WHAT ARE THE DIFFERENCES BETWEEN ORDINARY AND PERFORMANCE GRADED BINDERS?

Comparison between Ordinary & Performance Graded Binders

The primary differences between ordinary graded binder and performance graded binder is given in the following table

Ordinary Graded Binders

Performance Graded Binders

Binders are graded either based upon penetration or viscosity Binders are graded based upon pavement temperature, which are close to in service conditions of pavements
Binders are graded based on tests conducted at a particular critical test temperature only Binders are graded based on different ranges of pavement temperatures similar to field conditions
Past experience, empirical and semi-empirical test results are used Purely scientific and performance based studies are considered
Hardening and aging due to storage, mixing, spraying, exposure and oxidation are not considered Hardening and ageing during storage, mixing, spraying, exposure and oxidation is simulated by conducting RTFO and PAV tests
The properties of the binder at minimum pavement temperature are not considered Susceptibility of the binder to lower temperatures is carefully evaluated by conducting BBR and DT tests
The characteristics of flow and workability during mixing of the binder are not considered. Flow, workability and viscosity properties of the binder are determined at higher temperature by using
Visco-elastic properties are not much considered. Visco-elastic properties are determined by using DSR.
There is no concept of aging of bitumen. Accelerated ageing of the binder up to 7 – 10 years is simulated using the PAV test
A suitable binder is selected using values of penetration, viscosity, softening point and based upon location. Final selection of a suitable grade of binder is made after considering the location of the construction site, maximum and minimum design temperatures, design speed of vehicles and number of equivalent standard axle load repetitions.

 

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