Laboratory study on sustainable use of cement-fly ash-polypropylene fiber-stabilized dredged material

The major problem associated with gravity dam was siltation of reservoir which reduced its effective water storage capacity. In order to maintain effective storage capacity of reservoir, dredging of deposits was required and dredged material was disposed of haphazardly causing damage to the sensitive environment. A better alternative could be the possibility of utilization of dredged deposits in construction works involving large quantities of material. The dredged material consisted of very fine sandy silt possessing poor geotechnical characteristics and was required to be stabilized with suitable additives before use as construction material. This laboratory investigation evaluated geotechnical properties of dredged reservoir material stabilized with cement, fly ash and fiber for its probable use as subbase in lightly trafficked roads. Compaction, unconfined compressive strength and tensile strength tests were performed on appropriate combinations of the constituent materials. The results of study revealed significant improvement in unconfined compressive strength and split tensile strength after stabilization with cement and fly ash. The unconfined compressive strength and split tensile strength of cement-fly ash-stabilized dredged reservoir material improved further upon addition of polypropylene fiber. The composite possessed the potential to be utilized as sustainable material in subbase of roads subject to further validation before application in the field. The dredging of sediments improved effective storage capacity of reservoir and increased its sustainable life period. The utilization of fly ash could diminish the environmental and economic concerns arising out of its haphazard disposal.