The objective of this research is to evaluate the potential to partially replace the natural aggregates used for roadbase with reclaimed asphalt shingles (RAS). Three percentages of replacement were evaluated, namely 10, 20, and 30%. A control mix without RAS was tested for comparison. The physical properties of the mixtures, including particle size distribution, soundness, and abrasion were measured and compared with local material specifications. Additional laboratory testing to determine the compatibility (ability to achieve compaction), bearing strength, permeability, and shear strength were conducted. Overall, the mixtures would still meet the requirements for particle size distribution, soundness, and abrasion. The mixtures with RAS had a lower dry unit weight and higher optimum moisture content than the control. However, the addition of RAS to the natural aggregates could result in an exponential decrease in its bearing strength. RAS also reduced the permeability of the material. A replacement of 10% natural aggregates with RAS resulted in a 50% reduction in the California Bearing Ratio and an approximate reduction of 80% in the coefficient of permeability. Results from large-scale direct shear also show an increment in the cohesion and a decrease in the internal friction angle with the addition of RAS. A replacement of 10% natural aggregates with RAS resulted in a 20 kPa increase in cohesion, whereas the control material was cohesionless, and a reduction of 20% in the internal friction angle. Overall, it was concluded that replacements of natural aggregates with more than 10% RAS are not recommended for materials similar to those used in this study.

中文翻译：

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再生沥青瓦片部分替代路基骨料的力学性能

本研究的目的是评估用再生沥青瓦 (RAS) 部分替代用于路基的天然集料的潜力。评估了三个替代百分比，即 10%、20% 和 30%。测试不含 RAS 的对照混合物进行比较。测量混合物的物理特性，包括粒度分布、健全性和磨损，并与当地材料规格进行比较。进行了额外的实验室测试，以确定兼容性（实现压实的能力）、承载强度、渗透性和剪切强度。总体而言，混合物仍将满足对粒度分布、健全性和耐磨性的要求。与对照相比，具有 RAS 的混合物具有较低的干单位重量和较高的最佳含水量。然而，向天然骨料中添加 RAS 可能导致其承载强度呈指数下降。RAS 还降低了材料的渗透性。用 RAS 替代 10% 的天然骨料导致加利福尼亚承载比降低 50%，渗透系数降低约 80%。大规模直接剪切的结果还表明，随着 RAS 的加入，内聚力增加，内摩擦角减小。用 RAS 替代 10% 的天然骨料导致内聚力增加 20 kPa，而对照材料无内聚力，内摩擦角降低 20%。总的来说，得出的结论是，对于与本研究中使用的材料类似的材料，不建议用 10% 以上的 RAS 替代天然骨料。