Abstract. Polymer based resin is presently the most used resin for preparing of composites constructions, because of its undisputable benefits; however, there are some limits. The aircraft industry has especially strict requirements for fire, smoke and toxicity (FST) properties which are limited when using organic polymers. Conventional polymer resins resist to temperatures usually up to 120 °C and then they lose stiffness and strength. However, geopolymer matrix is a new type of resin with high potential for cost-efficient applications dealing with temperatures up to 1 200 °C.This paper presents compressive properties of a new geopolymer resin and a fibre reinforced composite with the geopolymer matrix (geocomposite). The effect of a harsh environment exposition on the strength was also evaluated, specifically the impact of the exposure in hot-wet and salt mist conditions. Samples were tested in accordance with ASTM D695 in case of pure resin and in accordance with ASTM D6641 in case of the geocomposite. All tests were performed at room temperature and additionally, pure geopolymer resin was tested at 400 °C. The high temperature caused 35 % decrease of the compressive strength in comparison with the room temperature. Geopolymers behaves like a ceramic and have some unique properties such as high thermal stability, non-flammability and do not generate toxic smoke and fumes.

Geopolymers are amorphous aluminosilicate materials which combine low temperature, polymer-like processing with high temperature stability and fire resistibility without toxic smoke generation. For larger expansion of geopolymer composites in aircraft industry, it is necessary to know how it behaves in contact with operating fluids. The specimens were divided into groups exposed to fuel, hydraulic oil, jet oil, and salt mist. Hot/Wet condition until saturation was also applied for one group. Mechanical testing was performed by means of tension, compression, in-plane shear, flexion and interlaminar shear on both reference non-treated and exposed specimens. The largest decrease in all measured strength values was caused by the salt mist. As the most significant, in-plane shear strength was decreased by 85 % by this environment. Operating fluids and hot/wet conditions decreased the shear strength approx. by 15 %. Geopolymer composites are an interesting alternative to existing polymeric and ceramic matrix materials and offers high potential for cost-efficient applications dealing with temperatures up to 1 200 o C.