Application of fly ash to reduce soil dispersivity in embankments

Abstract

Due to rapid development of modern highways and railroad in Serbia, the need for embankment materials has increased. Deposits of natural materials used for this purpose often contain dispersive soils. On the other hand, thermal power plants in Serbia annually generate several million tons of fly ash, which could be used to reduce the dispersion of material embedded in embankments. The paper presents the results of tests conducted for the first time in Serbia to assess the improvement in natural soil dispersivity with fly ash from a thermal power plant. The dispersivity of mixtures of fly ash and natural soil was tested according to ASTM and BS standards. To determine the optimal ash content, 10, 30 or 50% of fly ash was added to the soil samples. The results show that 30-50% of fly ash reduces the dispersivity of natural soil for one to two dispersion classes.