I am pretty sure it is not ASR but insufficient fine aggregate in the original concrete mix (no-fines). It appears as though there are large interconnected voids. The large voids are causing the spalling and popcorn like appearance. The slab is definitely getting worse with age and normal...
I am working on the renovation of a building that is structural steel frame with cast-in-place concrete slab. The building was built in the 1920s. The concrete slab mix must have been quite poor as the appearance is almost of popcorn or "fireproofing" slab in nature.
Needless to say, the...
