Abstract: A distinctive feature of the concrete mix according to the present invention resides in that the active filler incorporated therein has a fraction with a particle size of from 0.01 to 0.1 mm; as the acid-alkali-stable aggregate use is made of a material selected from the group consisting of sand and a mixture of sand and rubble at a weight ratio therebetween of from 1:1.07 to 1:1.25. The mixture has the following proportions of the ingredients, percent by weight:______________________________________ binder 9-14 active filler 19-32 aggregate the balance. ______________________________________The process according to the present invention consists in that prior to the moulding the resulting mix is cured in hermetically closed vessels for 7 to 14 days and the heat-treatment of the moulded mix to produce the final articles therefrom is effected under the following conditions: heating to 160.degree.-200.degree. C. for 4 to 9 hours, curing for 3-3.5 hours at this temperature and cooling to 20.degree.-25.degree. C.