Stable asphalt emulsions, methods of forming the same, and composite structures formed from the same

A method of forming an asphalt emulsion, wherein the method comprises the steps of:

• forming a base asphalt emulsion comprising a base asphalt component and water;
• forming an oxidized polyethylene emulsion separate from the base asphalt emulsion, wherein the oxidized polyethylene emulsion comprises an oxidized high density polyethylene and water, and wherein the oxidized high density polyethylene has an acid value of from about 5 to about 50 mgKOH/g;
• and
• combining the base asphalt emulsion and the oxidized polyethylene emulsion to form the asphalt emulsion, wherein the asphalt emulsion comprises the base asphalt component present in an amount of from about 45 to about 65 weight %, water present in an amount of at least about 25 weight %, and the oxidized high density polyethylene present in an amount of from about 1 to about 20 weight %, wherein all amounts are based on the total weight of the asphalt emulsion, and wherein the asphalt emulsion is free of aggregate and other mineral materials.

A composite pavement structure comprising:

• an underlying aggregate-containing asphalt layer;
• and
• an emulsion-derived asphalt layer disposed directly on and over the underlying aggregate-containing asphalt layer, wherein the emulsion-derived asphalt layer is formed from an asphalt emulsion comprising:
• a base asphalt component present in an amount of from about 45 to about 65 weight %, based on the total weight of the asphalt emulsion;
• water present in an amount of at least about 25 weight %, based on the total weight of the asphalt emulsion;
• an oxidized high density polyethylene present in an amount of from about 1 to about 20 weight %, based on the total weight of the asphalt emulsion;
• wherein the oxidized high density polyethylene has an acid value of from about 5 to about 50 mgKOH/g;
• and
• wherein the emulsion-derived asphalt layer as-deposited is free of aggregate and other mineral materials.