A.S. Adedimila  , A.O. Olutaiwo  , 
    Review of Advances in Grading Systems for Asphalt Binders in Hot-mix Asphalt Pavements,
    Journal of Engineering and Applied Sciences,
    Volume 3,Issue 4,
    2008,
    Pages 322-331,
    ISSN 1816-949x,
    jeasci.2008.322.331,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2008.322.331)
    Abstract: This study is intended to review the traditional methods of grading of asphalt binders and the advances that have been made in this area. A critical look is taken at the adequacy or otherwise of the traditional penetration method of grading still being employed in the country. Some of the basic characteristics of asphalt cement in use in the country were quantified using penetration grading system through experimental tests in a laboratory. The research carried out in this study shows that the conventional method of grading asphalt cement as is still being practiced in Nigeria is archaic. It is recommended that current methods based on viscosity and Superpave tests should be employed since many advantages accrue from these more advanced methods of grading.
    Keywords: Asphalt binder;HMA;grading;superpave;asphalt binder modifiers