Geology 101, Section 12262
20 November 1996
According to the Mine Faculty at the University of Arizona, cement is
manufactured primarily from suitable limestone and shale rocks. Arizona had two
dry-process cement plants in 1969, namely the Arizona Portland Cement Company
plant in Pima County, near Tucson, and the American Cement Corporation plant at
Clarkdale, in Yavapai County (52-53).
The use of cementing materials goes back to the ancient Egyptians and
Romans, but the invention of modern portland cement is usually attributed to
Joseph Aspdin, a builder in Leeds, England, who obtained a patent for it in 1824.
Currently, the annual world production of portland cement is around 700 million
metric tons (Danbury).
Many people use the words concrete and cement interchangeably, but
they're not. Concrete is to cement as a cake is to flour. Concrete is a mixture
of ingredients that includes cement but ...