A bio-resource resin for use as a replacement for a portion of asphalt in asphalt compositions includes a bio-oil derived from animal waste and including hydrocarbons; and a compatibilizing agent. The bio-oil is derived from animal waste by subjecting the animal waste to a conversion process selected from a hydrothermal conversion process and a thermochemical conversion process. This bio-resource resin can be employed as a substitute for a portion of asphalt in common asphalt compositions, and the compatibilizing agent improves the chemical compatibility between the bio-oil and the asphalt.