When more and more people pay attention to environmental protection, all walks of life are looking for sustainable resources, and artificial sand is prominent in the construction industry. And with the shortage of natural resources, the price of sand and gravel rises, and artificial sand is even more important.
The following is an introduction to artificial sand.
1. The characteristics of artificial sand compared with natural river sand
The river sand is directly excavated from the river, so it will be mixed with small pebbles and fine sand. These small pebbles are washed by the river for a long time, and the edges and corners are relatively round, while the artificial sand is produced by machines, and the edges and corners of the sand are relatively sharp and distinct. But the firmness will be slightly less than river sand.
Robustness and Durability
Although the firmness of artificial sand is slightly worse than that of river sand, there is no problem in using it in ordinary concrete. If it is to be used in concrete components that are often subjected to frictional impact, admixtures can be added, and then the lime-sand ratio of concrete, the crushing index of sand and the content of stone powder can be controlled.
Stone powder content
The powder content of artificial sand is less than 0.075mm of finely ground rock powder. It cannot react with cement by hydration, but it can have an excellent connection with cement crystalline stone and play a filling effect of micro-aggregates in the internal layout. . And it has good performance in the workability, pumpability and strength of adding concrete mixture.
Adhesion and Compression Resistance
The particle size of artificial sand is irregular. When using cement and other structures to bond, it tends to have better adhesion, more compression resistance, and longer service life.
Artificial sand is generally 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.
Generally, river sand, one kind of fineness modulus, can have various gradations, but the fineness modulus of artificial sand can be controlled artificially through the production process, and the production can be organized according to user requirements, which cannot be achieved by river sand. of.
2. Application of artificial sand in commercial concrete
The strength of commercial concrete is an important indicator for testing the performance of concrete. Under the same conditions, the strength of artificial sand commercial concrete is higher than that of river sand concrete. Mainly because artificial sand is formed by crushing limestone. The main component of artificial sand is calcium carbonate. When calcium carbonate is contained in a high concentration of calcium hydroxide, a chemical reaction will occur on the surface of artificial sand, while the silicon dioxide in river sand. The content is relatively high, and similar chemical reactions generally do not occur.
Artificial sand is relatively rough and has many edges and corners. In the mortar, machine-made sand particles have the function of skeleton, which inhibits the deformation of cement stone and the sliding of aggregate particles. There is a well-bonded interface between artificial sand and cement stone, and the pores at the interface will be less, and the stress concentration will be greatly reduced. The density of artificial sand is relatively high and the voids are relatively small, which greatly improves the compressive elastic modulus of commercial concrete. When the water-cement ratio is consistent with the amount of cement, the elastic modulus of artificial sand commercial concrete is much higher than that of ordinary concrete.
The dry shrinkage rate will increase with the increase of the stone powder content, mainly because the extremely fine particles in the stone powder will continue to increase with the increase of the stone powder content. Such extremely fine particles can increase the content of the cement slurry in the commercial concrete mixture. The drying shrinkage of commercial concrete is mainly due to the drying shrinkage of the cement slurry. Therefore, the increase of the cement slurry in the unit volume will lead to an increase in the drying shrinkage rate of the concrete.
Impermeability The impermeability of commercial concrete is related to the pore structure of the concrete. The stone powder in the artificial sand is considered to be the most important reason for improving the impermeability in commercial concrete. There is a saying that stone powder is only a filler in artificial sand. Although stone powder is not active, it effectively improves the compactness of commercial concrete and improves the bonding between cement stone and aggregate interface. There is also a saying that stone powder can effectively improve the structure of cement stone pores to improve the impermeability of commercial concrete.
When preparing commercial concrete, the company used 50% stone chips instead of river sand to improve the frost resistance of commercial concrete, and achieved good results. Using stone chips instead of river sand was about 10% less intense after 200 freeze-thaw cycles than without replacement. The application of artificial sand effectively improves the structure of the capillary pores of commercial concrete, thereby greatly improving the frost resistance of commercial concrete.
Artificial sand commercial concrete has advantages in workability, impermeability, strength, frost resistance and durability. Especially in low-standard commercial concrete, stone powder acts as a filling function of micro-aggregates, effectively improving The structure of the pores of the commercial concrete makes the artificial sand commercial concrete higher than the natural sand commercial concrete in many aspects.
3. The impact of the crusher producing artificial sand on artificial sand
Vertical Shaft Impact Crusher
The vertical shaft impact crusher is an effective method for producing cubic fine and medium fine aggregates and has been very popular from the 1980s and 1990s to the present. However, such machines are often used for the final step of crushing and product repair. Since the aggregate particle shape produced in the early production is unsatisfactory, a large amount of powder with a size of less than 4mm will be produced during the use of such machines, which is a serious situation. A stone powder coating is also formed on the surface of the coarse aggregate.
The main advantage of the cone crusher is that it produces less waste, and the disadvantage is that the particle shape is poor at most component sizes. The main factors affecting the particle shape are the size of the closed side and the size of the feed. Theoretically, feeds of various size distributions can be processed into cube-shaped particles by cone crusher. But in fact, due to the existence of the maximum extrusion force, the crushing process is limited and the process of the particle cubic shape is hindered. In order to make the cubic shape of the product as good as possible, the feed size distribution should be wide, and the feed of fine aggregate should be as little as possible, because the fine aggregate reduces the porosity of the material layer, which increases the energy consumption and reduces the crushing ratio.
Impact Crusher and Impact Crusher
The machine-made sand produced by the impact crusher has good gradation but poor grain shape, while the machine-made sand produced by the impact crusher has poor gradation but good grain shape.
The jaw crusher is suitable for the crushing of hard rock, but not for soft rock and viscous rock.
Compared with traditional river sand, artificial sand currently has better prospects and plays an important role in the construction industry. If you want to know more about the production of artificial sand or other issues such as crushers, you can continue to browse on our website.