Fuente: WIPO "circular economy" The present invention relates to a use of a wet industrial sludge when additivated with deflocculant for the manufacture of a slab obtainable by moulding with cement as a binder, comprising the composition of the sludge, on a dry basis and by weight, at least 65%, preferably at least 80% and more preferably at least 85% silicate rocks, with an average size less than 0.1 mm; and at least 6.5%, preferably at least 9% resin. The concrete slab obtained comprises at least one layer that, by weight, comprises 20% to 40% of wet industrial sludge, aggregate, cement and at least one water-repellent additive.