Achieving desired density is crucial for thin asphalt concrete (AC) overlay construction quality control and quality assurance purposes. Ground penetrating radar (GPR) can be implemented for AC pavement layer thickness and density prediction during compaction. However, the overlapping of GPR reflections from surface and bottom of the thin AC overlay, as well as the presence of surface moisture, jeopardizes the prediction accuracy. In this study, a pavement model with thin AC overlay was simulated using gprMax, a finite-difference time-domain-based tool. Surface moisture was simulated as a 2-mm film with mixed electrical properties of water and AC. A nonlinear optimization method was used to address the overlapping and surface moisture issues simultaneously. The error of the thin AC overlay dielectric constant and thickness prediction results was less than 7% and 10%, respectively. Field test during thin overlay compaction was also performed to validate the proposed method. The AC overlay thickness and density estimation accuracies were 91% and 99%, respectively.

中文翻译：

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使用探地雷达数据实时估算压实过程中薄沥青路面覆盖层的密度和厚度

实现所需的密度对于薄沥青混凝土 (AC) 覆盖层施工质量控制和质量保证目的至关重要。探地雷达 (GPR) 可用于在压实过程中进行交流路面层厚度和密度预测。然而，来自薄 AC 覆盖层表面和底部的 GPR 反射的重叠，以及表面水分的存在，危及预测精度。在这项研究中，使用基于有限差分时域的工具 gprMax 模拟了具有薄 AC 覆盖层的路面模型。表面水分被模拟为具有水和 AC 混合电特性的 2 毫米薄膜。非线性优化方法用于同时解决重叠和表面水分问题。薄交流覆盖层介电常数和厚度预测结果的误差分别小于 7% 和 10%。还进行了薄覆盖压实期间的现场测试以验证所提出的方法。AC 覆盖层厚度和密度估计精度分别为 91% 和 99%。