Yarns: Production, processability and properties
Polyester yarn is made from post-consumer waste such as bottles, fabrics, etc., in the composition of polyester ethylene terephthalate (PET), and because of its superior strength and elasticity it is applicable to a number of geotechnical applications: roadbed reinforcement of road and railway, crack prevention, increase of roadbed strength; reinforcement and stabilization of riverside, embankment and side slope, dyke reinforcement on soft ground for stress evenness, sedimentation adjustment, increase of stability and loading capacity of fundus, and reinforcement of the surface of roads and bridges.
In a study by T. Ochi et al.,16 pellets produced from PET bottles were melted and drawn to produce monofilaments; during this process, caution was taken to ensure that sufficient strength would be installed in the monofilaments. Subsequently, indents were marked on the monofilaments and they were cut to produce PET fibre. Temperature control of the monofilaments was found to be crucial for accurate indentation. The specifications of the PET fibre produced: specific gravity 1.34 ± 0.02, diameter (mm) 0.7, length (mm) 30 ± 1 or 40 ± 2, mass (mg) 15.2 ± 15% (30 mm length), and tensile strength above 450 MPa. The authors obtained desirable results for the wetting tension, alkali resistance, and combustion gases of the produced PET fibre. The mixability of the PET fibre was examined by hand mixing; the PET fibre was found to mix very easily with concrete. The machine-mixing ability of the PET fibre with concrete was also found to be good