The invention provides methods and compositions for treating wash water from concrete production with carbon dioxide. The treated wash water can be reused as mix water in fresh batches of concrete.

A drum drive system includes a controller configured to control a prime mover, a variable displacement pump, and a variable displacement motor of the vehicle to provide a target drum speed for a drum of the vehicle. To provide the target drum speed, the controller having programmed instructions to (i) initially operate the variable displacement motor at a maximum motor displacement and operate the variable displacement pump at a pump displacement that provides the target drum speed without needing to actively manipulate a prime mover speed of the prime mover, (ii) increase the pump displacement and decrease a motor displacement without needing to actively manipulate the prime mover speed while still providing the target drum speed, and (iii) increase the prime mover speed if necessary to maintain the target drum speed in response to the pump displacement reaching a maximum pump displacement and the motor displacement reaching a minimum motor displacement.

A shotcrete nozzle assembly comprising: a tubular body including a body sidewall defining a central passageway extending along a central longitudinal passageway axis, and water dispensing bores extending through the body sidewall and including: first and second sets of water dispensing bores positioned such that outlet openings thereof defined in an inner face of the body sidewall are disposed in a respective one of longitudinally spaced-apart first and second transversal planes extending perpendicularly to the passageway axis, at least some of the water dispensing bores being oriented such that the central bore axes thereof extend in a non-radial direction relative to the passageway axis, and such that an orthogonal projection of the central bore axes of the first and second sets of water dispensing bores onto one of the transversal planes forms first and second projected central bore axes which intersect each other at a first non-zero angle.

Mixing systems and methods that include a mixer housing and one or more disk assemblies for mixing and processing materials is disclosed. The disks rotate to mix an additive into the material and to carry agglomerated solids toward a discharge of the mixing system. The disks may have a plurality of fingers or lobes which extend from a central portion of the disks.

A constrictor valve can be associated with a conduit in fluid communication with a mixer to control a flow of cementitious slurry discharged from the mixer through the conduit. The constrictor valve can include a constrictor housing, a webbing constriction assembly, and a drive mechanism. The webbing constriction assembly includes a pair of rotatable members rotatably mounted to the constrictor housing and a plurality of webbing straps connected to the rotatable members and wrapped around the conduit. The drive mechanism includes a drive shaft and a gear assembly configured to rotate the rotatable members in opposing winding directions in response to the drive shaft rotating in a tighten direction to wrap the webbing straps tighter around the conduit to compress it and to rotate in opposing unwinding directions in response to the drive shaft rotating in a loosen direction to loosen the grip of the webbing straps on the conduit.

The present invention provides a producing method of concrete capable of appropriately controlling setting and hardening, and having excellent flexibility of production and handling of concrete. The producing method of concrete includes a cement paste mixing step and a concrete mixing step. In the cement paste mixing step, cement, mixing water and retarder are mixed together to obtain cement paste. According to this, setting and hardening of the cement paste are suppressed, and it is possible to store the cement paste for predetermined time. In the concrete mixing step, aggregate is input into the cement paste, and they are mixed together to obtain concrete. By the mixing operation, a setting-delaying effect is canceled.

Colloidal mixing of cementitious material into a liquid such as water to form a grout slurry for pumping to a location for use includes a mixing tank and a colloidal mixing mill which grinds and pumps the mixed material with the material being repeatedly circulated between the mill and the tank. The colloidal mixing mill includes a housing defining a generally cylindrical chamber containing a rotor shaped to define a clearance of the order of 3 mm between the front and rear wall of the housing and the rotor with holes from a dished front face of the rotor to the rear face to carry the mixed materials to the clearance where a shearing action takes place to shear the particles in the mixed materials prior to exit through the outlet.

An improved drum for a lorry-based concrete mixer is described. The drum comprises a drum body having an edge defining an aperture for permitting access to a drum body interior and a manhole cover hingedly attached to the drum body, the manhole cover being movable from an aperture dosed position, in which the aperture is sealed, to an aperture open position, in which the aperture is open and the drum body interior may be accessed. The drum further comprises at least one locking mechanism adapted to lock the manhole cover In the aperture dosed position, an edge of the manhole cover being trapped between the/each locking mechanism and the drum edge in the aperture closed position. The at least one locking mechanism is adapted to support the manhole cover in a retained position between the aperture dosed position and the aperture open position.

A cabling system and accessory for attachment to the rubber boot surrounding the metal chute area of either a front or rear loader concrete truck for improving and enhancing the function and purpose of the rubber boot and chute area of a ready mix concrete truck, and for increasing the safety, health, and environmental aspects of cleaning thereof, wherein physical exertion and risk of injury to the truck operator is minimized, wherein the quantity of water utilized for cleaning is reduced, wherein the overall cleanliness of the truck is improved, and wherein the functional life span of the boot, chute, mechanical parts, and the truck itself is increased.

A cabling system and accessory for attachment to the rubber boot surrounding the metal chute area of either a front or rear loader concrete truck for improving and enhancing the function and purpose of the rubber boot and chute area of a ready mix concrete truck, and for increasing the safety, health, and environmental aspects of cleaning thereof, wherein physical exertion and risk of injury to the truck operator is minimized, wherein the quantity of water utilized for cleaning is reduced, wherein the overall cleanliness of the truck is improved, and wherein the functional life span of the boot, chute, mechanical parts, and the truck itself is increased.