A discharge gate is provided for a gypsum slurry mixer, and includes a lower member having an inlet opening configured for receiving the slurry, and an outlet opening configured for delivering the slurry to a dispensing device. An upper member is attached to the lower member, at least one of the upper and lower members having at least one opening for accommodating insertion of an injection port for introducing the foam to the slurry. A cavity is configured for mixing the foam and slurry, and is defined by inner surfaces of the lower member and the upper member.

A mobile concrete mixing unit has an aggregate bin divided into two compartments by a water tank provided within the aggregate bin. A hydraulic reservoir is provided within the water tank in order to cool the hydraulic fluid within the hydraulic reservoir and warm the water within the water tank. The water tank also helps to keep the aggregate warm and flowable when used in low temperatures. A lower portion of the water tank includes sides that slope inwardly so that aggregate within the bin can drop freely onto a conveyor belt without bridging between the water tank and the sidewalls of the aggregate bin.

A mobile concrete mixing unit has an aggregate bin divided into two compartments by a water tank provided within the aggregate bin. A hydraulic reservoir is provided within the water tank in order to cool the hydraulic fluid within the hydraulic reservoir and warm the water within the water tank. The water tank also helps to keep the aggregate warm and flowable when used in low temperatures. A lower portion of the water tank includes sides that slope inwardly so that aggregate within the bin can drop freely onto a conveyor belt without bridging between the water tank and the sidewalls of the aggregate bin.

Provided herein are methods and compositions for carbonation of recycled concrete aggregates (RCA) to produce carbonated RCA. In addition, uses of the carbonated RCA, such as in building materials, and building materials containing RCA, are included. Carbonation of RCA may be used alone or may be used in combination with other carbonation processes associated with concrete manufacture, such as carbonation of wet concrete mixes and/or carbonation of concrete wash water.

An accelerated carbonatation method including the following steps: a) providing recycled concrete granulates with a grain size smaller than or equal to a value V.sub.1 being between 1 mm and 6 mm, in other words a 0/V.sub.1 sand; b) performing on the 0/V.sub.1 sand a separation step by defining a granulometric cut of a determined value V.sub.2 being between 0.1 mm and 0.2 mm so as to obtain: a 1st fraction whose grain size is less than V.sub.2, and a 2nd fraction whose grain size is between V.sub.2 and V.sub.1; c) subjecting the 2nd fraction to an accelerated carbonatation step in a dynamic carbonator so as to obtain carbonated recycled concrete granulates. Also, a method for valorizing concrete wastes and industrial gaseous discharges implementing the accelerated carbonatation method, in particular the gaseous discharges of a cement plant.

An apparatus for preparing foam for incorporation into cementitious slurry comprises a conduit having an inlet for receiving a gas feed and a surfactant feed, and an outlet for allowing the exit of foam. The conduit houses a porous plug that provides a partial barrier to fluid flow along the conduit, the plug comprising a plurality of particles that are packed in a regular array and that define a three-dimensional network of pores extending therebetween. The apparatus comprises a resilient component located between the plug and the conduit.

A method of preparing a concrete composition for downhole injection includes utilizing a controller to control a process including circulating process water in a process water supply loop for a predetermined period while monitoring and controlling the temperature and flow rate of the process water, circulating aqueous-based air entrainment solution in an aqueous-based air entrainment solution supply loop for the predetermined period and controlling the flow rate of the aqueous-based air entrainment solution and after the predetermined period of time in which the flow of process water and aqueous-based air entrainment solution have stabilized, simultaneously actuating valves to divert and mix the process water, the aqueous-based air entrainment solution and compressed air to produce an air-entrained foam and mixing the foam with a concrete composition to be deployed downhole.

A method of preparing a concrete composition for downhole injection includes utilizing a controller to control a process including circulating process water in a process water supply loop for a predetermined period while monitoring and controlling the temperature and flow rate of the process water, circulating aqueous-based air entrainment solution in an aqueous-based air entrainment solution supply loop for the predetermined period and controlling the flow rate of the aqueous-based air entrainment solution and after the predetermined period of time in which the flow of process water and aqueous-based air entrainment solution have stabilized, simultaneously actuating valves to divert and mix the process water, the aqueous-based air entrainment solution and compressed air to produce an air-entrained foam and mixing the foam with a concrete composition to be deployed downhole.

This disclosure describes volumetric mobile powder mixer (VMPM) systems and methods for VMPM operation and use. The VMPM is providing with a number of storage compartments (or bins) for liquid or solid ingredients including at least one powder storage bin, a powder transport system, a dust handling system, a solid/liquid mixing system, a cellular foam generator, a product delivery system, and a controller capable of monitoring the delivery and mixing of each of the ingredients, as well as the discharge of the final product. The controller determines if the proper mixture is being discharged by the VMPM and, if not, alerts the VMPM operator. In an automated embodiment, the VMPM controller is also configured to independently control the delivery and mixing of each of the ingredients, as well as the delivery of the final product.

The present invention relates to an apparatus for manufacturing fiber-reinforced concrete through shooting after inserting bubbles into normal concrete and a method for manufacturing the same, which: form fiber-mixed concrete in which the bubbles, fiber-mixed materials, and silica fume are mixed in the normal concrete or form the fiber-mixed concrete in which aggregates, water, and the bubbles are put into and mixed with a mixture, in which cement, the fiber-mixed materials, and silica fume are mixed; and then shoots the fiber-reinforced concrete in which excessive air included in the fiber-mixed concrete is reduced by spraying the fiber-mixed concrete with the high-pressure air when the fiber-mixed concrete is discharged, and of which a slump, drastically increased due to the large amount of bubbles, is reduced to a range of the slump of the normal concrete, thereby improving the production capacity of the fiber-reinforced concrete and shortening operating time.