Steel　bars　have　been　widely　used　as　soil　slope　nailing　in　highway　engineering　to　avoid　slope　instability,　while　concerns　have　been　raised　about　their　corrosion　in　an　aggressive　soil　environment.　Glass　fibre　reinforced　polymer　(GFRP)　or　basalt　fibre　reinforced　polymer　(BFRP)　bars　are　associated　with　better　resistance　to　corrosion　and　show　potentials　in　such　applications,　but　their　bonding　performance　with　concrete　is　inferior　comparing　to　steel　ones.　However,　associated　research　is　limited　to　small-scale　specimens　in　laboratorial　conditions,　and　hence　further　investigations　are　required.　In　this　study,　full-scale　field　pull-out　tests　with　a　maximum　bar　length　of　5.5　m　were　conducted　on　three　types　of　bars　(i.e.,　steel,　GFRP　and　BFRP)　embedded　by　grouting　in　a　soil　slope.　Test　results　show　that　the　only　failure　mode　of　the　specimens　was　the　breakage　of　bars,　which　was　different　from　laboratorial　results.　The　maximum　pull-out　forces　were　therefore　determined　by　the　ultimate　strengths　of　the　bars,　suggesting　that　a　bonding　length　of　5　m　was　adequate　to　exploit　the　strengths　of　the　bars　with　a　diameter　of　22　mm.　In　terms　of　the　load-slip　behaviors,　three　types　of　bars　showed　similar　patterns　before　the　yielding　of　the　steel　one.　The　pull-out　load　distributions　in　the　bars　showed　an　obvious　decrease　with　the　distance　to　the　free　ends,　and　such　decreases　were　more　obvious　for　steel　bars.　The　results　demonstrate　that　despite　the　significant　differences　in　mechanical　behavior　between　FRP　bars　and　steel　bars—particularly　their　lower　elastic　modulus　and　anisotropic　properties—GFRP　and　BFRP　bars　exhibit　comparable　or　even　superior　pull-out　resistance　in　soil　slope　nailing　applications,　offering　a　corrosion-resistant　alternative　for　highway　slope　stabilization　in　aggressive　environments.　©　The　Institution　of　Engineering　&　Technology　2025.