Optimizing hydration and mechanical properties of calcined coal gangue blended cement: Defining roles of triethanolamine and triisopropanolamine

The effects of triethanolamine (TEA) and triisopropanolamine (TIPA) on the hydration and mechanical properties of calcined coal gangue (CCG) blended cement were systematically studied and compared in this study by varied techniques, including calorimetry, mechanical measurement, hydration kinetic model, etc. Results show that the addition of TEA accelerates the nucleation and crystal growth (NG) process and promotes the pozzolanic reaction of CCG, which leads to an increase in the compressive strength of hardened CCG blended cement paste at all ages. In contrast, TIPA enhances the phase boundary reactions (I) and diffusion (D) processes of CCG blended cement, contributing to facilitating the hydration process after the acceleration period. Furthermore, the C-S-H formed in the presence of TIPA exhibits a higher elastic modulus and a more uniform distribution, resulting in a refined pore structure and enhanced mechanical properties. Specifically, the addition of 0.1% TEA and TIPA lead to an increase in the compressive strength of the hardened CCG blended paste by 29% and 45%, respectively. Hence, this study shows that the enhanced performance of CCG blended cement can be achieved through the addition of TEA or TIPA, in which TIPA exhibits superior performance in CCG blended cement.