Environmental degradation of foamed geopolymers

Abstract

Modern materials used in civil engineering should fulfill the numerous of requirements connected building standards, but not only. They should also be ecological and durable. Geopolymers are characterized by very good mechanical properties, high resistance against acids, chlorides and sulfates, high thermal resistance, and other properties confirmed by previous research. There is still a few amount of research connected with resistance, this materials for different environmental conditions, especially a lack of investigation connected with foamed geopolymers in this area. The main objective of the article is to analyze the possibilities of the development of new foamed geopolymer composites to increase durability, especially against degradation in corrosive water environments. This paper presents the influence on the mechanical properties of foamed geopolymer composites on the water environment. As raw materials, fly ash from the coal power plant ‘Skawina’ (located in: Skawina, Lesser Poland, Poland) and metakaolin (Czech Republic) were used. The chemical composition of the fly ash is typical for class F. Additionally, the composites were reinforced by flax fiber. Solid and foam samples were prepared. As a foaming agent, hydrogen peroxide (H2O2) was applied. The following research methods were applied: compressive strength, flexural strength, porosity measurements, water absorption in fresh and salt water. The results show that, however, environmental conditions have a significant influence on the mechanical properties of geopolymer composites; the geopolymer composites can be successfully produced with the addition of natural fibers and have good strength parameters even after long-term use (materials were tested after 360 days).