Fiber Reinforced Concrete Pipe

[jimtheprez]

There's a fair amount of controversy in FL re: whether Fiber Reinforce Concrete Pipe (FRCP) is 'equal to' Reinforced Concrete Pipe (RCP). I think Hardie Pipe is the only FRCP manufacturer that I'm aware of. The main weakness seems to be proper handling/installation. If that's not done right the joints seem to be brittle and can crack.

Any feedback positive/negative about FRCP use in RCP situations? Any limitations on use you would note? Thanks.

 

[cvg]

are you talking about FRPM which I believe stands for fiber reinforced polymer mortar pipe? If so, there are other manufacturers. Try Hobas

http://www.hobaspipe.com/

and I believe there are others.

The main limitation I see (for drainage) is that it is more expensive then reinforced concrete. For direct jacking, it is superior. For corrosion resistance it excellent.

 

[jimtheprez]

I think that the FRCP is different than the FRPM that you reference. My understanding is that FRCP is 'reinforced' with cellulose fibers (as opposed to asbestos fibers from an ealier day).

 

[cvg]

I would not recommend use in public right of way, but see no reason it couldn't be used in easements or on private property.

 

[jimtheprez]

That's kind of what I was thinking too, but didn't have any objective reason not to use it other than my ignorance of its long term behavior. Even on private property I'm a little concerned about professional liability if the pipe doesn't perform well (say under roadway/parking areas that might have sustained loads.)

 

[cvg]

well, Hardie makes a lot of claims on the website, but personally, I have never seen it used in 20+ years in the business. That may be because I am not working in the Florida area. However, there is a lot of un-reinforced concrete pipe used around here for irrigation (in the past). Typically, it gets replaced with RCP whenever it is being relocated or replaced. Cast in place, non-reinforced pipe has been used in the past around here also, but lately I don't see any public agencies allowing it in the right of way either.

As far as fiber reinforcing, there have been lots of claims about it's ability to strengthen concrete - however, from everything I have read, the fiber is strictly used to provide crack control and increased durability. Both are good, but the fibers should not be counted as structural reinforcement. Therefore I would consider FRCP as non-reinforced concrete pipe and treat it in the same way.

 

[jimtheprez]

That's the crux of the arguement down here. I think that the pipe is more accurately classified as fiber cement pipe. Given sufficient wall thickness it seems serviceable, I'm just concerned about its structural properties...especially impact resistance...as might be encountered by a backhoe when doing utility work in a right of way. I think the pipe integrity can be compromised in that area. Your comments re: fibers for crack control rather than reinforcement are correct as far as I can tell.

The pipe has good hydraulic properties, is much easier to lay (lighter), and has good joint properties (with fewer joints because of longer laying lengths). It has a lot of positive aspects, but I just don't see that it's appropriate to use in high traffic or dense utility situations.

 

[jgailla]

We never use FRCP, even though the Hardy pipe guys market everyone pretty good. For standard drainage situations it is inferior to RCP, although there may be some situations which are different as pointed out above. Cellulose fiber is not a proper structural reinforcing material. In a fluctuating groundwater table, which is ususally the case in Florida, the cellulose swells and shrinks with the moisture and eventually spalls the concrete, leading to a much diminished life span. It is more difficult to construct than RCP because the joints are more easily broken. If somebody wants to save money on inferior drainage pipe, use HDPE.