Effect of High-Speed Shear Preparation Conditions on Asphalt Aging and Prevention of Asphalt Aging

Abstract

In this research, to study the effect of a high-speed shearing method on asphalt aging, based on SK-70# matrix asphalt, the influences of the shear time, shear rate, shear temperature, shear ring, and air on asphalt aging were investigated by using penetration, a 5°C force ductility value, and a softening point as indexes and a high-shear emulsifier as the shear preparation instrument. The results show that oxygen aging in air is the main factor causing asphalt aging during high-speed shearing in laboratory experiments. A device that prevents asphalt from aging during high-speed shearing was invented. The device and method can effectively eliminate the contact between asphalt and oxygen in the preparation of asphalt and remove the heat generated inside the asphalt. A nitrogen layer is formed on top of the asphalt sample, which can prevent oxidation and reduce the temperature of asphalt to solve the asphalt aging problem in high-speed shear preparation. Subsequently, styrene-butadiene-styrene triblock copolymer (SBS)-modified asphalt was used to carry out relevant tests to verify the equipment and method, which proved the reliability of its preventive effect. This study has important reference significance for reducing the influence of thermal oxidation aging and accurately evaluating the properties of modifiers in the preparation of modified asphalt by a high-speed shear machine, providing important technological measures for the preparation of modified asphalt in the future.