Utilization Of Coal Ash From Fluidized-Bed Combustion Boilers As Road Base Material

A process has been developed to utilize the large quantities of ash discharged from coal-fired fluidized-bed combustion boilers as road base material. Since the 1980s, the fluidized-bed boiler has been the subject of much study because it can burn fuels such as anthracite that cannot be burnt in pulverized coal-fired boilers and other conventional boilers, and because it eliminates the need for a flue gas desulfurizing facility. However, the disposal of fluidized-bed combustion ash is increasingly difficult, and therefore costlier, because of tighter legislation on waste management. Meanwhile, the excavation of road base material is also subject to stricter regulations due to fears of environmental impact. This has caused a shortage of material for road construction in some areas. It would be useful if ash from fluidized-bed combustion could be processed into road base material, There would be an enormous demand for such a product. A simple and low-cost road base material production process has, therefore, been developed where the ash is mixed with water, molded, steamed, aged and crushed into small pieces. This paper discusses the conditions required to yield optimum products and the paving test results.