A porous inorganic product which is excellent in acoustic absorptivity and filtration efficiency and is high in strength is produced by bringing suitably sized organic foam particles, which have elasticity and can be shrunk greatly by heating or can be dissolved in a solvent, into contact with one another under pressure so as to deform each thereof, filling the gaps present between the organic foam particles with an inorganic binder such as cement, hardening the inorganic binder to form a hardened material, and shrinking the organic foam particles contained in the hardened material.
A method of making a pavement by installing a heat insulating course of lightweight concrete of low thermal conductivity includes crushing polystyrene foam, especially polystyrene foam waste, or by foaming particulate polystyrene to form particulate polystyrene foam which is then subjected to a rapid heating process. The heat-treated particles of polystyrene foam are blended with a cement paste comprised of cement and water to form a mixture which is then allowed to harden.
A lightened cement slurry for cementation of a well includes cement, at least one mineral filler, water, and resin particles obtained by polymerization from vinyl aromatic, alkyl acrylate or acrylic monomers, wherein the polymerization includes crosslinking.
The present invention relates to laminated acoustical tile products which are derived from compositions that are suitable to provide rigid, water-resistant phosphate ceramic materials. The tile products comprise a decorative facing comprising a substantially open-celled character and a backing layer of higher density, the backing layer and edges of the tile comprising substantially closed-celled facing characteristics. The backing layer provides structural strength and dimensional stability to the tile product whereas the decorative, open-celled facing provides access by sound waves to the interior regions of the board. The resulting composite material provides good acoustical performance, yet is capable of withstanding conventional handling stresses.
Present invention provides foamed gypsum moulded articles excellent in sound absorbing property and production thereof. The foamed gypsum moulded article has many foam-cells, and the foam-cells are interconnected through fine passages. The fine passages are formed using as a decomposition catalyst of hydrogen peroxide for expansion a cobalt compound produced by pretreating a water soluble cobalt salt with hydrogen peroxide in the presence of alkali. The foamed gypsum moulded article is preferably applicable to an interial wall, ceiling panel, and the like.
The porous sound-absorbing material manufactured is light and has excellent heat resistance to be applicable to the exhaust nozzle etc. of a jet engine, can effectively absorb noise as that from a jet engine, over a wide range of frequencies, is free from variations in porosity, and provides stable performance characteristics. An essential feature thereof is the formation of a skeleton of the material, with aggregates containing voids. Thus, a porous sound-absorbing material having a skeleton of aggregates with first voids is described, wherein diameters of first voids of the aggregates are 50 .mu.m to 100 .mu.m, approximately, and diameters of second voids between the aggregates are 100 .mu.m to 600 .mu.m.
