Soil Reinforcement by Waste Tire Textile Fibers: Small-Scale Experimental Tests

Due to the fast-growing number of cars, the amount of scrap tires is quickly increasing across the world. Because buried tires need a long period of time to dissolve, the accumulation of scrap tires in different countries has caused several social, economic, and environmental issues worldwide. Many researchers in geotechnical engineering have utilized scrap tires in various forms for soil reinforcement in recent years. A by-product of waste tire processing is waste tire textile fiber (WTTF). These WTTFs are classified as special wastes, and they are frequently buried or burned in violation of international law. This study experimentally shows that these materials could be recycled and mixed with soil to improve the mixture mechanical properties. A complete series of small-scale laboratory tests, including direct shear test, Brazilian tensile test, permeability test, and swelling test, was conducted to examine the possibility of reusing WTTFs as soil-reinforcing agents. Five different fiber percentages (FPs), i.e., 0%, 0.5%, 1%, 2%, and 4%, of soil dry weight were mixed with the soil and the mechanical behavior of the mixture was investigated. The test results suggest that adding fiber to the soil improves both its shear and tensile strengths. The material ductility increases by adding the fiber to the soil as well. Further, the soil mixed with the fiber has a greater permeability coefficient and has less swelling potential. The mixture with these improved mechanical properties can cause less lateral pressure in case of being used as a backfill material. As a result, rather than being buried or burned, these wastes could be utilized to enhance the mechanical properties of various types of soils in geotechnical applications. The testing procedures and results are reported, discussed, and compared with those from the literature.