Cutback type is used in road construction because it is not possible to use it in solid form. This type is obtained by dissolving pure bitumen with oil and petroleum solvents. The quality depends on the quality of the pure bitumen, the amount and type of solvent. The degree of lubrication of this type depends on the amount of petroleum solvent in them, and the higher this amount, the higher its lubricity, and typically the amount of these solvents is between 10 and 50 percent. Lack of access to heating devices, decomposition of bitumen at high temperatures, lack of penetration into porous minerals, safety of workers, time consuming, cooling during work and fire have caused it to be used in some cases. In order to adhere well to wet materials, the acidity of this type must be appropriate. This type of road construction is usually used to cover the surface of asphalt, cold asphalt or mixed on site. This type is classified into three categories according to the rate of traction and solvent type: RC (Rapid), MC (Medium) and SC (Slow).