PURPOSE: To obtain a roadbed material effectively utilizing mostly discarded coal ash and slag by forming a mixture of coal ash, cement and slag such as steel-making slag and spontaneously curing the formed product.
CONSTITUTION: A mixture of water and raw materials composed of 40-60wt.% of coal ash burnt at a low temperature (≤850°C), ≥15wt.% of cement and the remaining part of powder of steel-making slag, molten iron pretreatment slag and/or water-granulated blast furnace slag is formed with a press-forming machine and spontaneously cured to obtain the objective formed material having a prescribed form. In the case of using coal ash burnt at a high temperature (≥850°C), the above raw material is composed of 40-60wt.% of coal ash, 4-7wt.% (in terms of CaO) of lime powder or gypsum powder, ≥15wt.% of cement and the remaining part of powder of steel-making slag, molten iron pretreatment stag and/or water-granulated blast furnace slag.
HORII MASARU
HASHIMOTO MINORU
