Effects of urea on concrete durability 1

[ugandabob]

Any experience with urea containment? We are designing a concrete containment dyke around a urea tank with a 32.5% urea concentration. The concrete will not be continuously exposed to the urea; the dyke will be there in the event of a tank rupture.

What will the urea do to the concrete? I am thinking that the effects will be minimal due to the short exposure time, but there is no guarantee the dyke will be emptied promptly. Is a coating necessary? Type of material?

Thank you.

 

[TehMightyEngineer]

I have not had direct work with urea but have done work with harsh industrial chemicals and steam on reinforced concrete. I would also think that exposure limits would give little effect. Perhaps a coating right below the tank and on area that may see small drips, leaks, or small spills? I would imagine the corrosive properties of urea would be the most concerning so a corrosion inhibitor in the concrete might be a good idea. Beyond that I would think the exposure would be too short to cause major concrete deterioration.

Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries

http://www.americanconcrete.com

 

[TLHS]

I totally thought this was going to be a thread about peeing in the concrete mix.

 

[SlideRuleEra]

The Portland Cement Association (PCA) has a paper titled "Effects of Substances on Concrete and Guide to Protective Treatments". Page 29 says that urea itself has no effect on concrete. However, a note refers to deicers on page 28, which says that several deicers, including urea compounds, will cause scaling of non-air entrained concrete, but air entrained concrete is not attacked.

From this info, looks like just using air entrained concrete will a good move; no coating needed.

The paper is attached below:

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[msquared48]

If you are going to add urea to the concrete, what about methane for air entrainment? By entraining methane, you could actually make it easier to demo the concrete in the future.

Mike McCann, PE, SE (WA)

 

[Sawbux]

I did some work for storing urea fertilizer pellets way back in 1978. Info I have is that urea is slightly alkaline and so should not cause problems with bare concrete.

 

[dik]

TLHS... sugar can be problematic...

 

[ATSE]

SlideRuleEra: the download is not behaving

 

[SlideRuleEra]

ATSE - I tried just now and had no problem downloading. As a work-around, Google on the exact title, "Effects of Substances on Concrete and Guide to Protective Treatments". That should take you directly to the paper at "reseachgate.net".

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net