Effect of TEA on fly ash solubility and early age strength of mortar

The investigations focused on the dissolution behaviour of fly ash in alkaline solution and the effect of triethanolamine (TEA) addition. TEA is known as a grinding aid in cement production and is an Al and Fe chelating agent. To determine the effect of TEA on the dissolution behaviour of fly ash constituents, fly ash was mixed with a KOH solution at pH 13 and different dosages of TEA. Samples were taken after different times and analysed by ICP-OES. The effect of TEA on the heat evolution rates of fly ash cement pastes was investigated using isothermal calorimetry. Strength tests were also conducted to investigate the effect of TEA on plain Portland cement and fly ash/cement mortars. TEA was found to increase the dissolution rate of Al, Ca and Fe from fly ash. A slight, but reproducible, effect on heat evolution rates and an increase in early age strength was observed for fly ash cements.