Quote Originally Posted by Eric P View Post
Salt and concrete do not mix well. Florida DOT leads the country in salt vs chloride research.

They have stopped the use of epoxy coating on rebar. You can slow the migration of chloride to the rebar by densifying the concrete with fly ash, metacaolin, aggregate gradation, silica fume, nano silica, ect.

Rusting is not the only concern with salts. A relatively new understanding of a reaction (calcium oxychloride) that causes a gel to form and expand when it freezes. Freezing of this gel is in the 50-60F range and causes damages similar to freezing & thawing. Given that this is Florida thier concrete is not air entrained so damage is greater as the gel has no where to expand. This causes map cracking and for chuncks of concrete to "spall" off. To prevent this reaction fly ash or other pozzolans can be used to consume the CaOH reaction byproduct from cement hydration. This reaction not only mitigates the reaction but also densifies the concrete. Most concrete in FL did not contain fly ash until a few years ago.

Sinkholes are always a possibility in Florida with its limestone bedrock. Raising ocean levels can contribute to new sinkholes and accelerate thier growth. Increased CO2 increases the carbonic acid in rain water which increases the dissolving of limestone.
Was waiting for you to chime in on this, thanks.
I was remembering “rust bloom” or similar but didn’t want to say for sure.