Hydration and durability of low-heat cementitious composites for dam concrete: Thermodynamic modeling and experiments

To demonstrate the superiority of dam concrete, a systematic study was conducted to examine durability low-heat cementitious composite (LHCC) that is composed Portland cement (PC), fly ash (FA), and MgO expansive additive (MEA) with PC as reference group. Through GEMS software, XRD, SEM, EDS, difference mechanism in between two materials revealed from perspectives phase evolution microstructural characteristics. Water at 40 °C adopted for curing match long-term temperature field inside concrete dam. According results RCM, accelerated carbonation, rapid freeze–thaw cycle experiments, LHCC outperforms durability. The hydration process simulated by inputting reaction degree each calculated using MPK model into software. thermodynamic output shows portlandite first increases then decreases proceeds, C-S-H stratlingite are supplemented later stage, which reflects high performance FA involved hydration. In addition, hydrotalcite capable chloride ion adsorption increasingly generated consumption brucite. As clearly shown SEM images, there denser space grids formed overlapping almost no capillary pores. Meanwhile, when combined it strongly demonstrated can be hydrated produce dense fibrous large amounts, providing basis positive development