Raw soil building materials are materials that use unroasted soil as the main raw material and are used in construction projects after forming and processing. Soil materials have been one of the main building materials in China since ancient times, and there are still complete soil buildings in many areas. This is because the soil material can use local materials, return to nature after damage, greatly reduce the construction cost, reduce energy consumption, while the soil material also has the characteristics of humidity control, air permeability, fire prevention, etc., to create a suitable indoor environment for human beings. However, the traditional soil materials have the disadvantage of poor water resistance, which limits their further promotion and application. It has become an urgent problem to find ways to overcome the defects such as poor water resistance of soil materials.

The main mechanism of silicone oil emulsion as a water-repellent agent for raw soil is that silicone oil emulsion can form a hydrophobic film on the surface of raw soil, slow down the erosion of water on raw soil, and improve the water repellency of raw soil. However, in the process of preparing silicone oil emulsion, because the silicone oil itself is not easy to be emulsified, and with the increase of viscosity, it becomes more difficult to be completely emulsified, so selecting the appropriate emulsifier and emulsifying process is helpful to obtain excellent performance of silicone oil emulsion. But now researchers have found a good solution.

In this paper, the silicone oil with high viscosity was emulsified by the method of rotating phase emulsification, and a variety of compound non-ionic emulsifiers were used to prepare the silicone oil emulsion suitable for waterproofing the raw soil surface. The experimental results showed that the average water absorption of raw soil in 1 h decreased to 7.21%, 6.01%, 4.13% and 2.35%, respectively, when coated with 10%, 15%, 20% and 25% silicone oil emulsion on the surface of raw soil, and the water absorption rate gradually decreased with the extension of time, and finally tended to be flat. The contact Angle is 32°, 67°, 85°, 120°. With the increase of silicone oil content, the water resistance of raw soil clods is also enhanced.