Abstract: Loose, substantially sphere-shaped particles of a foamed plastic material, e.g., polystyrene, are blended with a binder consisting of a solution of 75-85% by weight of coal-tar pitch having a ring and ball softening point of 50.degree.-65.degree. C. in 15-25% by weight of phenol-free coal-tar oil having a distillation range of 150.degree.-275.degree. C. and 20-35% by volume of an epoxy resin. The resulting sticky mass is then blended with dry cement to produce a mass of loose particles of foamed plastic material coated with a film of dry cement. A second portion of dry cement and sufficient water to harden the cement are added and the moist mixture is pressed into the desired shape.