Effects of temperature and alkaline solution on electrical conductivity measurements of pozzolanic activity

The influence of alkaline solutions (which are unsaturated lime, saturated lime and ordinary Portland cement solution), reaction temperatures (40 °C, 60 °C and 80 °C), and quantity of tested sample in 200 mL of alkaline solution on the pozzolanic reaction of silica fume (SF) is considered on electrical conductivity measurements. The results reveal that raising the reaction temperature accelerates the pozzolanicity and 80 °C is a recommended reaction temperature for the rapid evaluation of pozzolanic activity. An ordinary Portland cement (OPC) solution is proposed and used as an alkaline solution for pozzolanic activity evaluation. Increasing the amount of SF also increases the chemical reaction rate. It was found that using 1.0 g of SF/200 mL of OPC solution yield the best results. This study could be used as a basis for further development of a more accurate, rapid evaluation of pozzolanic activity.