Influence of palm fiber on strength and crack characteristics of red clay

Abstract

Red clay is widespread in southern China, exhibiting undesirable properties of softening upon contact with water and cracking after losing water. Using red clay as roadbed filler frequently results in a series of geotechnical hazards such as foundation settlement and slope instability. Consequently, it is necessary to improve the engineering properties of red clay. Using natural plant fibers offers improved environmental sustainability and greater economic advantages compared to traditional methods involving lime and cement. In this study, palm fibers were used to improve the properties of red clay. The aim was to quantitatively analyze the influence of palm fiber content and length on the unconfined compressive strength (UCS) of red clay, study the capacity of palm fibers to inhibit soil desiccation cracking, and explore the underlying mechanisms by conducting UCS and desiccation tests. The results show that the UCS and residual strength of red clay can be significantly enhanced by palm fiber, and the soil damage form will be changed from brittle damage to ductile damage. Particularly noteworthy, the content of 0.45% palm fiber with a length of 20 mm increased the UCS by 43.4%. Palm fiber also effectively inhibited soil desiccation cracking, the content of 0.3% palm fiber with a length of 20 mm reduced the crack ratio by 54.4%. This study presents a novel approach for improving red clay, offering valuable insights for the use of palm fiber-improved red clay in road construction and slope protection projects.