Chapter 2 Flashcards
(37 cards)
Types of cement
- Ordinary Portland Cement
- Rapid Hardening Portland Cement
- Low-heat Portland Cement
Constituent materials of concrete
- Cement
- Aggregates
- Water
Production of concrete
- Batching
- Mixing
- Transporting
- Placing
- Compacting
- Curing
Testing of concrete
- Slump test
- Compacting Factor test
- Compressive Strength test
Testing apparatus for slump test
- Standard slump cone
- Base plate
- Temping rod
Placement of reinforcements
(B, T, NF, FF)
B: Bottom face
T: Top face
NF: Near face
FF: Far face
20H1303-150T
20, H, 13, 03, 150, T
20 - No. required
H - Type of bar
13 - Diameter
03 - Bar mark
150 - Spacing
T - Location
Types of foundation
- Strip foundation
- RC Pad foundation
- Raft foundation
- Pile foundation
End bearing
Shafts of the piles act as columns that carry the loads through the overlaying weak subsoil to a stronger and firmer lower strata
Skin friction
Held up by frictional resistance between the surface of the pile and adjoining ground
Replacement pile
Soil is removed by boring and the hole is filled with wet concrete
Displacement pile
Piles are driven down into the ground at spaced intervals
Advantages of replacement piles
- Lesser noise and vibration
- No risk of ground heave
- Drilling tools can break obstructions that cannot be penetrated by any form of displacement pile
Disadvantages of replacement piles
- Cast-in-situ underground, more difficult to construct and control properly
- Concrete cannot be inspected after installation
- Inflow of ground water may cause damage to the wet and unset concrete and may lead to reduced pile bearing capacity
Advantages of displacement piles
- Preformed before they are driven into the ground, quality can be controlled
- Can be driven into a predetermined set
- Any construction operations are unaffected by ground water level
Disadvantages of displacement piles
- Driving process generates unacceptable noise, dust and vibration
- Piles cannot be inspected after installation
- Piles may be damaged due to hard-driving
Materials used for sheet piles
- Timber
- Reinforced and pre-stressed concrete
Concrete cover for main bars in substructure
Not less than 50mm
Concrete cover for main bars in beams and walls
Not less than 25mm or not less than the diameter of the main bars
Concrete cover for main bars in column
Not less than 25mm
Concrete cover for main bars in slab
Not less than 20mm
Explain superstructure
Every element of the structure situated above the ground
Explain substructure
Every element of the structure below the level of ground
Explain backfills
Materials excavated from the site
