Abstract: A demolition agent for brittle materials in the form of a powder mixture comprising 100 parts by weight of quicklime, 0.05 to 5 parts by weight of a carbonate and either or both of 0.01 to 5 parts by weight of a hydroxy-carboxylic acid or its salt and 0.1 to 5 parts by weight of a fluidization agent. This demolition agent is used by admixing with water to obtain an aqueous slurry, pouring the slurry into a hole drilled in a brittle material and allowing it to stand to demolish the brittle material by means of expansive pressure from the slurry.

Abstract: A method for sheet forming a remarkably waterproof gypsum hardened body, in which a main component consisting of gypsum dihydrate, slag and calcium hydroxide and additives are added with a part of the main component coated with a hydrophobic diorganopolysiloxane fluid having a kinetic viscosity of 10-10,000 CS at 25.degree. to be sheet formed and cured. The hydrophobic diorganopolysiloxane fluid is uniformly dispersed through the sheet formed gypsum hardened body and its strong water repelling property makes the gypsum hardened body remarkably waterproof to be used suitably as both interior and outdoor construction materials.