The recovery potential of bricks wastes in obtaining environmental friendly materials is sustained by their pozzolanic properties, which can be exploited within a Portland cement—brick powder waste (BPW) system, thus reducing the amount of waste as well as the consumption of raw materials and CO2 emissions from cement factories. These properties were intensively studied and reported in the literature, for their assessment often being used direct analytical methods to highlight the presence of Ca(OH)2 and its subsequent reduction in abundance with time as the pozzolanic reaction proceeds. Since it is more difficult to quantify the pozzolanic activity of calcined clay in a Portland cement /brick powder mixture, for the present work classical determinations, such as thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM) were combined with the individual assessment of BPW in terms of pozzolanicity in order to study the variation of the Ca2+ respectively OH− ions concentration within a BWP—lime saturated solution. SEM analyses showed CH and CSH formation and the DTA curve highlighted a more intense peak around 500 °C after 28 days of hydration, where the Ca(OH)2 decomposition take place. The pozzolanicity test results showed a pronounced decrease of Ca2+ concentration after 28 days.
