Abstract
The author reviewed the significance of numerical formula concerning the constitutions of grading requirements for graded coarse aggregate. Exponent values of Talbot's formula were calculated from the averages of various grading limits specified in both the JSCE and ASTM standards. The exponents that might be a basis for building up the standards' requirements are found counted on being larger than 1/2. It is also able to explain with the equation thus established that the grading requirements shall be more in large sizes and less in small sizes than Talbot's standard gradings modified from his original formula having the exponent of 1/2. Rules are found how to specify the points of sieves that limit the ranges of grading and how to choose the ranges of grading in the standards. Adding new sieves of size considers a new systematic series of the test sieves to improve the relationship between the nominal maximum size and maximum size of aggregate.
