Japan's Fujitsu Limited (a major electronics manufacturer) and Shimizu Corporation (a major construction company) have succeeded in eliminating the need to transport concrete debris from a Fujitsu construction site in Kamata, Tokyo, by using Shimizu's technology to recycle concrete from demolished buildings on-site. This approach saves 11,000 trips by 10-tonne dump trucks, thus lowering carbon dioxide emissions by 580 tonnes.

Some consideration of construction traffic was necessary, as the construction site is adjacent to housing near a major train station, and is surrounded by narrow roads and routes used by school students. Trying to minimize the use of heavy-duty trucks, Fujitsu decided to work together with Shimizu, which was known for having developed recycling technologies at construction sites. Working together, the two companies were able to achieve complete on-site recycling of concrete by installing a processing plant on location.

A six-floor and an eleven-floor building previously stood at this site. After 30 years of use, they are now being rebuilt into a seven-floor and a three-floor building, which will be completed in October 2003. The demolition of the old buildings will generate 23,000 tonnes each of regular and lightweight concrete debris. The regular concrete debris can be separated into aggregate and cement powder without compromising quality by treating them with advanced heating and grinding processes. The aggregate is reused for the new buildings, while the cement powder as well as powdered lightweight concrete is utilized to strengthen the foundation of the new buildings.

The concrete debris, totaling 46,000 tonnes, can thereby be recycled on site for use in the construction of the new buildings, thus eliminating the need to carry waste concrete away from the site. While the aggregate recycling lowers the material cost of the new buildings, the overall cost is still slightly higher using this approach, due to costs associated with installation of the equipment. Nevertheless, the on-site recycling is considered a positive development if one counts the lower impact on local residents and overall benefits to society, and the companies expect this method to come into more widespread use.



Posted: 2003/01/04 08:04:30 AM
Japanese version

TAG Global warming , Manufacturing industry , Material reduction , Non-manufacturing industry , Technology , Transportation