The difference between machine-made sand and river sand: machine-made sand or river sand?

In the past two years, with the strengthening of environmental protection and rectification, traditional extensive sand and gravel enterprises have stopped work and rectified, facing transformation and upgrading, and the natural sand and gravel production capacity has also plummeted. As important building materials and concrete raw materials, sand and gravel are widely used in the construction of buildings and road engineering layers, and the market demand is huge. Machine-made sand ground from stone is gradually becoming a substitute for natural sand and gravel, and its application has become a universal trend in the world. What is the difference between machine-made sand and river sand? Is machine-made sand or river sand better?

1 appearance

Machine-made sand is a kind of sand and gravel material which is crushed by suitable professional sand-making equipment such as crusher. Compared with natural river sand, it has the characteristics of sharp edges and many needles.

Distinguish machine-made sand from river sand in appearance: River sand is dug directly from the river, so it will be mixed with pebbles and fine sand. These pebbles have been washed away by the river for a long time and have rounded edges and corners; Machine-made sand produced by sand and gravel equipment is angular.

2. Sturdy and durable

The firmness of machine-made sand is slightly worse than that of river sand, but it still reaches the standard of GB/T 14 1684293, and it is no problem to use it in ordinary concrete. However, when it is used in concrete components that are often subjected to friction impact, besides additives, it is also necessary to control the cement-sand ratio of concrete, the crushing index of sand and the content of stone powder.

3, stone powder content

Large silt content is an important feature that distinguishes machine-made sand from natural river sand. The mud content of machine-made sand and natural sand should be distinguished when distinguishing.

The silt content of natural sand means that the particle size is less than 0.075mm, and it is composed of cohesive clay particles with large plasticity index, which has no contact with the crystal stone after cement hydration, so the silt content of natural sand directly affects the composition of concrete strength.

The ground stone powder with the powder content of machine-made sand less than 0.075mm can not react with cement hydration, but it has excellent connection with cement crystal stone and plays the role of micro-aggregate filling in the internal layout.

In fact, if the powder content of machine-made sand does not exceed 20%, it has no adverse effect on the setting time and strength development of concrete, and it has good performance in the workability, pumpability and strength of concrete mixture.

4. Adhesion and compression resistance

The particle size of machine-made sand is irregular, and when it is bonded with cement and other structures, it often has better bonding force, greater compression resistance and longer service life.

5. Composition structure

Artificial sand is generally a raw material selected by people. The material is uniform and stable, and the mineral composition and chemical composition are consistent with the raw material, which is not as complicated as natural sand.

6, fineness modulus

Ordinary natural sand can have multiple gradations with a fineness modulus, and the fineness modulus of machine-made sand can be controlled artificially through the production process, and production can be organized according to the requirements of users, which is impossible for natural sand.

To sum up, machine-made sand is not only widely available, stable in material, easy to operate and control, good in performance, and can meet the construction needs, but also economical and feasible, which is the development direction of the future construction market and is also very conducive to the protection of the natural environment. With the layout construction of machine-made sand business and the further adjustment and optimization of industrial structure of enterprises, it has become the basic common sense of upstream and downstream enterprises to reduce or even bid farewell to the use of natural sand and gravel in the future. There is still a big gap in market demand at present. Whether for environmental protection or from the perspective of engineering quality, it is an inevitable trend to build and lay out artificial sand and machine-made sand on a large scale.