Kadowaki M.,Japan Development and Construction Co. |
Nakajima N.,Japan Development and Construction Co. |
Yokota S.,Japan Development and Construction Co. |
Yamamoto H.,Japan Development and Construction Co. |
Yamano M.,Japan Development and Construction Co.
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2014
The tsunami deposits that were produced during the Great East Japan Earthquake are mixtures of various types of waste. They are classified as a specified item and disposed of as waste. The national guidelines stipulate that the tsunami deposits that meet all the requirements (e.g. requirements for separation and disposal and freedom from toxic materials) and have been identified by prefectural or municipal governments should not be classified as waste. Under the circumstances, tests were conducted concerning the applicability of the rotary crushing and mixing method (NETIS KT-090048-V) that had been adopted for soil improvement for the purpose of expanding the use of the method for separating and disposing of tsunami deposits and modifying the separated deposits into recycled materials for use in public works. Separating tsunami deposits that are in the form of soil mass using solely vibrating sieves is extremely difficult. It was found that deposits could be separated much better by crushing and grinding soil masses using rotary crushing and mixing machines. It was also became clear that making an effective use of concrete produced as disaster waste or crushing and mixing tsunami deposits using quicklime as an additive was highly effective for separating and disposing of deposits. As a result of adding concrete waste or quicklime for separating and mixing deposits, separation and mixing were improved and the trafficability was enhanced owing to the improvement of separated soils. The soils modified using the rotary crushing and mixing method were considered applicable as recycled fill materials. Thus, using the rotary crushing and mixing method enables the separation of tsunami deposits, which are generally disposed of as waste unless modified, into waste and deposits and the use of separated deposits as recycled materials. Removing the deposits attached to waste as much as possible is expected to contribute to the reduction of the quantity of waste that needs to be treated at disposal sites. Disaster waste will be disposed of at high speed in the affected areas. We propose the rotary crushing and mixing method as a useful method that can meet diverse requirements. © 2014 The Society of Materials Science.