• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.63-71
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• 2005

Asphalt binder grading is to specify quality of asphalt binders relating to pavement performance in orderly manner, and provides the necessary information in selecting the appropriate asphalt binder for the hot mix design. For this purpose, United States has developed the PG-grading in 1995 and is implementing in practice. Recently, this American PG-grading system has been accepted as the domestic binder grading specification. However, the Asian (including Japan and China) and the most European countries are still use the traditional penetration and viscosity specification. The goal of this study lies in analysing the American PG-grading for its justification. As the result, the serious errors are found, and thus, to eliminate the errors, the more precise binder grading equation is introduced, Credibility of this study is checked by predicting the literature rut data with the equations mentioned. The prediction result are validating the claimes made in this study.

• International Journal of Highway Engineering
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• v.3 no.2 s.8
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• pp.91-102
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• 2001

On the basis of several experiments peformed, Bahia et al. (1998) concluded that the current Superpave PG-grading system failed to characterize grading specification of fill modified binders. This conclusion motivates us to investigate the correct grating system suited for modified asphalt binders. The main concept of this development is originated from the relationship between rut depth and binder properties at high temperatures. A new grading system for modified asphalt binders suggested here somewhat resembles to the unmodified binder grading one developed by Huh et al. (2000). Thus, this investigation will provide a unified single theoretical equation of high temperature grading that can apply both to modified and unmodified binders, and will check its effectiveness with the laboratory and the field rut data reported by independent studies. Successful results observed may allow to construction of a correct grading system in the near future.