Process for repairing asphalt pavement

#Asphalt road pavements are being subjected to increasingly severe load stress. The repeated deflection of the road pavement causes elastic-type failure and fatigue failure in the pavement, which manifests itself in the form of pavement surface cracking and fracturing patterns. Conventional repair methods involve asphalt overlays, or replacement of the pavement surface.

#A variety of paving grade asphalt compositions have been developed for the purpose of providing improved physical and mechanical properties in pavements under heavy traffic loads. Illustrative of these developments are the asphalt compositions disclosed in U.S. Pat. Nos. 2,871,212; 3,338,849; 3,374,104; 3,821,144; 3,879,323; 4,105,612; and the like.

#Also of increasing importance for reasons of economy and convenience are methods and materials for repairing and surfacing broken asphalt pavements. An important objective has been the development of materials for repair of asphalt pavements which exhibit increased flexibility and resistance to fatigue failure. Efforts to provide asphaltic binder materials with the desired elastomeric properties for asphalt pavement repair are typified by the technology of U.S. Pat. Nos. 2,310,972; 3,578,001; 2,700,655; 3,049,836; 3,253,521; 3,270,631; and 3,340,780.

#The following examples are further illustrative of the present invention. The reactants and other specific ingredients are presented as being typical, and various modifications can be derived in view of the foregoing disclosure within the scope of the invention.

#An FCC main column bottoms is topped to yield a residual fraction having a 650.degree. F. cut point. The residual fraction has a hydrogen content distribution in which the H.sub.Ar content is 35 percent, the H.sub..alpha. content is 37 percent and the H.sub..beta. content is 18 percent.

#A batch of the 650.degree. F. FCC/MCB residual fraction is heated to about 400.degree. F., and to the heated mass there is added ethylene-vinyl acetate (33 weight percent vinyl acetate) having a melt index of 43 in sufficient quantity to constitute about 20 weight percent of the total asphaltic admixture. While maintained at a temperature of about 375.degree. F., the asphaltic admixture is spread over a fatigued asphalt pavement which exhibits a pattern of cracks and fractures. While the spread asphaltic admixture is still plastic, a layer of fine aggregate is applied over the coated pavement surface. No fatigue cracking is evident when the repaired surface is resubjected to its normal traffic stress.