Abstract: This invention relates to a method for obtaining materials and products based on urea-formaldehyde resin. Thus, the invention is a method of obtaining composite materials and products, particularly for construction and building purposes, based on urea-formaldehyde resins. It relates particularly to cast materials and products. As the active filler and curing agent for the urea-formaldehyde resin there is used phosphogypsum, which is a by-product of phosphoric acid production and which can be used either moist or dried. Moist phosphogypsum usually contains 40 weight percent of water and is added in up to 40 to 90 weight percent of the overall mixture. The dried phosphogypsum contains only water of crystallization since its "loose" water has been extracted. It is added in quantities of from 30 to 50 weight percent of the overall mixture. This method does not require special temperatures and pressures, i.e., it can be used at atmospheric pressure and at room temperature.

Abstract: Method for accelerating the hardening and increasing the strength of Portd cement by mixing Portland cement with water and with a mixture containing dialuminum pentahydroxychloride, calcium sulfate and calcium oxide in weight ratios of 1:3.5 to 4.3:1.3 to 1.8, respectively, and up to 2 parts by weight of an alkali metal nitrite at temperatures up to 90.degree. C. and thereafter hardening the mixture at temperatures up to 100.degree. C. The mixing can be carried out either by wet mixing or dry grinding the ingredients.

Abstract: Composition for obtaining rapidly hardening portland cement containing caum sulfate and calcium oxide wherein active di-aluminium trioxide is included in the form of di-aluminium pentahydroxychloride having the weight ratio of Al.sub.2 O.sub.3 :CASO.sub.4 :CaO equal to 1:3.5 to 4.3:1.3 to 1.8.A method by which the composition is to be utilized, wherein 4 to 8 parts by weight of the composition are mixed with water, and initially introducing the dialuminium pentahydroxychloride. After its dissolution there are added, in succession, the calcium sulfate and the calcium oxide which are stirred and mixed with 100 parts by weight of pure clinker portland cement having a strength not less than 350. With the mixture thus obtained there are mixed cement pastes, cementsand mortars and concretes.

Abstract: A method for accelerating the hardening and increasing the strength of cets, including cement pastes, cement-sand mortars and concretes, which comprises mixing the cements with water plus an admixture at a temperature up to 60.degree. C., and thereafter allowing the mixture to harden at a temperature up to 100.degree. C. The admixture used comprises bialuminium pentahydroxychloride, gypsum, lime and alkali or alkaline earth nitrite.The method is applicable to different kinds of cement, such as rapid hardening cement, slag-cement, pozzolana-cement and belite-cement.

Abstract: A method for the production of an expanding cement which includes the steps n which so-called "Portland cement" is dry-mixed with an expanding additive which comprises 6 to 30% of the total weight of the cement. The expanding additive contains 2 to 8% dialuminium pentahydroxychloride, 4% to 15% gypsum, and optionally, a small amount up to about 7% lime. All percentages are by weight.The dialuminium pentahydroxychloride (Al.sub.2 (OH).sub.5 Cl 2.5 H.sub.2 O) is a source of aluminium ions, which are necessary to form an increased (expanded) quantity of ettringite. It has high solubility, forming a solution having a concentration above 50%, and has a high content of active dialuminium trioxide (approximately 46%), a low content of chlorine and is not hygroscopic. The lime component is not critical and its addition depends on the desirability for greater expansion (without lime) or lesser expansion and higher strength (with lime).