New insight into the combined effect of aluminum sulfate and triethanolamine on cement hydration

The combined effect of aluminum sulfate (AS) and triethanolamine (TEA) on cement hydration was investigated by techniques of setting time, compressive strength, calorimetry, XRD, and ICP-OES. The results indicate that the increased strength through the addition of AS mainly originates from the accelerated silicate phase reaction. Besides, the combined addition of TEA and AS leads to an aggravated retardation effect on C3S hydration, which could be caused by the changed ionic conditions in the pore solution, namely ionic species, concentration and states. Specifically, the complexed ions formed with TEA lead to a stronger inhibited effect on C3S hydration compared to that of free ions, which could be caused by the improved adsorption amount of TEA after complexation with ions. Furthermore, TEA complexed with ferric ions shows a higher adsorption amount than that with aluminate ions, which leads to a stronger retardation effect on C3S hydration.