CJFill-UW (Under Water) is designed for maximum axial and lateral load reduction, placed directly into water. Slightly denser than water, CJFill-Under Water can be tremied behind sheet piling, under relieving platforms, docks, and other structures.
Typical Physical Properties
|Wet Cast Density||65lb/cuft||75lb/cuft|
|Compressive Strength (ASTM C495 @ 28 days)||20KSF||40KSF|
CJFill-UW is optimized for providing similar strengths, but with significantly lower axial & lateral loads compared to traditional tremied fills. For example, 75lb/cuft Under Water CJFill provides a 40KSF unconfined compressive strength, at half the weight of flowable fill. This significantly reduces the likelihood of inducing settlement when filling below and around underwater structures.
Because the material cures into a self-supporting mass, it does not impart lateral loads on structures after it cures. Initial set and cure times vary with water temperature, but are generally around six hours. Because CJFill-UL is highly mobile, it can travel significant distances around underwater obstructions, ensuring fully encapsulation of piles and other structure elements.
If ballasted CJFill-UL isn’t feasible, CJFill-UW can also be poured above water for lightweight mass fills subject to inundation or flooding.
CJFill-UW Mix Designs
If placed directly into water via tremie, a sanded base slurry is most appropriate. Combined with an anti-washout admixture, the sand helps to ensure consistency within the placement. Neat mix slurry can be used to generate material placed into dewatered areas. Fly ash can be used to reduce the heat of hydration. The vast majority of CJFill-UW is generated using neat mix cement paste. In most markets, this is Type-1L cement, as Type I/II cement is being phased out throughout most of the United States. Material generated with Type-1L cement tends to require slightly higher water : cement ratio, but otherwise there are no impacts on mixes or physical properties. 1L cement is a blend of Portland Cement and up to 15% of limestone, though most 1L cements are around 8% limestone content.
Under Water CJFill has to be heavier than water; 65lb/cuft is the lowest practical density. It can be as heavy as 110lb/cuft. Density is infinitely variable within that range, and compressive strength increases with density. Wet cast density is set in the field, and is controlled by adjusting the ratio of cement paste to foam.
Supplementary Cementitious Materials
Supplementary cementitious materials, such as fly ash and slag, can be integrated into the paste component of Under Water CJFill. This is typically only done on very large placements, when neat paste is used as the base instead of a sanded base. This is because slag generally costs the same as Portland Cement, and fly ash, while generally cheaper, is difficult to source in some markets. SCMs also increase the relative alkalis content of paste, which is not problematic from an aggregate compatibility perspective, can cause compatibility problems with the preformed foaming agents used to generate the fill material.