1. Definition of lightweight mortars and concretes

The use of inert materials of different densities to make mortars has been widely known and exploited since the days of ancient Greece and the Roman Empire . However, the widespread use of lightweight aggregates in construction began primarily with the discovery of expanded clay, a lightweight aggregate with sufficient mechanical strength and a quality suitable for use in structural concrete applications. The process was developed by Stephen Hayde at the beginning of the 20th century in Kansas City (Missouri, USA).

Large-scale...