Investigation on bituminous mixes with blended modifiers

The modification of binder is ofter required due to its inferior quality de rived from indigenous crude and also due to diverse climatic conditions in India. Two modifiers namely, crumb rubber (CR) and ethyl vinyl acetate (EVA) and their blends were used to modify 80/100 grade bitumen. Both the modifiers were found to improve the various properties of bitumen like low temperature ductility, elastic recovery, water susceptibility, temperature susceptibility, viscosity and Marshall stability. CR when added to bitumen, increased the fatigue strength of the mix 1.7 times. EVA did not show much improvement in fatigue strength, but when CR and EVA were used together, the fatigue strength increased 1.9 to 2.2 times. The economic analysis indicated that the use of modified binders in road construction will be economical in the long term.