Effect of Cyclic Loading Frequency on the Behavior of a Stabilized Sand Reinforced with Polypropylene and Sisal Fibers

Abstract

When any material is subjected to dynamic loads, the evaluation of the repercussions of the cyclic loading on the mechanical properties is essential to understand its behavior better. Thus, based on the results of unconfined compression strength tests carried out with and without the application of cyclic loading, this work analyzes the effect of the frequency of the cyclic stage on the behavior of a stabilized sandy soil, unreinforced and reinforced with polypropylene and sisal fibers. The inclusion of fibers induces a decrease in the accumulated permanent axial strain obtained at the cyclic stage; this reduction is more significant for a frequency of 1.0–2.0 Hz and for the use of sisal fibers, due to the greater roughness and higher mechanical properties of this type of fiber. The cyclic stage induces an increase in stiffness for all frequencies studied. In terms of the unconfined compressive strength, the frequency has a low impact on unreinforced material, contrary to the effect on reinforced material, which induces a decrease in strength for a frequency of 1.0 Hz and an increase in strength for frequencies of 2.0 and 4.0 Hz for both types of fibers. Reinforcement with sisal fibers is more effective than the use of polypropylene fibers in terms of the improved unconfined compressive strength and stiffness of the specimens submitted or not to cyclic loading.