Hydroxyl-terminated polybutadiene-based polyurethane (HTPB-PU)-modified asphalt and preparation method thereof

A method for preparing a hydroxyl-terminated polybutadiene-based polyurethane (HTPB-PU)-modified asphalt, the HTPB-PU-modified asphalt comprising the following components in parts by weight:

• 90 parts to 97 parts of a base asphalt and 3 parts to 10 parts of HTPB-PU, wherein the HTPB-PU is prepared from raw materials comprising an isocyanate and a polyol, the polyol comprises hydroxyl-terminated polybutadiene (HTPB) with a weight percentage of not less than 80%, and the isocyanate is isophorone diisocyanate;
• and wherein the raw materials comprise 70 parts to 85 parts of the HTPB and 12 parts to 25 parts of isophorone diisocyanate, based on 100 parts by weight of a total weight of the raw materials, and further comprise a chain extender and a catalyst;
• the method comprising the following steps:
• (1) mixing isophorone diisocyanate with the polyol by stirring at a temperature of 110-130° C. to obtain a PU prepolymer;
• (2) adding the PU prepolymer into the base asphalt and stirring at a temperature of 160-190° C. with a stirrer to obtain a mixture;
• and
• (3) adding the chain extender and the catalyst into the mixture obtained in step (2) and continuously stirring to obtain the HTPB-PU-modified asphalt.