Effect of fines content and particle diameter ratio on maximum shear modulus of dense binary packing of spherical particles

The present paper investigates the effect of fines content and particle diameter ratio on the maximum shear modulus of dense binary packing of spherical particles. For this purpose, a series of 83 tests on dry samples were conducted by means of the Resonant Column apparatus. The experimental test results on dense mono-size packings showed that the particle diameter (from 2.21 to 6.20 mm) does not significantly affect the maximum shear modulus of mono-size packing. Additional test results on dense binary packings showed that by increasing the fines content at a constant particle diameter ratio, a rise and fall occurs in the maximum shear modulus; the maximum value occurs at threshold fines content. However, when the fines content remained constant, the maximum shear modulus increased as the particle diameter ratio increased. Ultimately, based on the equivalent inter-granular void ratio concept, a new modified expression is suggested to predict the maximum shear modulus of dense binary packings using mono-size packings results.