Building cements

Practically all the inorganic building cements, such as mud, lime, and gypsum cement, are prepared as mixtures of at least three components a binder, a filler, and a medium, the latter always water. The binder (or binding material) is a substance that acts cohesively, adheres to surfaces and, when... 

Probably the oldest known building cement, mud has been widely used since time immemorial, and its use still continues in many areas of the world. 

The two other main types of human-made building cements, lime cement and gypsum cement, have been and still are used in many areas of the world. Both these cements require quite elaborate thermal procedures for producing their main components, which are slaked lime in lime cement and plaster of Paris in gypsum cement. Making them involves the calcination of an appropriate type of stone, a process that has been practiced since prehistoric times. Slaked lime is made by the calcination of limestone plaster of Paris, by the calcination of gypsum (see Textbox 33) (Cobum et al. 1990 Lea 1962). 

Calcinating a mineral removes its volatile components, such as water or carbon dioxide and leaves an usually crumbly solid residue. Calcinated secondary minerals such as limestone are the basic components of building cements, and in extractive metallurgy operations they facilitate the smelting of metals. Calcinating limestone (composed of calcium carbonate), for example, drives away carbon dioxide, leaving a solid, friable residue of quicklime (composed of calcium oxide) ... 

The major uses of quicklime are as a component of ordinary glass, as a flux in metal smelting operations and (mostly), for making building cement and mortar (see Textbox 34). 

Fig. 1. General rules in the interpretation of building cementing material IR spectra.

Ceramics have followed a similar course, beginning with the ancient Mesopotamians who used bricks and made brick buildings. Cement, concrete, and to some extent glass have similarly been used largely for their mechanical properties. Paralleling the broadening of the uses of metals, however, ceramics have also over the last two centuries developed many uses not related to their mechanical properties. These include ceramic insulators, piezoelectric ceramics, solar cells, zeolite catalysts, and most recently the superconducting ceramics. 

---