A pre-tensioned centrifugal concrete pillar includes a concrete body, a steel cage including a plurality of pre-stressed rebars, a plurality of stirrups; and two plates, the rebars are steel strands, a plurality of conical through holes are provided on the plate, and multiple clips are disposed inside each conical through hole, each clip having a toothed inner surface, the multiple clips are spliced together to form a chock assembly for clamping each steel strand, and a peripheral surface of the chock assembly has a conical surface; a clamping hole is formed in the center of the chock assembly, the steel strand passes through a clamping hole and is clamped tightly. A method for manufacturing a pre-tensioned centrifugal concrete pillar is also included.

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 concrete curing blanket includes an absorbent sheet having a wicking layer, super absorbent materials, and a tissue layer, which are laminated together to form the absorbent sheet. The absorbent sheet is sized for being spread over a curing concrete slab. A vapor barrier is bonded to the tissue layer of the absorbent sheet to inhibit evaporation from the concrete curing blanket, and includes a plurality of perforations.

A manufacturing process of a cement product includes: (a) reacting at least one anhydrous or hydrated cement component with liquid or supercritical CO.sub.2 to form a cement composition; and (b) curing the cement composition to form a cement product.

The method according to the invention for producing a prestressed concrete workpiece is characterized in that the prestress is created by a heat treatment, wherein the concrete and the reinforcement therefor are selected in such a way that, when cooling the concrete workpiece from an elevated temperature, the heat expansion coefficient of the concrete is less than that of the reinforcement, and in that, during cooling, the concrete and the reinforcement adhere sufficiently strongly to one another if, during cooling, the concrete is hydrated at least to such an extent in order to be able to expand the reinforcement on account of the different heat expansion coefficients, and in that the concrete, together with the reinforcement, is brought to the elevated temperature in such a way that and is hydrated during cooling at least to such an extent that it is prestressed by the reinforcement after cooling.

The present disclosure relates to the technical field of solid waste recycling and fabricated buildings, and provides a solid waste large-mixing-amount concrete prefabricated laminated slab and a preparation method thereof. The solid waste large-mixing-amount concrete prefabricated laminated slab provided by the present disclosure comprises a prefabricated layer and a laminated layer. Transverse grooves and longitudinal grooves are formed in the surface of the prefabricated layer. During application, the grooves can be used for erecting pipelines, the contact area of the prefabricated layer and the laminated layer can also be increased, the combined effect of new concrete and old concrete is improved, the integrity of a floor slab is enhanced, and the effect of improving the overall stress capacity of the floor slab is achieved.

Provided herein are systems for carbonation curing and CO.sub.2 mineralization of concrete composites and methods of manufacturing a carbonated concrete composite. A method of manufacturing a carbonated concrete composites includes contacting concrete with CO.sub.2-containing gas streams in the carbonation reactor having a gas stream inlet and an outlet to provide optimal gas flow distribution and gas velocity. The concrete precursor includes a binder, one or more aggregates, and water. A gas stream is received at the carbonation reactor. The gas stream includes carbon dioxide. The concrete precursor is maintained at a suitable temperature in the carbonation reactor to thereby react the concrete precursor with the gas stream to produce carbonate minerals in the carbonated concrete composite.

The present disclosure is generally directed to processes and apparatuses for use in forming one or more flow channels within a prefabricated manhole assembly. More specifically, an exemplary apparatus embodying various aspects of the disclosure may contain a rigid channel form with a closed top portion, a curved bottom portion, a first end, and a second end. The apparatus may also contain a bung(s) removably positioned into an exterior hole through a sidewall of the prefabricated manhole that may receive one end of the channel form, the bung(s) interior end may further have an open-ended U-shaped slot. A sliding wedge may be used to engaged/disengage the flow channel form.

A reinforced concrete member precast yard structure including a precast and production workshop, a concrete mixing station, a curing and storage zone, an intelligent dispatching and control center, and water, electricity, and gas lines is provided. Automatic control equipment of each of the precast and production workshop, the concrete mixing station, and the curing and storage zone is connected to the intelligent dispatching and control center. Concrete in the concrete mixing station is transported to a corresponding production and precast zone through a plurality of concrete loading tracks. Reinforced concrete members produced in the precast and production workshop are transported to the curing and storage zone through transshipment equipment for curing and temporary storage. The precast and production workshop includes a rebar processing zone, a production, curing, and precast zone, and a pallet transshipment, production, and precast zone arranged in parallel with one another.

A method for making a carbonated precast concrete product includes: obtaining a mixture including at least one binder material, an aggregate, and water; molding the mixture into a molded intermediate; demolding the molded intermediate to obtain a demolded intermediate, the demolded intermediate having a first water-to-binder ratio; conditioning the demolded intermediate to provide a conditioned article having a second water-to-binder ratio less than the first water-to-binder ratio of the demolded intermediate; moisturizing at least one surface of the conditioned article with an aqueous medium, thereby causing a weight gain of the conditioned article and providing a moisturized product, a first portion of the moisturized product having a third water-to-binder ratio greater than a fourth water-to-binder ratio of a remainder of the moisturized product; and curing the moisturized product with carbon dioxide to obtain the carbonated precast concrete product.