Concrete sulfate exposure class 6

That would almost never be in a geotechnical report. You have to test specifically for sulphates in the soil or groundwater. There are some known areas of high sulphate soils and groundwater, and you can get an idea of these through information provided by the USDA Soil Conservation Service.

Areas that are high in gypsum would be suspect for soils and groundwater issues.

We often see this classification listed in the geotechnical report, but that could be because it is an issue in our area (Denver). I have seen it come up in California as well. I would think the geotech would be the one to determine this classification.

The geotechs we work with usually provide the recommendations based on experience with the soils. They offer to test the soils as well, but few do given the cost implications.

Occasionally there are sulphate contents, but normally not. The following is a typical geotech inclusion in their reports for this are. We have high sulphates.


Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Agreed with Curve and Brad. It's typically provided by the geotech. And depending on the region some geotech include this information in their standard report. If not you have to ask and there could be a fee to run the test.

In my area, the geotechs will not provide it unless you specifically request them to test for it.

Thank you all for the feedback. In my geographic area, soil sulfates are not a big problem. But I am about to start a new project in a different region and want to be prepared. I searched through the limited database of geotechnical reports I have for that region and found that most of them do not address sulfates at all. Two reports did test for sulfates and found the soils to be "non-corrosive".

I also reached out to a structural sub-consultant we use from that region and they said they "will look into it". I would think if sulfates are a known problem, most experienced structural engineers would know about it. So it seems like it's not likely to be a big issue and I won't worry too much if the owner decides not to pay for sulfate testing.

Here is what I found on PCA circa 2002. Not sure where you are located. Another resource is the local ACI or ready mix association.