Examination of the Performance of Sustainable Geopolymer Concretes Produced Using Waste Rubber Fibers: A Cleaner Concrete

Recently, geopolymer binders have the popularity they deserve in terms of the effort spent on them, as they provide the opportunity to produce high-performance and eco-friendly composites by minimizing the environmental and durability problems caused by cement production and usage. This study was designed to examine the effects of different ratios of waste rubber fiber (WRF) replaced with coarse aggregate on the performance of geopolymer concrete (GPC) samples. The binder part was obtained by substituting 2% nano silica to the granulated blast furnace slag (GBFS). Additionally, in this study, in which natural river sand was used as fine aggregate, WRF substitution was applied to coarse aggregate at different ratios (0%, 5%, 10% and 15%). Following the solid part of GPC samples was obtained as described, the alkaline activation was provided using a 12 M NaOH solution. At the end of 28-day curing period, compressive strength, flexural strength, splitting tensile strength, impact resistance, capillary permeability and elevated temperature performance properties were investigated in detail. Furthermore, the obtained experimental findings were interpreted with microstructural analysis. The results showed that the usage of WRF improved properties such as flexural strength, tensile strength, impact resistance, and also had a negative effect on compressive strength.