Rheological characterization of asphalt binders modified with soybean fatty acids

This investigation examines rheological properties of asphalts blended with soybean acidulated soapstock, a relatively low-cost and highly concentrated source of soybean fatty acids. Rheological tests indicate that as soybean acidulated soapstock is added, binders become softer, less stiff and their high temperature viscosities are reduced. The addition of 1% soybean acidulated soapstock reduces thermal stress accumulation. These findings suggest that soybean acidulated soapstock could be used as a fluxing agent (i.e., consistency reducer) for stiff, hard and viscous asphalt binders, increasing their workability and may improve low temperature performance of an asphalt binder by reducing thermal stress development.