文献类型：期刊文献

英文题名：Resistance of blended alkali-activated fly ash-OPC mortar to mild-concentration sulfuric and acetic acid attack

作者：Chen, Keyu[1];Wu, Dazhi[1];Fei, Sijia[2];Pan, Chonggen[3];Shen, Xinyuan[4];Zhang, Chaoxia[5];Hu, Juntao[1]

机构：[1]Zhejiang Sci Tech Univ, Sch Civil Engn & Architecture, Hangzhou 300018, Peoples R China;[2]Shanghai T&D Architectural Sci & Technol Co Ltd, Shanghai 200092, Peoples R China;[3]Ningbo Tech Univ, Sch Civil Engn & Architecture, Ningbo 315100, Peoples R China;[4]Shaoxing Univ, Sch Math Informat, Shaoxing 312000, Peoples R China;[5]Zhejiang Sci Tech Univ, Sch Mat Sci & Engn, Hangzhou 300018, Peoples R China

年份：2022

卷号：29

期号：17

起止页码：25694

外文期刊名：ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

收录：SCI-EXPANDED(收录号：WOS:000723546800006)、、EI(收录号：20242616347568)、Scopus(收录号：2-s2.0-85120039866)、WOS

基金：The authors sincerely thank the financial support from the National Natural Science Foundation of China (Grant No. 51678533), Zhejiang Province Basic Public Welfare Research Project (Grant No. LGG21E080012, LGG21E080006), Ningbo 2025 Science and Technology Major Project (Grant No. 2019B10049, 2020Z035, 2020Z040), Ningbo Education Science Planning Project (Grant No. 2019YGH025). The authors also thank the ANN technological support from T&D Architectural Science and Technology Co. Ltd.

语种：英文

外文关键词：Alkali-activated material; Fly ash; Acid resistance; Mild concentration; Microstructure

外文摘要：The traditional cementitious product is prone to suffer from a high degree of deterioration in the case of exposure to acid solutions because of the decomposition of the binder network. However, the degradation of concrete structures in service by mild concentrations of acid under conditions involving sewage, industrial waters, and acid rain is more common and results in a significant environmental problem. The utilization of alkali-activated materials has been seen to potentially offer an attractive option with regard to acceptable durability and a low carbon footprint. With the aid of visual observation, mass loss, compressive strength tests, X-ray diffraction, Fourier transform infrared spectroscopy, and field-emission scanning electron microscopy with energy-dispersive X-ray spectroscopy, the acid resistance of alkali-activated fly ash mortars in which the precursor was partially replaced (0-30% by mass proportion) with ordinary Portland cement (OPC) was evaluated after 180 days of exposure to mild-concentration sulfuric and acetic solutions (pH = 3). A conventional cement mortar (100% OPC) was used as a reference group. The results demonstrate that the addition of OPC into the alkali-activated system causes a significant increase in compressive strength (around 16.08-36.61%) while showing an opposite influence on durability after acid attack. Based on a linear mean value and nonlinear artificial neural network model simulation, the mass losses of the specimens were evaluated, and the alkali-activated pure-fly ash mortar demonstrated the lowest value (i.e., a maximum of 5.61%) together with the best behavior in the aspect of discreteness at 180 days. The results from microstructure analysis show that the coexistence of the N-A-S-H and C-S-H networks in the blend system occurred by both OPC hydration and FA. However, the formation of the gypsum deposition within the fly ash-OPC blend systems at sulfuric acid was found to impose internal disintegrating stresses, causing a significant area of delamination and cracks. In addition, alkali metal ion leaching, dealumination, as well as the disappearance of some crystalline phases occurred in specimens immersed in both types of acids.