Dismantling of Reinforced Concrete Using Steam Pressure Cracking System: Drilling and Crack Propagation

• Published in: Materials Vol. 16; no. 4; p. 1398
• Main Authors: Kamiya, Osamu, Takahashi, Mamoru, Miyano, Yasuyuki, Ito, Shinichi, Murata, Kenji, Kawano, Makoto, Maisawa, Arata, Nanao, Jumpei, Kazumi, Takashi, Nakatsu, Masanobu, Mizuma, Hiroyuki, Miyota, Tatsuya, Nagao, Kota, Iwama, Yuichi
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 07.02.2023; MDPI
• Subjects: Chemical reactions; Concrete; Concrete structures; Control methods; Crack propagation; Curing; Demolition; Dismantling; Drill bits; Drilling; Drilling and boring; Earthquakes; Efficiency; Energy consumption; Explosives; Fracture surfaces; Hammer drills; less vibration; Mechanical properties; Mechanical systems; Methods; non-pollution; Nuclear energy; Nuclear power plants; Nuclear reactors; quick dismantling; Rebar; Reinforced concrete; Reinforcing steels; remote system; Scanners; Software; Steam pressure; steam pressure cracking; Three dimensional analysis; Japan; China; quick dismantling; less vibration; reinforced concrete; non-pollution; remote system; steam pressure cracking
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16041398

This study investigated a new dismantling system for concrete structures using a steam pressure cracking agent. We improved the mechanical systems such that it can drill through reinforcing steel bars. Therefore, the control method of the system and shape of the drill tip were improved. When the drill tip is stuck with chips and stopped, it is automatically pulled out and reinserted to recover the rotation. By changing the tip angle of the drill bit from 75° to 90°, it became possible to cut reinforcing bars, which were difficult to cut previously. In addition, we designed a crawler-type mechanical system and improved it such that it can be moved to the appropriate position and operated at any angle. This study revealed that the energy required for the drilling process accounts for more than 90% of the total dismantling energy. Through experiments using an impact hammer drill and observations of fracture surfaces using a three-dimensional scanner, we analysed the characteristics of reinforced concrete. In addition, the feasibility of the design for dismantling reinforced concrete was confirmed based on the determined energy associated with crack propagation.