Abstract: Mineral binder based construction materials are disclosed, including thermally pre-treated silicate glass fibers and colloidal silica and further additives, which have increased fire resistance such that they have a delayed shrinkage when exposed to high temperatures relative to a mineral binder based construction material with conventional glass fibers and colloidal silica, but otherwise of identical composition. The claimed mineral binder based construction materials provide an improved resistance towards rupture, thus ensuring that corresponding structures maintain their integrity for longer periods of time when exposed to fire. Also disclosed are methods for the production of mineral binder based construction materials and the use of thermally pre-treated silicate glass fibers and colloidal silica to effect a delay in shrinkage of mineral binder based construction materials, when exposed to elevated temperatures.