Sensors for pH evaluation of concrete were made by a sol-gel process with alizarin yellow as pH indicator. The optical absorbance was measured with a visible spectrophotometer coupled with optical fibers. Results showed that the sensors had good reversibility, reproducibility, and fast response time.

中文翻译：

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溶胶-凝胶包埋的 pH 指示剂，用于监测胶凝材料的 pH 变化

用茜素黄作为pH指示剂，通过溶胶-凝胶法制备了用于混凝土pH值评估的传感器。用可见光分光光度计与光纤耦合测量吸光度。结果表明，该传感器具有良好的可逆性、重现性和快速的响应时间。