In order to obtain a deep understanding of the hydration of sprayed concrete, C3S pastes with and without aluminum sulfate (AS) were comparatively investigated. The results showed that AS significantly accelerated the hydration of C3S and refined the pore structure of the hardened C3S paste, by reacting with the calcium ions to produce ettringite;this acted as nucleation seeds to induce the formation of C–S–H gel. Differing from C–S–H based nucleation seeds, the ettringite-based nucleation seeds were formed in bulk solution where was away from rather than inside the ric...
