The invention is concerned with a hydraulic composition comprising in relative parts by mass with respect to first Portland cement: - 100 parts of a first Portland cement the particles of which have a D50 comprised between 10 and 25 µm, preferably between 10 and 16 µm, even more preferably between 11 and 15 µm; - from 25 to 76 parts of a second Portland cement the particles of which have a D50 comprised between 0.5 and 6 µm, preferentially between 0.5 and 5 µm; - from 85 to 200 parts of sand; - water; - the water content being such that the hydraulic composition comprises from 170 to 250 kg of water per cubic metre of hydraulic composition; - the volume distribution of particle size of the first Portland cement and of the second Portland cement being further such that the ratio D50 of the first Portland cement / D50 of the second Portland cement is greater than 2.