A method of sealing and strengthening the joints in an asphalt road surface and subsurface to prolong the useful life of the road utilizes a polymer modified cationic maltene emulsion containing polymer modified maltene oils and resins, and surfactants/and wetting agents. The emulsion is applied to the longitudinal joints and other joints in the asphalt pavement surface. The emulsion reduces voids in the asphalt pavement and chemically improves the asphalt binder properties, thereby altering the modulus of elasticity of the asphalt binders so that the resistance of the pavement to tension is increased, and the water absorption of the pavement is reduced.