Durability performance of polymeric scrap tire fibers and its reinforced cement mortar

In this study, cement-based application for polymeric scrap tire fibers (STF) which are hitherto used either as tire derived fuel or are disposed in landfills is explored. STF was characterized; surface morphology, organic and elemental composition of STF/crumb rubber inclusions were examined. Alkaline stability of the STF, the effects of STF on plastic shrinkage cracking, mortar microstructure and longterm durability were also analyzed. Results indicate that STF which consists mainly of polyester fiber was more stable in alkaline environment compared to commercial polyethylene terephthalate (PET) fibers. Relative to the plain reference mixture, 0.4% STF and 0.3% PET fibers reduced the plastic shrinkage crack area of mortar by 97.5 and 99.4%, respectively. While inductively-coupled plasma mass spectrometer test showed that the sulfur content of the alkaline degradation test solution filtrate was < 10 mg/L, scanning electron microscope-energy dispersive X-ray spectroscopy analyses revealed slight increases in the S/Ca and (Al + Fe)/Ca ratios of the specimens containing STF. However, these increased atomic ratios were insignificant; hence no degradation of the hardened properties of the STF reinforced specimens in terms of length expansion and loss of mechanical strength under accelerated curing condition and external sulfate attack were observed.