Hu Yiqi, Wang Zhuo, Chen Zhilong, Wang Cheng, Ding Shijun, Nie Zhibao, Hou Tianxin, Zhao Gaowen
School of Highway, Chang'an University, Xi'an 710064, China.
Key Laboratory for Special Area Highway Engineering, Ministry of Education, Chang'an University, Xi'an 716400, China.
Materials (Basel). 2024 Sep 11;17(18):4454. doi: 10.3390/ma17184454.
In salt lake areas, the cast-in-situ concrete structure has been corroded by the combination of sulfate and chloride for a long time. The incorporation of basalt fiber materials into concrete helps to improve the durability of concrete. In this paper, experiments were conducted to study the corrosion deterioration mechanisms of basalt fiber-reinforced cast-in-situ concrete under sulfate, chloride, and combined attack. The appearance, size, mass, flexural, and compressive strength of specimens were investigated during the immersion period to determine the changes in the physical and mechanical properties of specimens. Moreover, the microstructure and mineral changes of specimens during the immersion period were observed by Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS), X-ray diffraction (XRD), and Thermogravimetric (TG)/ Derivative Thermogravimetric (DTG) analyses. Results show that premixed chloride has a significant detrimental influence on the strength development of cast-in-situ concrete, with concrete powder spalling occurring on the surface of the specimen. Severe corrosion degradation of specimens occurs under the external sulfate and internal chloride combined attack, resulting in lower flexural and compressive strength. The compressive strength and flexural strength of the corroded specimens decreased by 15.4% and 24.8%, respectively, compared with the control group at 28 days. Moreover, premixed basalt fiber has a beneficial influence on cast-in-situ concrete. When the basalt fiber content is 0.5%, the flexural strength of the specimen is increased by 16.2%. The filling and bridging effect of basalt fiber alleviates the negative effects caused by corrosion. In addition, increasing fiber content is beneficial for enhancing its effectiveness when the fiber content is less than 0.5%. This paper provides a valuable reference for the application of basalt fiber-reinforced cast-in-situ concrete under the condition of sulfate-chloride compound corrosion.
在盐湖地区，现浇混凝土结构长期受到硫酸盐和氯化物的联合侵蚀。在混凝土中掺入玄武岩纤维材料有助于提高混凝土的耐久性。本文通过试验研究了玄武岩纤维增强现浇混凝土在硫酸盐、氯化物及复合侵蚀作用下的腐蚀劣化机理。在浸泡期间对试件的外观、尺寸、质量、抗折和抗压强度进行了研究，以确定试件物理力学性能的变化。此外，通过扫描电子显微镜（SEM）、能谱仪（EDS）、X射线衍射（XRD）和热重（TG）/微商热重（DTG）分析观察了浸泡期间试件的微观结构和矿物变化。结果表明，预拌氯化物对现浇混凝土的强度发展有显著的不利影响，试件表面出现混凝土粉末剥落现象。在外部硫酸盐和内部氯化物的联合侵蚀作用下，试件发生严重的腐蚀劣化，导致抗折和抗压强度降低。与28天龄期的对照组相比，腐蚀试件的抗压强度和抗折强度分别降低了15.4%和24.8%。此外，预拌玄武岩纤维对现浇混凝土有有益影响。当玄武岩纤维含量为0.5%时，试件的抗折强度提高了16.2%。玄武岩纤维的填充和桥接作用减轻了腐蚀造成的负面影响。此外，当纤维含量小于0.5%时，增加纤维含量有利于提高其效果。本文为硫酸盐-氯化物复合腐蚀条件下玄武岩纤维增强现浇混凝土的应用提供了有价值的参考。
