Effect of Synthesis Conditions on Particle Size Morphology, Structure, and Acceleration Performance of C-A-S-H Nanoparticles

In recent decades, C-S-H (calcium-silicate-hydrate) nanoparticles have been regarded as promising accelerators for early-age compressive strength enhancement of cementitious materials. In previous research, C-A-S-H (calcium-alumina-silicate-hydrate) nanoparticles were synthesized and exhibited superior acceleration performance than C-S-H nanoparticles. However, how the synthesis conditions affect the performance of C-A-S-H nanoparticles has not been comprehensively investigated, limiting the optimization of the performance of C-A-S-H nanoparticles. This study explores the effect of synthesis conditions (i.e., pH value, reactant droplet rates, and reaction time) of C-A-S-H nanoparticles to accelerate the hydration of portland cement. The results show that the obvious differences in acceleration performance among C-A-S-H nanoparticles are derived from varing pH values, reactant droplet rates, and reaction times, and the optimal synthesis condition is identified to provide guidance on the production of high-performance C-A-S-H nanoparticles.