The fractal characteristics of cement-based materials with grinding aid via BSE image analysis

Energy conservation and emission reduction are crucial for the cement industry to meet "carbon peak" and "carbon neutrality" targets, with a particular emphasis on grinding aids. The impact of different grinding aids (triethanolamine (TEA), maleic acid-modified trieth-anolamine (MTEA), triisopropanolamine (TIPA), and TEA-CNA composite) on the microstructural evolution of cement-based materials and their relationship with macro-scopic mechanical properties is investigated in this study using backscattered electron (BSE) imaging and fractal theory. The results show that TIPA effectively refines cement particles, promotes hydration (77.30% at 28 days), and reduces porosity. MTEA enhances late-stage hydration, while TEA inhibits silicate phase hydration. Statistical parameters, fractal dimensions, and multifractal parameters from BSE images were used to describe the microstructure. Whereas the fractal dimension of porosity is associated with both hydration and particle packing, the fractal dimension of unhydrated particles is primarily determined by the grinding aid. A negative correlation between pore structure fractal dimension and compressive strength (R² = 0.7444) was observed. The multifractal analysis shows TIPA with the most uniform particle and pore distribution, and multifractal parameters, such as ∆D_{q_particle}, are negatively correlated with compressive strength (R² = 0.8924). This study provides insights into the effects of grinding aids on cement hydration and microstructure, offering guidance for their optimal selection and application.