Comparison of Pelletized Lime with Other Anti-Stripping Additives

摘要

Project performed in cooperation with the Oregon Department of Transportation and the Federal Highway Administration Stripping is a common problem in HMA pavements in Oregon, especially in Eastern Oregon. Stripping is the degradation of the bond between the aggregate and the asphalt binder due to the presence of water this mechanism of degradation can lead to loss of capacity and cracking in the pavement. A common additive used in the industry to mitigate stripping damage is powdered lime. However, challenges with air-borne powdered lime have SHAs investigating alternatives to powdered lime. The purpose of this study was to determine the effectiveness of potential alternatives to powdered lime additive in preventing stripping. This research evaluated the moisture susceptibility of five anti-stripping additives with three separate aggregates. The aggregates exhibited a range of potential stripping from not susceptible to susceptible. Results indicate that Aggregates 1 and 3 are likely susceptible to stripping, with Aggregate 3 likely being the most susceptible. Powdered lime increased the TSR and ECS ratios for the susceptible aggregates. Mixtures with Additive 4 exhibited similar performance to mixes containing powdered lime. Additive 2 exhibited improved performance compared to the control but TSR and ECS ratios were lower than the specimens with powdered lime. Results from mixtures with Additive 3 exhibited limited improvements in TSR and ECS ratios. Additives 4 and 2 should be considered for future use in HMA when stripping could be an issue.