Characterization of lightweight aggregates produced with clayey diatomite rocks originating from Greece

A clayey diatomite rock originating from Greece, mainly composed of opal-A, smectite and vermiculite was tested for the production of lightweight aggregates (LWAs) by mixing the raw material with 2–5% sawdust. The mixtures were pelletized, dried at 100 °C and burnt to 1100 °C. The laboratory LWA had strength and density similar to commercial LWAs originating from Germany and Denmark. The porosity of their mantle was lower than that of the inner part. Pores were abundant ranging from irregular to spherical and from 2 to 500 μm in size, resulting in low apparent density values. The texture of the Greek and German LWA was clearly amorphous, whereas subhedral crystal assemblages were detected in the interior of the Danish LWAs. LWA produced by the Greek clayey diatomite rocks can be utilized for the production of LWA on an industrial scale.