RMC Basics
1. Density of RMC = 2400 kg/m³ (same as RCC).
2. 1 Transit Mixer capacity = 6–7 m³ of RMC.
3. 1 m³ RMC (M20) = ~320 kg cement, 160 l water, 660 kg sand, 1250 kg aggregate.
4. 1 m³ RMC requires 8 bags of cement (M20).
5. 1 m³ RMC (M25) = ~11 bags cement.
6. Bulk RMC is generally ordered in multiples of 1 m³.
7. RMC batching tolerance: ±2% for cement & water, ±3% for aggregates.
8. 1 RMC plant = 30–120 m³/hr production capacity.
9. RMC wastage on site = 1–2% (during pumping & placing).
10. RMC delivery speed = 30–40 min per trip (within 10 km radius).
Concrete Pumping & Placement
11. Pump output capacity = 30–50 m³/hr for stationary pump.
12. Boom pump output = 80–120 m³/hr.
13. Max pumping height of boom = 35–50 m.
14. Average placement rate (manual labour) = 5–6 m³/hr.
15. Needle vibrator compacts 5–6 m³/hr effectively.
16. Plate vibrator covers 15–20 m²/hr.
17. Recommended slump for RMC (pumpable) = 100–125 mm.
18. For mass concreting (foundations), slump = 75–100 mm.
19. Vibrator should penetrate full depth + 100 mm overlap into previous layer.
20. Max layer thickness for compaction = 300 mm.
Curing & Strength
21. Minimum curing for RMC = 7 days (normal cement), 14 days (blended cement).
22. Strength gain of RMC: 7 days = 70%, 14 days = 90%, 28 days = 100%.
23. Initial setting time of RMC = 30 minutes (min).
24. Final setting time of RMC = 10 hours (max).
25. Cube size for RMC testing = 150 × 150 × 150 mm.
26. Number of cubes = 1 set (3 cubes) per 30 m³ or per shift.
27. RMC acceptance = Average of 3 cubes ≥ target strength (fck + 1.65 × SD).
28. Safety factor in mix design = 1.65 × standard deviation (IS 10262).
29. Compaction factor for RMC (workable mix) = 0.85–0.92.
30. Water-cement ratio in RMC (M20–M25) = 0.45–0.55 (max 0.50 for durability).
