The artificial aggregates (AAs) were manufactured from the parent batch powders consisting of bottom ash produced at thermal power plant and dredged soil by direct sintering method at 1050~1200°C for 10min. The bloating phenomenon could be occurred in AAs due to a gas-capturing caused by large quantity of liquid formed at the specimen surface. Increasing the amount of the Na2O added enlarged the area of black core and size of the macro pores in the aggregates. The inside black core got out of the surface of the specimens sintered at 1200°C showing the rugged and cracked surface, but this morphology did not cause a water absorption to increase.

The artificial lightweight aggregates (ALAs) were manufactured using dredged soil produced at thermal power plant and waste catalyst slag by direct sintering method at 1050~1250°C for 10min. The ALAs of 100% dredged soil showed the black core phenomenon even at the low sintering temperature as 1050°C and become lightened by bloating pores in black core area with sintering temperature. On the other hand, the aggregates with 100% waste catalyst slag did not showed black coring and bloating phenomenon and had the low forming ability and many cracks inside. Adding the dredged soil to the waste catalyst slag decrease the specific gravity by promoting the black coring and bloating inside. The water absorption(%) of ALAs decreased with sintering temperature. The ALAs fabricated in this study showed the specific gravity of 0.8~2.0 and water absorption of 2~16% so it could be applied to various fields such as the lightweight concrete or the field of the porous carriers for purification of a contaminated soil or water.

The artificial aggregates were fabricated by two sintering methods to recycle the dredged soil produced at thermal power plant in Korea. The first one is the direct sintering method in which the green body is to put into the furnace of preheated at the desired temperature, and the other is the temperature-rising sintering method in which the green body is to put into the furnace of 800~900 oC, heated with a heating rate of 15 °C/min to the final sintering temperature. The aggregate manufactured by the direct sintering method showed the highest bloating behavior than that of the temperature-rising method. To provide the holding time in the input step was to decrease the bloating behavior in the temperature-rising sintering method. The water absorption for the all aggregates was decreased with sintering temperature, and the values of aggregates made by direct sintering was higher than that of the temperature-rising sintering method. The aggregate made of dredged soil by using various sintering methods had the specific gravity of 0.9~1.8 and water absorption of 3~14 %, and so could be applicable for many fields such as civil, environmental, and agricultural engineering fields.