13 Recycled Concrete Aggregates are highly porous and may therefore absorb more water 14 than natural aggregates. Several methods allow for the measurement of water 15 absorption requiring drying at temperature above ambient conditions. We show here 16 that, for temperatures above the ambient temperature (> 30°C) and at low relative 17 humidity, the drying of recycled aggregates removes some bounded water contained in 18 hardened cement paste and increases both measured porosity and water absorption. 19 Porosity and XRD suggest that porosity increases due to ettringite dehydration. Thus, 20 the drying step required to characterize recycled aggregates leads to a systematic 21 overestimation of the water absorption. Moreover, this overestimation induces an error 22 in mix-design leading to a higher effective water/cement ratio. If absorption and water 23 content are measured with the same preparation protocol, correction is not needed. We 24 finally propose a correction method for the water absorption measured according to the 25 standard protocol (drying at 105°C).

中文翻译：

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再生骨料的吸水率：测量、温度影响和实际后果

13 再生混凝土集料是高度多孔的，因此可能比天然集料吸收更多的水 14。几种方法允许测量需要在高于环境条件的温度下干燥的水 15 吸收。我们在这里 16 表明，对于高于环境温度 (> 30°C) 和相对较低的 17 湿度，再生骨料的干燥去除了 18 硬化水泥浆中包含的一些结合水，并增加了测量的孔隙率和吸水率。19 孔隙率和 XRD 表明，由于钙矾石脱水，孔隙率增加。因此，20 表征再生骨料所需的干燥步骤会导致系统性 21 高估吸水率。此外，这种高估会导致混合设计中的错误 22，从而导致更高的有效水灰比。如果使用相同的制备方案测量吸收和水 23 含量，则不需要校正。我们 24 最后提出了根据 25 标准协议（105°C 干燥）测量的吸水率的校正方法。