Inference of acidification mechanism inside the road embankment using the Neogene Sandstone containing Pyrite

Some of the Neogene sedimentary rocks containing Pyrite holds the risk of heavy metal elution due to acidification. Thus, when reusing the rocks as embankment material, countermeasures for heavy metal leakage and acidification are required. These countermeasures include “roller compaction” and “soil cover using cohesive soil”. Therefore, the authors estimated that it is possible to take rational countermeasures such as reusing the rocks to the road embankment without these countermeasures if it can verify the acidification mechanism inside the embankment. This study conducted the outside exposure test for almost 4 months using 3 types of full-scale size embankment constructed of the Neogene sandstone containing pyrite that rapidly acidified. Thereby, it was inferred that the seepage water supplying the oxygen and heats affects the internal environment and proceeding acidification inside the embankment.