Disclosed is a composite gypsum board comprising a set gypsum core disposed between face (e.g., Manila) and back (e.g., Newsline) cover sheets. The set gypsum core is formed from a core slurry comprising stucco, water, and optional additives, such as foaming agent, migrating starch, accelerator, retarder, dispersant, etc. A dense layer formed from a dense layer slurry comprising stucco, water, fiber (e.g., paper fiber), and optionally, strength-enhancing starch, is disposed between the core and the face paper. The dense layer slurry contains a greater concentration of fiber, and optionally, strength-enhancing starch, than the core slurry, but the concentration of one or more other additives (e.g., accelerator, retarder, dispersant, or combinations thereof) is lower or the same in the dense slurry as compared with the core slurry. Also disclosed is a method of making board using one board mixer. In embodiments, paper fiber is added to water to form a suspension. The suspension is introduced, while in a non-laminar state, into the dense slurry. Further disclosed is apparatus, such as an extractor and an additive injection system, which can be a part of a cementitious slurry mixing and dispensing assembly.

A device for adding and mixing an additive into a hydraulically settable mixture includes a tubular cavity for conducting the hydraulically settable mixture through in an intended flow direction, wherein a static flow-influencing element, in which there is an aperture that leads into the cavity and is intended for introducing the additive, projects into the cavity.

A device and a process for the continuous application of a refractory slurry to a surface incorporate a batch reactor (10) for the controlled mixing of the slurry, a product vessel (60) in communication with the batch reactor (10) to contain the mixed slurry, and a variable-rate spraying applicator or nozzle in communication with the product vessel and with an air supply. A controller (100) controls input to, output from, and the operation of, the batch mixer (10), and monitors batch production. The controller (100) monitors the amount of slurry contained in the product vessel (60). If the level of slurry in the product hopper is such that the product hopper cannot accommodate an additional batch of slurry, the controller interrupts batch production and resumes production when the product hopper can accept the contents of the batch reactor (10).

A gunite trailer includes a frame operable to be coupled to a vehicle. A compressor is disposed on the frame, a cement bin is coupled to the frame and operable to deliver cement, a sand bin is coupled to the frame and operable to deliver sand, and a mixing bin is coupled to the frame and operable to receive the sand from the sand bin and the cement from the cement bin. A delivery connection is operable to receive the sand and the cement from the mixing bin. The delivery connection is operable to be coupled with a delivery system. The delivery system is operable to combine the sand and the cement with a fluid at a point of application to form gunite. The delivery system is operable to convey the gunite to a surface.

An additive injection system can be a part of a cementitious slurry mixing and dispensing assembly. The additive injection system can be used to inject an additive into an auxiliary slurry discharge conduit carrying a secondary flow of cementitious slurry produced in the assembly such that the secondary slurry stream is different from a main slurry stream discharged from a main slurry discharge conduit.

A method for reinforcing a structure comprising the following steps: preparation of UHPFRC comprising a cement precursor mix, of water, a fluidizing agent and metal fibers, transporting the UHPFRC by pumping to a suitable spray nozzle, spraying the mix onto a surface of the structure by the addition of a compressed air stream in the spray nozzle.

A shotcrete nozzle assembly comprising: a tubular body operatively connectable to a concrete source, the tubular body including a stream controlling section for controlling a stream of fresh concrete projected from an outlet body end, the stream controlling section including at least one helicoidal conduit defined within the body sidewall, each helicoidal conduit extending helicoidally around a central conduit between an air inlet end operatively connectable to a pressurized air source and an air outlet end located towards the outlet body end, each helicoidal conduit being twisted around the central passageway to guide pressurized air exiting through the air outlet end along an helicoidal path extending away from the outlet body end and around the stream of fresh concrete exiting the outlet body end.

A device that compensates for abrupt variations in fluid flow rate for a pump line is described. One or more aspects pertain to a system to accomplish automated in-situ placement of a concrete wall or embankment, where a fluid concrete is pumped into place, consolidated, and screeded to a finished surface, with remotely controlled or automated equipment.

A system and method for applying a construction material is provided. The system may include a batching and mixing device configured to mix blast furnace slag material, geopolymer material, alkali-based powder, and sand to generate a non-Portland cement-based material, the non-Portland cement-based material including 4% to 45% geopolymer material by weight; greater than 0% to 40% blast furnace slag material by weight, 10% to 45% alkali by weight, 20% to 90% sand by weight, less than 1% sulfate by weight, and/or no more than 5% calcium oxide by weight; a conduit configured to transport the non-Portland cement-based material from the batching and mixing device; and a nozzle configured to receive the non-Portland cement-based material and combine the transported non-Portland cement-based material with liquid to generate a partially liquefied non-Portland cement-based material, wherein the nozzle is further configured to pneumatically apply the partially liquefied non-Portland cement-based material to a surface.

A system for applying a building material, including: a movement device for modifying a site of application in a space; a first component of the building material; a second component of the building material; and a mixer for mixing the first component and the second component, the mixer including a drive and a mixing chamber provided with a stirrer shaft and a conveyor device, the conveyor device being designed as a screw conveyor with windings, and the mixer being adapted to the building material.