Study on Characteristics of Functional Overlaying Sand Using Waste Roof-tile

Abstract

It is a big subject to secure the sand capping material when executing the overlaying sand method for the countermeasure of eutrophication at stagnated and enclosed water. Functional Overlaying Sand (FOS) granulated with cement and Fine Demolished Concrete (FDC) was clarified not only to be safety but also to restrict the dissolution of phosphate ion, higher restriction effect than natural sand. In this study, another additional material, waste roof-tile, is studied for the replacement material of FDC, comparing the physical and chemical characteristic between them. Moreover, granulating the FOS replacing with waste roof-tile (FOSWR), and evaluate the various performance as the sand capping material. Density, pH, dissolution and removal ability of toxic matters, and restriction ability of phosphate and sulfate ions dissolved from sedimentation mud are evaluated for each material. As a result, waste roof-tile has ability to remove some toxic matters such as Pb, Cd,, Cr. It was clarified that utilization of waste roof-tile for FOS components led the decrement of ability on phosphate ion removal comparing with FOS. However, the use of waste roof-tile can decrease the density, restrict the raise of pH and dissolution of toxic matters from FOSWR itself.