Reinforced Thermosetting Resin (RTR) vs. Reinforced Polymer Mortar (RPM) Pipes

[Akel]

Can anyone tell me the practical difference between RTR and RPM? I went through AWWA C950, AWWA M45 and ASTM D3262 and the only thing mentioned is that RPM contains aggregates while RTR does not.

So what advantage does one offer over the other? Are they suited for different applications or can they be used interchangeably?
I'am currently working on a project with gravity storm drainage and sanitary waste water collection system with pipe sizes ranging from 160mm to 800mm and with depths of cover between 1m to 4m and currently specifying RPM pipes as per the Standard Specs. but got a reviewer comment asking me to use RTR "because it is more economic".

 

[LittleInch]

I hate to see a post with no replies so I'll try to address some here, but really this might be in the wrong forum.

Try in the water treatment and distribution forum and you might get more "traction"

As far as I can see RTR also goes under GRE and FRP or globally "fibreglass", i.e. some sort of filament or mesh wrapped around a mandrel and impregnated and layered with epoxy or some sort of resin.

RPM seems more like concrete with polymer fibres to act as re-inforcement and either spun in a mould or poured into a mould to end up with "concrete" pipe much thinner than standard steel reinforced concrete pipe.

RTR/GRE doesn't really like abrasive material so the storm water idea isn't best suited for this I feel and I don't really see much in the way of GRE sewer pipes, mainly on cost grounds so not sure why your client is saying it is "more economic". Does he or she mean lower cost materials or total life cycle?

Low pressure / gravity GRE is a push fit connection similar to concrete pipes, but is easily damaged and can crack more easily under loads than concrete.

At the smaller sizes use of PE, PVC and other "plastics" is commonplace.

Bit of a vague question so a bit of a vague answer...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Akel]

Thank you for your reply.

The recommended pipe was not GRE but FRP, specifically it used polyester resin, not an epoxy resin as in GRE.

Anyways after more digging around I think I did find the answer. The aggregate filler is added to the pipe in order to economically increase pipe wall thickness and therefore stiffness. Without the aggregate filler, the manufacturer would have to increase the stiffness by using thicker glass and resin layers which is not cost effective. This would mean that RPM should be more economic than RTR.