In the EU there is a pressing need for the change of the current economy into a so-called circular economy in recent years. The rational management of natural resources and the use of waste materials are becoming more and more important. It is also supported by the growing ecological awareness of society, including the consciousness of sustainable development. Nowadays, it is the construction industry that has the most significant impact on pollution. Therefore, numerous attempts are made to reduce energy consumption and the amount of waste generated by it. These are the main issues stimulating the research on new innovative materials such as geopolymer composites. They have a significantly lower carbon footprint than traditional construction materials. Moreover, the synthesis of geopolymers requires 2-3 times less energy than traditional Portland cement, not to mention the fact that 4-8 times less CO2 is generated. In addition, the above process has another environmental benefit i.e. the possibility of using anthropogenic raw materials (minerals) such as slags and fly ashes for the production. One of the limitations for the wide use of such materials is their relatively low brittle fracture behaviour. Nowadays, one of the most important research areas is the improvement of their mechanical properties. To improve the mechanical properties it is possible to reinforce the matrix by fibres addition, especially natural fibres that are renewable resources. The main objective of the article is to analyse the mechanical properties of new composites and assessment the possibility to replace traditional building materials within eco-friendly alternatives.