用原位合成吸水性树脂表层处理方法提高混凝土耐硫酸盐腐蚀性

硫酸盐腐蚀是导致混凝土耐久性劣化的一个重要因素.用原位合成吸水性树脂对混凝土表面处理,为改善混凝土耐硫酸腐蚀提出了一种新方法,即利用高吸水性树脂预聚溶液浸渍混凝土,经红外辐射引发自由基共聚反应原位合成吸水性树脂,通过合成的吸水性树脂吸水膨胀、密实微裂缝或孔隙,截断硫酸盐侵蚀性介质的传输路径提高混凝土抗硫酸盐腐蚀能力.通过试验,研究了硫酸钠溶液在水泥砂浆(处理前后)中的渗透状况,并利用扫描电镜、X射线衍射分析了混凝土受硫酸盐腐蚀的特征.结果表明:用原位合成高吸水性树脂处理砂浆后,能显著降低50 g/L硫酸钠溶液在水泥砂浆内部的渗透速度;经50次硫酸钠溶液干/湿循环处理后的水泥砂浆表现出良好的抗硫酸盐腐蚀性能.

IMPROVEMENT OF THE SULFATE CORROSION RESISTANCE OF CONCRETE BY SURFACE TREATMENT USING SUPER-ABSORBENT RESIN SYNTHESIZED IN SITU

Sulfate attack is a key factor that results in the deterioration of concrete. A novel method was presented to improve the sulfate corrosion resistance of concrete with surface treatment by super-absorbent resin (SAR) synthesized in situ, i.e., a prepolymer solution of SAR soaked into the capillary pores of hardened concrete, initiated by infrared ray and synthesized SAR according to radical copolymerization, and then after water had been absorbed, the swollen SAR filled the capillary pores, thus prevening external sulfate penetration into the concrete. The osmosis of SO42-in cement mortar was compared before and after treatment by SAR. The sulfate corrosion characteristic of cement mortar was confirmed by scanning electron microscopy and X-ray diffraction. The laboratory testing results indicate that the osmosis of 50 g/L sodium sulfate solution in cement mortar treated by SAR was evidently reduced, and the cement mortar specimens treated by SAR has not been severely deteriorated after 50 cycles of sodium sulfate solution immersion.