durability of manufactured sand

The durability of manufactured sand (M-Sand) depends on several factors, including its source rock, production process, and particle characteristics. Compared to natural sand, M-Sand can exhibit comparable or even superior durability if properly processed. Here’s a breakdown of key aspects affecting its durability:

1. Factors Influencing Durability of M-Sand
– Source Rock Quality:
– M-Sand made from hard, durable rocks (e.g., granite, basalt) is more resistant to abrasion and weathering than softer rocks (e.g., limestone).
– Poor-quality parent rock may lead to higher fines or weaker particles.

– Production Process:
– Proper crushing, screening, and washing reduce flaky/elongated particles and excess microfines (<75µm), improving strength and durability.
– Over-crushing can generate excessive fines, reducing durability.

– Particle Shape & Gradation:
– Cubical or rounded particles (achieved via VSI crushers) enhance packing density and reduce voids, improving concrete durability.
– Flaky/angular particles may increase water demand but can be mitigated with admixtures.

– Microfines Content:
– Controlled microfines (<10–15%) can improve workability but excess fines increase water absorption and shrinkage cracks.
– IS 383 (2016) limits microfines to ≤15% for concrete.

2. Durability Performance in Concrete
– Abrasion Resistance: M-Sand’s hard particles often outperform natural sand in abrasion resistance when sourced from strong rocks.
– Freeze-Thaw Resistance: Low porosity and proper gradation enhance resistance to freeze-thaw cycles in cold climates.
– Sulfate & Chemical Attack: Dense, low-permeability M-Sand concrete reduces sulfate/chloride ingress if cementitious materials are optimized.
– Shrinkage & Cracking: Properly graded M-Sand with minimal fines reduces drying shrinkage compared to poorly processed alternatives.

3. Standards & Testing
– IS 383 (2016): Specifies M-Sand gradation, silt content, and strength requirements for concrete/mortar.
– ASTM C33/C144: Provides guidelines for aggregate durability in the U.S.
– Tests for Durability:
– Los Angeles Abrasion Test (resistance to wear).
– Sodium Sulfate Soundness Test (