Process for the preparation of cement/mortar/concrete compositions or systems, (for simplicity hereafter “cement” compositions or systems or even “cements”), of a generally known type containing low or medium (standard) “filler(s)”, and/or optionally HP filler(s), as carbonate-based filler(s), namely coarse low or medium calcium carbonate(s), namely coarse marble(s); Product comprising, or consisting of, the pre-blend (A) of coarse, low or medium (or optionally HP) “calcium carbonate-based filler” pre-blended with at least an UF; Aqueous compositions (B) obtained by mixing the above pre-blend (A) of coarse filler(s) with UF(s) with an aqueous system such as mix water, aqueous mix fluid; Product (C) consisting of, or comprising, the pre-blend (A) or the compositions (B), treated or pretreated with at least one superplastifier or aqueous system containing superplastifier(s); Cement and Use of cement.

The invention concerns a polycondensate containing (I) at least a structural unit, which is an aromatic moiety bearing a polyether side chain comprising 9 to 41 alkylene glycol units, (II) at least a structural unit, which is an aromatic moiety bearing at least one phosphoric acid ester group and (III) at least a methylene unit (—CH.sub.2—), the polycondensate having a polycondensation degree of 10 to 75. Also concerned are building material mixtures containing said polycondensates and the use as dispersant for inorganic binders.

The present invention relates to a continuous process for preparing a comb polymer, without organic solvent, by esterification and/or amidification of an acidic homopolymer or copolymer, which consists in performing the esterification and/or amidification of said homopolymer/copolymer by reaction at elevated temperature in the mixing and transportation zone of a tubular reactor, optionally equipped with a water removal system, in the presence of at least one poly(alkylene glycol) in solid or molten form and of an antioxidant, said esterification and/or amidification taking place at a temperature greater than or equal to 170° C.

A mortar composition, in particular for preparing a viscoelastic body or structure, or for for acoustic damping of at least one of a ship, an offshore installation and a building, includes: 1-20 wt % of a hydraulic binder, 30-80 wt % of aggregates, 5-75 wt % of a polymer, and 0.5-40 wt % of a porous filler.

A mortar composition, in particular for preparing a viscoelastic body or structure, or for for acoustic damping of at least one of a ship, an offshore installation and a building, includes: 1-20 wt % of a hydraulic binder, 30-80 wt % of aggregates, 5-75 wt % of a polymer, and 0.5-40 wt % of a porous filler.

Provided is a cement composition that has high fluidity (for example, a 0-drop flow value of 200 mm or more) before curing and exhibits high compressive strength (for example, 320 N/mm.sup.2 or more) after curing. The cement composition includes a cement, a silica fume having a BET specific surface area of from 10 m.sup.2/g to 25 m.sup.2/g, an inorganic powder having a 50% cumulative particle size of from 0.8 μm to 5 μm, a fine aggregate having a maximum particle size of 1.2 mm or less, a water reducing agent, an antifoaming agent, and water. The ratio of the cement is from 55 vol % to 65 vol %, the ratio of the silica fume is from 5 vol % to 25 vol %, and the ratio of the inorganic powder is from 15 vol % to 35 vol % in the total amount of 100 vol % of the cement, the silica fume, and the inorganic powder.

Provided is a cement composition that has high fluidity (for example, a 0-drop flow value of 200 mm or more) before curing and exhibits high compressive strength (for example, 320 N/mm.sup.2 or more) after curing. The cement composition includes a cement, a silica fume having a BET specific surface area of from 10 m.sup.2/g to 25 m.sup.2/g, an inorganic powder having a 50% cumulative particle size of from 0.8 μm to 5 μm, a fine aggregate having a maximum particle size of 1.2 mm or less, a water reducing agent, an antifoaming agent, and water. The ratio of the cement is from 55 vol % to 65 vol %, the ratio of the silica fume is from 5 vol % to 25 vol %, and the ratio of the inorganic powder is from 15 vol % to 35 vol % in the total amount of 100 vol % of the cement, the silica fume, and the inorganic powder.

A method and device for producing lightweight panels with a core of gypsum or of cement and gypsum, with pores for decreasing volumetric weight, and with a covering made of cardboard or of a sheet of glass fibers. The production line does not change except for the addition of a device which forms closed hollow cavities within a suspension in an area where an upper sheet covers the suspension. Air pressure which is fed into the formed cavities is slightly higher than the hydraulic pressure of the suspension, so as to prevent the gaps being filled by the suspension. The layers are less thick, and the type and dimensions of the cavities and the thickness of the walls are varied depending on the desired qualities of the panels.

A method and device for producing lightweight panels with a core of gypsum or of cement and gypsum, with pores for decreasing volumetric weight, and with a covering made of cardboard or of a sheet of glass fibers. The production line does not change except for the addition of a device which forms closed hollow cavities within a suspension in an area where an upper sheet covers the suspension. Air pressure which is fed into the formed cavities is slightly higher than the hydraulic pressure of the suspension, so as to prevent the gaps being filled by the suspension. The layers are less thick, and the type and dimensions of the cavities and the thickness of the walls are varied depending on the desired qualities of the panels.

The present disclosure relates to a liquid agent that mitigates shrinkage of cement, particularly cement used in a hydrocarbon-producing well. The anti-shrinkage agent includes a slow-setting calcium aluminate cement as well as gypsum and may exhibit shelf-life stability, physical stability, or both. The present disclosure further relates to methods of cementing a hydrocarbon-producing well using the anti-shrinkage agent and to cements containing the anti-shrinkage agent.