Fiber-optic sensor has drawn wide attention in the non-destructive testing and evaluation of civil engineering materials due to its high accuracy and resolution as well as cost-efficiency. Currently, using optical fiber as the temperature sensor is proposed to conduct the thermal integrity profiling (TIP) of concrete structures. However, concrete is not a thermally homogeneous material as assumed in current studies of concrete TIP. Its essential components, such as aggregates may cause thermal inhomogeneity problems when implementing fiber-optic sensors for TIP. In this paper, we use the concrete structures with different grades of aggregates to conduct numerical simulation for non-destructive thermal testing. The goal is to investigate how the thermal inhomogeneity caused by aggregates would influence the testing result. Firstly, we establish three concrete structure models with three different grades of aggregates based on the scenarios where these concrete structures will be used. Then, we numerically simulate the thermal process on these models and extract the temperature at the location where optical fiber would be installed. The influence caused by the inhomogeneity of aggregate size and distribution as well as the possible method to minimize the effect are evaluated in the paper. Overall, aggregates of concrete have a significant influence on the accuracy of TIP analysis, and defects could be veiled if no proper treatment to the data is implemented for TIP analysis.

光纤传感器由于其高精度，高分辨力和高成本效益而在土木工程材料的无损检测和评估中引起了广泛的关注。当前，提出使用光纤作为温度传感器来进行混凝土结构的热完整性分析（TIP）。然而，混凝土不是如目前对混凝土TIP的研究所假定的热均质材料。当其为TIP实施光纤传感器时，其基本组件（例如聚集体）可能会导致热不均匀性问题。在本文中，我们使用不同等级骨料的混凝土结构进行无损热测试的数值模拟。目的是研究骨料引起的热不均匀性如何影响测试结果。首先，我们将根据使用这些混凝土结构的场景，建立具有三种不同等级的骨料的三个混凝土结构模型。然后，我们在这些模型上数值模拟热过程，并提取将要安装光纤的位置的温度。本文评估了由于骨料尺寸和分布的不均匀性所造成的影响，以及可能使作用最小化的方法。总体而言，混凝土骨料对TIP分析的准确性有重大影响，如果未对TIP分析进行适当的数据处理，则可能掩盖缺陷。我们在这些模型上用数值模拟了热过程，并提取了将要安装光纤的位置的温度。本文评估了由于骨料尺寸和分布的不均匀性所造成的影响，以及可能使作用最小化的方法。总体而言，混凝土骨料对TIP分析的准确性有重大影响，如果未对TIP分析进行适当的数据处理，则可能掩盖缺陷。我们在这些模型上用数值模拟了热过程，并提取了将要安装光纤的位置的温度。本文评估了由于骨料尺寸和分布的不均匀性所造成的影响，以及可能使作用最小化的方法。总体而言，混凝土骨料对TIP分析的准确性有重大影响，如果未对TIP分析进行适当的数据处理，则可能掩盖缺陷。