Effect of Glass Fiber Reinforced Polyesters Pipe Wastes on the Properties of Fine Grained Soils

Industrial wastes used as additives in soils are widely applied due to their low cost and ability to prevent environmental pollution. This study investigates the effect of Glass Fiber Reinforced Polyester (GRP) pipe-cutting waste on the shear strength of fine-grained soils. This effect was evaluated for silty soils in the laboratory and clayey soils in the field. GRP was added to the clay at several ratios of cement weight using the deep mixing method at the site. The laboratory results revealed that cohesion increased up to nearly four times compared to the natural state, with the optimum GRP content determined as 2-3%. It was determined that the soil achieved maximum compaction in the laboratory and the highest resistance in the field when 3% of the waste was used. In field applications, a 3% GRP addition provided approximately a 7% increase in unconfined compressive strength. It was observed that GRP waste had a positive effect on the strength of fine-grained soils and improved the homogeneity of the soil mixture produced using the deep mixing method. The waste provides convenience during the drilling and retraction stages, increases workability, and results in a better mechanical mixture. This indicates an effective alternative additive for soil improvement in terms of strength, compressibility, and recycling through the practical use of waste in producing deep mixed columns.