Overview
Status of removal of surplus fillingThe freezing pile head treatment method uses the expansion pressure generated when water freezes to create horizontally controlled cracks in the pile head, and the excess concrete can be easily removed by a heavy lifting machine.
It is low-noise, low-vibration, and dust-free, and can be used for pile head treatment in a shorter period of time than conventional methods.
It is low-noise, low-vibration, and dust-free, and can be used for pile head treatment in a shorter period of time than conventional methods.
Advantages
It has the following advantages over other methods of removal, such as hand breaker and static crushing.- i. It can be constructed with low-noise,low-vibration,and dust-free.
- ii. The crack initiation position can be controlled.
- iii. High construction efficiency.
- iv. Less risk of damaging the pile rebar because there is less need to break and scrape it off for correction after the excess concrete is removed.
| Freezing Pile Head Treatment Method | Static crushing method | Hand breaker (Seriya (using stone splitter)) method | |
|---|---|---|---|
| Noise/Vibration Dust control | ○ | △ | × |
| Construction efficiency | 6 units/group/day | 3 units/group/day | 1 unit/group/day |
| Pressure | Approx. 200MPa | Approx. 60MPa | - |
Features
- When water freezes into ice, the volume expands by approximately 9%.
This method is based on this principle, in which refrigerated pipes are installed horizontally in a rebar cage of a cast-in-place pile in advance, and the water in these freezing pipes is frozen using liquid nitrogen, causing the freezing pipes to expand and creating horizontal cracks in excess concrete. - When the refrigeration pipes are installed at the time of rebar cage assembly, and the refrigeration pipes are cooled with liquid nitrogen after the completion of root cutting, cracks will occur about 10 minutes after the start of cooling.
After that, remove excess concrete with a crane.
Achievements
- 508 piles at 14 sites (as of Jan 2022)
- On-site piles can be used for both construction method and building purposes.