A composite low-carbon cement strategy: High ferrite cement with addition of ferroaluminate cement

High ferrite cement (HFC) has gained attention recently due to its low-carbon emissions and superior durability. To enhance the competitiveness of mechanical properties of HFC, a composite low-carbon cement strategy was proposed with the addition of ferroaluminate cement (FAC) clinker. This study investigated the physical properties, mechanical properties, hydration heat, hydration products, pore structure, and volumetric deformation of HFC with the incorporation of FAC clinker. The results showed that the early hydration of ye'elimite (C4A3S) leads to a rapid formation of ettringite (AFt), which enhances the mechanical properties of HFC. The optimal strength properties were achieved with the incorporation of 0.5 wt% FAC clinker, increasing 18 % and 7.8 % of compressive strength at 3-day and 28-day, respectively. In addition, the incorporation of FAC clinker reduced the setting time and increased the standard consistency water consumption. Hydration heat, X-ray diffraction (XRD), thermogravimetric (TG), and scanning electron microscopy (SEM) tests revealed that excessive FAC clinker hinders the hydration of tricalcium silicate (C3S) and compromises the stability of AFt in HFC. Volumetric deformation and low-field nuclear magnetic resonance (LF NMR) testing indicated that the addition of FAC clinker lowered the volumetric deformation and refined the pore distribution, contributing to a higher performance of HFC.