WHAT WENT INTO
A FLORIDA POUR?
Concrete does not report its own chemistry. It reports it later, when it fails. A crew ordering the mix it has always ordered can receive a materially different cement. What went into a given Florida pour is a fact somebody either wrote down or did not.
The materials changed. Nobody had to write it down.
Without a record, a dispute years out is one party's memory against another's.
Fly ash is a coal byproduct. The coal fleet has been changing for years.
Fly ash does not come from a fly ash factory. It is a byproduct of burning coal for electricity, which means its regional availability tracks decisions made by utilities and regulators rather than by the concrete industry. When generation changes in a region, what a local plant can source changes with it.
Fly ash class. Other SCMs. Type 1L cement.
Three variables sit inside a mix.
Fly ash
class
Fly ash is supplied as Class F or Class C. They differ in chemistry, they differ in alkali silica reaction mitigation behaviour, and they are not interchangeable at the same replacement percentage. When a regional supply shifts from one to the other, the concrete changes. Nothing on an order form has to change for the material in the truck to change.
Other
SCMs
Fly ash is one supplementary cementitious material among several, slag being another. The chemistry behavior of each differs from Class F fly ash.
Type 1L
cement
Type 1L is portland limestone cement, a blended cement in which finely ground limestone replaces a portion of the clinker. Its governing specification is ASTM C595/C595M. Its reactivity, water demand, admixture behaviour and cold weather behaviour differ from Type I.
In each case a material can move underneath a specification, the specification is reused because reuse is normally good practice, and the finished slab does not show which version it got.
Reactive aggregate. Alkali. Moisture.
ASR is an internal expansive reaction, sometimes called concrete cancer, and it works from the inside outward over years.
Whether a given aggregate is reactive is a question for testing, under methods such as ASTM C1260. A PSIP record does not test aggregate.
A pool shell lives in near constant water, with wet and dry cycling at the waterline, and moisture is one of the three things ASR needs.
The photograph shows what the ticket shows.
On a concrete pour, a PSIP record holds the specified mix design, the cement type, and the supplementary cementitious material by type, or that none is specified, as the contractor states them at setup, before placement. On a pool shell, it holds the batch tickets for each shoot day, the delivery method, wet shotcrete or dry gunite, and the nozzle operator by name, as the builder states it. Every batch ticket is photographed, and the photograph records what the ticket shows. Tickets vary, and many do not list everything in the load, so the contractor adds what he knows in the notes, as his own statement. PSIP records the work and certifies that it was recorded. The contractor is responsible for local building codes, permits and licensing. PSIP certification is not an inspection, a code approval or a warranty. No material supplier can pay for a say in PSIP, and PSIP does not recommend products.