Cement-Based Self-Leveling Composition

A fluid floor screed manufactured from a self-leveling composition, which comprises:

• a) a self-leveling composition which has been poured onto a support, said self-leveling composition, comprising:
• Portland cement (CEM I) or composite cement (CEM II or CEM III), sand, water, at least one plasticizer (I) and at least fine mineral aggregates having dimensions not exceeding 200 μm, wherein:
• a) a quantity of fine particles of dimensions not exceeding 100 μm present in the self-leveling composition, from cement and fine mineral aggregates, is at least equal or greater than 500 kg per m3 of said composition;
• b) a water-to-cement ratio (W/C) is equal or greater than 0.6;
• c) the plasticizer (I) is a water-soluble or water-dispersible organic compound containing at least one aminodi (alkylenephosphonic) group and at least one polyoxyalkyl chain, or at least one salt of the compound, the compound having the following formula:
• wherein:
• R is a hydrogen atom or a monovalent hydrocarbon group, containing from 1 to 18 carbon atoms and optionally one or more hetero atoms;
• 50% to 100% of the groups Ri are ethylene, 0 to 50% of the groups Ri are propylene and 0 to 5% of any other groups Ri are the same or different from each other and represent an alkylene selected from the group containing butylene, amylene, octylene or arylene;
• said arylene being selected from the group containing styrene or methylstyrene;
• the groups Ri optionally containing one or more hetero atoms;
• Q is a hydrocarbon group containing from 2 to 18 carbon atoms and optionally one or more hetero atoms;
• A is an alkylidene group containing from 1 to 3 inclusive carbon atoms;
• the groups Rj are the same or different from each other and are selected from the group consisting of
• i) the group A—PO3H2, wherein A is as defined hereinabove,
• ii) and the group
• wherein B is an alkylene group containing from 2 to 8 carbon atoms, and A is as defined above;
• n is an integral number between 20 and 250;
• r is a number of (R—O(Ri—O)n) groups carried by Rj;
• q is a number of (R—O(Ri—O)n) groups carried by Q;
• the sum (r+q) is at most equal to 3;
• and
• “y” is an integral number equal to 1 or 2;
• and wherein fluidity of the self-leveling composition before pouring is such that, when a sample of the composition is poured into a reference cone having a minor diameter of 55 mm, a major diameter at the bottom of 95 mm, a height of 70 mm, and then the filled cone is removed, a circular free spreading is obtained to a diameter of at least 15 cm;
• and
• b) a support.

A hardened floor screed manufactured from a self-leveling composition, which comprises:

• a) a self-leveling composition which has been poured onto a support and hardened, said self-leveling composition, comprising:
• Portland cement (CEM I) or composite cement (CEM II or CEM III), sand, water, at least one plasticizer (I) and at least fine mineral aggregates having dimensions note exceeding 200 μm, wherein:
• a) a quantity of fine particles of dimensions not exceeding 100 μm present in the said self-leveling composition, brought by cement and fine mineral aggregates, is at least equal or greater than 500 kg per m3 of said composition;
• b) a water-to-cement ratio (W/C) is equal or greater than 0.6;
• c) the plasticizer (I) is a water-soluble or water-dispersible organic compound containing at least one aminodi (alkylenephosphonic) group and at least one polyoxyalkyl chain, or at least one salt of the said compound, the compound having the following formula:
• wherein:
• R is a hydrogen atom or a monovalent hydrocarbon group, containing from 1 to 18 carbon atoms and optionally one or more hetero atoms;
• 50% to 100% of the groups Ri are ethylene, 0 to 50% of the groups Ri are propylene and 0 to 5% of any other groups Ri are the same or different from each other and represent an alkylene selected from the group containing butylene, amylene, octylene or arylene;
• said arylene being selected from the group containing styrene or methylstyrene;
• the groups Ri optionally containing one or more hetero atoms;
• Q is a hydrocarbon group containing from 2 to 18 carbon atoms and optionally one or more hetero atoms;
• A is an alkylidene group containing from 1 to 3 inclusive carbon atoms;
• the groups Rj are the same or different from each other and are selected from the group consisting of
• i) the group A—PO3H2, wherein A is as defined hereinabove,
• ii) and the group
• wherein B is an alkylene group containing from 2 to 8 carbon atoms, and A is as defined above, hereinabove,
• n is an integral number between 20 and 250;
• r is a number of (R—O(Ri—O)n) groups carried by Rj;
• q is a number of (R—O(Ri—O)n) groups carried by Q;
• the sum (r+q) is at most equal to 3;
• and
• y is an integral number equal to 1 or 2;
• and wherein the fluidity of the self-leveling composition before pouring is such that, when a sample of this composition is poured into a reference cone having a minor diameter of 55 mm, a major diameter at the bottom of 95 mm, a height of 70 mm, and then the filled cone is removed, a circular free spreading is obtained to a diameter of at least 15 cm.