The main differences between river sand and stone dust (also called quarry dust or manufactured sand) are in their origin, composition, particle size, and applications. Here’s a detailed comparison:
1. Origin & Production
– River Sand:
– Naturally obtained from riverbeds through dredging.
– Formed by the erosion of rocks over time.
– Stone Dust:
– A byproduct of crushing stones in quarries (from granite, basalt, limestone, etc.).
– Artificially manufactured in crushers.
2. Composition
– River Sand:
– Contains rounded, smooth particles due to natural water erosion.
– Mostly silica (SiO₂) with minor impurities like clay and silt.
– Stone Dust:
– Angular, rough particles with sharp edges (due to mechanical crushing).
– Contains fine rock powder and mineral residues from parent rock.
3. Particle Size & Gradation
– River Sand:
– Well-graded with uniform particle sizes (0.075mm to 4.75mm).
– Fewer fines (less than 75 microns).
– Stone Dust:
– Irregular gradation with more fine p
icles (<150 microns).
– Higher percentage of dust (can be up to 20%).
4. Properties
| Property | River Sand | Stone Dust |
|——————-|————|————|
| Shape | Rounded & smooth | Angular & rough |
| Workability | Better (easier to mix) | Less workable (harsh mix) |
| Water Demand | Lower | Higher (absorbs more water) |
| Strength | Good for general use | Higher compressive strength in concrete |
| Silt Content | Low (~3%) | High (~15-20%) unless washed |
5. Uses
– River Sand:
– Ideal for plastering, masonry, and concrete where smooth finish is needed.
– Used in landscaping and filtration systems.
– Stone Dust:
– Used as a substitute for sand in concrete blocks, pavements, and filling joints.
– Good for base layers in road construction due to compaction properties.
6. Environmental Impact
– River Sand:
– Excessive mining causes riverbank erosion and ecological