Table of Contents
This information is vital for civil engineers during site inspections, tests, etc. Site knowledge about 12 topics is given in this post.
Knowledge
1.1 Grades of Concrete
| Grades of concrete | Mix Ratio ( C:S:A) |
| M5 | 1:4:8 |
| M10 | 1:3:6 |
| M15 | 1:2:4 |
| M20 | 1:1.5:3 |
| M25 | 1:1:2 |
1.2. Standard Conversion Factors
| 1 meter | 3.28 feet |
| 1 meter | 39.37 inches |
| 1 meter | 100 cm |
| 1 meter | 1000 mm |
| 1 foot | 12 inches |
| 1 inch | 2.54 cm |
| 1 inch | 8 soot |
1.3. Unit Weight of Civil Engineering materials
| Material | Unit weight (kg/m³) |
| Cement | 1440 kg/m³ |
| P.C.C | 2400 kg/m³ |
| R.C.C | 2500 kg/m³ |
| Cement plaster | 2000 kg/m³ |
| Bitumen | 1340 kg/m³ |
| Glass | 2500 kg/m³ |
| Water | 1000 kg/m³ |
1.4. Clear Cover For Different R.C.C members
| Member | Clear cover |
| Foundation | 75 mm |
| Raft Foundation | Top = 50 mm Bottom = 75 mm Sides = 75 mm |
| Strap Beam | 50 mm |
| Beam | 25 mm |
| Column | 40 mm |
| Flat Slab | 20 mm |
| Slab | 15 mm |
1.5. Basic Area Units
| 1 Kanal = 20 Marla |
| 1 Marla = 272.24 square feet |
| 1 Kanal = 502 meter square |
| 1 Marla = 25.10 square meter |
| 1 Hectare = 10000 square meter |
| 1 Acre = 43560 square feet |
1.6. Unit weight of Steel Per Meter
| Diameter of Steel | Weight kg/m ( d²/162) |
| 6 mm | 0.222 |
| 8 mm | 0.395 |
| 10 mm | 0.616 |
| 12 mm | 0.888 |
| 16 mm | 1.578 |
| 20 mm | 2.466 |
| 25 mm | 3.853 |
1.7. Curing of Types Of Cement
| 1. For O.P.C ( Ordinary Portland Cement) | 7 days |
| 2. Super Sulphate Cement | 10 days |
| 3. Cement with minerals and admixtures | 14 days |
1.8. Grades of Steel
| 1. Mild Steel | Fe 250 | Tensile strength 250 N/mm² |
| 2. HYSD ( High Yield Strength Deformed Bars) | Fe 415 Fe 500 | 415 N/mm² 500 N/mm² |
1.9. Setting Time of Cement
| Types of Cement | Initial setting time | Final setting time |
| OPC (Ordinary Portland Cement) | 30 minutes | 600 minutes |
| Portland Blast Furnace Cement | 30 minutes | 600 minutes |
| RHC ( Rapid Hardening Cement) | 30 minutes | 600 minutes |
| LHC (Low Heat Cement) | 60 minutes | 600 minutes |
1.10. Grades of OPC ( Ordinary Portland Cement)
| 33 Grade | 33 N/mm² |
| 43 Grade | 43 N/mm² |
| 53 Grade | 53 N/mm² |
1.11. Crushing Strength Of Brick
| Type of Brick | Crushing Strength |
| 1. First class brick | 10.5 N/mm² |
| 2. 2nd class brick | 7 N/mm² |
| 3. 3rd class brick | 3.5 N/mm² |
1.12 Water Absorption Of Brick
| 1st Class Brick | not less than 15% by weight |
| 2nd Class Brick | not less than 20% by dry weight |
| 3rd Class Brick | 22% by dry weight |
Note: Water Absorption for Building stones not ≥ 5% by weight
1.13. Knowledge About Brick -(India only)
| 1. Standard size of bricks = 19 cm × 9 cm × 9 cm |
| 2. Modular size of Bricks = 20 cm × 20 cm × 20 cm |
| 3. No. of bricks in 1-meter cube Brick masonry = 500 Bricks |
| Read Also: Difference Between Flexible Pavement & Rigid Pavement |
