Since hydroxide ions were found to be accelerating and protons to be retarding, the pH in the mixing water inevitably plays an essential role in the CAC hydration. The starting pH mainly influences early hydration (initial CA dissolution and dormant period). More detailed studies on pore solution during the CAC hydration are required to elucidate these observed effects. However, studying the evolution of the pH and ionic concentration over time requires preparing multiple pore solution filtrates, which is an equipment-and work-intensive method. Crucially, it is difficult and cumbersome to characterize the chemical changes of hydrating CAC during the first seconds or minutes when conventional mixing methods are used at low water-to-solid ratios.