Control of expansive soil desiccation cracks via helical auxetic yarn

Abstract

Soil shrinkage leads to cracking of expansive soil during desiccation. Prevention of crack propagation in soil is of paramount importance. This research examines the effect of auxetic yarns, in control of expansive soil desiccation cracks. In this study, auxetic yarns with optimal properties were produced. Using an innovative test method, the influence of auxetic yarn structure on the prevention of soil crack propagation was investigated. It was found that the inclusion of auxetic yarns in the expansive soil results in a 9.94% reduction in crack propagation of the soil. In order to confirm the positive effect of auxetic yarns on the behavior of the soil samples, pull-out test was conducted on the auxetic yarns incorporated in the soil samples. The interaction between the soil and the auxetic yarn was found to be much higher than the interaction between the equivalent non-auxetic yarn and the same soil. This was not only attributed to the transverse expansion of auxetic yarn, but also to the helical structure that occurs in such yarn during the pull-out. The auxetic effect of the yarn results in a 27.3% increase in the force needed to pull the yarn from the soil matrix.