Ceramic tiles waste as replacement material in Portland cement

The pozzolanic reactivity of real ceramic waste from different tile manufacturing companies was evaluated and its suitability as a partial Portland cement replacement was analysed. The raw material was finely ground and physico-chemically characterised using X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) and laser analysis particle size distribution (ADL). Percentages of ceramic waste (from 15 wt% to 50 wt%) to substitute Portland cement were used to assess this material's pozzolanic behaviour, and samples were cured at 20°C for different curing times. pH tests and conductivity measurements were used to evaluate its pozzolanic character, while mortars were utilised to evaluate compressive strength behaviour. The microstructural evolution of the developed binders was assessed in pastes by XRD, thermal analysis, Fourier transform infrared spectroscopy (FTIR) and SEM analyses. A strength gain due to pozzolanic activity was observed after 28 d and 90 d curing. The results prove that mortars with up to 35 wt% of tile ceramic waste comply with the requirements established for fly ash pozzolanic materials.