Effects of elevated temperature on the mechanical properties of concrete with aggregate of waste porcelain tile

Abstract

The waste porcelain tile can be used as recycled aggregate in concrete, which will reduce the environmental pollution and alleviate the shortage of natural aggregate. The effects of waste porcelain tile of the mechanical properties of concrete at room temperature were positive. However, the properties of concrete with waste porcelain tile exposed to elevated temperature were unclear. In this experimental study, 45 groups of 100mm × 100mm × 100 mm and 15 groups of 100mm × 100mm × 300 mm specimens were prepared, and 180 specimens of concrete were heated to the target temperature. Variables included aggregate substitution rate (0%, 50%), aggregate categories (coarse and fine aggregate), and exposure temperature (25, 200, 400, 600, and 800 °C). Combining X-ray fluorescence spectrometry (XRF), X-ray diffractometry (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis and differential scanning calorimetry (TGA-DSC), the effects of high temperature on the concrete properties with waste porcelain tile recycled aggregate were investigated. The results showed that the mass loss of concrete with porcelain tile aggregate increased with increasing temperature. The compressive strength of concrete with porcelain tile coarse aggregate gradually decreased with rising temperature. The compressive strength of concrete with porcelain tile fine aggregate increased by 0.8% after being heated at 200 °C. The reduction in splitting tensile strength of concrete with porcelain tile aggregate was slight after exposure temperature below 200 °C. The elastic modulus of porcelain tile coarse and fine aggregate concrete decreased with rising temperature. After being heated at 600 °C, the elastic modulus of porcelain tile coarse and fine aggregate concrete decreased by 90.5% and 89.6%, respectively, compared with room temperature. It is recommended that waste porcelain tile fine aggregate should be used in recycled concrete in preference to porcelain tile coarse aggregate.