Very Thin Overlays in Texas
Very Thin Overlays in Texas
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DOI：
10.1016/j.conbuildmat.2015.07.157
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发表时间：
2015-10
影响因子：
7.4
通讯作者：
Dar-Hao Chen;T. Scullion
中科院分区：
文献类型：
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作者：
Dar-Hao Chen;T. Scullion
由于超薄覆盖层（VTO）在重铺路面作业中具有经济可行性，TxDOT正在扩大其使用范围。目前，VTO混合料的厚度为25毫米（或更少），而不是50毫米，每平方码的成本比传统的致密分级材料低30%。薄垫在许多城市环境中也是理想的，并且非常适合许多维护应用。本文总结了为保证薄覆盖层工程的成功而制定的规范的要求和合理性。为了评估VTO混合物的性能，选择了三个现场项目，并为每个地点设计了使用当地材料的混合物。到目前为止，VTO的性能一直非常好，具有优异的防滑性和抗裂性。与任何覆盖层一样，最终的IRI也会受到原有平顺性的影响，但粗糙度降低的典型范围约为35-50%。为了减轻现有密封涂层的低打滑和出血，构建了精细的PFC选项（19 mm），其高空隙率大于20%。自由沥青不会迁移到表面，薄PFC确实增加了400%的防滑性，并大大降低了轮胎路面的噪音。到目前为止，地区工作人员对VTO的性能非常满意，更多的路面路段已计划放置相同的VTO混合料。
TxDOT is expanding its use of Very Thin Overlays (VTO) as they are economically viable in resurfacing operations. Currently, the VTO mixes are placed at thicknesses of 25 mm (or less) rather than 50 mm mats and they are 30% less expensive per square yard than the traditional dense graded materials. The thin mats are also ideal in many urban situations and highly desirable for many maintenance applications. This paper summarized the requirements and rational of the specifications that were developed to ensure successful thin overlay projects. To evaluate the performance of VTO mixtures, three field projects were selected and mixtures were designed for each location using local materials. The VTO performance to date has been very good with excellent skid resistance and crack resistance. Like any overlay, the final IRI is impacted by the pre-existing ride, but the typical range of reduction on roughness is about 35–50%. To mitigate low skid and bleeding of existing seal coat, fine PFC option (19 mm) with a high air void of greater than 20% was constructed. The free asphalt did not migrate to the surface and the thin PFC did increase skid resistance by 400% and substantially reduced tire-pavement noise. District staffs are very pleased with the VTO performance to date, more pavement sections have been scheduled to place the same VTO mixes.