Cementitious binder and composition for self-leveling cementitious floor screed, and self-leveling screed thus produced

Cementitious binder for self-leveling floor screed limited withdrawal, to be mixed with aggregates and water, characterized in that it comprises from 70% to 85% by weight of Portland cement, 7% to 18% by weight of sulphoaluminate clinker and from 6% to 14% by weight of calcium sulphate, with a molar ratio calcium sulphate C $ / calcium sulfoaluminate CA $ between 5 and 7. The cementitious composition including this binder enables a screed autonivelante characterized in that it has a mechanical resistance to compression at 24 hours of at least 1 MPa, withdrawal 7 days, measured at a relative humidity of 50% less than 500 microns / m and a swelling value endogenous measured 7 days less than 1000 microns / m, and a very low recovery edges B.