With the decreasing natural sand, the mechanism sand market has shown great potential and vitality. Especially in recent years, the great demand for construction which has promoted the rapid development of the sand and gravel market. Then, compared with natural sand such as river sand, sea sand, and mountain sand, what are the advantages of machine-made sand? What are the characteristics?
The mechanism sand is made of professional sand making equipment, so has the characteristics of sharp edges, needle-like shape and roughness compared with natural river sand. River sand is directly excavated from river, so it will be mixed with small pebbles and fine sand. These small pebbles are washed by the river for a long time, so the edges and corners are relatively round.
2. Ruggedness and durability
The ruggedness of artificial sand is slightly worse than that of river sand, but it still meets the superior product index of GB/T141684293 standard. There is no problem in the use of ordinary concrete. However, in the concrete members that are often subjected to frictional impact, in addition to the use of admixtures, the lime-sand ratio of concrete, crushing index and stone powder content of sand should be controlled.
3. Stone powder content
The large amount of powder is an important feature of mechanism sand different from natural river sand. The powder content of mechanical sand should be separate from the mud content of natural sand. The mud content of natural sand means that the particle size is less than 0.075mm, which is composed of sticky clay particles, and the plasticity index is large. It has no connection effect with the crystallized stone after cement hydration, so the mud content of natural sand is directly affects the composition concrete strength. The powder content of artificial sand is a fine rock powder of less than 0.075 mm, which cannot react with the cement hydration, but it has an excellent connection with the cement crystallized stone, and the filling effect of the micro-aggregate in the internal layout. In fact, if the powder content of mechanical sand does not exceed 20%, it has no adverse effect on the cohesion time and strength development of concrete, and has the workability, pumpability and strength of the added concrete mixture.
4. Adhesion and pressure resistance
The graininess of machine-made sand is irregular. When bonding with a structure such as cement, 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 materials, and are not as complicated as natural sand.