Building and Construction Materials

Abstract

In England, in the 1700s, it was noticed that certain particular types of limestone containing clay minerals and silica could be calcined and that the product, after grinding and mixing with clear water, would set to a hard cement. This new type of cement was stronger than the cements in previous use at that time, such as the pozzolan cement. Another important advantage was also noticed by the first users, namely that it sets under water and hence could be used for piers, lighthouse foundations, and canal locks. In reference to this type of cement, the mother limestones were designated as hydraulic limes or water limes. Further investigations demonstrated that a mixture of pure limestone with clay and silica sand also produced a natural cement having these valuable properties. Later, in 1824, an Englishman, Joseph Aspdin observed that by calcinating at high temperature a limestone, called Portland stone, extensively used at that time as dimension stone in Great Britain, it was possible to obtain a cement of superior quality, especially strength, in comparison with natural cement. It was the beginning of the well-known Portland cement. Since the 19th century Portland cement has been indispensable for civil engineering applications. In these applications Portland cement is the main ingredient in a castable or moldable mixture of cement with water and aggregates.