We investigate aerogel-aerogel composites to develop new materials for thermal insulation applications with reduced fragility and without release of dust. Two different kinds of highly insulating silica aerogels (SiO2) were embedded into a cellulosic aerogel: a high-density (0.25 g/cm(3)) tetramethylorthosilicate (TMOS) based and a low-density (0.15 g/cm(3)) waterglass based hydrophilic granular silica aerogel which are added to the salt hydrate melt of 59 wt.% calcium thiocyanate and 2 or 3 wt.% of cellulose during the synthesis of a cellulosic aerogel. The silica aerogel species show a different behavior regarding the interaction with the cellulose network in the composite examined by scanning electron microscopy. With the synthesis method we were able to produce non-fragile aerogel-aerogel composites and a strong stiffening effect regarding Young's modulus was achieved compared to pure aerogels. Density obtained is 0.04-0.15 g/cm(3) and thermal conductivity reached is between 0.04-0.05 W/mK. (C) 2015 Elsevier B.V. All rights reserved.