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首页> 外文OA文献 >Improvements to a Transport Model of Asphalt Binder Oxidation in Pavements: Pavement Temperature Modeling, Oxygen Diffusivity in Asphalt Binders and Mastics, and Pavement Air Void Characterization
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Improvements to a Transport Model of Asphalt Binder Oxidation in Pavements: Pavement Temperature Modeling, Oxygen Diffusivity in Asphalt Binders and Mastics, and Pavement Air Void Characterization

机译：路面沥青结合料氧化运输模型的改进：路面温度模型，沥青粘合剂和胶乳中的氧气扩散率以及路面空洞特性

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摘要

Although evidence is mounting that asphalt binder oxidizes in pavements, and that oxidation and subsequent hardening of asphalt binder has a profound effect on pavement durability, important implementation issues remain to be better understood. Quantitative assessment of asphalt binder oxidation for a given pavement is a very important, but complex issue. In this dissertation, a fundamentals-based oxygen transport and reaction model was developed to assess quantitative asphalt binder oxidation in pavements. In this model, oxygen transport and reaction were described mathematically as two interlinked steps: 1) diffusion and/or flow of oxygen from the atmosphere above the pavement into the interconnected air voids in the pavement; and 2) diffusion of oxygen from those air voids into the adjoining asphalt-aggregate matrix where it reacts with the asphalt binder. Because such a model calculation depends extensively on accurately representing pavement temperature, understanding oxygen diffusivity in asphalt binders and mastics, and characterizing air voids in pavements, these key model elements were studied in turn. Hourly pavement temperatures were calculated with an improved one-dimensional heat transfer model, coupled with methods to obtain model-required climate data from available databases and optimization of site-specific pavement parameters nationwide; oxygen diffusivity in binders was determined based on laboratory oxidation experiments in binder films of known reaction kinetics by comparing the oxidation rates at the binder surface and at a solid-binder interface at the film depth. The effect of aggregate filler on oxygen diffusivity also was quantified, and air voids in pavements were characterized using X-ray computed tomography (X-ray CT) and image processing techniques. From these imaging techniques, three pavement air void properties, radius of each air void (r), number of air voids (N), and average shell distance between two air voids (rNFB) were obtained to use as model inputs in the asphalt binder oxidation model. Then, by incorporating these model element improvements into the oxygen transport and reaction model, asphalt binder oxidation rates for a number of Texas and Minnesota pavements were calculated. In parallel, field oxidation rates were measured for these corresponding pavement sites and compared to the model calculations. In general, there was a close match between the model calculations and field measurements, suggesting that the model captures the most critical elements that affect asphalt binder oxidation in pavements. This model will be used to estimate the rate of asphalt binder oxidation in pavements as a first step to predicting pavement performance, and ultimately, to improve pavement design protocols and pavement maintenance scheduling.
机译：尽管有越来越多的证据表明沥青粘合剂在人行道上被氧化，并且沥青粘合剂的氧化和随后的硬化对人行道的耐久性产生了深远的影响，但重要的实施问题仍有待更好地理解。对于给定的路面，沥青粘合剂氧化的定量评估是一个非常重要但复杂的问题。本文建立了一种基于基本原理的氧气输送和反应模型，以评估路面中沥青胶结剂的定量氧化。在该模型中，氧气的输送和反应在数学上被描述为两个相互关联的步骤：1）氧气从人行道上方的大气扩散和/或流动到人行道中相互连接的空隙中； 2）氧气从这些空气中扩散到邻接的沥青-骨料基体中，并在其中与沥青粘结剂反应。由于这种模型计算在很大程度上取决于准确表示路面温度，了解沥青结合料和胶泥中的氧气扩散率以及表征路面中的空隙，因此依次研究了这些关键模型元素。使用改进的一维传热模型计算小时路面温度，结合使用方法从可用数据库中获取模型所需的气候数据，并在全国范围内优化特定地点的路面参数；根据实验室氧化实验，在已知反应动力学的粘合剂膜中，通过比较粘合剂表面的氧化速率和膜深度处的固体-粘合剂界面的氧化速率，确定粘合剂中的氧扩散率。还定量了骨料填料对氧气扩散性的影响，并使用X射线计算机断层扫描（X射线CT）和图像处理技术来表征人行道中的空隙。通过这些成像技术，获得了三种路面气隙特性，每个气隙的半径（r），气隙的数量（N）以及两个气隙之间的平均壳距（rNFB），以用作沥青粘合剂中的模型输入氧化模型。然后，通过将这些模型元素改进内容纳入氧气传输和反应模型中，计算了许多德克萨斯州和明尼苏达州路面的沥青粘合剂氧化速率。同时，测量了这些相应的路面的现场氧化速率，并与模型计算结果进行了比较。通常，模型计算与现场测量之间存在密切匹配，这表明该模型捕获了影响路面沥青结合料氧化的最关键元素。该模型将用于估算路面中沥青粘结剂的氧化速率，以此作为预测路面性能的第一步，并最终改善路面设计协议和路面维护计划。

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  • 作者

    Han Rongbin;

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  • 年度 2011
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  • 正文语种 en_US
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