The thermal expansion deformation of concrete is significantly influenced by high temperature and moisture content. Before being heated at elevated temperatures of 100°C, 200°C, and 300°C, the initial moisture content of concrete specimens was maintained at 0%, 3.22%, and 6.55%, respectively. The temperature in the furnace was maintained at the constant temperature until the concrete center also reached the target temperatures. The effects of moisture content and heating temperature on the compressive strength, mass loss, the rate of linear expansion (RLE), and the coefficient of thermal expansion (CTE) were analyzed. The difference of the thermal deformation of concrete before and after the furnace was maintained at the constant temperature were compared. The results showed that when the target temperature was 100°C or 300°C, the relatively lower moisture content resulted in a larger thermal expansion behavior. The RLE and CTE of concrete with the moisture content of 3.22% were the largest when the temperature was up to 200°C, and the volume expansion of concrete rapidly increased under this circumstance. After being heated and maintained at the target temperature until the center temperature of the concrete specimen also reached the target temperature, the RLE and CTE of concrete could be increased by 50% and 30%, respectively. Therefore, the holding time of heating temperature significantly influenced the thermal expansion behavior of concrete.

中文翻译：

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含水率和加热温度对混凝土热膨胀变形的影响

混凝土的热膨胀变形受高温和含水量的显着影响。在 100°C、200°C 和 300°C 的高温下加热之前，混凝土试件的初始含水量分别保持在 0%、3.22% 和 6.55%。炉内温度保持在恒定温度，直到混凝土中心也达到目标温度。分析了水分含量和加热温度对抗压强度、质量损失、线膨胀率（RLE）和热膨胀系数（CTE）的影响。比较了恒温炉前后混凝土热变形的差异。结果表明，当目标温度为 100°C 或 300°C 时，相对较低的水分含量导致较大的热膨胀行为。含水率为3.22%的混凝土的RLE和CTE在温度达到200℃时最大，此时混凝土的体积膨胀迅速增加。加热并保持在目标温度直至混凝土试件中心温度也达到目标温度后，混凝土的RLE和CTE可分别提高50%和30%。因此，加热温度的保持时间显着影响混凝土的热膨胀行为。在这种情况下，混凝土的体积膨胀迅速增加。加热并保持在目标温度直至混凝土试件中心温度也达到目标温度后，混凝土的RLE和CTE可分别提高50%和30%。因此，加热温度的保持时间显着影响混凝土的热膨胀行为。在这种情况下，混凝土的体积膨胀迅速增加。加热并保持在目标温度直至混凝土试件中心温度也达到目标温度后，混凝土的RLE和CTE可分别提高50%和30%。因此，加热温度的保持时间显着影响混凝土的热膨胀行为。