水泥基矽土注浆材料抗海水侵蚀性能研究

Study on Seawater Erosion Resistance of Cement⁃Based Silica Grouting Material

为研究水泥基矽土注浆材料抗海水侵蚀性能,根据对工程现场附近海域的海水水化学分析结果配制人工海水溶液,以此对注浆结石体浸泡养护,通过对不同龄期的结石体试件开展抗压强度、L-NMR、XRD、FT-IR和SEM等测试揭示了其在不同侵蚀龄期下的抗侵蚀性能变化规律。研究结果表明:随侵蚀龄期上升,材料抗蚀能力先增大后减小,侵蚀前期由于侵蚀产物“填充效应”和侵蚀离子的“盐激发”效应优化了结石体孔径分布,7 d时抗蚀系数K最大,0.7、1.0和1.5水灰比对应抗蚀系数分别为1.26、1.23和1.18,后逐渐下降;60 d后AFt和Friedel盐等侵蚀产物破坏了硬化浆体结构,小孔转变为大孔,导致抗蚀系数K小于1.0,水灰比1.5时,180 d对应K值仅为0.45,在相同的侵蚀条件下,不同的水灰比表现出的抗蚀性有所差异,水灰比越小,抗蚀性越强,因此在滨海区域使用CIS进行注浆时,应在保证浆液可注性的同时尽量降低水灰比。

To study the seawater erosion resistance of cement-based silica grouting material,an artifi-cial seawater solution was prepared based on the hydrochemical analysis of seawater near the project site.The solution was used to immerse and cure the grouted stone samples.Tests on compressive strength,L-NMR,XRD,FT-IR,and FT-IR,and SEM,were conducted on specimens at different ages to reveal the changes in erosion resistance over time.The results indicate that the corrosion resis-tance of the material initially increased and then decreased with prolonged exposure.In the early stages of erosion,the"filling effect"of erosion products and the"salt excitation"effect of erosion ions opti-mized the pore size distribution of the grouted stone,with the maximum erosion resistance K observed at 7 days.The K values for water-cement ratios of 0.7,1.0 and 1.5 were 1.26,1.23 and 1.18,respec-tively,before gradually decreasing.After 60 days,erosion products like Aft and Friedel's salt compro-mised the hardened grout structure,causing small pores to transform into larger ones,resulting in a K value less than 1.0.At a water-cement ratio of 1.5,the K value at 180 days was only 0.45.Under the same erosion conditions,the erosion resistance varied with different water-cement ratios,with lower ratios exhibiting stronger resistance.Therefore,when CIS is used for grouting in coastal regions,it is recommended to minimize the water-cement ratio while ensuring the injectability of the grout.