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混凝土损伤层性能劣化规律对研究硫酸盐侵蚀作用下混凝土耐久性具有重要意义。采用超声波平测法,研究了硫酸盐与干湿交替作用下不同水胶比混凝土的损伤层厚度变化规律,从损伤层角度分析了混凝土的损伤劣化特点与性能退化规律,并采用X衍射方法对混凝土中的主要侵蚀产物进行分析。研究结果表明:随着水胶比增大,混凝土中钙矾石和石膏不断增多,氢氧化钙含量逐步减小,宏观表现为混凝土损伤层中超声波速逐渐减小,损伤层厚度增大。当混凝土损伤层越厚、声速越低时,表明其密实度降低,损伤劣化程度增大。通过测量混凝土损伤层厚度,可以有效判断硫酸盐侵蚀作用下混凝土损伤劣化情况。
The performance degradation of concrete damage layer is of great significance to study the durability of concrete under sulfate attack. The variation of damaged layer thickness of concrete with different water-cement ratios was studied by ultrasonic flattening method. The damage characteristics and performance degradation of concrete were analyzed from the damage layer. X-ray diffractometry The main erosion products in concrete are analyzed. The results show that with the increase of water-cement ratio, the content of ettringite and gypsum in concrete increases and the content of calcium hydroxide decreases gradually. The macroscopic manifestation is that the ultrasonic velocity decreases and the thickness of damaged layer increases in the concrete damage layer. When the thickness of concrete damaged layer is thicker, the lower the sound velocity is, the lower the density is and the more the degree of damage degradation is. By measuring the thickness of concrete damaged layer, the deterioration of concrete under the sulfate attack can be effectively judged.