Hello all,

I'm a civil engineer for Black and Veatch's underground power delivery department, and we have run into a bit of a problem on a few of our projects with pumping thermal grout into an underground casing pipe.  Inside the casing pipe are 8" Schedule 40 PVC conduit pipes that are going to hold the electric cables, but these conduits are very weak (can only handle about 25 psi when the temperature of the setting grout is taken into consideration).  If a pump is used, pressures can exceed that low of a threshold.  I was wondering if anyone here had ever run into this problem before and how you monitored/fixed it.  We have looked into placing water inside the conduit pipes in order to offset the pressure of the thermal grout, but I was hoping to find a few more opinions on the matter from people who have experienced and dealt with this in the past.

This is nothing more then a math problem, you can only pump so far before it exceeds 25 PSI then you have to move the pump and tie into the pipe again and start pumping again. I do not know what the math looks like but I know some of the guys here can tell you how to figure it out.

have you considered agilia? its extremely flow able but has high strength. looks like water coming out of the ready mix truck

lafarge is the only company that makes it I believe

Why do you have to use that pvc pipe and not a higher quality one

All the grouting I have done has been wih a mix 300kg cement/m3,flyash and water

This is pumped at the slump of water

For small cavities I strain it through shadecloth on the hopper

I always have the plant washout the barrels before loading

If your pipe has 25psi rating from the inside,I suspect it will be higher in compression from the outside 

What is the size of the cavity you are filling

Whats the distance you need to pump it

What is the vertical component

If you can fill the pipe with water and seal it,that sounds like a positive move

I forgot to ask,what are the specifications for your grout