复合改性水玻璃固化黄土机理研究

MECHANISM OF LOESS SOLIDIFIED WITH COMPOUND MODIFICATION SODIUM SILICATE

对复合改性水玻璃溶液固化黄土进行了试验研究,并通过化学组成和矿物成分分析、微观结构分析探讨了复合改性水玻璃固化黄土的机理。试验结果表明:复合改性水玻璃固化黄土的强度有明显提高;X射线衍射图谱中密集低矮的非晶质物相峰群仍存在,但是部分矿物衍射强度比普通水玻璃固化的有所升高;SEM图像显示胶凝材料特有的裂纹减少,黏结比较紧密;MIP数据显示复合改性后孔隙表面积增大,最可几孔径减小。复合改性水玻璃溶液固化黄土的强度增加的机理在于:K+的加入使生成的聚合物增多,胶凝裂纹减少、黏结趋于紧密,促使了最可几孔径的减小和小孔隙的增多,强化了骨架颗粒的连接强度,并将骨架颗粒黏结成为一个空间网状整体,从而改善了土体的强度。

Solidification is one of the chemical methods for collapsible loess treatment.For better solidification effect,sodium silicate is modified by various methods.The mechanical strength of loess reinforced with compound modification sodium silicate is studied in this paper.The physical components such as chemical composition and mineral composition,microstructure are tested and analyzed by carrying out X-ray diffraction,scanning electron microscope and mercury porosimeter.The results show that the mechanical strength of reinforced loess is significantly improved.Diffraction intensity of parts of the mineral is increasing in the X-ray diffraction patterns.Low density amorphous phase peak groups still exists.The SEM images show that crack of gel films is reduced,and bonding relatively is tended to close.Surface area of pores is increased and mode pore diameters are reduced after sodium silicate is modified.The mechanism of loess reinforced with the compound modification sodium silicate is due to reinforcement of the bond strength of cement in microstructure and formation of three dimensional networks of frame.