What Are Aggregates?
Construction aggregates are coarse- to medium-grained materials used in construction, infrastructure and concrete production. They provide strength, stability and durability in a wide range of applications.
NPC Aggregate Production
NPC produces and crushes a wide range of aggregate materials, including sand, gravel, crushed stone, and recycled concrete.
Our aggregates are sourced and processed at four quarries in KwaZulu-Natal:
Concrete Stone
Conversion Factor: 1.4
Used primarily in concrete production and structural applications:
- 28mm: Industrial floors, foundations and thick slabs
- 20mm: Most structural elements including floors, columns and beams
- 14mm: Thin slabs, blocks and self-compacting concrete
- 10mm: Specialist concrete applications
Crusher Sand
Conversion Factor: 1.5
- 10mm: Concrete and precast applications
- 7mm: Concrete applications
- 5mm: Asphalt and sand filtration
Pavement Layer Stone/Gravel
Conversion Factor: 1.7
Designed for road construction and infrastructure:
- G2: Base layer
- G3: Base layer
- G4: Base layer / Sub-base
- G5: Sub-base
- G6: Selected sub-grade fill material
- G7: Sub-base
- G8: Lower sub-grade fill material
- G9: Lower sub-grade fill material
Ballast
- 63mm: Railway lines – heavy axle
- 53mm: Drainage layer / Railway lines – normal axle
Specialised Materials
- Dump rock (unselected): Fill layers
- Rock fill (up to 500mm): Embankments and drainage
- Shotrock (100mm–500mm): Pioneer layer / coarse fill
- Gabion (up to 250mm unselected): Retaining walls, barriers and erosion control
- Handstone: General structural and protection applications
- First crush (up to 200mm): Normal fill
Quality & Compliance
NPC aggregate products are tested to ensure compliance with relevant SANS and COTO specifications where applicable, supporting consistent performance across construction and infrastructure projects.