. The mineral composition and chemical composition are consistent with the raw material, and it is not as complicated as natural sand. One kind of sand, one fineness modulus, corresponds to only one gradation; while general natural sand, one fineness modulus, can have multiple gradations.
Natural sand is mainly used in: building decoration, terrazzo aggregate, stone paint, and sand mining paint.
Natural sand can also be used to make marble, floor tiles, ceramic tiles and decoration, with the advantages of luster, smoothness, firmness and wear resistance.
Synthetic sand is mainly used in the construction industry and can be widely used as a substitute for natural sand.
What is the reason for the appearance of synthetic sand?
Synthetic sand, as the name suggests, is to use mechanical equipment to artificially sand, and make the stone into sand through the process of stone hitting stone and stone hitting iron in the sand making machine. The particle surface of synthetic sand is rough, with many edges and corners, the combination between aggregate and cement and aggregate is good, and the mechanical bite force is high, so the concrete with synthetic sand is stronger than the concrete with natural sand.
However, in the process of stone processing, due to the intense collision and the stone itself has a certain amount of soil, the sand will contain a certain amount of stone powder and mud powder. The existence of mud powder will seriously affect the gradation of sand, while the existence of stone powder can make up for the shortcomings of large gap, large water demand and poor fluidity caused by sand in concrete.
In order to solve the problem of the powder content of synthetic sand, we can learn the principle of river sand making, make a sand washing machine, and remove the mud powder in the sand through the washing of the sand washing machine, so that the sand can reach the construction sand. The standard, this method is the wet production line.
Where is the synthetic sand produced?
Since the production of sand requires the use of water to wash the sand and gravel, since the emergence of synthetic sand, it is mainly concentrated in places with rivers or abundant water resources, and the powder in the synthetic sand is washed away by the cleaning of the sand washing machine. . Therefore, there must be abundant water resources around the production line of synthetic sand, otherwise the produced sand will not meet the standard of construction sand, and it will still be a pile of waste.
Related equipment for producing synthetic sand?
The manufacture of sand requires the use of a sand making machine, which generally refers to a vertical impact crusher. It is widely used in various industries such as various ores, cement, refractory materials, emery, glass raw materials, machine-made construction sand, stone materials and various metallurgical slag.
Due to its excellent low wear characteristics, sand making machines are also used for high abrasiveness and secondary disintegration crushing production. In addition, due to the low pollution to the product, the sand making machine is very suitable for the production of glass quartz sand and other high-purity materials, and the sand making machine can almost meet the production requirements of any form of sand and gravel.
What is the difference between stone chips and synthetic sand?
Although the raw materials of stone chips and synthetic sand are the same, they have essential differences.
Grain size
Poor gradation of stone chips, needle-like and irregular, can not only improve the strength of concrete, but also affect the fluidity of concrete. It is used as road cloth in asphalt mixing plant. Because the particle shape is needle-like, it is easy to scratch the tires of passing vehicles. The shape of synthetic sand particles is round, polygonal cube, with large surface area, which is easy to bond between cement and admixture, which is beneficial to improve the strength of concrete.
Powder content
The powder content in the stone chips is seriously exceeding the standard, and it can usually be used after being processed by the washing equipment. However, in the process of synthetic sand processing, a device such as a dust collector can be used to control the powder content in the material. Compared with the water washing process, the post-processing is more convenient and the environmental pollution is less.
Gradation
The stone chips are crushed and classified. Since some crushed stones are produced during the construction of crushed stones, their powder content is seriously exceeding the standard, and fine sand and medium sand are seriously lacking. But synthetic sand is different. Synthetic sand has adjustable gradation and less dust content, which is more practical due to the use of commercial concrete batching plants.
Compressive strength
The compressive strength of stone chips is low, and the compressive strength of synthetic sand is high.
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