Strength and durability properties of fiber reinforced high performance geopolymer mortars

The occurrence of this much CO2 emission in Portland cement (PC), which is the owner of approximately 7-8% of the current CO2 emission released all over the world and produced at very high temperatures (1400-1500°C), involves very serious risks. According to the latest data, approximately 105 million m3 of cement has been produced annually in our country. In order to prevent this situation, geopolymer mortars, which have a lower carbon footprint compared to Portland Cement, come to the fore. It is undeniable that geopolymer mortars use factory by-products as a base material and their compressive strength and durability properties can compete with normal concrete, but poses problems in terms of ductility and tensile strength. In this thesis, a geopolymer mortar was prepared with a mixture of "80% Class C Fly Ash + 20% Portland Cement" and polyamide fiber and pva fiber reinforcement were added to the mixture to improve its ductility. By increasing the deformation capacity of the mixture with the addition of fiber, it is aimed to create a multi-crack effect, that is, it is aimed that the material moves away from the rigid structure and gains ductility. In this context, the compressive strength, three-point bending strength, four-point bending strength and durability properties (freeze-thaw, sulfate resistance and SEM) of the prepared mixture were investigated. As a result, it was observed that the final compressive strength of the prepared mixture was 35.2 MPa, and the fibers added to the mixture increased the ductility capacity. While the flexural strength of the fiberless mixture was 3.67 MPa, this value increased to 5.6 MPa with fiber replacement. With the durability tests carried out, it was observed that freeze-thaw did not have a negative effect on the increase in strength up to 90 cycles, but decreased the strength in 90 cycles. It was observed that the strength of the samples exposed to 5% MgSO4 decreased.