Owing to its extremely low thermal conductivity and good thermal stability, silica aerogel has a potential application for the protection of concrete linings, with the aim of delaying the heating of the high performance concrete and extending the performance of the main concrete structure of the tunnel under fire. A recent collaborative study with Empa’s Concrete/Construction Chemistry Lab shows layers of 40-50 mm of the aerogel cement mortars are able to avoid fire spalling of high-performance concrete cubes [1].