During cast-in-place pile construction, when concrete is poured underwater, a certain over-pour amount is required to ensure the strength of the pile-head concrete. The over-poured portion at the top of the pile must be chipped away, a process we call pile-head treatment. As the last important procedure in pile foundation engineering, how is pile-head treatment done? Here is an on-site "six-step" demonstration for your reference!

Provisions of the Technical Code for Building Pile Foundations

1. Surveying and setting out

Level surveying is used to mark out the actual pile-top elevation, uniformly identified with red paint.

Construction setting-out

Red paint marking

2. Circumferential cutting with a toothless saw

Use a toothless saw to cut circumferentially around the pile head to a depth of 3-4 cm, then use a pneumatic pick to chip a V-shaped groove from top to bottom along the pile head to peel off the concrete. The main reinforcement must not be damaged during circumferential cutting.

Circumferential cutting

Chipping the V-shaped groove

3. Exposing the pile-head reinforcement

Use a pneumatic pick to peel the main reinforcement from top to bottom along the pile head.

Peeling off concrete with a pneumatic pick

Formed pile-head reinforcement after exposure

4. Cutting off the pile head

After all reinforcement is exposed, drill horizontal breaking holes at 20 cm circumferential spacing at 3 cm above the pile-top elevation using a pneumatic drill. Insert steel chisels into each breaking hole and strike them repeatedly back and forth so that the concrete breaks off along the circumferential breaking holes.

Breaking holes drilled with a pneumatic drill

Repeatedly striking the steel chisel with a sledgehammer

5. Hoisting away the pile head

Drill lifting holes in the already broken pile head, insert steel chisels, and use lifting equipment to hoist out the broken and detached pile head. The lifting equipment should raise and lower vertically and must not sway from side to side, to avoid the pile head tipping over and bending the main reinforcement of the pile foundation into sharp kinks.

Hoisting away the pile head

6. Pile-head cleaning

Pile-head cleaning involves manually chipping away excess concrete and cleaning the top, forming a section that is slightly higher in the center and slightly lower around the edges, ensuring the pile-top surface is flat and dense.

Manual chipping of excess concrete

Finished pile head after cleaning