Modification of Asphalt and Asphalt Paving Mixtures by Sulfur Additives

Abstract

Five series of investigations have been undertaken to evaluate the rheological, durability, and chemical effects of sulfur addition to asphalts and asphalt paving mixtures. Sulfur was added to asphalt or asphalt concrete at normal mixing temperature of 150 DEG C. The original and aged (both laboratory and natural) sulfur asphalts, at sulfur-asphalt weight ratios of 0.02 to 1.80, were tested for penetration, ductility, softening point, percent asphaltene, percent total and free sulfur, mixture stability, and hydrogen sulfide evolution. The addition of sulfur to asphalt at working temperature of 150 DEG C resulted in an increase in asphaltene content, percent bonded sulfur, and evolution of hydrogen sulfide. Data also indicated the existence of optimum sulfur concentration for sulfur modification and sulfur-asphalt concrete stability. /Author/