STUDY ON ELUTION REDUCTION OF HEXAVALENT CHROMIUM FROM RECYCLED BASE COURSE MATERIAL USING WASTE SYRUP

In the civil engineering field, the utilization of recycled materials is promoted so as to reduce environmental burden. In particular, the utilization of concrete accessory product generated by the dismantlement of the concrete construct is an urgent issue in the light of both environment conservation and the shortage of repository site. Most concrete accessory products are recycled as the recycled base course material. However, it is at risk of the elution of the trace of hexavalent chromium from the recycled base course material. A major countermeasure to this problem is the reduction treatment to harmless trivalent chromium by reducing substances. There are many different types of the reducing substances. Among them, low cost is required for the reduction material because the recycled base course material is inexpensive. Therefore, in this study, waste sugar syrup is focused on with attention to two points such as reducibility and low cost. The elution test for the hexavalent chromium in cement paste is conducted, and the reducibility of the sugar contained in the waste syrup is verified. As a result of the reduction test using the waste syrup, it becomes clear that the eluted hexavalent chromium concentration decreases below the effluent standard.