Valencia-Saavedra William, Aguirre-Guerrero Ana María, Mejía de Gutiérrez Ruby
Composite Materials Group (GMC-CENM), Universidad del Valle, Cali 76001, Colombia.
Molecules. 2022 Aug 19;27(16):5296. doi: 10.3390/molecules27165296.
Hybrid alkali-activated cements (HAACs), also known as cements with high percentages of alkali-activated supplementary materials, are alternative cements that combine the advantages of ordinary Portland cement (OPC) and alkali-activated systems. These cements are composed of a minimum of 70% precursor material and a maximum of 30% OPC mixed with an alkaline activator. This article evaluates the corrosion performance of reinforced HAAC concrete based on fly ash (FA) under exposure to chlorides (FA/OPC, 80/20). Its performance is compared with that of a binary alkali-activated cement (AAC) based on FA and granulated blast furnace slag (GBFS) (FA/GBFS, 80/20). The tests performed on the concrete matrix correspond to the compressive strength and permeability to chloride ions. Using accelerated corrosion techniques (impressed voltage) and electrochemical tests after immersion in 3.5% NaCl, the progress of the corrosive process in the reinforcing steel is evaluated. The FA/OPC exhibit a better corrosion performance than the FA/GBFS concrete. At the end of the exposure to chlorides, the FA/OPC hybrid concrete presents the best performance, with a 49% lower corrosion rate than that of the FA/GBFS. Note that according to the polarization curves, the values of the proportionality constant B in the alkaline-activated concretes differ from the values recommended for concrete based on OPC.
混合碱激发水泥（HAACs），也被称为高比例碱激发辅助材料水泥，是结合了普通硅酸盐水泥（OPC）和碱激发体系优点的替代水泥。这些水泥由至少70%的前驱体材料和至多30%的OPC与碱性激发剂混合而成。本文评估了基于粉煤灰（FA）的增强HAAC混凝土在氯化物环境（FA/OPC，80/20）下的腐蚀性能。将其性能与基于FA和粒化高炉矿渣（GBFS）的二元碱激发水泥（AAC）（FA/GBFS，80/20）的性能进行了比较。对混凝土基体进行的测试包括抗压强度和氯离子渗透性。使用加速腐蚀技术（外加电压）以及在浸泡于3.5%NaCl后进行电化学测试，评估了钢筋中腐蚀过程的进展。FA/OPC表现出比FA/GBFS混凝土更好的腐蚀性能。在氯化物暴露结束时，FA/OPC混合混凝土表现出最佳性能，其腐蚀速率比FA/GBFS混凝土低49%。需要注意的是，根据极化曲线，碱激发混凝土中的比例常数B值与基于OPC的混凝土推荐值不同。
