Tendon Encapsulating or Not - Post Tensioned Slabs

[geotech753]

Does anyone have any references for determining the corrosivity of the soil to reinforcing steel in Post-Tensioned Slabs to determine if encapsulating the tendons is necessary? I believe CalTrans has their limit at 500 ppm of chlorides. I also believe that soil moisture contents below 17.5 percent significantly reduces the chloride ion activity. However, I have not found anything specific to PT Slabs. Anyone have anything?

 

[boffintech]

ACI 323.6 PT slabs with grouted wedge pockets not normally kept dry or with grouted wedge pockets in contact with ground are required to encapsulated.

 

[geotech753]

I have not had a chance to look at the ACI 323.6.

Post-Tensioning Institute - in their recent updates to the manual "Standard Requirements" Section 6.3: Soils with chlorides greater than 200ppm need to be encapsulated. It seems pretty stringent.

I looked at IBC, and IBC sends you to ACI and ACI refers more to chlorides in the materials for concrete.

I will see of ACI 323.6 is something different.