I was recently at a symposium on "The Meaning of Concrete". During the introduction, an excerpt from Peter Schjeldahl's book Columns and Catalogues was shown: Concrete is the most careless, promiscuous stuff until it is committed, when it becomes fanatically adamant. Liquid rock, concrete is born under a sign of paradox and does not care. It doesn't care about anything, lazy and in love with gravity but only half in love [...] Promiscuous, doing what anyone wants if the person is strong enough to hold it, concrete is a slut, a gigolo, of materials. Every other material - wood, clay, metal, even plastic - has self-respect, a limit to what it will suffer to have done with it, and at the same time is responsive within that limit, supple in the ways it consents to be used. Not concrete. I'm not sure if this is actually true or if the author is simply indulging in metaphor... I've found that the amount of water and the nature of aggregate can change the behavi...