4 ms·

> (fire resistance for instance is much better than steel). Specifically, steel melts/weakens in a fire, which can result in loss of structural integrity, whil

• baud147258 9y ago
  When the steel is inside concrete (in case of reinforced concrete), doesn't the concrete protect the steel? And since it's how most steel is used in construction, doesn't steel has an advantage here?
  • masklinn 9y ago
    Concrete does provide some form of insulation as it has a fairly low rate of heat transfer. At the end of the day it'll still heat up though, and it's that heating up which weakens the steel, direct contact is not a requirement (there are specific methods like insulated concrete form which have higher fire resistance).
    • MrLeap 9y ago
      I have a technique I'd use to add heat resistance to steel. Only necessary If we lived in a doomed world where engineers didn't exist and I was asked to make steel more heat resistant. Cover steel beams in a relatively thick later of plaster of paris mixed with very find grain sand. I built a charcoal forge out of that material (I used quartz sand I got from a pool supply store) and it's ludicrously heat resistant. It's lined with 4mm of aluminum (melting point 660°C) and the plastersand layer is about 25mm thick. I can melt steel bar above it without causing any visual changes in the aluminum body. I've used it about 20 times in the last year. Lots of spalling on the plaster layer but for most architectural applications I doubt you need to have a blower fueled inferno happen > 2 times a week during the summer. I wager real engineers have more cost effective, data driven solutions. Just thought it was a neat fact.
      • jacquesm 9y ago
        They did a similar thing with spray on asbestos but this is obviously no longer an option.
      • blackguardx 9y ago
        If you use a clay like fire clay instead of plaster, it will be much more durable.
        • jacquesm 9y ago
          Hm, the fire clay I'm familiar with is extremely brittle once it has been through a heating cycle, do you have some specific kind in mind? The stuff I know is more like glass.
          • blackguardx 9y ago
            The stuff I used wasn't that brittle. It is also designed to be used as a furnace lining, unlike plaster. https://en.wikipedia.org/wiki/Fire_clay https://en.wikipedia.org/wiki/Fire_clay
      • baud147258 9y ago
        I think it would be so expensive to protect all the steel going into reinforced concrete that you could go directly with another material.