Polymer modified mastic asphalt is applied in asphalt or bitumen modification processes by incorporating polymer additives into the asphalt binder. This is typically done through a blending process where the polymer is mixed with heated bitumen to achieve a homogenous mixture. The modified binder is then used in the production of asphalt mixtures, enhancing properties such as elasticity, durability, and resistance to deformation. This results in improved performance of the pavement under various environmental conditions.