FLORIDA ALREADY LIVES
IN THE POST-COAL CHEMISTRY.
FPL closed its last coal-fired plant on January 1, 2021. Crystal River retired its original units in 2019. Big Bend Unit 1 converted in 2022. Florida ready-mix has operated on out-of-state rail-shipped fly ash or alternative SCMs for years. Combined with coastal humidity above 80 percent RH and the Miami oolitic limestone aggregate base, Florida is where the post-2018 chemistry change is already fully visible.
The transition is over. The chemistry vulnerability remains.
Texas and Tennessee are mid-transition. Florida already finished the transition years ago. The Florida residential concrete supply has been operating on out-of-state ash or alternative supplementary cementitious materials since roughly 2022 to 2023.
Crystal River 2019. FPL 2021. Big Bend 2022 to 2023.
The Florida coal-plant base contracted in a tight four-year window. The dates below are the structural reference set.
- December 2019: Duke Energy Florida retired the two original Crystal River coal units.
- January 1, 2021: FPL (NextEra) closed its last coal-fired plant.
- 2022: Tampa Electric converted Big Bend Unit 1 to combined-cycle natural gas.
- Spring 2023: Tampa Electric retired Big Bend Unit 3.
The Florida coal-plant base is structurally smaller as of 2026 than at any prior point in the post-war era. The residential fly ash supply that historically protected Florida concrete has not been a Florida-sourced supply for several years.
Out-of-state ash. Alternative SCMs. Type 1L cement.
With the in-state coal-plant base contracted, Florida ready-mix moved onto three substitute supply vectors. None of them reproduce the chemistry profile of the locally sourced Class F fly ash that historically protected Florida concrete. The substitution happened over several years, in supply-driven steps.
Out-of-state
rail ash
Rail-shipped fly ash from coal regions outside Florida became the primary substitute as the in-state coal base retired. The 2024 to 2025 railroad labor and freight corridor logistics shock affected this supply directly, which means the substitute itself is now exposed to a transportation reliability question that did not exist when Florida ran on local supply.
Alternative
SCMs
Slag cement where the regional supply chain supports it. Silica fume in higher-spec mixes. Blended cements where the producer carries them. The category mix varies by plant and by region within Florida. The chemistry behavior of each substitute differs from Class F fly ash in ways that the residential mix design generally does not document.
Type 1L
cement
Portland-limestone cement (ASTM C595 Type 1L) now accounts for the majority of blended cement shipped in the United States. Florida is inside that national pattern. The cement chemistry that arrives at the Florida ready-mix plant in 2026 is not the cement chemistry that arrived in 2018.
Florida concrete in 2026 is not chemically the same product that Florida concrete was in 2018. The change happened over several years, in supply-driven steps, with no statewide documentation event marking the transition.
Coastal humidity. Reactive aggregate. Same residential project.
ASR formation requires three conditions present together: reactive aggregate, sufficient alkali content in the cement paste, and sufficient moisture. In Florida, the moisture condition is structural to the climate, not occasional. The aggregate question is open for site-specific testing. Two of the three conditions are baseline, not exceptional.
Miami oolitic limestone is widely used in South Florida residential construction. Whether the specific aggregate is reactive under ASTM C1260 in residential concrete service requires local testing.
The Pool and Hot Tub Alliance (PHTA) recognizes ASR as an industry threat. AQUA Magazine has documented pool-deck failure patterns consistent with ASR-driven cracking in Florida residential pool projects. Recognition exists at the industry-association level. Documentation exists in the trade press.
Florida is where the rolling crisis has already arrived.
Florida is the state where the rolling-chemistry crisis is no longer rolling; it has arrived. The supply-side transition is complete. The climate condition is structural. The aggregate question is open for project-level testing. Florida is the demonstrated end state of the trajectory that other regions remain in motion against.
The protocol documents what the supply chain no longer documents for you.
PSIP-certified contractors document the actual SCM source on the batch ticket, verify the chemistry against the exposure class on the project, and retain the closeout packet on a permanent record. The protocol is structurally independent of every material supplier. The protocol scores. The protocol does not recommend products.