Influence of burnt ash additives on stabilisation of soft clay soils

Abstract This paper discusses the results of the improvement in compaction, consolidation and shear strength parameters of soft clay when stabilised with burnt ash additives those derived from a furnace in the thermal power industry. Different combinations of soil–ash mixtures are prepared with the addition of ash in the range of 10–40 % by weight of soil to arrive the optimum dosage of ash which one exhibiting maximum UCS. Herein the ash additives including both the fly ash and bottom ashes are used as the stabilising agents. The influence of curing time is also studied on UCS strength property of various soil combinations. Results indicate that the stabilisation of soft clay with ash additives is improving the UCS up to certain level of ash amounts, and further the strength is decreased. The strength of soil–fly ash mixture is much more than the strength of soil–bottom ash mixture, and it was found to be 4.86 times the strength of soft clay. The mixing of ash additives in the soil could lead to speed up the time required to consolidate the clay soil and become more permeable.