A new concept of mathematical model on the compacted bulk density (solid volume ratio) of aggregate is proposed to investigate the complex nature of packing particles with randon shape and wide range grading. The model expressed as a second order polynomial of the sieve residuals (volume content ratio for each particle size) can be determined mathematically from the constitutive combinations of the models for two particle size mixing, whose coefficients are derived from three basic.parameters representing special characteristics of particles packing. Properties of these three parameters are studied through the derived values from experimental results, and their influences on the behavior of the model (grading of the closest packing etc. ) are discussed in detail.
