Standard Test Average Test Average ASTM C 97 Absorption (3) 0.26 % Bulk Specific Gravity (3) 2 662 ASTM C 99 Modulus of Rupture Day (3) 2 000 psi ASTM C 170 Compressive Strength Day (5) 20 200 psi ASTM C 241 Abrasion Resistance Day (3) 33.9 Ha ASTM C 880 Flexural Strength Day (5) 1 600 psi