1. Low-grade concrete (C10–C30)
Properties: High slump (120–180 mm), good workability, soft aggregates, high fluidity.
Wear characteristics:
Low abrasion; materials act as lubricant.
Wear increases slightly with extended mixing time.
Uniform, mild wear on blades and liners.
Service life: Normal; replacement cycle ~2,500–3,000 working hours.
2. Medium-grade concrete (C40–C50)
Properties: Lower water-cement ratio, harder aggregates, higher friction, medium slump (80–120 mm).
Wear characteristics:
Wear increases linearly with mixing time.
Accelerated uniform wear on blade edges and liner bottoms.
Localized wear at mixing arm roots under prolonged operation.
Service life: Reduced by 15–20% vs. low-grade concrete; ~2,000–2,500 hours.
3. High-grade concrete (C60 and above)
Properties: Very low water-cement ratio, dry/hard consistency, high-hardness crushed stone (granite/basalt), sharp edges, low slump (≤60 mm).
Wear characteristics:
Severe abrasive wear dominates; cutting and squeezing wear from hard aggregates.
Wear doubles with slight over-mixing (≥60 s).
Rapid, localized wear at blade tips and arm roots; risk of aggregate crushing.
Service life: Reduced by 30–50% vs. low-grade concrete; ~1,200–1,800 hours.
4. Key influencing factors & mitigation
Mixing time (standard: 30–60 s)
Under-mixing: Non-uniform mix → localized aggregate concentration → (localized wear).
Over-mixing:
Low-grade: Minor extra wear.
Medium-grade: Linear wear increase.
High-grade: Dramatic wear acceleration (2×–3×).
Aggregate & workability
Hard aggregates (granite/basalt): Shorten liner/blade life by 20–30%.
Dry/hard concrete (slump ≤50 mm): Increase impact/friction; reduce cycle by 20–30%.
High-fluidity concrete (slump ≥160 mm): Mild wear; extend cycle by 10–15%.