Pig as in Pigment I assume. Would be curious/odd if it were a swine reference (likely a story behind it if so).
btw - I believe the white epoxy was chosen due to the immediate adhesion characteristics required for the vertical surface of the concrete, its height, and the necessity of expedient construction. Other horizontal based coatings may not be optimal for all of the necessary vertical uniformity considerations/factors - especially the heat & the effects of immediate adhesion integrity.
There is likely going to be another phase to the finishing of the sidewall concrete surface. The holes left by the wood form bolts require "filling". I suspect they will have another "step" regarding either the removal of the coating of epoxy before the final finish or ?. Shouldn't have to wait long to find out.
Yes, the “pig” is the pigment in the solution. IIRC, the coating had to be continually agitated to keep the pigment properly mixed. The white served to reflect sunlight and helped keep the temps lower.
My guess is they’ll leave the epoxy coating. It shouldn’t harm the concrete, and it will eventually weather/erode away, especially after water flows over it.