Investigation of mechanical properties of cementless new generation recycling based high performance infrastructure pipes

This study aims to produce new-generation high-strength cementless geopolymer concrete pipes as an alternative to cement-based concrete pipes commonly used in groundwater and sewage networks. Mixtures of binder materials were formed using different amounts of ground granulated blast furnace slag (GGBFS) and silica fume (SF). Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) were used as activators. These fiber-free geopolymer concrete mixtures were prepared at different molarities (9M, 12M, 15M), and the optimal mixture was determined based on their mechanical properties. All samples used %65 coarse aggregate (4-8 mm) and %35 fine aggregate (0-4 mm). The activator amount was adjusted according to consistency criteria. After storing the samples for 7, 28, and 56 days, their mechanical properties were examined, identifying 9M-S0 as the optimal mixture. The sodium hydroxide/sodium silicate ratio was kept constant. After determining the optimal 9M-S0 mixture, the mechanical properties of steel fiber-reinforced mixtures (%0.5, %1, and %1.5 by weight) were examined in laboratory and water environments. The optimal mixture was determined based on flexural and compressive strengths. Considering the continuous exposure to chemical environments in infrastructure projects, the prepared mixture samples were kept in a sulfate environment for 6 weeks, and their compressive strength and weight changes were examined. Fiber-reinforced and non-fiber-reinforced pipes were produced for infrastructure projects. Compressive strength tests showed that steel fiber-reinforced geopolymer concrete pipes exhibited better performance compared to traditional cement-based concrete pipes. Keywords: Geopolymer, Infrastructure pipe, Water networks, sewage, High Performance, Recycling