This rapid-hardening mortar composition includes: a rapid-hardening admixture; cement; and a fine aggregate, wherein the cement is contained in an amount of 100 parts by mass to 2,000 parts by mass with respect to 100 parts by mass of the rapid-hardening admixture, the rapid-hardening admixture is a composition that contains: calcium aluminate; inorganic sulfate in an amount of 50 parts by mass to 200 parts by mass with respect to 100 parts by mass of the calcium aluminate; and a setting modifier in an amount of 0.1 parts by mass to 10 parts by mass with respect to 100 parts by mass of the calcium aluminate, and an average particle diameter of the calcium aluminate is in a range of 8 μm to 100 μm, and an average particle diameter of the setting modifier is in a range of 5 μm or less.

A strength enhancing admixture for cementitious and/or pozzolanic compositions including, based on the total dry weight of the admixture, calcium silicate hydrate in an amount of from about 0.5 to about 94 weight percent, and: i) at least one alkanolamine in an amount of from about 0.5 to about 55 weight percent; ii) at least one inorganic accelerator in an amount of from about 0.5 to about 85 weight percent; and iii) at least one carbohydrate in an amount of from about 0.5 to about 50 weight percent; wherein the calcium silicate hydrate includes a product of a reaction of a water-soluble calcium compound with a water-soluble silicate compound in presence of a water-soluble dispersant; and wherein the at least one inorganic accelerator includes any inorganic accelerator(s) other than calcium silicate hydrate.

A strength enhancing admixture for cementitious and/or pozzolanic compositions including, based on the total dry weight of the admixture, calcium silicate hydrate in an amount of from about 0.5 to about 94 weight percent, and: i) at least one alkanolamine in an amount of from about 0.5 to about 55 weight percent; ii) at least one inorganic accelerator in an amount of from about 0.5 to about 85 weight percent; and iii) at least one carbohydrate in an amount of from about 0.5 to about 50 weight percent; wherein the calcium silicate hydrate includes a product of a reaction of a water-soluble calcium compound with a water-soluble silicate compound in presence of a water-soluble dispersant; and wherein the at least one inorganic accelerator includes any inorganic accelerator(s) other than calcium silicate hydrate.

A low strength backfill material having a 28 days compressive strength less than approximately 2.0 MPa is provided. The backfill is suitable for use in areas with dense underground utilities due to its high excavatability and good thermal conductivity. The backfill includes a cementitious binder of approximately 1 weight percent to approximately 10 weight percent and fine aggregates in an amount of approximately 40 to approximately 75 weight percent. Filler is provided at 20 microns to approximately 100 microns for high flowability. A density-controlling agent of 0.0001-5 weight percent is used such that the density of a cured backfill material is approximately 1600 kg/m.sup.3 to 2000 kg/m.sup.3. Thermally conductive particles having a size range of approximately 0.01 microns to 500 microns in an amount of approximately 0.1 to 10 weight percent are evenly dispersed throughout the backfill.

A low strength backfill material having a 28 days compressive strength less than approximately 2.0 MPa is provided. The backfill is suitable for use in areas with dense underground utilities due to its high excavatability and good thermal conductivity. The backfill includes a cementitious binder of approximately 1 weight percent to approximately 10 weight percent and fine aggregates in an amount of approximately 40 to approximately 75 weight percent. Filler is provided at 20 microns to approximately 100 microns for high flowability. A density-controlling agent of 0.0001-5 weight percent is used such that the density of a cured backfill material is approximately 1600 kg/m.sup.3 to 2000 kg/m.sup.3. Thermally conductive particles having a size range of approximately 0.01 microns to 500 microns in an amount of approximately 0.1 to 10 weight percent are evenly dispersed throughout the backfill.

A composition including: a first component A, includes: between 68 and 99.9 wt.-% of an aqueous dispersion of at least one polymer, the aqueous dispersion including the polymer with an amount of between 20 and 90 wt.-%; between 0 and 2 wt.-% of a nonionic or ionic dispersing agent; a second component B, includes: between 10 and 30 wt.-% of a nonionic, non-aqueous liquid carrier, between 0 and 20 wt.-% of calcium sulfate, between 10 and 89.9 wt.-% of at least one hydraulic binder, between 0 and 10 wt.-% of a thixotropy agent; wherein both components A and B are prepared and stored separately and mixed directly before application; and with the proviso that the first component A furthermore includes: between 0.1 and 15 wt.-% of a monovalent metal salt, and the second component B furthermore comprises: between 0.1 and 25 wt.-% of a polyamine.

A composition including: a first component A, includes: between 68 and 99.9 wt.-% of an aqueous dispersion of at least one polymer, the aqueous dispersion including the polymer with an amount of between 20 and 90 wt.-%; between 0 and 2 wt.-% of a nonionic or ionic dispersing agent; a second component B, includes: between 10 and 30 wt.-% of a nonionic, non-aqueous liquid carrier, between 0 and 20 wt.-% of calcium sulfate, between 10 and 89.9 wt.-% of at least one hydraulic binder, between 0 and 10 wt.-% of a thixotropy agent; wherein both components A and B are prepared and stored separately and mixed directly before application; and with the proviso that the first component A furthermore includes: between 0.1 and 15 wt.-% of a monovalent metal salt, and the second component B furthermore comprises: between 0.1 and 25 wt.-% of a polyamine.

Provided is a concrete hardener composition. The concrete hardener composition includes a sodium silicate compound, an acid compound and a balance amount of solvent. The sodium silicate compound includes sodium silicate or a mixture of sodium silicate and sodium methylsilicate. The acid compound includes acetic acid, glycolic acid, ethylenediaminetetraacetic acid, tartaric acid, nitric acid, boric acid or a combination thereof. The solvent includes water or a mixed solution of water and polyol. Based on the total weight of the concrete hardener composition, the content of silicon is between 5 wt % and 15 wt %, and the content of the acid compound is between 2 wt % and 30 wt %.

Provided is a concrete hardener composition. The concrete hardener composition includes a sodium silicate compound, an acid compound and a balance amount of solvent. The sodium silicate compound includes sodium silicate or a mixture of sodium silicate and sodium methylsilicate. The acid compound includes acetic acid, glycolic acid, ethylenediaminetetraacetic acid, tartaric acid, nitric acid, boric acid or a combination thereof. The solvent includes water or a mixed solution of water and polyol. Based on the total weight of the concrete hardener composition, the content of silicon is between 5 wt % and 15 wt %, and the content of the acid compound is between 2 wt % and 30 wt %.

A cement composition based on a sulfoaluminate clinker is described, together with its use for agglomerating and inerting sediment/dredging sludge, and the relative inerting method and apparatus.