Utilization of High Calcium Fly Ash as Filler Materials in Bituminous Concrete Mixes for Flexible Pavement

A bituminous paving mixture is a mixture of coarse aggregate, fine aggregate and bitumen mixed in suitable proportion to result strong and durable mix to withstand traffic load. In this paving mix, normally cement is used as filler material. A study has been carried out in this study to explore the use of high calcium fly ash, a by-product of a coal based thermal power plant in bituminous paving mixes. For comparison, control mixes with cement and has also been considered. Marshall Test has been considered for the purpose of mix design as well as evaluation of paving mixes. It is observed that the mixes with high calcium fly ash as filler exhibit marginally inferior properties compared to control mixes and satisfy desired criteria specified by a much higher margin. Hence, it has been recommended to utilize high calcium fly ash wherever available, not only reducing the cost of execution, but also partly solve the binding properties. The results obtained showed that the high calcium fly ash could improve the properties of bituminous mixes for flexible concrete.