© 2022 Elsevier LtdMany researchers have recently turned to making studies based on asphalt modification by adding polymeric type additives to different rheological properties to asphalt. However, because of the cost of these additives, requiring special mixing plants and causing environmental pollution, it is necessary to increase the asphalt coating performance by producing low-cost additives equivalent to the additives in the market and environmentally friendly additives. In this study, a new additive not previously described in the literature was produced in the laboratory by chemically synthesizing tall oil, a by-product of the paper manufacturing, with boron oxide. FTIR, TG/DTG and SEM analyses were used to determine the microstructural characteristics of the produced modifier. FTIR analysis showed that a chemical synthesis had occured. While TG/DTG analysis determined the thermal structure characterization, the SEM analysis showed that the new modifier was distributed homogeneously the asphalt matrix. The rheological properties of the modified asphalts were investigated by conducting penetration, softening point, ductility, flash point test, rotational viscosity (RV), Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR) tests. The experimental results showed that the workability of the asphalt binder increased while the temperature sensitivity decreased. In addition, the rutting and fatigue resistance of the asphalt binder increased, but the low temperature performance was badly affected after a certain additive ratio. As a result, it appears that this new additive may be better suited to hot climate regions. Finally, it is thought that this new tall oil based boron additive (TOBO) obtained in the laboratory will be important for road pavement construction because it is easy to produce and environmentally friendly.