Asphalt Concrete Anti- Stripping Techniques (executive summary)

In 1999 the South Dakota Department of Transportation initiated a research project to assess asphalt concrete anti-stripping techniques. The overall objective of the research was to evaluate the effectiveness of anti-stripping additives in reducing the moisture damage of HMA mixtures. The research evaluated the best method of adding lime to HMA mixtures to minimize personnel exposure and environmental impacts, determined the effectiveness of other anti-stripping additives, and developed guidelines for future use of anti-stripping additives in South Dakota. The research constructed six test sections at two locations in the eastern and western parts of the state, respectively. The test sections included none (control), lime, UP5000, and liquid anti-strip additives. The mixtures were sampled during construction and two years after construction. The moisture sensitivity of the various mixtures was evaluated in the laboratory using resilient modulus, tensile strength, resistance to permanent deformation, and resistance to thermal cracking. The analysis of the laboratory data indicated that the addition of lime has the best potential of reducing the moisture sensitivity of South Dakota's asphalt concrete mixtures. On the other hand, the two years in-service did not show any significant variations in the performance of the various treatments. Based on the data generated from this research, it has been recommended that lime on wet aggregate should be used to minimize moisture damage of asphalt concrete mixtures in South Dakota