Subject: How does thixotropy and fluidity affect draining in homes?

When we were looking at draining at school, I found out about thixotropy, 
fluidity and how it works, and found out something about it affecting drains 
and the way some buildings are built. I've tried checking several search 
engines about how (thixotropy and fluidity) it affects the way buildings are 
built and even though I found some interesting things, I stil don't 
understand. Is there a more basic way of explaining?

Whne I first asked, this question, it was replied that I didn't ask enough 
about what I don't understand. Well, the major thing of what I didn't 
understand is how the way fluidity and thixotropy can affect draining, and why 
it can cause cracks. What causes draining to have low fluidity "in" it? When 
the search engines were browsed, i really had no idea about how it works, and 
so I can't really demonstrate how a drain works.

Re: How does thixotropy and fluidity affect draining in homes?