Effect of suction on the resilient modulus of soils reinforced with polypropylene fibres

Madrid R.; Merchan V.; Martínez D. · Transportation Geotechnics (2026) · DOI: 10.1016/j.trgeo.2026.102430

Resumen

Road embankments are subjected to complex loading regimes, including traffic-induced cyclic stresses and environmental fluctuations, which dictate their long-term performance. Material scarcity frequently necessitates using marginal expansive clayey, soils, demanding stabilization to ensure adequate mechanical performance. While fibre reinforcement effectively enhances soil shear strength and ductility, the coupled influence of matric suction and cyclic loading on fibre-stabilized soils remains poorly understood, under field representative unsaturated conditions. This study investigates the effect of matric suction on the resilient modulus (Mr) and post-cyclic unconfined compressive strength (qu) of compacted clay reinforced with polypropylene micro and macrofibres. Varied fibre contents and geometries were evaluated. Repeated-load triaxial tests were conducted across a range of suction states, quantified via the filter paper method to establish the Soil–Water Retention Curve (SWRC). The results indicate that resilient modulus increases monotonically with decreasing degree of saturation, confirming that matric suction significantly enhances resilient stiffness. Unconfined compressive strength similarly improved with elevated matric suction across all reinforcement configurations. While Fibre inclusion further modified the mechanical response, the magnitude of improvement was highly contingent upon fibre content and geometry. These findings elucidate the coupled effects of suction and fibre reinforcement on the behaviour of compacted clayey soils and support the incorporation of suction on compacted clays, providing a framework for incorporating matric suction into predictive constitutive models for resilient modulus under unsaturated conditions. Copyright

Instituciones: Universidad de Lima