Lightweight aggregates - vermiculite, perlite, pumice - for insulating concretes

Various lightweight aggregates both natural and processed, are used in concrete having densities between 240 and 1920 kg/m3 and compressive strengths between 0.7 and 41.5 MPa. Processed vermiculites and perlites, being at the lower end of the density spectrum, are used in insulating concretes having thermal conductivities from 0.07 to 0.15 W/(me 0 C). Pumice, having a higher density, produces concrete having a thermal conductivity from 0.25 to 0.50 W/(m.°C). Although deposits of these materials exist in Canada, very few have been exploited; hence the country is almost entirely dependent on foreign sources. The Canadian deposits are not as large nor as high in quality as many of the foreign deposits. This report discusses their mineralogy and geology, distribution of the world's deposits, mining and processing, and their properties and applications, for both construction and other purposes. The specifications pertaining to concrete, plaster and other structural applications are also described.