Studying the tensile strength of geopolymers reinforced with recycled PVC fibers obtained from cable waste

Abstract

In geopolymers, electronic waste (E-waste) can express a new generation of geopolymer composites as it reduces environmental pollution and the problem of solid waste. In this research study, the insulation of the outer cover of the electric wire (cable) was made in the form of fibers. The recycled PVC fibers were integrated into the geopolymer matrix at weight fractions of 0, 3, 5, and 8 wt.%. The specimens were subsequently cured at 80 °C for 18 h, followed by ambient curing for a duration of up to 14 days. To create fiber-reinforced geopolymer, the fibers were added with an aspect ratio of 7.5 to the geopolymer. The experiment was designed using the Taguchi method, and the findings were examined by analysis of variance (ANOVA). The tensile strength of the fiber-reinforced geopolymer and the conventional geopolymer at different curing ages (1, 3, 7, and 14 days) were compared. The experimental results revealed that the sample cured for 14 days and containing 8 wt% recycled polyvinyl chloride (PVC) fibers achieved the highest tensile strength. If all the other factors that affect strength stay the same, adding recycled PVC fibers from 0 to 8% by weight to the matrix makes the tensile strength of aluminosilicate geopolymers 17% higher. The curing time was found to be the most effective factor in increasing the tensile strength of geopolymers reinforced with recycled PVC fibers. The scanning electron microscope (SEM) images indicated that the incorporation of fibers into the structure resulted in enhanced strength owing to the robust PVC/matrix interface. The Fourier transform infrared spectroscopy (FTIR) results indicated that Si-O-Al bonds were established in the geopolymers reinforced with PVC fibers, resulting in enhanced structural strength. Therefore, the geopolymer composite reinforced with E-waste fibers was an alternative to conventional geopolymers, as it showed an increasing trend in properties as well as a reduction in the discharge rate of E-waste in nature.

Keywords: Cable; E-waste; Geopolymer; PVC; Taguchi method.