New Jersey Lightweight Fill
The Job
This New Jersey lightweight fill project is located in Secaucus, New Jersey. It’s part of a two building, wood framed multifamily structure over a concrete podium. The site is located very close to the Hudson River, so the underlying soils are poor, and there is a high likelihood of future flooding. As a result, the ground was improved using rammed aggregate piers, but then needed to be brought up approximately 2′ above existing grade.
The Challenge
Rammed aggregate piers were only able to improve the site soils so much. To avoid the costs of rigid inclusions or piles, the design team had to reduce the load applied by the backfill needed to elevate the site. The maximum unit weight was 30lb/cuft, and because of potential flooding, the material had to be permeable, in order to reduce uplift potential.
The Solution
CJGeo proposed using 25lb/cuft CJFill-High Permeability to backfill the stem walls, to bring the building pad up approximately two feet. 25lb/cuft CJFill-HP is provides excellent bearing capacity, but is hand excavatable.
Hand excavatability was important on this project. There was extensive under slab plumbing required, and the lightweight fill couldn’t impede on its installation. A great advantage of 25lb/cuft CJFill-HP is that it provides a clean, stable working surface that easily supports mini and mid-size excavators.
CJGeo mobilized a wet batch cellular concrete plant crew to the site. The crew used silt fence to break the roughly 80 thousand square foot pour into roughly 150CY placements. Each individual pour on this New Jersey lightweight fill project allowed the plumbing contractor to drive their mini excavators on it the following day. The plumbers enjoyed the clean, dry working surface.
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Pennsylvania Pipe Abandonment
The Job
This Pennsylvania pipe abandonment project is located at a drinking water reservoir near York, Pennsylvania. As part of a dam reconstruction, the existing outfall pipe was specified for grouted abandonment.
The Challenge
The existing outfall pipe is 48″ cast iron pipe, and approximately 200 feet long. The pipe passes approximately 45 feet below the crest of the earthen embankment, concrete core dam structure. To ensure that the pipe would not serve as a conduit for water after abandonment, the specification calls for cellular grout with a maximum permeability of 1×10-6 centimeters per second.
During design, there were concerns about leaks in the pipe draining out some of the cellular concrete after placement stopped, but before it reached initial set. To address this, a secondary grouting program using chemical grout was designed to top off any void volume in the outfall pipe after the cellular grout set.
The Solution
CJGeo proposed using 60lb/cuft CJFill-Standard cellular grout for the abandonment. 60lb/cuft CJFill-ST exceeds the minimum compressive strength requirement, and has less than 1×10-6 cm/sec permeability.
CJGeo mobilized a dry batch cellular grout plant to the site to complete this Pennsylvania pipe abandonment project. The crew performed the grouting in fewer than two hours. The dry batch plant generates the 60lb/cuft cellular grout onsite directly from bulk cement powder.
Placement was through sacrificial grout pipes installed by the general contractor. The GC also constructed masonry bulkheads on both ends of the structure.
Exploratory holes drilled in the bulkheads the following day confirmed uniform fill, and no need for the secondary grouting work.
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| Virginia to Maine | North Carolina to Florida | Everywhere Else |
| James Corbin | Andrew Taliaferro | Martha Moore |
| d: 804-442-7371 | d: 804-471-3061 | d: 804-404-2683 |
Michigan Pipe Abandonment
The Job
This Michigan pipe abandonment project is located in Saginaw, Michigan. It is a 2900LF of 8″ grouted abandonment for the local municipality.
The Challenge
The utility contractor who installed the replacement water main was required to fill the old pipe with grout after tying in the new pipe. Because of the relatively small diameter, they were going to have to dig approximately 15 access holes if they used traditional flowable fill. The contractor really didn’t want to have to do that. So, they sought a highly mobile grout that would eliminate the need for digging access points.
The Solution
CJGeo proposed using CJFill-Ultra Lightweight cellular grout for this Michigan pipe abandonment. Because the project volume is approximately 40 cubic yards. CJGeo proposed using wet batch generation, with a local ready mix provider supplying the raw slurry.
Wet batch generation is well suited for projects like this because the volume of slurry required is much less than a full load of cement. The equipment for wet batch generation is very portable–typically just two pickup trucks, one pulling a 20′ trailer with equipment.
Confirmation of fill for this Michigan Pipe Abandonment project was material venting a fire hydrant at the far end of the placement. Pumping pressures were less than 20psi for the duration of the grouting process.
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| Virginia to Maine | North Carolina to Florida | Everywhere Else |
| James Corbin | Andrew Taliaferro | Martha Moore |
| d: 804-442-7371 | d: 804-471-3061 | d: 804-404-2683 |
Texas Annular Space Grouting
The Job
This Texas annular space grouting project is located in Lockhart, Texas. It is a 42″ treated water pipeline for the Alliance Regional Water Authority.
The Challenge
The annular space grouting for this tunnel was specified for cellular concrete. The minimum allowable compressive strength was 300psi at 28 days, when tested according to ASTM C495. The 42″ treated water pipeline was installed inside of a 60″ casing pipe.
The tunnel was approximately 460LF, and crossed under a frontage road and Texas State Highway 130, about 20 miles south of Austin.
The Solution
Due to the Texas cement market being extremely strained, CJGeo proposed using onsite dry batch generation to make the cellular grout onsite. This has a few advantages over using ready mix (wet batch generation):
- purchasing cement directly from a cement plant bypasses ready mix plant’s cement allocation limits
- bulk material doesn’t go bad onsite
CJGeo used a relatively high water:cement ratio to account for temperatures of 105 degrees during the placement and generation. This helped to ensure that material did not prematurely set during placement, and allowed CJGeo to generate and place all of the 40lb/cuft CJFill-Standard cellular grout material in just three hours.
Confirmation of fill for this Texas annular space grouting project was material venting from the 12 o’clock vent on the far end of the tunnel. Pumping pressures were less than 15psi for the duration of the grouting process.
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| Virginia to Maine | North Carolina to Florida | Everywhere Else |
| James Corbin | Andrew Taliaferro | Martha Moore |
| d: 804-442-7371 | d: 804-471-3061 | d: 804-404-2683 |
Nashville Annular Space Grouting
The Job
This Nashville annular space grouting project is located at Nashville’s Central WWTP, which is undergoing extensive improvements to provide service to a growing population.
The Challenge
As part of an upgrade, 400LF of 66″ pipe was slip lined. Once the carrier pipe was selected, the space around its 57.1″ OD needed to be filled.
The Solution
CJGeo proposed using CJFill-ST at 45lb/cuft for this Nashville annular space grouting project. CJFill-ST is batched onsite directly from bulk cement, eliminating supply chain issues with ready mix.
Because the selected CJFill-ST only weigh 45lb/cuft, buoyancy control of the new carrier is simple. By filling it with water, it won’t float during grouting. This allowed CJGeo to grout the entire annulus in a single lift. Single lift grouting significantly reduces the likelihood of partial fills, fouled injection tubing, or trapped voids.
A CJGeo crew placed the 87CY of CJFill-ST in less than an hour to perform this Nashville annular space grouting project. CJFill-ST can be made two ways; wet batch or dry batch. With wet batch, a ready mix truck brings the base slurry to the site, and the foam is either added to the truck, or injected downstream of a pump. For dry batch generation, which was used here, a mobile batch plant mixes the cement and water onsite. The mixing quality using dry batch is significantly better than wet batch.
This project had a relatively high compressive strength requirement due to new foundation installation adjacent to the slip lined pipe. With cellular concrete, there are two ways to increase compressive strength–increase the cement content by increasing the density, or increasing the quality of the mix. Since annular space grouting projects are very sensitive to carrier pipe buoyancy control, increasing mix quality is a better option than increasing density. CJGeo’s three mobile batch plants all use high shear colloidal mixing. Colloidally generated material can have 28 day strengths up to two times ready mix batched material at the same density & cement content.
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| Virginia to Maine | North Carolina to Florida | Everywhere Else |
| James Corbin | Andrew Taliaferro | Martha Moore |
| d: 804-442-7371 | d: 804-471-3061 | d: 804-404-2683 |
Pit Fill With Lightweight Flowable Fill
The Job
An abandoned water treatment plant at a federal facility was being rehabilitated and brought back into service. As part of the project, lightweight flowable fill was needed to fill a 12′ deep tank below the building floor needed to be filled before installing a new floor and equipment.
The Challenge
The majority of the pit is below ground water level. The original foundation design used a 62PCF fill density for the pits, presuming they would only ever hold water.
The backfill material also needed to completely encase a number of new micropiles installed for machine bases.
The designer had two competing interests–given the closeness of the water table to finish floor, avoid any buoyancy of the fill material, while using the lightest possible material to avoid inducing any settlement.
The Solution
CJGeo proposed filling the pit with CJFill-UW, at 70lbs/cuft. At 70lb/cuft, there are no uplift concerns, and the material is just barely denser than water, which helps minimize the amount of anticipated settlement. To help ensure future excavatability, CJGeo used a sanded base slurry (as opposed to the usual neat mix slurry) to generate 830CY of lightweight flowable fill material. The 28 day design strength was 150psi. The average 28 day tested compressive strength was 200psi. The removability modulus of the material is 0.75, which means the material is readily excavatable.
Traditional “lightweight” flowable fill is closer to 95lb/cuft. At 150psi, 95lb/cuft material has a removability modulus of 1.18. This is above ACI’s benchmark value of 1 for ease of excavatability.
For this project the CJFill-UW was generated by adding preformed foam to ready mix truck drums. The drum blends the slurry & foam as it rotates. The blended CJFill-UW discharges via the chute directly into the placement area.
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| Virginia to Maine | Everywhere Else |
| Kirk Roberts | Martha Moore |
| d: 804-396-4845 | d: 804-404-2683 |
Lightweight Temporary Dam Foundation
The Job
This lightweight temporary dam foundation installation was part of flood proofing project a nuclear power plant. The temporary dam can be quickly installed between two large structures in the case of anticipated storm surge. This is to keep flood waters from inundating a sensitive area.
The Challenge
The cooling water pipes for a reactor pass under where the dam goes in the case of a predicted flood. If placed, the dam exceeds the design load of the underlying cooling pipes.
The Solution
The designer elected to excavate 3′ of fill from above the pipes and replace it with 25lb/cuft CJFill-UL . Removing 3′ of 120lb/cuft material and replacing it with 3′ of 25lb/cuft, reduces dead load by roughly 275lb/sqft. The 25lb/cuft material can float, however. So, to address buoyancy, given the minimal cover (2″ of asphalt), geogrid cast into surrounding high density flowable fill acts as a hold down.
CJGeo poured the lightweight temporary dam foundation in two lifts. To void being in a cold joint, the geogrid was placed on sewer bricks. This ensures at least 6″ of embedment in the top layer of CJFill. To assess the readiness of the CJFill-Ultra Lightweight for paving, CJGeo cast a test slab for the customer to run heavy equipment over prior to loading the production area.
This was the first project where CJGeo utilized geogrid for buoyancy control of cellular concrete.
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| Virginia to Maine | Everywhere Else |
| Kirk Roberts | Martha Moore |
| d: 804-396-4845 | d: 804-404-2683 |
BNA Culvert Abandonment
The Job
As part of a Nashville International Airport’s BNA Vision project, several hundred feet of culvert needed to be filled with grout. The culvert abandonment work is part of installing a new drainage system to accommodate a new terminal.
The Challenge
Due to long runs with no intermediate access, the engineer specified cellular concrete as the abandonment grout. Access to the site was across an active taxiway, so the fewest deliveries possible was very important. The minimum design requirements were:
- 28 day compressive strength minimum = 100psi
- maximum wet cast density = 35lb/cuft
The Solution
To address the need to limit the number of deliveries, CJGeo performed the culvert abandonment using CJFill-UL . CJFill-UL is batched onsite directly from bulk cement. By using bulk cement onsite, there were no concerns about hot loads of ready mix. A single semi was able to deliver all the raw material for the placement.
Each of the runs on this project is greater than 250LF. By using highly mobile grout, there are no questions about the pipes being filled completely. CJFill-UL is so mobile it will flow by gravity up to a few hundred feet. The material is always pumped. This allows for placement from either the high or low end of individual runs. Because the density of the material is very low, it takes very little additional pressure to place from the low end.
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| Virginia to Maine | North Carolina to Florida | Everywhere Else |
| James Corbin | Andrew Taliaferro | Martha Moore |
| d: 804-442-7371 | d: 804-471-3061 | d: 804-404-2683 |
Parsippany Annular Space Grouting
The Job
This Parsippany annular space grouting project is part of a microtunneled installation of 48″ sanitary line in two runs under an interstate. Each tunnel is 60″ diameter, one was 725LF, the other 530LF. They shared a shaft. The project’s goal is to replace an aging stretch of large diameter gravity sewer that runs parallel to the interstate.
The Challenge
The owner specified a grouted annular space for the tunnels. The long pumping distance and relatively tight annulus drove the need for a highly mobile, lightweight grout.
The Solution
CJGeo placed 270CY of 35lb/cuft CJFill-ST (36ksf unconfined compressive strength) cellular grout to fill the annulus on both tunnels. Because the shared shaft wasn’t easily accessible, grouting was performed from each end towards the shared shaft over two back to back days.
CJGeo used onsite dry batching to generate the cellular grout for this Parsippany annular space grouting project. Dry batch generation uses bulk cement, eliminating risks associated with the ready mix supply chain. Cellular grout made using the dry batch process is also much higher quality, which allows CJGeo to get higher strengths with lower densities. This lowers pumping pressure, buoyancy, and costs.
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Facing a similar challenge? Give us a shout or shoot us a text.
| Virginia to Maine | North Carolina to Florida | Everywhere Else |
| James Corbin | Andrew Taliaferro | Martha Moore |
| d: 804-442-7371 | d: 804-471-3061 | d: 804-404-2683 |
Dumfries Pipe Abandonment
The Job
This utility relocation included abandonment grouting as part of a VDOT roadway reconstruction and realignment of US Route 1 in Dumfries, Virginia. This Dumfries pipe abandonment job is located in a rapidly growing town in Northern Virginia. US Route 1 is a major local traffic corridor, as well as a bailout route for I-95 congestion.
The Challenge
1,575LF of pipe, a combination of 54″ & 60″ needed to be completely filled with grout. Due to sequencing, the pipe was underneath new roadway at the time of abandonment. So, the fewer the number of access points, the better.
The Solution
CJGeo placed 995CY of 25lb/cuft CJFill-Ultra Lightweight cellular grout to completely fill the pipe run. The material was placed in a single day, from a single access point near the center of the pipe run.
To facilitate such a large placement in a single day on this Dumfries pipe abandonment job, CJGeo used dry batch generation. Dry batch generation mixed water with bulk cement onsite, using a mobile batch plant. CJGeo’s mobile batch plants are designed specifically to generate cellular concrete. They generate preformed foam at the same time as making the cement slurry. The preformed foam and cement slurry pass through an in line mixer, at up to 200CY/hour.
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Facing a similar challenge? Give us a shout or shoot us a text.
| Virginia to Maine | North Carolina to Florida | Everywhere Else |
| James Corbin | Andrew Taliaferro | Martha Moore |
| d: 804-442-7371 | d: 804-471-3061 | d: 804-404-2683 |
