Need concrete resistant to H2SO4

[w5ehx]

I need to patch some wells and pipe with something that is resistant to 60ppm(I think) H2SO4 at a wastewater treatment plant. We are going to coat the wells and pipes with epoxy coating for this use. But the wells are in such bad shape, we will have to do some patching to get a monolithic surface.

Any suggestions? Manufacturers? Anyone work in wastewater?

 

[JedClampett]

You can get some cementatious overlays that are hydrogen sulfide resistant, but getting actual cast-in-place concrete that is will be a problem.
Someone made a presentation to our company a while back about a concrete that was corrosion resistant, but it sounded suspicious and I haven't heard from them since.

 

[Ron]

Do you want something resistant to Hydrogen Sulphide (H2S) or Sulphuric Acid (H2SO4)?

There are some polymer coatings for concrete that are resistant to both. One company (I can't remember the name but I'll check my notes) that produces a spray applied plastic soup that hardens into a nice protective shell.

 

[LittleWheels]

If you are going to coat everything with an epoxy coating afterwards, why do you need a particularly chemically-resistant repair mortar? In any case, the major problem is getting your repair to stick and that is usually the result of poor preparation/application or an incorrect specification.

Fosroc or any other manufacturer of repair mortars should be able to suggest a repair system suitable for sewerage wet wells.

 

[Ussuri]

If it really is acid you wish to protect against you might want to use a glass flake coating.

http://www.corrocoat.com

 

[w5ehx]

The Hydrogen Sulfide is in the air in these wells and pipes. There is a bacteria that eats the H2S and with a little Oxygen, creates the acid. (Apparently, somebody makes a concrete admixture that the bacteria can't live on. Looking into that.)

I want to make the concrete repairs also acid resistant because eventually the coating will fail. And yes, surface prep is the key. Unfortunately, these wells are so eaten up, I am not sure I will even have a well left after it is cleaned up. The patches are going to be pretty thick in places. I am thinking about building a box within a box. Anybody ever done that with good results?

I have never heard of glass flake coating. I will follow the link.

 

[dicksewerrat]

What size are these pipes? Are they pressurized? CIPP may be a solution for you. They can make resins that are not affected by pH as low as 3. One person that has a Sulfide cementious repair system in Bill Shhok in Iowa. I think th name of the company is AP/M Permaform. Web site:

http://www.permaform.net

Tell Bill Hello from Dick C from Mpls

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[unclesyd]

Here is one that we have used their products for repair around our waste treatment plant.

http://www.sauereisen.com/c_prod/c_resist.asp

 

[sdz]

I have been looking for a way to give acid resistance to concrete for an upcoming job and found the following. It looks promising but I have not yet used it in a job.
===================================
Xypex Admix C-5000 is added to the concrete mix at the time of batching.

- Highly resistant to sulphates and chlorides.
- Concrete protection from aggressive chemicals
with a pH range of 3-11 in constant contact

http://www.xypex.com.au

 

[LittleWheels]

<I am thinking about building a box within a box. Anybody ever done that with good results?>

That is now pretty much standard practice in Oz when refurbing sewage wet wells. The interior is lined with HDPE. The concrete itself does not have to be particularly resistant to sulphide attack.

Xypex and other admixtures are helpful to some extent, depending on structural detailing, loading and other complicating factors, including cost.

 

[w5ehx]

sdz,

You may also want to check out Aluminaliner by Quadex. It is a calcium aluminate admix.

http://www.quadexonline.com/

Their website focuses on rehab of structures, but you can also use it to build new ones.

w5ehx

 

[sewerratt]

If you're looking for a sprayable or trowelable product, consider Dynastone. It is related to the quadex material chemically (I think) and we use it to rehab manholes. It has excellent H2SO4 resistance.

http://www.dynastone.com

We also did a repair on a manhole years ago with the permaform people noted in the thread. worked real well for the application.

 

[monjid]

First you need to check the integrity of the existing structure (reinforcements and concrete) I recommend to use epoxy modified cement coating for reinforcements after cleaning them (refer to Sika web site i.e. Top Armatec 110 EC) then with cementitious repair mortar silica fume containing. As a lining below epoxy I think to use Also Epoxy Cement lining system I know from Sika (Sikagard 720 EpoCem) that has a high chemical resistance and is compatable to epoxy when coated on top of it.
Another solution after repair by using Sulphur Concrete Polymer lining uo tp 2 mm thick. I knew recently a Polish company producing this system(

http://www.marbetwil.com.pl)

 

[minorchord2000]

My experience with coatings and admixtures shows mixed results. Concrete is highly susceptible to attack from H2S04 and other acids regardless of the protection you give it. I prefer the "diaper" technique where the concrete is protected by at least 40 mils of HDPE (sometimes two layers of HDPE with an interstitial leak detection system). These coating sales people will say it protects against this and that. Under real world conditions especially during retrofit projects, they rarely live up to their hype.

 

[Zambo]

Last time I worked on a wastewater project the pipes and manholes were lined with HDPE. Basically ribbed HDPE sheet was cast as a liner to the pipes and shaft walls. Towards the end of the project one of the contractors managed to get Xypex (as mentioned in posts above) approved as an alternative so no liner was required. One of the reasons was that the liners tended to become detached and for the pipes fully detach and get carried by the flow causing a blockage downstream. The Xypex admixture claimed to give the same protection while being integral to the cast concrete.

 

[johnnyceramic]

ceramic john
your manholes with h2so4 problems are becomeing a nightmare to cities ageing
swer systems ceramic cement spray coatings can handle these inviorments they
were origanlly redevelopmed by the department of energy for nuclear waste
containment. a good resource for this would be the ceramic concrete association
international (newly formed) but you can contact them through yahoo groups
ceramic cement best of luck ceramic john