A process for the preparation of a hardening accelerator composition by reaction of a water-soluble calcium compound with a water-soluble silicate compound, said reaction being effected in the present of a water-soluble dispersant having at least one polyalkyleneglycol structural unit with a functional group at one end of the polyalkyleneglycol, being able to interact as an anchor group with the surface of cement particles, the hardening accelerator composition and its use.

The invention relates to a process for the preparation of a hardening accelerator composition by reacting a calcium source selected from calcium hydroxide, calcium oxide with a water-soluble silicate compound in the presence of at least one water-soluble polymeric dispersing agent and the hardening accelerator composition obtainable by said process. The composition has a low content of anions and of alkali cations and is therefore broadly applicable in building material mixtures.

The invention relates to a process for the preparation of a hardening accelerator composition by reacting a calcium source selected from calcium hydroxide, calcium oxide with a water-soluble silicate compound in the presence of at least one water-soluble polymeric dispersing agent and the hardening accelerator composition obtainable by said process. The composition has a low content of anions and of alkali cations and is therefore broadly applicable in building material mixtures.

A process for the preparation of a hardening accelerator composition by reaction of a water-soluble calcium compound with a water-soluble silicate compound, said reaction being effected in the presence of a water-soluble dispersant having at least one polyalkyleneglycol structural unit with a functional group at one end of the polyalkyleneglycol, being able to interact as an anchor group with the surface of cement particles, the hardening accelerator composition and its use.

A process for the preparation of a hardening accelerator composition by reaction of a water-soluble calcium compound with a water-soluble silicate compound, said reaction being effected in the presence of a water-soluble dispersant having at least one polyalkyleneglycol structural unit with a functional group at one end of the polyalkyleneglycol, being able to interact as an anchor group with the surface of cement particles, the hardening accelerator composition and its use.

A carbon-sequestering concrete composition and method of production are disclosed. The composition comprises geopolymer binder components, aggregates, and alginate beads formed from brown algae powder through ionic gelation. The alginate beads significantly increase CO2 absorption surface area compared to algae powder, creating a matrix across the concrete surface that enhances long-term sequestration and improves durability. The beads interact synergistically with other concrete components, including geopolymers, fly ash, and ground granulated blast furnace slag, to enhance pozzolanic reactions and create additional sites for carbon dioxide capture. The alginate beads also facilitate the dissolution of minerals like olivine, further enhancing carbon capture. The composition demonstrates superior carbon sequestration capabilities, enabling sustained CO2 absorption throughout its service life. The method includes forming alginate beads, incorporating them into the concrete mixture, and allowing for initial hardening and drying processes that promote carbon dioxide absorption directly from the air.

A process for the preparation of a calcium silicate hydrate seed composition useful as a hardening accelerator for cementitious compositions, comprises making a first jet and a second jet to collide in an interaction zone in the presence of an aqueous solution of at least one polymeric water-soluble dispersant. The first jet comprises an aqueous solution of a calcium compound, and the second jet comprises an aqueous solution of a silicate compound. Calcium silicate hydrate seeds precipitate and a primary calcium silicate hydrate seed composition is obtained. The primary calcium silicate hydrate seed composition is subjected to a shearing treatment, preferably a continuous shearing treatment. Unlike the traditional approaches for synthesizing CSH particles, the new process is readily scalable and the obtained calcium silicate hydrate seed composition is more stable against sedimentation, viscosity-increase or gelation.

A method of paving a road including mixing soil beneath a location onto which the road will be paved with water, a coarse aggregate crushing waste (CACW) and cement in the form of a powder to form prepared soil and paving over the prepared soil to form a paved road. Furthermore, the prepared soil includes 5 to 20 wt. % of the CACW, and 0.1 to 5 wt. % of the cement, based on the total weight of the soil. Moreover, the prepared soil has a maximum dry density of at least 2.2 grams per cubic centimeter (g/cm.sup.3) and an unconfined compression strength of at least 1100 kilopascals (kPa).