Improvements on Pozzolanic Reactivity of Coal Refuse by Thermal Activation

Today, coal refuse as industrial solid waste stockpiled on the ground is one of the greatest threats to the environment. One of the practical solutions to utilize this huge amount of solid waste is to activate the coal refuse and utilize it as substitution for portion of ordinary Portland cement. The key purpose of activation is to enhance the pozzolanic property of the coal refuse.Many scientists and engineers found that thermal activation is a practical approach on increasing pozzolanic property. For thermal activation, temperature and time are two important parameters which significantly determine the activation effect. In this paper, a systematic research has been conducted to seek for anoptimal solution for enhancing pozzolanic reactivity of the relatively inert solid waste-coal refuse in order to improve the utilization efficiency and economy benefit forconstruction and building materials.The mechanical property analysis shows that coal refusethat activated at 700°C to 800°C with 1 hour to 1.5 hours has much higher reactivity when compared with coal refuse activated at 500°C to 600 °C with 1 hour to 1.5 hours. And 28-dayscompressive strength value of prepared blended cementitious material containing 25% of the 700°C 1h activated coal refuse based pozzolanareaches 43.4MPa, which is higher than 28-days strength of OPC group as control.