River sand is widely used as construction material all over the world, especially in production of concrete. As the demand for sand continues to increase, sand mining seemed to have popped up as one perfect solution to meet the demand. But, sand mining has been causing huge environmental damage. Extreme instream sand mining is causing degradation of rivers. It is also lowering the stream bottom, which can ultimately lead to bank erosion.
Various government & non govt. organizations and research institutes are striving to identify alternative materials to supplement river sand.
Manufactured sand is popularly known by several names such as crushed sand, rock sand, green sand etc. M-sand is produced by crushing or rock-on-rock or rock-on-metal vertical shaft impactor (VSI). In case of manufactured sand all the processes mentioned can be done at manufacturing plant itself and controls are much better in producing quality M sand. M-sand also be used for making masonry mortar and shall confirm to requirements of IS:2116-1980.
| River sand | M-sand, P-sand and Stone Dust | |
| Marine products | 2-4 % | Nil |
| Oversized material | 6-10% | Nil |
| Clay and silt | 5-20% | Nil |
Plastering Sand is fine grade of sand which is used for plastering and creating renders both internally and externally. Thanks to its fine particles, this Plastering Sand creates a very smooth and even finish to your plastering. It can also be used for pavement jointing to fill cracks of artistic paving.
Stone Dust is a coarser version of sand. Although it was generally a waste product, a by-product of crushing stone. Stone dust is also known as rock dust or quarry dust, and some products just have the brand name. The stone dust is collected using a screen that keeps the larger pieces of crushed stone above the screen while allowing the rock dust to fall through. Once, stone dust was considered waste material as it was simply the by-product of crushing other stones. However, it was realized that this by-product had the potential to be used in several useful ways. The most common use for stone dust is as a base layer or setting bed for laying stone pavers.
| River sand | M-sand 1 | M-sand 2 | |
| Specific gravity | 2.65 | 2.78 | 2.71 |
| Water absorption | 1.9% | 1.66% | 1.59% |
| Compressive strength(N/mm2) | 20.12 | 21.2 | 21.39 |
Above are the results of Compressive strength of river sand compared with 2 specimens of concrete with M-sand of mix design M20. Compressive strength of concrete made with M-sand is marginally higher (6%-9%) when compared to that of river sand.
Currently, the alternatives to sand (like m-Sand, copper slag, recycles construction waste and powdered glass are progressively being used in many EU nations, US and Singapore. The use of such materials needs to be encouraged in our Indian construction too.
Striking a balance between increasing needs of the construction industry and environmental concerns to save river beds amongst excessive sand mining is the need of the hour. The government needs to take stringent steps and come out with a policy for sand mining and encourage the use of alternatives because as long as our national regulations will be lightly enforced, harmful effects will continue to occur.