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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."
Newsflash: Concrete is manufactured in factories with VERY high quality control standards.
Each batch is specifically formulated to be as identical to the ones before it as possible. While there might me MINOR variances in mix, most of our modern construction absolutely depends on the homogeneousness of the concrete batches. If we really had to deal with widely disparate batches, ntohing large could ever be built, as the overall strength of the finished product could not be counted on. Yes, there are exceptions to this, some of which have caused rather spectacular engineering catastrophes. But the reason they are a big deal is precisely because they are so rare.
Now, if we were still mixing concrete by hand using slave labor like the Romans, then wide variations in concrete batches would be an issue. But we don't. We use complicated mathematics, and specialized weighing and measuring and mixing machines, all tied together by tried and tested computers and software platforms. Concrete hasn't been an issue of "every mixed batch of concrete is different from the last" for at least 50 years, if not longer.
Also, the types of concrete mixed for high-temperature use such as this WOULD be very different than the types mixed for use in bridges.
Concrete used to be my family's business back in the 50's - 70's. I grew up on stories about the concrete business. Not that I would even need that history to understand this though. Don't any of you ever watch the Discovery Channel? Geez.
Official Heretic from the "Church of Global Warming". Proven right thanks to whistle blowers. AGW = Flat Earth Theory
Ice isn't even necessary. It's been my experience that dripping tap water on a hot bulb is enough to cause an implosion.
We hope your rules and wisdom choke you / Now we are one in everlasting peace
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.
Heh - thanks. I'd be pretty upset too if my butt was on a 700 (?) degree burner too, I guess.
:-)
Oddly, of all the things in the kitchen that make me think "be careful with this thing" -- knives, the stove, garbage disposal -- "measuring cup" was never really on the list until that day.
That said, it'd probably be kinda fun to do in a controlled environment in a MythBusters blowing stuff up kind of way.