Gravel and pre-crushed rocks become sand and grit
The shortage of sand generates a bottleneck in supply in the construction industry. Sand is often extracted from natural resources. Gravel that occurs in larger grades is then broken down to usable grain sizes.
Therefore, the goal is to produce grits from gravels or crushed rocks from quarries, which are similar or similar to the properties of the sand. Here is an overview of the criteria in decreasing priority:
- The grain surface should be as rough as possible, so that a viable matrix can be formed by the grains.
- Within the overall grain distribution, the coarse grain fraction should be larger. This increases the load-bearing capacity of the concretes and reduces the need for glue or cement.
- Ideally, the proportion of the grain range 0 - 0.25 mm should be as small as possible.