Admixture for obtaining rapid hardening portland cement and a method by which it is to be performed

摘要

Composition for obtaining rapidly hardening portland cement containing calcium sulfate and calcium oxide wherein active di-aluminium trioxide is included in the form of di-aluminium pentahydroxychloride having the weight ratio of Al2O3:CASO4: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.