Strength properties and microscopic mechanism of lime and fly ash modified expandable poly styrene lightweight soil reinforced by polypropylene fiber

Abstract

Lime and fly ash modified expandable poly styrene (EPS) lightweight soil reinforced by polypropylene fiber (FELS) is a new type of lightweight subgrade material. In order to study the road performance and strength formation mechanism of this material, California Bearing Ratio Test (CBR) and Scanning Electron Microscopy (SEM) were performed on FELS with different EPS and fiber content. The results show that: (1) the CBR value of FELS decreases with the increase of EPS particle content. EPS particles can take on a part of the skeleton, and at the same time play the role of weight reduction and volume replacement. (2) The addition of fiber can improve the CBR value of FELS and bear part of the tensile stress and shear stress of soil under pressure. The reinforcement effect of 0.1% fiber is the best content. (3) With the increase of curing age, the CBR value of the sample increases continuously. The increase of curing age can make the internal ion exchange and hydration reaction of the structure more complete and enhance the shear resistance. The results of this study can provide a reference for the application of FELS in subgrade engineering.

Keywords

• Subgrade engineering
• Lightweight soil
• California bearing ratio test
• Microscopic mechanism