Evaluation of Isolane-SP as an Anti-Strip Additive in Hot Mix Asphalt Mixtures
AuthorAbou Sejaan, Vladimir
AdvisorHand, Adam J.T.
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Moisture damage of asphalt pavements has been a fundamental topic in the past few years. These pavements are designed to perform well in resisting heavy loads and high traffic volumes. However, when winter comes and the water infiltrates into the pavement, it freezes, and stripping occurs and therefore triggering other modes of failures. This is where Anti-Strip additives come to place. Historically, Lime has shown to be an effective additive on the issue of stripping. However, Lime treatment is expensive, and companies are trying to find alternatives with other chemicals or Liquid Anti-Strip additives. The literature shows that Liquid Anti-Strip additives have demonstrated an effective way to solve the stripping issue; however, the chemical components of the asphalt binders and aggregates are complex and one Anti-Strip additive will not be operative with all asphalt binders and aggregate sources. Isolane-SP, a new Liquid Anti-Strip additive in the market, has shown encouraging results for the past few years. Because of the outcomes recorded previously with Isolane-SP outside Nevada and California, University of Nevada Reno has put Isolane-SP to test. This project consisted of studying the effects of Isolane-SP on two different asphalt binders, one from Nevada and one from California, in order to comprehend whether the chemicals of the additive and asphalt binder are compatible or not: as a consequence, it was deductible that the addition of Isolane-SP to the asphalt binder made it more susceptible for cracking. Furthermore, this project consisted of treating four sources of aggregates (Lockwood, Rocky Ridge, Hat Creek, and Western Nevada Materials) with Isolane-SP in order to waterproof the aggregates: the tests were positive, however, after leaving the aggregates in open air, Isolane-SP oxidized, and the aggregates absorbed the water. Additionally, two asphalt mixtures, based on Nevada and California specification, were tested against moisture damage using Tensile Strength Ratio test and following it with Hamburg Wheel-Track test. Isolane-SP did not show the effectiveness anticipated and another additive called Isolane-SP2 was proposed. Isolane-SP2 did show better results, however, the outcomes were not enough for the product to be an effective replacement of Lime that is currently used in Nevada and California against stripping and moisture damage.