A foam of very small, microscopic bubbles of surfactant, each bubble containing a small quantity of water, is mixed with a water/cement mixture having a water to cement ratio of less than 0.33. The small bubbles have a ball bearing effect on the smaller cement and sand particles, increasing plasticity or flowability and thus reducing the water requirements of the mixture. The foamed cement mixture is laid to form a desired concrete structure, and the bubbles disintegrate or transform to leave voids of similar size uniformly dispersed throughout the concrete structure.
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a Continuation-In-Part of application Ser. No. 08/877,539 filed Jun. 17, 1997, abandoned which was a Continuation-In-Part of application Ser. No. 08/782,409 filed Jan. 14, 1997, now U.S. Pat. No. 5,900,191.
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.
A method is provided for incorporating a foaming agent into mixtures of particulates and then forming a foam within the mixture to increase the flowability of the particulates. A method is also provided for excavating solid particulates, incorporating a foaming agent into mixtures of solid particulates, and then forming a foam within the mixture to increase the flowability of the particulates. The particulates can be transported through pipelines or boreholes. Examples of particulates include, but are not limited to, mine tailings, ores, sand, coal, soils, clays, silts, aggregates, and mixtures thereof.
A method is provided for incorporating a foaming agent into mixtures of particulates and then forming a foam within the mixture to increase the flowability of the particulates. A method is also provided for excavating solid particulates, incorporating a foaming agent into mixtures of solid particulates, and then forming a foam within the mixture to increase the flowability of the particulates. The particulates can be transported through pipelines or boreholes. Examples of particulates include, but are not limited to, mine tailings, ores, sand, coal, soils, clays, silts, aggregates, and mixtures thereof.
A precast concrete bridge system containing one or more sections wherein each section includes a horizontally disposed, load-bearing span that is integrally cast with a pair of vertical side walls. Each wall contains lightweight cores encapsulated in the concrete to create a series of longitudinally extended beams in each wall so that the beams in one wall are coaxially aligned with the beams in an adjacent wall. The cores constitute between 16-35 % of the total section volume.
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.
