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+ Foundations
+ Sorption
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Kenneth Tully

PFAS & Concrete/Cements?

Celia Milton  Follow

Gareth, PFASs impacts to concrete are more of a concern as a result of the concrete remaining as a long lasting source of PFASs to the environment via long term leaching. We are working on some treatment solutions to prevent this. Cheers, Ian

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Colin Banks  Follow

Thankyou for the answers; appreciate it. Just thought I would clarify that I am not referring to PFA (eg - ashes etc). I am referring to perfluoroalkyl and polyfluoroalkyl substances (PFAS). Thanks, Ian.

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Andrew Wiltshire  Follow

Just a note that this might well be very confusing to those working in the field of cement and concrete, where PFA is used to refer to fly ash (a common component in many modern concretes). Also, sorry to say that I can't really help you with your question. Although organics are not normally a durability concern for concrete unless they're acidic.

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Bill Welden  Follow

In addition to my previous answer, another effect that may occur is the undesirable volume changes. Check the quality and chemical composition of your PFA. If the PFA contains high amounts of CaO and or MgO (especially TYPE C), volume changes may occur and possibly undesirable cracking.

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Alfred Montestruc  Follow

PFA consumes Ca(OH)2 from concrete reducing the pH value. Such effect is considered problematic in the corrosion of steel in concrete. The lower the pH value, the faster steel corrosion will occur. Therefore, replacing some cement with PFA will enhance the internal environment for corrosion of steel.
On the other hand, PFA will result in fine stable material that block some of the capillary pores reducing the the ingress of oxygen and water into concrete. This reduces steel corrosion.
Hence, there are two effects: one negative and one positive. The final effect depends on the quality of PFA and concrete used in the construction.

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