New Millimeter-Wave Heterodyne Interferometric Reflectometry Technique for Fast and Accuraate Assessment of Pavement Surface Condition

公路路面的纹理和横断面测量对公路安全至关重要。它的质地提供了防滑能力，而横向轮廓决定了表面排水。目前，高速公路机构无法实时测量这些特性。高精度激光正在研究中，但这些激光很脆弱，而且成本高昂，无法全面实施。这项研究将集中于研究和开发一种新的快速、准确和低成本的实时测量路面特性的技术，包括横向剖面、微观和宏观纹理以及检测新建沥青路面中的混合料离析区域。这项新技术将对安全和新的施工质量控制产生重大影响。这项新技术将基于使用毫米波在90到100 GHz的甚高频范围内实现的外差、反射和干涉测量的原理。反射法用于微波和光学中的反射测量。外差干涉法作为精确测量电子材料表面粗糙度的最佳方法之一，在光学领域得到了广泛的应用。与其他技术相比，毫米波具有两个独特的特征，这可以解释为准确的非破坏性、非接触式高分辨率表面测量：更高的频率和更大的绝对带宽。这些特点结合在一起，可以生产出分辨率非常高、尺寸很小的系统。所提出的技术似乎是最好的候选技术，可以满足本项目中解决的路面问题所需的所有关键技术指标，即快速准确的测量、非常精细的分辨率、低成本和小尺寸。本研究的主要目的有四个。第一个目标是研究和开发一种在90到100 GHz频率范围内的新型毫米波轮廓仪。第二个目标是分析表面反射和干涉图案。这对于准确的数据采集和测量结果的处理是必需的。第三个目标是制作评估新传感器所需的各种实验室测试样本。第四个目标是在实验室和现场测试中对新传感器进行评估。这项拟议的新技术尚未被研究和开发用于土木工程应用。因此，它不仅将为这里解决的路面问题提供独特的解决方案，而且还应该开辟一系列新的应用，这些应用在现有的技术和系统中是不可行的。这种用于路面应用的新技术的成功研究和开发将证明在90到100 GHz范围内使用毫米波进行高分辨率路面测量的可行性，并为未来研究和开发用于土木工程应用的先进的低成本毫米波传感器铺平道路。因此，拟议的研究应该会对土木工程目前和未来的一些应用产生强烈的影响。

Texture and Transverse profile measurements of highway surfaces are critical for highway safety. It is the texture which provides skid resistance and the transverse profile that dictates surface drainage. Currently, highway agencies can not measure these properties in real time. High accurancy lasers are under investigation but these are fragile and cost prohibitive for full-scale implementation. The proposed research will focus on the research and development of a new fast, accurate, and low-cost technique for measuring pavement surface characteristics in real time, including transverse profiles, micro and macro textures, and detecting areas of mix segregation in newly constructed asphalt surfaces. This new technology will have a major impact on both safety and new construction quality control. The new technique will be based on the principles of heterodyne, reflectmetry, and interferometry implemented using millimeter waves in the very high frequency range of 90 to 100 GHz. Reflectometry is used in microwaves and optics for reflection measurement. Heterodyne interferometry is used in optics as one of the best methods for accurate measurment of surface roughness of electronic materials. Compared to other technologies, millimeter waves have two uniquely distinct characteristics, which can be explained for accurate non-destructive, non-contact high-resolution surface measurements: higher frequencies and larger absolute bandwidths. These characteristics together can produce systems that have very fine resolution and small size. The proposed technique appears to be the best candidate that can meet all the key specifications required for the pavement problems addressed in this project, namely fast and accurate measurement, very fine resolution, low cost, and small size. There are four major objectives in this research. The first objective is to research and develop a new millimeter-wave profilometer in the frequency range of 90 to 100 GHz. The second objective is to analyze surface reflections and interference patterns. This is needed for accurate data acquisition and processing of the measured results. The third objective is to fabricate various laboratory test specimens needed for the evaluation of the new sensor. The fourth objective is to evaluate the new sensor in both laboratory and field tests. The proposed new technique has not yet been studied and developed for civil engineering applications. It thus not only will provide a unique solution for the pavement surface problems addressed here, but also should open up a whole range of new applications, which have not been feasible with available techniques and systems. Successful research and development of this novel technique for pavement applications will demonstrate feasibility of using millimeter waves in the 90 to 100 GHz range for high-resolution pavement surface measurements, and pave the way for future research and developments of advanced low-cost millimeter-wave sensors for civil engineering applications. The research proposed should therefore have a strong impact on a number of current and future applications of civil engineering.