What is the bottom diameter (mm) of the standard mould used in slump test of the concrete?
Correct Answer: D. 200
📚 Detailed Explanation: Bottom Diameter of Slump Cone
Why D (200 mm) is correct: The slump cone is a frustum of a right circular cone. Per IS 1199, its dimensions are fixed. The bottom (base) diameter = 200 mm provides a stable base while the top opening (100 mm) is the filling end. The larger base sits flat on the non-absorbent surface during filling and compaction.
Complete Slump Cone Dimensions
| Dimension | Value |
|---|---|
| Top diameter | 100 mm (10 cm) |
| Bottom diameter | 200 mm (20 cm) |
| Height | 300 mm (30 cm) |
| Thickness of metal | ≥1.5 mm |
- Memory trick: 10–20–30 (top diameter cm – bottom diameter cm – height cm).
- Each layer is compacted with 25 strokes of the 16 mm diameter, 600 mm long tamping rod.