Host: Japan Society of Material Cycles and Waste Management
Coal fly ash (FA) was tested as soil water holding agent because FA recycles and water holding agent for dry soil reclamation are strongly requested. In this study, the effect of coal fly ash amendment on water holding capacity of natural soils was investigated. Apatite synthesis treatment, organic treatment using chtosan, sodium alginate, and guanidine hydrochloride, and their combined treatment were tested for FA modification. Water holding capacities of pure soils (decomposed granite soil (DGS) or akatama soil (AS)) and FA-mixed soil were measured by drying experiments at natural temperature and 40 degree C. Apatite-synthesis and organic treatment was effective on increasing WHC of FA at 40 degree C. On the other hand, combined treatment decreased WHC of treated FA. The same effects were found for WHC of FA-mixed soils. Soil mixed with apatite-synthesized and organic-treated FA had higher WHC at 40 degree C than those of pure soils and raw FA-amended soils, FA modified by combined treatment decreased soil WHC. The effect of FA amendment on soil WHC is very complicated. It shows the dependency on FA treatment method, drying temperature, and soil type.
