Core failures during rapid concrete placement are almost always mechanical rather than cosmetic. When self-compacting concrete is pumped into vertical column or shear-wall formwork, lateral hydrostatic pressure can exceed 60 to 80 kPa. If the internal plywood core contains unglued pockets, veneer gaps exceeding 3mm, or unseasoned core plies with excessive moisture content (>14%), structural shear failure occurs.

Under thermal pressure generated by cement hydration (which easily reaches 50°C to 65°C inside dense pours), trapped moisture within core voids turns into localized steam pockets. This expands internal air pockets, shearing the adhesive bond line between adjacent plies. The result is instant panel deflection, surface bulging, or catastrophic blowouts on the jobsite.