【Paper】
Waste Molten Slag Evaluation through Diffusion Tests Designed for Various Utilization Conditions
Hirofumi Sakanakura*, Satoshi Mizutani**, Tomohiro Tasaki***, Akiko Kida***, Masahiro Osako*** and Shin-ichi Sakai***
* Akita National College of Technology
** Kyoto University
*** National Institute for Environmental Studies
† Correspondence should be addressed to Hirofumi Sakanakura:
Akita National College of Technology
（1-1 Iijimabunkyou-cho, Akita-shi, 011-8511 Japan）


Abstract
In order to promote the use of waste molten slag as a construction material, the long-term environmental impact of slag must be appropriately evaluated. Slag is used in a variety of ways including as a roadbed material, as a concrete aggregate, etc. An evaluation method is required to reflect the different conditions of utilization. As for monolithic materials, diffusion tests have been used as a tool for estimating long-term environmental impact. In this paper, an application method for the diffusion test has been examined considering those cases where slag has been used directly as a roadbed material and as an aggregate in a mortar.
The main results of the tests were: 1）An improved analysis method using a release flux slope was proposed; 2）The specific surface area of a slag particle was calculated by determining the working sphericity; 3）The size of slag particles for the execution of the diffusion test could be as small as one to two millimeters. Results showed that the release mechanism for slag was a diffusion-controlled type; and 4）The potential environmental impact of slag in a mortar was not significant.


Key words: waste molten slag, diffusion test, effective diffusion coefficient, release flux, internal diffusion