Incorporation of unserviceable tire waste in red ceramic

Abstract

A spent tire without the legal possibility of running is classified as unserviceable tire waste. In this work, incorporation of rubber tire waste (RTW) in clay ceramics used in the production of bricks and roofing tiles was for the first time evaluated. The raw materials were initially characterized in terms of its mineralogical and chemical composition by X-ray diffraction (XRD) and X-ray fluorescence (XRF), respectively. Physical and mechanical properties of RTW incorporated ceramics such as bulk density, water absorption, linear shrinkage, flexural and compressive strength were determined. Besides, thermal analyses by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were carried out in the plain RTW. Different ceramic compositions were prepared with amounts of 0.5; 1; 1.5 and 2 wt% RTW incorporated into the clay ceramic. Prismatic specimens were prepared by uniaxial pressing and then sintered at 850 and 950 °C. The results indicate that the investigated waste contributes to a saving in energy during the ceramic sintering due to its high amount of carbon. An increase in the ceramic porosity above 1.5 wt% of RTW was responsible for increasing the water absorption. Within standard deviations, both the shrinkage and strength were not impaired. The clay ceramic with 1 wt% of RTW sintered at 950 °C was the most suitable condition observed. Hence, these results showed a viable alternative to RTW, turning it into an environmentally friendly by-product for civil construction materials.