January 2023 Vol. 78 No. 1
Rehab Technology
Rehab News: New Chemical Grout Injection Technology; Avanti Adds Grouts to NSF/ANSI/CAN 61 Certified Product Line
New Chemical Grout Injection Technology
(UI) — Injecting chemicals to stabilize, lift, seal or compact weak soils and rocks is not new. Polyurethane grout material has been used for this purpose since the 1960s. However, the limitations of this process, to shallow depths of 20 feet or less, have often been frustrating, not only for asset owners but installers, as well.
As the material is injected, it begins to synthesize (cure) inside the injection tube. While the synthesis rate can be accelerated or retarded by controlling the chemical temperature, that control is short-lived.
The deeper or longer the injection tube, the longer time the chemical has to cure before exiting the tube. While this is happening, the diameter of the injection tube effectively shrinks in diameter, as the cured material bonds to the tube wall. Another side effect is that the chemical being injected can lose its desired effect the deeper it is injected, as it cools once leaving the tube.
This frustration is being abated by Deep Horizons Injection Grouting (DHIG). Developed by Polymer Technologies Worldwide Inc. (PTW), this innovative system of injecting chemical grout has been successfully applied up to 100 feet below ground surface, without foreseeable limitation.
The injection system for the DHIG chemical is like any other, in that pumps feeding the chemical must be powerful enough to overcome the strength of the soil materials, as well as any line friction.
The significant advantage of the DHIG technology is that the material is combined at the tip of the casing, which allows for full material strength to occur where needed, versus inside the feed line, which is standard practice using most existing systems.
Another benefit is that the material can be injected from a lateral point, to avoid interference with nearby surrounding project activity. This results in reduced time, cost and impacts to the public and the environment.
For example:
- A leaking cross drain can be sealed without closing down a busy highway or interstate system.
- A sanitary lift station can remain in operation while a leaking influent line is sealed.
- A building can remain in operation while a basement wall is sealed.
- A leaking earthen dam can be sealed without lowering water levels.
- Retaining walls can be sealed at depth, without excavation or injection from the face, which can further weaken the wall.
- Stabilizing embankments – bridges, railroads, roadways, canal banks, etc.
- EPA-related concerns such as underground oil, frack well, hazmat or radioactive leaks at any depth can be sealed, preventing catastrophic contamination of surrounding freshwater aquifers or ecosystems.
- Sealing abandoned wells and mine shafts, while allowing for future material removal so that the well or shaft can be put back into service.
FOR MORE INFORMATION
Polymer Technologies Worldwide Inc., polymertechnologiesus.com
Avanti Adds Grouts to NSF/ANSI/CAN 61 Certified Product Line
(UI) — Avanti International’s AV-150 Acrylate Gel and AV-278 Low Vis Hydro are now certified by the Water Quality Association (WQA), as being tested and certified in compliance with NSF/ANSI/CAN 61 Drinking Water System Components.
“These products join other Avanti grouts that have earned the potable water certification,” said Roger Borremans, technical director. “The rigorous tests they are put through by WQA, per the NSF/ANSI/CAN 61 standard, ensures the products are safe to use near drinking water sources.”
Avanti also points out that NSF 61 certification is vastly different from self-proclaimed “compliance.”
Following are details about the latest in a growing list of such Avanti products.
AV-150 Acrylate Gel is a low-viscosity, chemically activated acrylate gel. This high-solids grout can permeate most geologies and cures within a controllable timeframe of 20 seconds to ±5 minutes. Once cured, it creates an effective, strong, long-lasting water barrier while providing superb soil stabilization.
Specific characteristics and features include:
- Stops water infiltration into manholes, sanitary and storm sewer mainlines, joints, laterals, tunnels, mines, and various other geotechnical applications and underground structures, by stabilizing external substrate
- Ground modification/slope stability for prevention of landslides, erosion, or any place where site conditions or project requirements dictate modification of the existing soil properties
- High-solids content
- Controllable reaction times, from seconds to minutes
- Available in 44-pound pails, 484-pound drums, and 2,420-pound totes
AV-278 Low Vis Hydro is a moisture-activated, MDI-based polyurethane. The chemical reaction is catalyzed by mixing AV-279
Low Vis Accel with AV-278 and injecting it as a single component. AV-278 uses moisture as an initiator and is designed with soil permeation in mind.
Its low viscosity allows for soil penetration and its high-expansion properties fill voids, stop active or potential water leaks, and stabilize soils. AV-278 withstands wet/dry cycles and forms a dense, closed-cell, impermeable semi-rigid foam.
Specifics include:
- Fills voids on the exterior of below-grade structures
- Stops leaks in below-grade structures
- Low viscosity allows for excellent permeation
- Free rise expands 4,000-6,000%
- Withstands wet/dry cycles
- Controllable reaction time by adjusting AV-279 catalyst volume
- Multiple packaging variations available:
- 0- x 2.0-fluid-ounce barrier cartridges (case of 12)
- 3- x 2.5-fluid-ounce dual cartridges (case of 6)
- 8-poud containers
- 44-pound pails
- 484-pound drums
FOR MORE INFORMATION
Avanti International, (800) 877-2570, avantigrout.com
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