CICECO-Aveiro Institute of Materials, DEMaC-Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
Sensors (Basel). 2022 Jul 18;22(14):5356. doi: 10.3390/s22145356.
The sulfuric acid attack is a common form of degradation of reinforced concrete in contact with industrial wastewater, mine water, acid rain, or in sewage treatment stations. In this work, new pH-sensitive IrOx electrodes were developed for monitoring the pH inside mortar or concrete. To test their ability, the pH sensors were embedded in mortar samples at different depths and the samples were exposed to sulfuric acid solution. In another set of experiments, iron wires were placed at the same depths inside similar mortar samples and their corrosion was monitored as the acid attacked the mortar. Severe acid attack led to cement dissolution and formation of gypsum. The new pH sensors succeeded in measuring the pH changes inside the mortars. The pH gradient, from the high acid environment to the high alkaline mortar interior, occurred in a narrow region. Corrosion of the iron electrodes started only when the acidic solution was in their close vicinity.
硫酸侵蚀是接触工业废水、矿井水、酸雨或在污水处理站的钢筋混凝土常见的降解形式。在这项工作中，开发了新的 pH 敏感 IrOx 电极用于监测砂浆或混凝土内部的 pH 值。为了测试它们的能力，将 pH 传感器嵌入到不同深度的砂浆样品中，并将样品暴露在硫酸溶液中。在另一组实验中，将铁丝放置在类似的砂浆样品中相同的深度，监测当酸侵蚀砂浆时铁丝的腐蚀情况。严重的酸侵蚀导致水泥溶解和石膏形成。新的 pH 传感器成功地测量了砂浆内部的 pH 值变化。从高酸环境到高碱性砂浆内部的 pH 值梯度发生在一个狭窄的区域内。只有当酸性溶液靠近铁电极时，铁电极才开始腐蚀。
