Compressive strength study of fiber reinforced cement stabilized fly ash, stone dust and aggregate mixture as structural layer of pavement.

Scarcity of good quality granular base and sub base materials propels the researchers and road authorities across the globe to explore the use of alternative materials or industrial waste like fly ash (FA). Moreover, the use of industrial waste, like fly ash, would reduce the requirement of huge quantity of crushed stone aggregates and thereby save energy and environment. Many researches have carried out research on virgin and stabilised fly ash for use as upper structural layer of pavement. Research shows that the strength of stabilised fly ash do not meet the requirement of sub base or base due to presence of high volume of fine particles. Hence, stone dust (SD) and aggregates (AG) has been mixed with fly ash to enhance the gradation of fly ash prior to cement stabilisation. In order to enhance the strength and brittle behaviour of stabilized mix, randomly oriented polypropylene fibre (FI) has been used for reinforcement. Therefore, an extensive experimental programme was carried out to assess the suitability of cement stabilized fly ash and fly ash-stone dust-aggregate (FA-SA) mixture with or without fibres for use as base/sub base in terms of unconfined compressive strength (UCS). Cement dosage was varied from 4% to 8% in 2% intervals and fibre percentage was varied as 0.25%, 0.35%, 0.5% and 0.75%. This study proposes a mixture of 60FA-40SA with 8% cement for use as a stabilised base as the 7-day UCS of the mixture satisfies the strength requirement of stabilised base. The results of inclusion of fibre resulted in ductile behaviour of stabilised fly ash. The fibre and parent material matrix was found to play an important role in strength alteration of the mixture due to addition of fibre. An optimum fibre dosage of 0.25% was observed in case of stabilised fly ash and fly ash-stone dust-aggregate mixture. [ABSTRACT FROM AUTHOR]