Solidification Properties of Dredged Materials Stabilized with Waste Plasterboard Powder and Reinforcement Effect Brought by Wrapping the Mixtures in Geotextile

Though the sediments dredged from floors of lakes and ports are beneficial earth materials, the utilization is still stagnant due to continuing restraint of construction investment. On the one hand, plasterboard wastes occurring abundantly with the renovation and demolition works of building are recently bringing the stringency of a residual capacity at controlled type landfill site. In the present study, we have investigated the California bearing ratio (hereinafter referred to as "CBR"), unconfined compressive strength, resilient modulus and constant pressure shear strength after having stabilized the base material which was composed of lake mud, sea sand and waste plasterboard powder with equivalent quantities in dry mass. According to the results obtained from CBR-test and unconfined compression test, the mixing of a waste plasterboard powder reduced apparent water content in base material, and as an effect by this, the hardening progress with the passage of time certainly exceeded a difference of the stabilizer amount added. Successively, having examined the resilient moduli concerning mixtures with a material age of 28days, it was found that these values were equal to or greater than the existing granular base course materials. Secondly, we have examined relation between shearing stress and displacement for specimens (a diameter of 100mm and a height of 50mm) which were made by wrapping the stabilized base material in geotextile and have compared the strength parameter to specimens without covering. As a consequence, it was ascertained that the angle of shear resistance in specimens with geotextile became 10 to 25degrees larger than that in specimens without covering and that meanwhile the cohesion generally tended to become largish in the latter.