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Shuttle Launch Pad Damaged During Discovery's Launch
pumpkinpuss writes "Launch pad 39A at the Kennedy Space Center suffered unusual damage during the shuttle Discovery's blastoff Saturday. Pictures from a NASA source show buckled concrete and numerous concrete blocks or bricks, presumably from the flame trench, littering a road behind the pad."
My friends own a commercial concrete contractor, and current concretes are WAY more advanced than I'd ever have thought.
These days, concrete is like any other advanced man-made composite. The knowledge about cement, water, sand and aggregate types and mixes have been refined to the nth-degree. Then start add-mixing plasticizers, hardners, cure retarders / accelerators, humidity control agents, etc.
The really advanced stuff is like epoxy. Normal concrete is ~3,000psi. My friend was pouring 12,000+ psi concrete for a large structural member in a sub-foundation. The form blew out, and concrete flowed out the hole and setup - within a few hours, even jackhammers became ineffective - it was like drilling steel. They wound up bringing in heavy demo equipment to get out what should have only taken a few men.