Abstract: A method for grouting a decommissioned nuclear reactor containing residual water. A first, water-absorbent grout is used to grout the bottom portion of the reactor vessel. The water-absorbent grout is formed of cement and a water-absorbent particulate material, such as expanded perlite, exfoliated vermiculite or granulated bentonite. Excess water is absorbed by the particulate material, so that the residual water is incorporated in the fill material when it sets. A set retarder may be included to extend the time for uptake of residual water by the particulate material. Foam may also be included to reduce density and increase pumpability. The remaining, upper portion of the reactor vessel is grouted using lightweight cellular cement grout, lacking the water-absorbent particulate material, so that total weight of the fill remains low enough that the grouted vessel can be removed using the facility's installed crane system.

Abstract: A method for grouting a decommissioned nuclear reactor containing residual water. A first, water-absorbent grout is used to grout the bottom portion of the reactor vessel. The water-absorbent grout is formed of cement and a water-absorbent particulate material, such as expanded perlite, exfoliated vermiculite or granulated bentonite. Excess water is absorbed by the particulate material, so that the residual water is incorporated in the fill material when it sets. A set retarder may be included to extend the time for uptake of residual water by the particulate material. Foam may also be included to reduce density and increase pumpability. The remaining, upper portion of the reactor vessel is grouted using lightweight cellular cement grout, lacking the water-absorbent particulate material, so that total weight of the fill remains low enough that the grouted vessel can be removed using the facility's installed crane system.

Abstract: A method and composition for grouting a water-flooded cavity. Water and portland cement are combined to form a fluid cement slurry, the slurry being substantially free of sand or other aggregate material, and the slurry is then colloidally mixed so as to achieve an ultra-fine mixing thereof. An anti-washout admixture is mixed with the slurry in a predetermined amount, and a superplasticizing agent is also preferably included, both the anti-washout admixture and the superplasticizer agent being substantially free of defoaming agents. Finished foam is then mixed with the slurry to form a stable foamed cement grout which is injected into the water-flooded cavity. The anti-washout admixture is preferably a modified cellulose ether solution.

Abstract: A method for filling a void using an aggregate material, such as mine tailings, the fill material being pumped from a site which is located remote from the void. A fluid, aerated material is formed by mixing the particulate solid material with finished foam. The aerated material may also include cement or another binder for applications requiring structural strength. The bubble structure which results from incorporating the foam constituent in the fill material renders this much more fluid and pumpable, thereby allowing the use of much higher solids-to-water ratios than would otherwise be possible while still being able to pump the material over significant distances. This reduces the possibly of fluidic collapse of the material in the void, and produces other advantages as well.

Abstract: A method for filling a void using an aggregate material, such as mine tailings, the fill material being pumped from a site which is located remote from the void. A fluid, aerated material is formed by mixing the particulate solid material with finished foam. The aerated material may also include cement or another binder for applications requiring structural strength. The bubble structure which results from incorporating the foam constituent in the fill material renders this much more fluid and pumpable, thereby allowing the use of much higher solids-to-water ratios than would otherwise be possible while still being able to pump the material over significant distances. This reduces the possibly of fluidic collapse of the material in the void, and produces other advantages as well.

Abstract: A method for filling an underground void, such as a mine stope, without danger of causing mud slides therein, with the material being pumped from a site which is located remote from the void. A fluid, cementitious material is formed by mixing hydraulic cement, water, particulate solid material, and foam material. The bubble structure which results from incorporating the foam constituent in the fill material renders this much more fluid and pumpable, thereby allowing the use of much higher solids-to-water ratios than would otherwise be possible while still being able to pump the material over significant distances. This reduces the possibly of fluidic collapse of the material in the void, and produces other advantages as well. In the case of stopes, the particulate solid component is ordinarily provided using the tailings from the mine operation.

Abstract: A method and composition for grouting a water-flooded cavity. Water and portland cement are combined to form a fluid cement slurry, the slurry being substantially free of sand or other aggregate material, and the slurry is then colloidally mixed so as to achieve an ultra-fine mixing thereof. An anti-washout admixture is mixed with the slurry in a predetermined amount, and a superplasticizing agent is also preferably included, both the anti-washout admixture and the superplasticizer agent being substantially free of defoaming agents. Finished foam is then mixed with the slurry to form a stable foamed cement grout which is injected into the water-flooded cavity. The anti-washout admixture is preferably a modified cellulose ether solution.

Abstract: A method and composition for grouting a water-flooded cavity. Water and portland cement are combined to form a fluid cement slurry, the slurry being substantially free of sand or other aggregate material, and the slurry is then colloidally mixed so as to achieve an ultra-fine mixing thereof. An anti-washout admixture is mixed with the slurry in a predetermined amount, and a superplasticizing agent is also preferably included, both the anti-washout admixture and the superplasticizer agent being substantially free of defoaming agents. Finished foam is then mixed with the slurry to form a stable foamed cement grout which is injected into the water-flooded cavity. The anti-washout admixture is preferably a modified cellulose ether solution.

Abstract: A method for forming a radiation-absorbing barrier around a radioactive component by flowing a radiation-absorbing cement grout into a container which encloses the component. The radiation-absorbing cement grout comprises a cement slurry, a finished foam material, a bentonite gel, and a radiation-absorbing metal constituent.

Abstract: A method for forming a radiation-absorbing barrier around a radioactive component by flowing a radiation-absorbing cement grout into a container which encloses the component. The radiation-absorbing cement grout comprises a cement slurry, a finished foam material, a bentonite gel, and a radiation-absorbing metal constituent.

Abstract: A method and apparatus for continuous production of a quick-setting foamed cement grout, in which the individual constituents of the grout are proportionally adjustable. Finished foam and cement slurry are mixed at metered rates to form a foamed cement grout which is pumped to a wye connection proximate a remote injection site. Sodium silicate solution is added at the wye connection at a metered rate, using a second metering pump. The sodium silicate solution mixes with the foamed cement grout to greatly accelerate the setting time thereof, and compressed air may also be added to accelerate the passage of the material through the injection hose and nozzle. The quick-setting material is particularly suited for use with a tunnel boring machine (TBM), to grout the annular cavity between the tunnel bore and the segmented liner which is installed therein.

Abstract: An apparatus for continuous production of finished foam material, in which the proportions of the constituents are monitored and continuously adjustable during operation of the machine. The liquid components are metered by positive-displacement, progressive-cavity, screw-type pumps driven by variable speed motors. Rates of flow are monitored by flow meters, and the relative proportions of the constituents can be closely adjusted by varying the speeds of the pump drive motors and observing the flow meter readouts. The finished foam produced by the apparatus may be used, for example, for the preparation of foamed cement grouts or for fighting fires.

Abstract: An apparatus for high capacity production of high-fluidity, colloidally mixed cement slurry. Water and cement dust are combined at metered rates by a premixing assembly which discharges into a mixing tub. The high-speed, high-shear pump recirculates the material through the tub to produce the colloidally-mixed slurry. The high-fluidity slurry may be provided to a second pump, preferably of the positive-displacement, progressive-cavity, rotor-stator type, for supplying the slurry at a metered rate. Finished foam material may also be provided to the slurry metering pump at the metered rate, so the materials are mixed to form a foamed cement grout in which the weight and quality of the material is precisely adjustable.

Abstract: A pumpable cement grout and method for use thereof for grouting liner pipes. The pumpable cement grout is a mixture of a hydraulic cement, water in an amount sufficient so that the water-to-cement ratio of the grout is from about 0.60 to about 1.00 by weight, and pregenerated aqueous foam in an amount sufficient to adjust the wet density of the grout to a value of from about 48 to about 72 pounds per cubic foot. The pressure at which the grout is injected into the cavity is maintained at or below a predetermined maximum pressure, so as to avoid collapsing the liner pipe.

Abstract: A method and apparatus for filling cavities in underground excavations. Sodium silicate and aqueous foam are mixed with cement slurry to produce a quick-setting foamed cement grout having a meringue-like consistency. The high viscosity of the grout combines with the very fast initial set time to minimize the problem of grout flowing out of the cavity following injection. The method and apparatus are particularly suited to grouting of the annular cavity which is formed between the tail shield of a tunnel boring machine and a segmental tunnel liner which is assembled therein.

Abstract: A slipliner for renovating a semi-elliptical conduit such as a masonry sewer line. The bottom of a semi-rigid cylindrical liner pipe is split longitudinally and a floor panel is mounted across the bottom of the pipe to spread the edges of the cut. This bends the lower side walls of the pipe outwardly so that these correspond to the generally vertical side walls of the conduit, while the upper portion of the pipe remains generally cylindrical so as to correspond to the top wall of the conduit and the floor panel corresponds to the generally horizontal bottom wall of the conduit. The slipliner of the present invention is thus much more closely matched in shape to the semi-elliptical conduit than would be a conventional, cylindrical liner.

Abstract: An apparatus and method for the continuous generation and placement of a foamed cement grout. The assembly is mounted on a fixed or mobile frame. There is a continuous foam generator, and this supplies finished foam to an intake port of a screw-type, positive-displacement pump. Cement slurry is also supplied to the intake portion of the pump, and this is mixed with the foam in the body of the pump and discharged from this through a conduit to the injection site on a continuous basis. The ratios of foam and slurry can be adjusted on a continuous basis to compensate for variations in grout quality which are observed at the injection site. The assembly is also provided with an onboard power generator and a water pump for flushing the grout out of the injection lines.

Abstract: A pumpable cement grout and method for use thereof for grouting annular cavities. The pumpable cement grout is a mixture of a hydraulic cement, water in an amount sufficient so that the water-to-cement ratio of the grout is from about 0.60 to about 1.00 by weight, and pregenerated aqueous foam in an amount sufficient to adjust the wet density of the grout to a value of from about 48 to about 72 pounds per cubic foot. The grout is pumped into an annular cavity formed intermediate a tubular external member and an internal member disposed in the tubular external member, so that the grout fills this cavity by flowing in a generally longitudinal direction therethrough. The tubular external member may be a concrete sewer pipe, and the internal member may be a plastic liner pipe. The pressure at which the grout is injected into the annular cavity is maintained at or below a predetermined maximum pressure, so as to avoid collapsing the plastic liner pipe.

Abstract: A mobile train for mixing foamed cement grout within a tunnel and injecting the grout into the annular cavity between the tunnel bore and liner. Cement slurry is suppled to the train through a conduit from a remote mixing plant, and finished foam is formed by a foam generator on the train and mixed with the cement slurry to form the fooamed cement grout. The train is movable longitudinally through the tunnel so that the liner can be grouted in segments while at the same time avoiding the need to pump the foamed cement grout over excessively long distance. The train is made up of several wheeled cars which are pulled through the tunnel by a tractor.

Abstract: A pumpable cement grout and method for use thereof for grouting of annular cavities. There is a pumpable cement grout having portland cement, water in an amount sufficient so that the water-to-cement ratio of the grout is from about 0.6 to about 0.68 by weight, and pregenerated aqueous foam in an amount sufficient to adjust the wet density of the grout to a value of from about 55 to about 72 pounds per cubic foot. The grout is pumped into an annular cavity formed intermediate a tubular external member having a longitudinal extent and an internal member disposed in the tubular external member, so that the grout fills the cavity by flowing in a generally longitudinal direction through the tubular external member. The tubular external member may be a concrete sewer pipe, and the internal member may be a plastic liner pipe. The pressure at which the grout is injected into the annular cavity may be maintained at or below a predetermined maximum pressure, so as to avoid collapsing the plastic liner pipe.