Formula and Pavement Properties of a Composite Modified Bioasphalt Binder Considering Performance and Economy

As a by-product of petroleum, asphalt reserves have dwindled with the exhaustion of petroleum resources. Therefore, it is necessary to seek alternative asphalt binders to reduce asphalt consumption without sacrificing the pavement properties of asphalt mixtures. At present, bioasphalt modification technology has been widely studied to partly replace asphalt binders. However, balancing performance and economy is more difficult with modified bioasphalt binders than with typical modified asphalt binders [e.g., 5% styrene-butadiene-styrene (SBS)-modified asphalt binder]. Hence, a new modification technology using bio-oil, nanomaterials, and polymers was developed in this study. The optimal modification formulas of the composite modifiers are determined via the orthogonal experimental design method. The pavement properties (high-temperature performance, low-temperature performance, antiaging performance, and water stability performance) of the proposed modified bioasphalt binders and their mixtures were tested against those of the 5% SBS-modified asphalt binder and AH-70 base asphalt binder, and the results showed that the proposed modified bioasphalt binders exhibited satisfactory pavement properties. An economic analysis showed that the costs of the proposed modified bioasphalt binders are lower than those of the 5% SBS-modified asphalt binder.