Abstract:
Concrete articles of improved strength are prepared by impregnating the articles with aqueous solutions of alkali metal or alkaline earth metal polysulfides and heating them at temperatures above 110.degree. C.
Abstract:
This invention discloses improved residential roofing products with durable active protection against algae discoloration. Versatile organometallic salts and chelates for this purpose are incorporated in manufacture of composite concrete tile and asphalt shingle products via integrated process modifications. These chemically stable non-volatile microbiocides, with exceptional effectiveness against both green and blue green algae, are tailored for specific matrix compatibility. By virtue of their composition and surface activity they serve a dual function in process improvement and product performance. The control of microbiocide activity, long term, significantly advances the state-of-the-art protection against algae and the service life of these products.
Abstract:
A method is disclosed for rehabilitating an exposed cut surface of a rock formation after rock cutting has occurred so that the fresh cut surface becomes weathered and natural within several weeks to facilitate restoration back to its original shade as a part of the natural scenery. Weathering occurs by applying a solution containing FeCl.sub.2 or MnSO.sub.4 to the surface of the rocks to be colored. These rocks are limestone, dolostone, phosphorite and concrete. A method for preparing a weathering solution is also disclosed.
Abstract:
Composite inorganic microporous or ultrafiltration membranes are formed by depositing a film of inorganic particles on a porous inorganic substrate. In a second step, the particles comprising the film are bonded or joined together by passing a supersaturated solution of the particle composition through the particle film, thereby to effect crystal growth on the particles, and to find tune the film pore size. The entire process is conducted at low temperatures, generally less than 90.degree. C.