Shotcrete is commonly used as the primary support material in tunnel construction,differing significantly fromconventional cast-in-place concrete.The operational process of shotcrete construction involves two stages:pumping and spraying.From the perspective of admixtures,shotcrete requires water-reducing agents to ensurefluidity during pumping and accelerators to facilitate rapid hardening upon spraying.It is important to balancethe performance of shotcrete in the two-stage process.This study utilized aluminum sulfate (AF)and sodiumaluminate (AA)as the primary accelerators and polycarboxylate and naphthalene-based superplasticizers aswater-reducing agents.A rheometer,isothermal calorimeter,low-field nuclear magnetic resonance (NMR),andscanning electron microscope (SEM)were used to systematically understand the early hydration process ofcement paste.The setting time,rheological properties,hydration behavior and microstructure development wereevaluated with the introduction of combination of various water-reducing agents and accelerators.The resultsindicate that polycarboxylate-based superplasticizers significantly enhance fluidity but delay hydration,partic-ularly when combined with sodium aluminate accelerators,resulting in extended setting times and slower freewater conversion into bound water.In contrast,aluminum sulfate accelerators induce higher early hydrationheat,accelerating strength development but also increasing yield stress and plastic viscosity.The interactionbetween water reducers and accelerators creates a complex balance:while polycarboxylate superplasticizersimprove workability,their presence alters hydration kinetics,influencing both hydration heat release and calcium hydroxide consumption.These findings quantitatively assess the interrelationship between rheology,hy-dration,and microstructure development in cement-based materials,providing a valuable referenceforbalancing workability and early performance in shotcrete applications.