Abstract
In March, 2000, the circular notice of Ministry of Construction decided that the elusion test of hexavalent chromium (Cr6+) had to be carried out when cement or cement stabilizer was used or improved soil was reused on particular ground improvements such as the Deep Mixing Ground Improving Method. In November, 2007, the Ministry of Land, Infrastructure, Transport and Tourism instructed that the elusion test of Cr6+ was carried out for the recycled sand from used cement-concrete. Kansai Geotechnology & Environment Research Center was accredited as the certified testing laboratories of the elusion test of Cr6+ under ISO/IEC 17025 by JAB, in 2007.
In this report, the analyses of amount and secular change of elution of Cr6+, kinds and area of construction, etc. are done by the elusion test data of 3 years in the past. Then it becomes clear that 87% of samples achieve the soil environmental quality standards for elution of Cr6+ and the elution of Cr6+ is controlled by addition of the stabilizer coped with Cr6+.
