NCDOT abandonment grouting
The Job
This NCDOT abandonment grouting project is located outside of Chapel Hill, North Carolina. The abandonment grouting is the final step in a gravity main replacement project. The scope requires filling 3,023 linear feet of 24″ RCP gravity sewer with NCDOT-approved flowable fill.
The Challenge
This gravity main runs entirely in a cross-country backwoods right of way. Along the alignment, there are a few road crossings, which require the NCDOT approved material.
Because the new pipe is in the same right of way, there are multiple locations where new and old pipe alignments cross. This breaks it into a collection of smaller runs, as opposed to one continuous run of pipe.
The Solution
If this was one continuous run of pipe, it would be a great candidate for dry batch generation cellular grouting. The 352CY project volume would only take about two hours to fill.
However, being broken into multiple, shorter runs in the middle of the woods, meant that wet batch equipment was more appropriate from an access and productivity perspective.
CJGeo mobilized a wet batch crew to the site, and it took them two days to complete the work. There were a total of 11 runs of pipe and six placement points. The longest run was 1113 linear feet, the shortest only 56.
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NCDOT pipe abandonment
The Job
This NCDOT pipe abandonment project is located outside of Wilmington, North Carolina. It is part of a large highway improvement project to improve capacity in the rapidly expanding southern coastal North Carolina area.
The Challenge
NCDOT requires grout fill for most abandoned pipes within their right-of-way. Traditionally this is done using flowable fill mixes. Using flowable fill for short abandonment is generally pretty simple.
However, this project has more than 100,000 linear feet of pipe ranging from 6″ to 36″ to fill. Most flowable fill mixes won’t go more than a couple hundred feet in best cast conditions. The utility contractor was looking at having to dig up to five hundred access points to place flowable fill. That’s incredibly time consuming and costly.
The Solution
The utility contractor reached out to CJGeo about performing the abandonment grouting on this project, using low density cementitious material (cellular concrete).
Due to the highly variable pipe diameters and run lengths, CJGeo proposed a mix of wet batch and dry batch cellular concrete generation.
Wet batch was used for the lower volume runs. Dry batch is best suited for large volume runs. Over the course of a few months, CJGeo mobilized multiple times to fill runs as long as a mile at a time.
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Indiana Pipe Abandonment
The Job
This Indiana pipe abandonment project is located in Anderson. Anderson is in central Indiana, near Indianapolis. The project is a water main relocation out of a park.
The Challenge
Plans call for safe loading the pipe being replaced. It’s important to fill abandoned utilities to prevent them from being groundwater conduits, or eventually failing completely. This can cause significant amounts of settlement, and transport soils long distances, neither of which is desirable.
The Solution
Using traditional flowable fill would have required close to 10 access points to place material into the pipe. This would have torn up a bunch of the park that the pipe ran though, and taken quite a bit of time.
CJGeo proposed filling the pipe from a single access point near the middle, using CJFill-Ultra Lightweight cellular grout. The beauty of cellular grout for abandonment is that it’s pumpable thousands of feet. In this case, the first run was 770 linear feet. The second run was 488 linear feet.
It would be possible to grout the entire run in a single stretch, however there was already an excavation at this point to blind a connecting pipe, and there was a nearby fire hydrant.
CJGeo sent a dry batch plant to the site, and the grouting work took less than an hour of pumping to completely fill the pipe.
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New York Pipe Abandonment
The Job
This New York pipe abandonment project is located in Newburgh, New York. Newburgh is on the Hudson River, about an hour upstream of New York City.
The Challenge
As part of a sanitary sewer upgrade project, 5,399 linear feet of gravity sewer ranging from 6″ to 24″ was specified for grout filling. The highest volume run was a 1,022 linear feet continuous run of 24″ pipe. The longest run was 1,469 linear feet of 18 inch” pipe. Each run did have intermediate manholes, but most manholes were a few hundred feet apart.
The Solution
Traditionally, the customer would have dumped flowable fill in the manholes in an attempt to completely fill the lines by gravity. However, many of the manholes were off road, and some of them were hundreds of feet apart. This makes gravity discharge of flowable fill into manholes unreliable for ensuring complete fill.
CJGeo proposed performing the abandonment grouting using 30lb/cuft CJFill-Ultra Lightweight cellular grout. Since cellular grout will flow much further at nominal pressures, CJGeo was able to place through multiple manholes at once, which significantly reduced access requirements.
Due to the relatively low volume on this project, continuous wet batch was the best method for generating the cellular grout for this project. Wet batch uses slurry delivered by ready mix truck, with Aerlite-iX added downstream of CJGeo’s slurry pump.
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Facing a similar challenge to this New York pipe abandonment project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Underground Storage Tank Fill
The Job
This underground storage tank fill project by CJGeo is located at a food manufacturing facility near Harrisonburg, Virginia. The tank is 30 thousand gallons, and designed to store diesel to feed backup power generation for the facility. As part of an equipment upgrade, the tank is no longer in use, and had to be filled.
The Challenge
The best way to address unused underground storage tanks that aren’t removable is to fill them. If left empty and out of mind, abandoned empty tanks can cause serious problems, such as sudden collapse, which can significantly affect operations. Unfilled, out of use tanks can also accumulate groundwater, leading to potential environmental liabilities.
The Solution
CJGeo proposed 30lb/cuft CJFill-Ultra Lightweight (CJFill-UL) to fill the tank. CJFill-Ultra Lightweight is easily hand and machine excavatable to ensure that when the tank is removed in a few years that it’s not difficult.
While easily hand excavatable, CJFill-Ultra Lightweight still provides more than adequate compressive strength. In this case, total loads were just a few hundred pounds per square foot, whereas the CJFill material provides more than 17ksf of unconfined compressive strength. The American Concrete Institute publishes a removability modulus calculation which helps to quantify the ease of removal of controlled low strength materials, read more about it and how it relates to cellular concrete here.
It took CJGeo less than an hour to completely fill this tank. Confirmation of complete fill was uniform material venting from the tank vent ports.
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Tunnel Adit Fill
The Job
This tunnel adit fill project is part of the Purple Line project outside of Washington, DC. Specifically, the adit is located at the pedestrian connection between the Purple Line project and WMATA’s Bethesda station on the Red Line.
The Challenge
Plans call to connect the Purple Line to the Red Line using an adit constructed during the original construction of the Red Line. The adit is approximately 30 feet wide by a 35 foot tall arch. During preparation to blast from a shaft dropped adjacent to the station, a fault was identified passing through the adit.
The construction and design teams were concerned about stability of the adit during blasting operations as the Purple Line access tunnel was excavated towards it. The team determined that filling the adit to plug and stabilize it during blasting would be the most risk appropriate move.
Filling the adit would fulfill the design challenge of stabilizing the rock during blasting. However, it created the following challenges:
- the tunnel adit fill material would need to be removed after blasting was completed
- the adit is approximately 100 feet below grade
- there is very limited space up top
- material couldn’t segregate, and had to be pumped approximately 250 feet in addition to the 100 foot drop
The Solution
The tunnel engineer of record recommended CJGeo to the contractor. The EOR is familiar with CJGeo’s cellular concrete generation and placement expertise, and thought that cellular concrete would be the lowest risk way to fill the adit, while facilitating excavation and removal afterwards.
CJGeo took five days onsite to fill the adit, in lifts up to eight vertical feet. Due to the potential dead load from the rock cover, 400psi CJFill-Standard was the material of choice. By using our colloidal mixing dry batch process, the material set off quickly, ensuring that it would not consolidate during cure as lower energy mixing methods can suffer from.
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North Carolina Abandonment Grouting
The Job
This North Carolina pipe abandonment project is located in Raleigh, North Carolina. It is part of the Upper Walnut Creek sewer replacement. After installation of a new gravity sewer, more than three miles of 42″ sewer was requiring abandonment grouting. The specification calls for completely filling the pipe with controlled low strength material (flowable fill).
The Challenge
The primary challenge for the general contractor on this project was minimizing cost and time. The owner’s specification calls for an NCDOT-approved flowable fill material. Most flowable fills can only be placed for up to a few hundred feet before requiring another access point. The contractor wanted to minimize the number of placement points to ensure the fastest placement possible.
The Solution
CJGeo designed a grouting program using one of our NCDOT-approved mixes. Using dry batch generation, CJGeo can make up to 200 cubic yards per hour of material, which is enough to fill 562 feet of 42″ pipe per hour.
CJGeo mobilized a dry batch cellular grout plant to the site, and made a total of 5,539 CY of cellular concrete to complete this North Carolina abandonment grouting project over a few weeks. Some of the pipe was completely full of water. Even though cellular grout is significantly lighter than water, it can still displace water out of pipes.
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Facing a similar challenge to this North Carolina abandonment grouting project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Virginia Pipe Abandonment
The Job
This Virginia pipe abandonment project is located in Norfolk, Virginia. It is part of the HRSD’s capital improvement program. After installation of a new gravity sewer, 875 linear feet of 24 inch sewer required grout filling for abandonment.
The Challenge
The primary challenge for the general contractor on this project was avoiding installing placement points every 150 feet to use traditional flowable fill. The owner’s specification if using traditional flowable fill requires placement points every 150 feet. The owner allows other controlled low strength materials to be pumped further, as long as uniform material vents at the far end of each placement.
The Solution
CJGeo proposed using 30lb/cuft CJFill-Ultra Lightweight cellular concrete. CJFill-Ultra Lightweight is pumpable thousands of feet per placement. This eliminates the need for most intermediate access points.
CJGeo mobilized a wet batch cellular grout plant to the site, and made 101 CY of cellular concrete grout to complete this Virginia pipe abandonment project in a few hours. The pipe was completely full of water. Even though cellular grout is significantly lighter than water, it can still displace water out of pipes.
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Facing a similar challenge to this Virginia pipe abandonment project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Michigan Pipe Abandonment
The Job
This Michigan pipe abandonment project is located in Grand Rapids, Michigan. As part of the Coldbrook Pumping Station decommissioning project, 2250LF of 48″ pipe, and 2300LF of 60″ pipe were specified for grout filling.
The Challenge
The primary challenge for the general contractor on this project was the sheer volume of abandonment grouting. The project also had a significant amount of smaller diameter pipe, but it was in shorter runs, so was easy for them to self-perform with flowable fill.
The Solution
CJGeo proposed using 25lb/cuft CJFill-Ultra Lightweight cellular concrete. CJFill-Ultra Lightweight can be pumped thousands of feet per placement. This eliminates the need for most intermediate access points. Placement points on this project were in the driveway of a fire station, next to a new riverwalk project, and also on the grounds of the pumping station.
CJGeo mobilized a dry batch cellular grout plant to the site, and made around 200 cubic yards per hour of CJFill-Ultra Lightweight to finish this Michigan pipe abandonment project. Each run was up to 2500 feet long at a time. The abandonment work took five days onsite. By utilizing on site dry batching, a snow storm and cold overnight temperatures did not affect the work.
After the crew was completed with this work, they moved to Detroit to perform annular space grouting on a 17′ diameter CSO outfall structure.
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New Jersey Pipe Abandonment
The Job
This New Jersey pipe abandonment project is located in northern New Jersey. First, the general contractor installed a new force main by micro tunneling. After the the new micro tunneled force main was in service, the existing force main had to have grout filling. The pipe is 24″, and about 6300 feet long.
The Challenge
The pipes ran underneath an existing roadway, so digging access points for flowable fill installation would have been expensive, time consuming, and disruptive to traffic. The general contractor recommended CJFill Low Density Controlled Low Strength Material (LD-CLSM) as an alternative to the controlled low strength material that the township typically uses.
In addition to the old force main abandonment, a wet well structure also required abandonment. The original plan was to use flowable fill, however there were concerns about inducing settlement if the fill material was heavy.
The Solution
CJGeo proposed using 25lb/cuft CJFill-Ultra Lightweight cellular concrete. CJFill-Ultra Lightweight can be pumped thousands of feet per placement. This eliminates the need for most intermediate access points.
CJGeo mobilized a dry batch cellular grout plant to the site, and made around 150 cubic yards per hour of CJFill-Ultra Lightweight to finish this New Jersey pipe abandonment project. Each run was up to 2500 feet long at a time. The abandonment work took two days onsite, with the preformed foam supplied by Aerix Industries. After the abandonment grouting was done, the CJGeo crew did the wet well abandoning work with 25lb/cuft CJFill-Ultra Lightweight.
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