Delamination is a serious form of deterioration in concrete bridge decks. Infrared thermography (IRT) is an advance non‐destructive testing method for concrete bridge deck delamination detection by capturing the absolute thermal contrast (ΔT) on the concrete surface caused by the disruption in heat flow due to subsurface defects. However, as the ambient environmental conditions (e.g. wind velocity and solar radiation) of a bridge could significantly affect the measurement outcomes of IRT, the optimal times for infrared data collection are still unclear. In this paper, a series of experimental and numerical studies were carried out to investigate the effects of the rate of heat flux and wind velocity on ΔT on the surface of bridge decks with the aim of identifying the optimal inspection times for different geometry characteristics of delamination (i.e. size and depth). The developed model is firstly validated by the experimental data and then a series of parametric studies were carried out. The result shows that the heat flux rate plays an important role in the development of ΔT on concrete surface, especially for a relatively shallow and small size delamination. However, the influence of heat flux rate gradually diminishes with the increase in size and depth of delamination. In addition, it demonstrates that there is a positive linear correlation between the total heat energy (external irradiation) and square of the delamination depth. The current research represents an important step towards the development of an effective and efficient way for defect detection using IRT.

中文翻译：

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周围环境条件对使用红外热像仪（IRT）检测桥梁混凝土面板分层的影响

分层是混凝土桥面板中严重的恶化形式。红外热成像（IRT）是一种先进的非破坏性测试方法，可用于混凝土桥面板脱层检测，方法是捕获由于地下缺陷引起的热流中断而在混凝土表面产生的绝对热对比度（ΔT）。但是，由于桥梁的周围环境条件（例如风速和太阳辐射）可能会严重影响IRT的测量结果，因此仍不清楚红外数据收集的最佳时间。在本文中，进行了一系列实验和数值研究，以研究热通量和风速对桥面板表面ΔT的影响，目的是确定不同分层几何特征（即尺寸和厚度）的最佳检查时间。深度）。首先通过实验数据验证了所开发的模型，然后进行了一系列参数研究。结果表明，热通量率在混凝土表面ΔT的发展中起着重要作用，尤其是对于相对较浅和较小尺寸的分层而言。然而，热通量率的影响随着分层的大小和深度的增加而逐渐减小。此外，它表明总热能（外部辐射）与分层深度的平方之间存在正线性关系。当前的研究代表了迈向使用IRT进行缺陷检测的有效途径的重要一步。