×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Sulfates in Hardened Concrete

Sulfates in Hardened Concrete

Sulfates in Hardened Concrete

(OP)
I am assisting an industrial client reviewing cracking distress in an 8-inch thick elevated slab. Visual petrography suggests that there is evidence of external sulfate attack limited to crack surfaces, likely a result of the chemicals to which the slab is exposed. The slab is reinforced with epoxy coated rebar, and there are no current indications of corrosion of the rabar or structural distress. I plan to recommend (which we previously recommended) that the cracks (which appear to be shrinkage and temp related) are sealed with an appropriate sealant for use in such a severe environment in combination with an appropriate chemical resistant surface coating.

The client has asked us to also perform sulfate content testing on the cores which were obtained. It seems that they want to know if the sulfates are penetrating the concrete surface in addition to that which is detected within the cracks. I don't think that is it necessary, but I was going to try to oblige them with testing. I have a lab experienced with the typical chlorides, carbonation, and sulfate testing of soils, but they are not aware of a standard test for sulfates in hardened concrete. I can not find a standard for this or information for comparative purposes of the results if we were to find a test method.

Has anyone had experience testing for sulfates in hardened concrete? Any suggested laboratories or references for discussion based on the results of the tests? Any thoughts on the subject would be appreciated.

RE: Sulfates in Hardened Concrete

Xray diffraction or Xray fluorescence will detect sulfates. Though sulfates in soils are usually the attach mechanism in concretes, any source of sulfates can create attack. I would recommend that you test the cores as your client suggests. Gradient sulfate testing is not difficult. You can drill into the cores at different depths to determine depth of penetration.

I developed a procedure for gradient chlorides sampling that could be used for sulfate testing as well....it is attached.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources