Effect of Surface Modification of Polypropylene Fiber on Desiccation Crack Performance of Soil-Cement

Abstract

In this paper, digital image correlation (DIC) technology was used to evaluate the properties of fiber surface modification (alkali treatment, acid treatment, and silane coupling agent treatment) and fiber content (0%, 0.25%, 0.5%, and 1%) to alleviate desiccation cracks of cement stabilized soft soil subgrade with high water content. The strain of specimen surface, the crack length, and the crack area during drying shrinkage process were measured and compared with those of unmodified specimens, so as to access the degree of restriction of fiber surface modification and fiber content on cracks. In addition, the moisture change of the specimens during drying shrinkage process was tested to increase the understanding of the drying shrinkage behavior, and SEM and mercury intrusion porosimetry were used to reveal the mechanism of fiber modifying and reinforcing soil-cement. The results show that the fiber modification effectively reduced the maximum tensile strain and compression strain on the surface of specimens, the crack lengthy and the crack area, and the fiber modified by silane coupling agent effectively reduced the degree of desiccation cracks of specimens, which provides a theoretical basis for engineering practice.

Keywords

• pp fiber
• surface modification
• soil-cement
• desiccation cracking
• dic