This study investigated the effect of the incorporation of the supplementary cementitious material (SCM) of hydrophobic silica on the mechanical properties and hydration behavior of ordinary Portland cement (OPC), compared to those of silica fume. Silica fume is a well-known SCM owing to its good compatibility with OPC by providing acceleration and pozzolanic reaction. This study revealed that mortars containing hydrophobic silica developed higher compressive strength than pure mortar and mortar with regular silica fume during all curing ages. Furthermore, it was confirmed that it contributed to produce more hydration products and consume more portlandite, implying its acceleration and pozzolanic reaction, respectively. Although its particle size is larger than that of silica fume, its hydrophobicity accelerated the hydration reaction due to the better dispersion of OPC in the system, which leads to more exposure of cement particles to available water. These effects could cause higher dissolution of the particles and faster interfacial precipitation of hydration products. Therefore, the hydrophobic silica outperformed the acceleration effect of silica fume.

这项研究调查了掺入疏水性二氧化硅的胶结材料（SCM）对普通硅酸盐水泥（OPC）的机械性能和水化行为的影响，与硅粉相比。硅粉是一种众所周知的SCM，因为它通过提供加速和火山灰反应而与OPC具有良好的兼容性。这项研究表明，在所有固化年龄中，含有疏水性二氧化硅的砂浆均比纯砂浆和具有普通硅粉的砂浆具有更高的抗压强度。此外，已证实其有助于产生更多的水合产物并消耗更多的波特兰石，分别暗示其加速和火山灰反应。尽管其粒径大于硅粉，由于OPC在系统中的分散性更好，其疏水性加快了水合反应的速度，这导致水泥颗粒更多地暴露于可用水中。这些作用可能导致颗粒的溶解度更高，水合产物的界面沉淀更快。因此，疏水性二氧化硅的性能优于硅粉的加速作用。