Surface and Colloidal Aspects of Cement Industry

Mankind has used some form of cement for thousands of years to build houses and monuments. Some examples are the pyramids (3000 BC) and the Colosseum (2000 BC), indicating an early awareness of the role of surface and colloidal chemistry. In modern times, besides small structures such as houses, the use of cement has been widened to include very large constructions such as dams. The main aim of using cement is to bind two bricks with a material consisting of very fine particles, and which hardens after water has evaporated. 

In general, there are two main classes of constructional cements nonhydraulic, which do not set under water, and hydraulic. Their composition can be indicated by the following two examples  

Nonhydraulic cements were among the most common of the ancient cements. The relatively high solubilities of portlandite (Ca[OH]2) and gypsum means that they deteriorate rapidly in moist or wet environments. Many decades ago, the Romans used lime-based cements and mortars (cement plus sand) by ramming the wet pastes 

It is likely that, during the early Roman period, silica and alumina, as well as volcanic earths, were used as cements. Portland cement is made from finely ground limestone and finely divided clay to give a burned product containing 70% CaO, 20% Si02, 4% FeA, and 4% A1203, plus smaller amounts of minor oxides (e.g., NazO, K20, MgO, etc.). 

The major raw materials used for modern cement making are 

---