In recent years, more and more utilities have been moving underground.  Everything from cable lines to telephone lines, and even electrical lines in some areas, are being placed under streets across the country.  This makes them less vulnerable to changes in the weather but also makes them harder to access when repairs need to be made.

Historically, once a utility trench was excavated, it would be filled in using compacted earth – a time-consuming, laborious method that has the potential to damage the pipes or lines underneath.  The current market for trench backfilling has seen a shift toward flowable fill, which is easier to place and lowers the risk of damaging the pipes below.  Unfortunately, some common problems occur with traditional flowable fill mixes.



Excess Bleed Water

Many traditional flowable fill mixtures call for a disproportionate ratio of water to cement.  By adding more water to the mix, it becomes flowable, but you end up with a lot of extra bleed water.  Also, once the fill mix has been poured, most of that excess water will rise to the surface and you may have to pump it out the next day.

Pumping Challenges

An extra wet concrete mix will also segregate during the pumping process.  As you put pressure on the mix, the excess water will speed ahead of the mix.  Unfortunately, this doesn’t leave behind enough water to keep the concrete mix moving and can create a plug along the pipe.

Make a Better Mix


Fortunately, there is a solution to these two problems: add a specialty foaming admixture, such as Fill Flow. These chemicals create millions of air bubbles in the concrete mix.  This makes the mix flowable without adding excess water and ensures that the overall strength of the concrete stays low enough to excavate in the future.  For more information about Fill Flow and how it can help improve your concrete, check out the product demo video.  Don’t forget to follow us on social media to learn more about how we can help improve your concrete.