Influence of different supplementary cementitious materials on water distribution and rheological behavior of blended cement paste

The water state plays a crucial role in influencing the rheological characteristics of cementitious materials. This research aims to elucidate the effect of supplementary cementitious materials (SCMs) with various features on the rheological parameters of blended cement paste from the standpoint of particle interactions and water state and migration. Quantitative analysis of gel/absorbed water, capillary/flocculation water, and free water in blended cement paste were conducted to offer a comprehensive explanation of their structural build-up process. Both fly ash (FA) and ground granulated blast furnace slag (GGBFS) exhibit the ability to reduce water freedom degree and increase rheological parameters, albeit through distinct mechanisms. FA primarily restricts water freedom by reducing the content of capillary water with high freedom degree and increasing the content of adsorbed water with low freedom degree. GGBFS reduces water freedom degree by forming smaller flocculation structures and increasing the content of flocculation water. Although tungsten tailings powder (TTP) also increases the content of adsorbed water, the primary factor impacting its rheological properties is the weakening of interparticle interactions due to the increased mean distance between particles. This research offers guidance on regulating rheological performance of cementitious materials.