*Article* **Strength Parameters of Foamed Geopolymer Reinforced with GFRP Mesh**

**Rafał Krzywo ´n \* and Szymon Dawczy ´nski**

Faculty of Civil Engineering, Silesian University of Technology, 44-100 Gliwice, Poland; szymon.dawczynski@polsl.pl

**\*** Correspondence: rafal.krzywon@polsl.pl; Tel.: +48-32-237-22-62

**Abstract:** The foaming of geopolymers lowers their density, thus opening up new environmental benefits, including acoustic and thermal insulation. At the same time, foaming disturbs the homogeneity of the material, which worsens the strength parameters, and particularly those related to tension, which can be improved by introducing reinforcement. This paper presents the results of research on foamed geopolymers reinforced with glass fiber meshes, a type of reinforcement that provides an adequate bond. The samples tested here were based on three types of coal fly ash, and were foamed with varying doses of hydrogen peroxide. Samples were cured at 40 ◦C and were tested after 28 days of maturing at ambient temperature. The strength parameters of the synthesized geopolymers were determined via laboratory testing, and were used to evaluate load-bearing capacity models of the tested samples reinforced with glass fiber mesh. The results showed the importance of the type of ash on the strength properties and efficiency of reinforcement. At the same time, a slight deterioration in the glass fibers was noticed; this was caused by the presence of sodium hydroxide solution, which was used as an activator.

**Keywords:** foamed geopolymer; reinforcing lightweight concrete; glass fiber composites
