Scarcity of natural materials and sustainable solutions have become major concerns of civil-engineers. As a part of it, the pavement engineers started using low-carbon emission binder materials such as geopolymer binders and recycled materials in different layers of flexible and rigid pavements. The present article focused on flexural behavior of geopolymer stabilized aggregate bases by replacing natural fine aggregates with copper-slag at a replacement dosage of 0, 5, 10, 15, 20 and 25% by total weight of dry aggregates and different dosages of geopolymer binder (3, 4 and 5% by weight of total dry aggregates). A set of prismatic specimens were prepared and subjected to both static and repeated four-point bending for the determination of flexural strength and indirect tensile fatigue test was conducted to determine the fatigue life of geopolymer stabilized mixes at different stress ratios (0.6, 0.7 and 0.9). Further, the changes in microstructure with respect to type of geopolymer binder are investigated through scanning electron microscopy (SEM) at constant dosage of 5%. The study revealed an insignificant reduction in flexural strength with a maximum replacement dosage (20%) of natural aggregates with copper-slag. Further the results revealed a significant influence of dosage of geopolymer binder on flexural strength and fatigue behavior of geopolymer stabilized aggregate mixes.