BT 5 - Cast In Place

Cast-In-Place

• Also referred to as "poured-in-place"

• Concreting technique which is undertaken 'in situ or at the site utilizing temporary formworks.

• This is the preferred choice for foundations, slabs, columns, beams, walls, roofs, etc.

trimmed or cut

Ordered and placed as needed and does not need to be______ after installation.

Wash water

______ is frequently recycled using devices that collect wash water and return it to the drum where it can be returned to the plant for recycling.

Extra concrete

_______ is often returned to the plant for recycling or to manufacture jersey barriers or retaining wall blocks, or washed to recycle aggregates.

Set retarding admixtures

______ can be added to return concrete to allow for storage and future use.

Thermal mass

_______ improves energy performance when appropriately insulated.

3 inches thick

Creates an air barrier when _______ or more.

light or natural colored

Using_______ materials reduces heat island effect.

honeycombs and entrapped air.

Consolidation compacts fresh concrete to mold it within the forms. It eliminates __________ and _______.

Vibration

______ is the most widely used method for consolidating concrete.

Advantages for Cast in place

• Most commonly used

• Level of Strength

• Versatile as it is formed and built on site.

• High degree of insulation, specifically for basement walls.

• Provides thermal insulation

• Sound-blocking ability.

• Cost savings for smaller projects.

Disadvantages for Cast in place

• Labor intensive

• Length of time for curing

• Removing formworks & formwork supports/ scaffolds

• Consistency of concrete may vary

• Not cost-effective building technology for bigger projects like multi-storey edifices, repetitive sprawling structures

Installation

• Placement of formwork

• Provisions of reinforcement bars

• Pouring concrete

Concrete Cylinder Test

Done to determine the compressive strength of concrete

7, 14, and 28 days

Concrete Cylinder Test — Conducted every _________

7 Days

How many days? ~65-75% of 28-day strength

14 Days

How many days?  ~85-90%

28 Days

How many days? Design stretch achieved

56 Days

How many days? Continued strength

2,500-3,000 psi

Residential slabs. How many PSI?

3,000-4,000 psi

Sidewalks and driveways. How many PSI?

4,000-5,000 psi

Commercial slabs. How many PSI?

5,000-8,000 psi

Structural columns and beams. How many PSI?

10,000 psi and above

High-performance concrete. How many PSI?

Slump test

• Done to determine the workability of concrete

• Acceptable slump range: 6-8 inches

1. Isolation joints or expansion joints

2. Construction Joints

3. Control joints

Types of Slab Joints

Cementitious Material

10-15% - Ready Mix Concrete (RMC)

60-75% - Ready Mix Concrete (RMC)

Water

15-20% - Ready Mix Concrete (RMC)

IS 9103, ASTM 494

Chemical admixtures are also used

less strength

Cast-in-situ concrete has _______ as compared to precast concrete

Re-shoring

Used to replace the formwork and continue to support the concrete while construction loads are applied to it