Jiang Hong, Wang Kewei, Wang Hui
School of Municipal and Transportation Engineering, Anhui Water Conservancy Technical College, Hefei 231603, China.
School of Civil Engineering and Geographic Environment, Ningbo University, Ningbo 315000, China.
Materials (Basel). 2023 Aug 14;16(16):5615. doi: 10.3390/ma16165615.
Secondary aluminum ash (SAA) is a type of common solid waste which leads to pollution without treatment. Due to its chemical reactivity, the application of SAA to reactive powder concrete (RPC) may help solidify this solid waste while increasing its performance. However, RPC is usually in active service when used with steel bars. NaCl can corrode the steel bars when reinforced RPC is used in a coastal environment. In this study, the corrosion resistance of reinforced RPC was investigated. The specimens were exposed to an environment of NaCl with freeze-thaw cycles (F-Cs) and dry-wet alternations (D-As). The corresponding mass loss rates (MRs), the electrochemical impedance spectroscopy (EIS) curves and the dynamic modulus of elasticity (DME) were measured. The results show that the MR and the DME of reinforced RPC decrease with increasing values of F-C and D-A. F-C and D-A increases lead to increased electrical resistance (R). The real part value corresponding to the extreme point of the EIS curve is increased by 0213.7% when the SAA is added. The relationship between the imaginary part and the real part of the EIS fits the quadratic function. The equivalent circuit of the reinforced RPC is obtained from the EIS curves. The R of the rust is calculated by using the equivalent circuit. The rust's R decreases in the quadratic function with the mass ratio of the SAA. After 200 NaCl F-Cs, the MR, the DME and the R vary within the ranges of 23.4113.6%, -2.93-4.76% and 4.9213.55%. When 20 NaCl D-As are finished, the MR, the DME and the R vary within the ranges of 34.7202.8%, -13.21-14.93% and 120.48486.39%. The corrosion area rates are 2.368.7% and 28.7125.6% higher after exposure to 200 NaCl F-Cs and 20 NaCl D-As. When the SAA is mixed, the MR is decreased by 013.12%, the DME increases by 03.11%, the R of the reinforced RPC increases by 26.01152.43% and the corrosion area rates are decreased by 21.39~58.62%. This study will provide a novel method for solidifying SAA while improving the chlorine salt resistance of RPC.
二次铝灰（SAA）是一种常见的固体废弃物，未经处理会造成污染。由于其化学反应活性，将SAA应用于活性粉末混凝土（RPC）可能有助于固化这种固体废弃物，同时提高其性能。然而，RPC与钢筋一起使用时通常处于实际服役状态。当在沿海环境中使用钢筋增强RPC时，NaCl会腐蚀钢筋。在本研究中，对钢筋增强RPC的耐腐蚀性进行了研究。将试件暴露于含有冻融循环（F-Cs）和干湿交替（D-As）的NaCl环境中。测量了相应的质量损失率（MRs）、电化学阻抗谱（EIS）曲线和动态弹性模量（DME）。结果表明，钢筋增强RPC的MR和DME随着F-C和D-A值的增加而降低。F-C和D-A的增加导致电阻（R）增大。添加SAA时，EIS曲线极值点对应的实部值增加了0213.7%。EIS虚部与实部的关系符合二次函数。从EIS曲线得到钢筋增强RPC的等效电路。利用等效电路计算锈层的R。锈层的R随SAA质量比呈二次函数下降。经过200次NaCl冻融循环后，MR、DME和R在23.4113.6%、-2.93-4.76%和4.9213.55%范围内变化。当完成20次NaCl干湿交替后，MR、DME和R在34.7202.8%、-13.21-14.93%和120.48486.39%范围内变化。暴露于200次NaCl冻融循环和20次NaCl干湿交替后，腐蚀面积率分别提高了2.368.7%和28.7125.6%。当掺入SAA时，MR降低了013.12%，DME提高了03.11%，钢筋增强RPC的R提高了26.01152.43%，腐蚀面积率降低了21.39~58.62%。本研究将为固化SAA同时提高RPC的抗氯盐性能提供一种新方法。
