Advantages of Robo sand or m sand are :
- No or near zero impurities.
- Controlled gradation of particles. Hence, no wastage.
- No over sized particles or shingles, stones and pebbles.
- Generally dry, so doesn’t fiddle with the concrete mix proportions.
- Higher concrete compressive strength achieved.
- Zero silt content.
- Cheaper than marine sand or river sand.
- Easier to spot adulteration judging by oversized or undersized particles and color (greyer the purer, browner the impurer)
- Extraction of sand from river and sea beds is an environmental hazard.
There aren’t many disadvantages of Robo sand unless the manufacturer is not much into quality control. They may be :
- There is a possibility of hard soil or hard clay strata crushed along with the desired rock.
- Often murrum boulder is also present. It gets crushed into finer particles and disturbs the mix design, workability and setting times of concrete.