Continuum percolation thresholds for mixtures of spheres of different sizes

Using Monte-Carlo simulations, we find the continuum percolation threshold of a three-dimensional mixture of spheres of two different sizes. We fix the value of r, the ratio of the volume of the smaller sphere to the volume of the larger sphere, and determine the percolation threshold for various values of x, the ratio of the number of larger objects to the number of total objects. The critical volume fraction increases from phi(c) = 0.28955 +/- 0.00007 for equal-sizcd spheres to a maximum of phi(c)(max) = 0.29731 +/- 0.00007 for x approximate to 0.11, an increase of 2.7%. (C) 2002 Elsevier Science B.V. All rights reserved.