A geopolymeric material is described having compressive strength at 28 days ranging from 15 to 100 N/mm.sup.2, obtainable by curing for 12 hours at a temperature ranging from 20 C. to 60 C., from a geopolymeric aqueous mixture comprising the following inorganic components in the following parts by dry mass: metakaolin 15-65 potassium silicate and/or sodium silicate 20-40 aggregates recycled from CDW (Construction and Demolition Waste) 5-300; said geopolymeric aqueous mixture is obtainable by mixing 20-175 parts by mass of water with said inorganic components, and has a viscosity at 23 C. between 100 and 10000 Pa.Math.s, wherein: i) the viscosity is measured via Brookfield methodology, ii) the aggregates recycled from CDW belong to one or more of the classes 17.01.01, 17.01.02, 17.01.03, 17.01.07 according to the European Waste Catalogue, iii) the aggregates recycled from CDW have a grain size less than or equal to 4 mm, preferably less than or equal to 2 mm.

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.