Patent ID: 8470088

Claim:
A castable composition producing, when cast with a water content of 2.8 wt % or less, a cast product having a porosity equal to or less than 10 volume percent when measured after exposure to 230 degrees F., wherein the composition has a property selected from the group consisting of: (a) the composition contains at least four grain fractions, of which three adjacent grain fractions are separated by gaps having a particle diameter ratio of the largest particle diameter of the gap range to the smallest particle diameter of the gap range of at least the square root of two, and the three adjacent grain fractions have remaining weight percentages that are, with respect to the respective immediately larger particle size fractions and in order of decreasing particle size, smaller, larger and smaller in value; (b) the composition contains at least four grain fractions, of which three adjacent grain fractions are separated by gaps having a particle diameter ratio of the largest particle diameter of the gap range to the smallest particle diameter of the gap range of at least the square root of two, and the three adjacent grain fractions have remaining weight percentages that are, with respect to the respective immediately larger particle size fractions and in order of decreasing particle size, larger, smaller, and larger in value; and (c) the composition contains at least four grain fractions separated by gaps having a particle diameter ratio of the largest particle diameter of the gap range to the smallest particle diameter of the gap range of at least the square root of two, and the remaining weight percentages are at least 40% in each of the at least four grain fractions.