Cinders are the residue, which remains after material such as coal, is burnt.
Cinder blocks are building blocks that are made from cement and cinders.
Most of the blocks in the market these days are concrete masonry blocks. However, you find the term cinder block used in lieu of concrete blocks. I am not sure if they are still being made.
Even when I lived in West Virginia, coal country, they were called cinder blocks and actually they were made from cement.
Thanks for responding Lufti. It almost sounds as if the cinders were comparable to the fly ash we use in concrete today.
It seems a little strange that they called them cinder blocks. They must have been using a fairly high percentage of cinder being that they aquired the name "cinder" block. I wonder if it was significantly more than the 15%-20% of cementitious materials that we sometimes replace with fly ash. But, then again the cinders were probably a constant in their block recipe whereas fly ash is not always present in a concrete mix.
pricklyPete - The cinders that Lutfi refers to are the aggregate in the blocks, not a cement substitute. Cinders come from burning "chuncks" of coal, not the pulverized coal used in modern industrial boilers that creates microscopic flyash spheres. Cinders are more like to bottom ash than fly ash.
Add this little bit of trivia to your "history of cinder block" thread.
Seems that an acquaintence of mine, a long time ago, built a barbecue pit out of cinder block, the real thing, block built with cinders from stoker fired coal combustion.
On its first occasion to be used, he came outside to check on the progress of the cooking, only to find that the entire barbecue pit was aflame (big time).
Seems that the unburned carbon content of the cinders used in the block construction was excessive, and, when used in this application, the carbon ignited, and burned the whole barbecue pit to a crisp. (Almost took his house with it.)
I thought this anecdote might help define for you just what the cinders in "cinder" block was, back when it really was made actually using cinders.
