The influence of basalt fiber filament length on shear strength development of chemically stabilized soils for ground improvement

Abstract

In recent years, adding fiber reinforcements into chemically stabilized weak soils to resolve brittleness at the post-peak shear strength state is becoming an increasingly popular research area. However, there is little to no research investigating the shear developments initiated through the hybridization of ground improvement techniques using high-strength basalt fibers and sustainable chemical stabilizers such as rice husk ash (RHA). This study investigated how different basalt fiber filament lengths can reinforce and consequently influence shear response in such chemically stabilized soils. A series of triaxial compression tests, scanning electron microscopy (SEM), and X-ray powder diffraction (XRD), considering curing periods, were carried out on fiber-reinforced and unreinforced chemically stabilized specimens containing: weak clay soil, varied lengths of basalt fibers filaments, RHA, and cement in their specified combinations. Based on the results, an increment in basalt fiber filaments length significantly increased the deviatoric stresses, increasing cohesion and angle of internal friction by 81% and 63%, respectively. SEM imagery showed a highly reinforced soil composite at the microstructural level. At the same time, XRD analysis justified the presence of solid calcium aluminosilicate hydrate bonds, a product of pozzolanic activity. The fiber reinforcing mechanism through interfacial contacts between basalt fiber filaments and the new stabilized soil composite was investigated and validated to form a new construction material for use as a base course during ground improvement.