Wei Hong, Fan Yanan, Sun Lei, Du Hongxiu, Liang Renwang
College of Civil Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
Materials (Basel). 2022 Mar 25;15(7):2436. doi: 10.3390/ma15072436.
In this study, the effects of soybean-urease-induced carbonate precipitation on a high-temperature damage repair of concrete were explored. C50 concrete specimens were exposed to high temperatures from 300 to 600 °C, then cooled to an ambient temperature and repaired by two different methods. The influences of the damage temperature and repair methods on surface film thickness, average infrared temperature increase, water absorption, and compressive strength were investigated. Scanning electron microscopy (SEM) images were carried out to further study the mechanism involved. The results revealed that the white sediments on the surface of the repaired specimens were calcium carbonate (CaCO) and calcium oxalate (CaCO). The surface film thickness reached up to 1.94 mm after repair. The average infrared temperature increase in the repaired specimens at different damage temperatures was averagely reduced by about 80% compared with that before the repair. It showed more obvious repair effects at higher temperatures in water absorption and compressive strength tests; the compressive strength of repaired specimens was 194% higher than that before repairs at 600 °C. A negative pressure method was found to be more effective than an immersion method. This study revealed the utilization of SICP on repairing high-temperature damage of concrete is feasible theoretically.
本研究探讨了大豆脲酶诱导的碳酸盐沉淀对混凝土高温损伤修复的影响。将C50混凝土试件暴露于300至600°C的高温下，然后冷却至室温，并采用两种不同方法进行修复。研究了损伤温度和修复方法对表面膜厚度、平均红外温度升高、吸水率和抗压强度的影响。通过扫描电子显微镜（SEM）图像进一步研究其作用机理。结果表明，修复后试件表面的白色沉积物为碳酸钙（CaCO₃）和草酸钙（CaC₂O₄）。修复后表面膜厚度达到1.94mm。修复后不同损伤温度下试件的平均红外温度升高与修复前相比平均降低了约80%。在吸水率和抗压强度试验中，高温下显示出更明显的修复效果；在600°C时，修复后试件的抗压强度比修复前提高了194%。发现负压法比浸泡法更有效。本研究表明，利用大豆脲酶诱导的碳酸盐沉淀修复混凝土高温损伤在理论上是可行的。
