Calm and Clean Demolitious Method of Concrete Structures by Using Expansive Demolitious Agents

1991 Fiscal Year Final Research Report Summary

• Project/Area Number: 01460176
• Research Category: Grant-in-Aid for General Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: コンクリート工学・土木材料・施工
• Research Institution: Kyushu Institute of Technology
• Principal Investigator: WATANABE Akira Kyushu Institute of Technology, Professor, 工学部, 教授 (90039066)
• Co-Investigator(Kenkyū-buntansha): TAKAYAMA Shunich Kyushu Kyoritsu University, Associate Professor, 工学部, 助教授 (50039137) ; IDEMITSU Takashi Kyushu Institute of Technology, Associate Professor, 工学部, 助教授 (30039078)
• Project Period (FY): 1989 – 1991
• Keywords: Demolitious Engineering / Expansive Demolitious Agents / Pollution on Construction

Research Abstract

At the first year, many types of demolitious methods which were practically used for oncrete structure and its characteristics of these methods were investigated. Through the comparison with real workes of these methods and reasonable demolitious design, the situation of demolitious method by using expansive agents and its effective design method was considered.
If there was no restriction about working circumstances, the impact method was most effective. Under the condition of antinoise, the many crushing methods using oil pressure were found to be comparatively effective for demolitious works of the members in concrete structure. However, for large sizable and massive concrete foundations, upper both methods were unsuitable as demolitious method.
Therefore, the next year, we tried to apply the expansive agent for the demolition of massive concrete on the condition of antinoise, non-shocked and non-scattering. For the application of expansive demolitious agent, the characteristics of arising presure under various temperature, mixed rate of agent and water and degree of restriction by reinforcement were made clear experimentally.
In the last year, the practical applicability was discussed through the experiments to control a crack direction and to demolish a reinforced concrete members. From these tests, the following were resulted.
(1) The control of the crack was possible by making a notch with few milli meters depth inside of the bore hole.
(2) Cover of reinforced concrete was easily peeled off by pouring the expansive demolitious agent alternately in the ditches made by joint cutter (cutter ditches).
(3) The effective demolition of the part of reinforced concrete member was possible by the application of the pair with two bored holes and cutter ditches.