Reinforcing effect of recycled polypropylene fibers on a clayey lateritic soil in different compaction degrees

Natalia De Souza Correia,Sabrina Andrade Rocha

doi:10.28927/sr.2021.061520

Abstract

The present research investigates the reinforcing effect of recycled polypropylene (R-PP) fibers on a compacted clayey lateritic soil in different compaction degrees. R-PP fibers of 12 mm length were mixed with the soil in the contents of 0.1 and 0.25% of soil dry weight. Unconfined compression strength tests (UCS), direct shear tests and indirect tensile strength (ITS) tests were conducted. Fibers addition showed no significate alterations in the optimum compaction parameters. The study evidenced increases in UCS, changing the soil behavior from a brittle failure to a ductile failure, while fiber contribution was most effective for 0.25% R-PP fibers content and 95% compaction degree. The use of fibers improved the shear stress-strain behavior of the composites and soils compacted at different degrees of compaction showed similar shear behavior, which is coherent to the soil water retention curves (SWRC) results. Significant increases in the tensile behavior of soil-mixtures for both fiber contents used were observed, and fibers increase was more significate than increase in soil degree of compaction. The stretching of the fibers and fibers orientation at the sheared interface in direct shear tests and the fiber “bridge” effect in ITS tests could be observed.

Highlights

Fiber reinforcement remains a viable soil improvement technique that has been the focus of a growing number of investigations due to a wide range of applications and combinations for use in geotechnical works
This study aims at investigating the effect of recycled polypropylene (R-PP) fibers on a compacted clayey lateritic soil in different degrees of compaction
3.1 Behavior of R-PP fibers on soil compaction properties Figure 4 presents the compaction curves of clay of high plasticity (CH) soil mixtures with 0.1% and 0.25% fiber content, compared to respective natural soils

Summary

Introduction

Fiber reinforcement remains a viable soil improvement technique that has been the focus of a growing number of investigations due to a wide range of applications and combinations for use in geotechnical works. Research has shown that the fibers randomly distributed in the soil matrix have the advantage of intercepting the potential zone of rupture, and by fibers tensile strength mobilization, improve the soil stress-strain behavior, making the mixture more ductile (Consoli et al, 2012; Li & Zornberg, 2013; Shukla, 2017; Yetimoglu & Salbas, 2003; Zornberg, 2002). According to Freilich et al (2010), there is a need for advancing studies in clayey soil-fibers due to the greater complexity related to fiber interaction mechanism in cohesive soils. The behavior of soils reinforced with polypropylene fibers has been widely studied (Anagnostopoulos et al, 2013; Cai et al, 2006; Mirzababaei et al, 2017; Plé & Lê, 2012; Tang et al, 2007)

Objectives

Methods

Results

Conclusion