Improving the flexural modulus and thermal stability of pitch by the addition of silica fume

The effects of sand and silica fume on the flexural modulus and thermal stability of pitch were investigated mechanically and thermomechanically. Both modulus and softening temperature were increased by sand addition and further increased by the further addition of silica fume, except that an excessive amount of silica fume caused the modulus to decrease. An effective composition involved 29 vol.% sand and 2 vol.% silica fume.